HomeMy WebLinkAboutAPA2905-I204v1ALA.Sl\A J. /iY.-l lO~EC.:il'Jl B.E.SF.G~r.
IC JS!N(• CCl!E~!S C~ LICEbSZ
APFLICA1 f C~: i!lEBFBC~ 1C
CC!!l!i'I (..~): D. J., I. 204
tROTECTION STRATEGIE3 FOR PERESRINE FALCONS
AND OTHER RAPTORS ACONG THE PLANNED
~iJRTHWESi ALASKAN G;\S PIPELINE ROUTE
David G. Roseneau
C. Eric Tull
R. Wayne Nelson
of
LGL ALASKA RESEARCH ASSOCIA7ES, INC.
Final ~~eport
prepared ~or and Funded by
N~rthwest Alaskan Pipeline Company
administered by
i-1•Jc.,.. ~lorthwest, l ;:c;.
Fluor· Con·iract No. 478085-9-!<127 Task II
June 1981
LGL A1aska ~.:::search :~ssociates, Inc.
P.G. Sox 806(17
·.-irhur:ks, Ali ska 997C8
\907) 47 ·-6519
REPORT USE
· .. This report contains detailed information on the nest locations of
the endangered peregrine falcon and other raptor species in Alaska.
This information is contained in Volume II of this report. Because of
the sensitive nature of this information, we recommend that Volume II
of this report be considered as confidential and be made available
only on a need-to-know basis.
FINAL REPORT
This report has been preceded by two interim reports.* Because of
the refinements, revisions and additions in this final version, it shoul~.
1t be cons ide red to supersede the earlier draft reports, and those reports -~.
should not be quoted.
This report should be cited as:
~oseneau, D.G., C.E. Tull and R.W. Nelso~. 1981. Protection strategies
for peregrine falcons and other raptors along the planned Northwest
Alaskan gas pipeline route. Unpubl. rep. by LGL Alaska Res. Assoc.,
Inc., Fairbanks, for Northwest Alaskan Pipeline Co. and Fluor
Northwest, Inc., Fairbanks. 2 volumes, 332 p.
* LGL Ecological Research Associates, Inc. 6 Oct. 1980. Development of
protection strategies for peregrine falcons: a draft and preliminary
version of a single chapter for an interim report. Unpubl. rep. for
Northwest Alaskan Pipeline Co. and Fluor Northwest, Inc.
Roseneau, D.G., C.E. Tull and R.W. ~elson. 22 Nov. 1980. Synopsis of
peregrine falcon populations and ecology, and development of protective
measures with regard to the proposed Northwest Alaskan Gas Pipeline
Company gas pipeline project in Alaska: interim report. Unpubl. rep.
by LGL Ecol. Res. Assoc., Inc., Fairbanks, Alaska, for ~orthwest
Alaskan Pipeline Co. and Fluor Northwest, Inc.
ACKNOWLEDGEMENTS
·.. Numerous people provided important information for this review. We
particularly wish to thank U. Banasch and R. W. Fyfe, Canadian Wildlife
Service, Edmonton; C. M. White, Brigham Young University, Provo; J. R.
Haugh, U.S. Geological Survey, Anchorage; D. Money and R. E. Ambrose,
U.S. Fish and Wildlife Service, Anchorage~ D. Mossop, Yukon Game Branch,
Whitehorse; C. Yanagawa and R. Schideler, Alaska Department of Fish and
Game/State Pipeline Coordinator's Office, Fairbanks; and B. Kessel and
D. D. Gibson, University of Alaska, Fairbanks. We are also grateful to
all the other unnamed individuals who have provided useful information
that was used in this report.
Many individuals at LGL Alaska Research Associates, Inc., aided in
this study. P. J. Bente, T. J. Olson and J. M. Wright helped provide
informatio'n from pipeline route alignment sheets and maps. A. M.
Springer, S. R. Johnson and D. M. Troy reviewed and assisted in the
editing of portions of the report. E. Kimbrough typed the report. She
was assisted in the final typing by J. Hig·gins, who also typed the
earlier drafts. C. H .. Welling, D. Whitford and P. D. Hollingdale
assisted in the preparation of the report.
.i
'
'
' ... 1 ·.
2
2 . 1
2. 1 . 1
2.1.1.1
2.1.1.2
2. 1. 2
2.1.2.1
2.1.2.2
2.1.2.3
2.1.2.4
2.1.2.5
2.1.2.6
2.1.2.7
2. 1. 2. 8
2.2
2. 2.1
2.2.2
2.3
2.4
2. 4. 1
2.4.2
2.4.3
2.5
2. 5. 1
2.5.1.1
2.5.1.2
2.5.1.3
2.5.2
2.5.2.1
2.5.2.2
2.5.2.3
2.5.2.4
2.5.3
2.6
2. 6.1
2.6.2
2.6.3
iii
TABLE OF CONTENTS
INTRODUCTION "'••••••••.,••••e:l'eote••v•••••••••••••'•''"
PEREGRINE FALCON .................................... .
DISTRIBUTION, POPULATION SIZE AND PRODUCTIVITY .... .
Throughout Alaska ............................... .
Di stri buti on .................................. .
Population Size ............................... .
Adjacent to Proposed NWA Gas Pipeline ROW ....... .
Sagavanirktok River ........................... .
Yukon River ................................... .
Tanana River .................................. .
Sa 1 cha River .................................. .
Chena River .......... " ........................ .
Grapefruit Rocks, Mile 39 Elliott Highway ..... .
Jim River Canyon .............................. .
Koyukuk River ................................. .
NESTING HABITAT ................................... .
Arctic Slope .................................... .
Interior A 1 ask a ................................. .
REPRODUCTIVE PHENOLOGY ............................ .
FOOD HABITS, HUNTING HABITAT AND HUNTING RANGE .... .
Food Habits ..................................... .
Hunting Habitat ................................. .
Hunting Range ................................... .
IMPACTS OF PIPELINE ACTIVITIES .................... .
Disturbance ..................................... .
Construction and Operation Activities ......... .
Aircraft Passage .............................. .
Human Presence Near Nests ..................... .
Direct Impacts .................................. .
Intentionally Destructive Acts ................ .
Man-made Structures and Obstructions .......... .
Environmental Contaminants .............. · ...... .
Changes in Prey Availability .................. .
Habitat Loss .................................... .
PROTECTIVE MEJl.SURES ............................ 0. o.
Spatial Restrictions ····o···· ················o···
Temporal Restrictions ... 0 ••• 0 ••••••••••••••• 0 ••••
Procedural Restrictions •o·····················•oo
Page
1
4
4
4
a.
6
9
9
13
16
21
21
23
23 ,.
24 F< ..
25 -·~ ~-26
27
29
33
33
37
38
40
40
46
51
54
58
58
59
60
62
63
64
65
70
70
-2.. 7
2; 1.1
2.7.1.1
2.7.1.2
2.7.2
2.8
2.9
2. 9.1
2.9.2
2.9.3
3
3.1
3 .1.1
3.1.1.1
3.1.1.2
3. 1. 2
3.1.2.1
3.1.2.2
3.1. 3
3.1.3.1
3.1.3.2
3.1_.4
3.1.4.1
3.1.4.2
3. 1. 5
3.1.5.1
3.1.5.2
3.2
3.2.1
3.2.2
3.2.3
3.2.4
3.2.5
3.3
3.4
3. 4. 1
3.4.2
3.4.3
3.4.4
3.4.5
TABLE OF CONTENTS (Continued)
PROPOSED PROTECTIVE MEASURE~ FO~ NWA PIPELINE ........ .
USFHS. Rccomended Protectiv'e Measures ..........•...•
Gener~l Restrictions .•....•...••..................
Specific Sites ................................... .
Other Recorrmende:J Res tri cti ons ..................... .
POTEr!TIAL PIPELitlE CO:lFLICTS 1-!ITH :~EST LOCATIONS ..... .
RECO~:MHiDATIONS ...................................... .
Recommendations re Restrictions .................... .
Recommendations re Potential Conflicts ............. .
Other Recor:111endations ....•.....•.....•..............
OTHER RA PTORS •..••...••..•....•.•.••••..••.•........•.•.
01 STRI BUTION AND POPULATION SIZE ..................... .
Gyrfa 1 con .......................................... .
Throughout A 1 aska •..............•.................
Adjacent to Proposed NWA Gas Pipeline ROW ........ .
Rough-legged Hawk .................................. .
Throughout A 1 ask a ................................ .
Adjacent to Proposed NWA Gas Pipeline ROW ........ .
Go 1 den Ea g 1 e ....................................... .
Throughout A 1 aska ................................ .
Adjacent to Proposed NWA Gas Pipeline ROW ........ .
Bald Eagle ......................................... .
Throughout Alaska ................................ .
Adjacent to Proposed NWA Gas Pipeline ROW ........ .
Osprey ............................................. .
Throughout Alaska ................................ .
Adjacent to Proposed NWA Gas Pipeline ROW ........ .
NESTING HABITAT ..•.••.................................
Gyrfa 1 con .......................................... .
Rough-1 egged Hawk .................................. .
Go 1 den Ea g 1 e .•......................................
Ba 1 d Eag 1 e ......................................... .
Osprey ............................................. .
REPRODUCTIVE PHENOLOGY ............................... .
HUNTING HABITS ....................................... .
Gyrfalcon .......................................... .
Rough-1 egged Hawk .................................. .
Gal den Eagle ....................................... .
Bald Eagle ......................................... .
Osprey ............................................. .
Page
74
74
74
85
86
90
91
91
92
92
95
96
96
~~ '~ 97 .. ~ ...
97 _j_
98
99
99
100
100
100
102
102
102
103
104
104
105
106
107
108
11 0
113
113
114
115
115
116
-
' 3'-. 5
3. 5. 1
3.5.1.1
3.5.1.2
3.5.1.3
3.5.2
3. 5. 2.1
3.5.2.2
3.5.2.3
3.5.2.4
3.5.3
3.6
3.7
3. 7.1
3.7.1.1
3.7.1.2
3.7.1.3
3.7.1.4
3.7.2
3.8
3.9
3. 9.1
3.9.2
3.9.3
4
4. 1
4.2
5
5. 1
5. 1. 1
5.1. 2
5 .1. 3
5.2
5. 2. 1
5.2.2
5.3
5. 3.1
5.3.2.
v
TABLE OF CONTENTS (Continued)
IMPACTS OF PIPELINE ACTIVITIES •••••••••••••••••.•••••
Disturbance ................................. o •••• o ••
Construction and Operation Activities •••••••••••.
Aircraft Passage ••••••••••••••••••••••••••••.•••.
Human Presence Near Nests ••••••••••••••••.•..••••
Direct Impacts ••.••••••••..••••••••••••••••.••.•••.
Intentionally Destructive Acts ••.•.•••••••..•••.•
Man-made Structures and Obstructions •••••••.•••..
Environmental Contaminants ••••••••••••.•••••••••.
Changes in Prey Availability .••••••••••••...•••.•
Habitat Loss ••••.•.••.••......•.•••.•...•.•.•.•••••
PROTECTIVE t~EASURES •..•.•...•....•••....••••••...•...
PROPOSED PROTECTIVE MEASURES FOR NWA PIPELINE ••.•.•.•
State of Alaska Protective Measures .•••.••.••...•..
General Restrictions .•..•..•.•..•..•.•••••••.••..
Temporal Criteria ••.•••..•..••••••••••.•.......•.
Spatial Criteria ••••..••.•..•••••••••••.••.••.•••
Specific Sites ••.•.•.•••••...••••••••.•••••.....•
Other Protective Measures ..•..••..••.••••••..••••••
POTENTIAL PIPELINE CONFLICTS WITH NEST LOCATIONS •...•
RECm1MENDATIONS •••.••••••.••.•..••••••••..••.••.•....
Recommendations re Restrictions .••••.••.•••••......
Recommendations re Potential Conflicts •••••.•...•..
Other Recornmenda tions ••.•...•.••.••••••.•••••.•••.•
REFERENCES •••••..•.••••••.•••••••..•••••••....••••.•.••
LITERATURE CITED .................................... .
PERSOUAL COM1•1U~·:Icft.TIO~:s A:'D urtPUBLISHED DATA •••.•....
APPENDICES ••••••.•.••••••.•.•....•••.•••..•••...•..•••.
PRODUCTIVITY OF PEREGRINE FALCONS .••..•.•.•••••......
Sagavanirktok River .•.•.•..•......••.....•..•......
Yukon River •••..•..••.•..............•........••...
Tanana River .••.•.•.•••••...........•.•••••.....••.
NESTING PHENOLOGY OF PEREGRINE FALCONS ...•....••....•
Arctic S 1 ope ••••••••••....•..•.....•.•..•••.•....••
Interior A 1 aska ••..••..•..••.••..••..••.••••...•...
Page
117
117
118
122
127
134
134
135
136
138
139
140
159
159 .•
159 . t:
165 ~ ......
167 ·~
170
171
172
173
173
177
177
173
178
194
196
196
1?6
197
198
199
199
203
FOOD HABITS OF PEREGRINE FALCONS . . . . • • • • . • • . • • . . . . . . . 208
Arr:tic Slope . . • . . • • . • • • • • . . . . . . . • . . . . . . . • • . . . . . . . . . 208
Interior A 1 aska • . • . . . • • . • • . • • . • . . • • . • • . . • . . . • . • . . . . 209
~ 5. 4
5. 4.1
5.4.2
5 .... 5
5. 5. 1
5.5.2
5.5.3
5.6
5.7
vi
HUNTING HABITAT OF PEREGRINE FALCONS .............. .
F.. p. tu17d.raius ...... c ••• , .......... 0 ... 0 .... e 0 r 0 .... G .. D •
F. p . ana t~ . . . . "' . . . . . . .. . . . . . . . . . . .. "' .. . . 1'1 •• r • • • • o • •
HUNTING RANGE OF PEREGRINE FALCONS ............. " ... .
F.. p. tundrius ............... .J> ............. c. ........ .
F. p. aMt1Am •••••••••.•••••.•.•..••.• , •. e-.oeoo• .. ••
0 ther Peregrines ................................. .
NORTHWEST TERRITORIES GUIDELINES FOR GEOLOGICAL
OPERATIONS IN AREAS FREQUENTED OY PEREGRINE FALCONS .
CHARACTERISTICS OF PEREGRINE FALCON NEST LOCATIONS
Page
210
210
211
214
214
214
215
216
BETWEEN 2 and 15 MILES FROM THE ROW .. . .... .. ... .. .. . 218 (
I
vii
LIST OF TABLES
fable
1 Numbers of peregrine falcons (F. p. tundrius) occupying
nesting habitat in the Sagavanirktok River drainage,
Page
Alaska, 1958-78 .•..•.••.•....••..•.........•••••.•..•.... 11
2 Numbers of peregrine falcons (F. p. tundrius) occupying
nesting habitat in the Sagavanirktok River drainage,
Alaska, 1979-80 .......................................... 12
3 Productivity of peregrine falcons (F. p. tundrius) nesting
along 'the Sagavanirktok River, Alaska, 1970-79 ........... 14
4
5
Numbers of peregrine falcons (F. p. anatum) occupying
nesting habitat along the Yukon River between Stevens
Village and Tanana, Alaska, 1974-80 ...................... .
Productivity of peregrine falcons (F. p. anatum) nesting
along the Yukon River between Stevens Village and Tanana,
A 1 aska, 197 4-80 ......................................... .
6 Numbers of peregrine falcons (F. p. anatum) occupying
nesting habitat along the Tanana River between Fairbanks
15
17
and Tetlin Junction, Alaska, pre-1963 and 1963-80 ........ 19
7 Productivity of peregrine falcons (F. p. anatum) nesting
along the Tanana River between Fairbanks and Tetlin
Junction, Alaska, 1968-70 ................................ 22
8 Prey species of peregrine falcons nesting on the Arctic
Slope, Alaska . .. ... ... .. . .. . . .. .. ... . ... . . . .. . .. . .. . ... .. 34
9 Prey species of peregrine falcons nesting in 'interior
A 1 aska . . • . • . . . . . . . . . . . • . . . . . . . . . . . . . . . . . • . . . . . . • . . . . . . . . . 3 5
10 General types of impacts to raptors ...................... 41
11 Factors that affect the sensitivity of peregrine falcons
to disturbances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
12 Influence of timing of disturbance on the possible effects
on raptors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • . . . . . . . . . . . 45
viii
LIST OF TABLES (Continued)
Table Page
fl Recommended minimum distances for ground activities to
protect peregrine falcon nest sites in northern areas 66
14 Recommended minimum distances for aircraft activities to
protect peregrine falcon nest sites in northern areas 71
15 September 1980 USF\~S recol!11lended res tri cti ons for protec-
tion of peregrine falcons................................ 75
16 October 1979 USHJS r~cor:1llended tems and cond.i ti ons for
protection of the endangered peregrine falcon in Alaska.. 81
17 Peregrine falcon nest locations along the NWA pipeline
corri dar ............•.•..................................
18-37 Char~cteristics of individual peregrine falcon nest
locations ............................................... .
38 Recommended status of peregrine falcon nest locations
39 Nest locations within 1 mi of facilities, etc. and
recorrmendations re potential conflicts .................. .
40 Nest locations between 1 mi and 2 mi from facilities, etc.
and recommendations re potential conflicts .............. .
41 Recommended minimum distances for ground activities to
Vol.
Vol.
93
Vol.
Vol.
protect gyrfalcon nest sites in northern areas ........... 142
42 Recommended minimum distances for ground activities to
protect golden eagle nest sites in northern areas ........ 145
43 Recommended minimum distances for ground activities to
protect bald eagle nest sites in northern areas .......... 148
44 Recommended minimum distances for ground activities to
protect osprey nest sites in northern areas .............. 150
45 Recommended minimum distances for aircraft activities to
protect gyrfalcon nest sites in northern areas ........... 152
46 Recommended minimum distances for aircraft activities to
protect golden eagle nest sites in northern areas ........ 154
47 Recommended minimum distances for aircraft activities to
protect bald eagle nest sites in northern areas .......... 156
48 Recommended minimum distances for aircraft activities to
protect osprey nest sites in northern areas .............. 158
II
' ~.
II ~~
~"" ~
#f.
II
II
ix
LIST OF TABLES (Continued)
Table Page
~-State of Alaska temporal and spatial protection criteria
for nesting raptors •...•.................•........•....•. 160
SO ·Nest locations of golden eagles, gyrfalcons, rough-legged
hawks and bald eagles along the NWA pipeline corridor .... Vol. II
51-77 Characteristics of individual nest locations of the other
t · ·Vol. II rap or spec1es .......................................... .
78
79
Recommended nest locati.ons for State of Alaska list of
sensitive wildlife areas · ................................ .
Recommended temporal and spatial protection criteria for
nesting gyrfalcons, rough-legged hawks, golden eagles,
bald eagles and ospreys ................................. .
175
176 ,,
Vol. II ·~ 80 Golden eagle nest locations within l/2 mi of facilities,
etc. and recommendations re potential conflicts ......... .
81
82
83
Gyrfalcon nest locations within l/2 mi of factlities, etc.
and recommendations re potential conflicts .............. .
Rough-legged hawk nest locations within 1/2 mi of
facilities, etc. and recommendations re potential
conflicts ............................................... .
Bald eagle nest locations within l/2 mi of facilities,
etc. and recommendations re potential conflicts ......... .
Vol. II
Vol . II
Vol. II
.
\ , .
X
LIST OF FIGURES
. _n gure Page
~ . ..
1 ~ · Reproductive phenology of peregrine falcons nesting in
arctic and interior Alaska ....•..•.. ·-.................... 30
2 Reproductive phenology of gyrfalcons, rough-legged hawks
and golden eagles in arctic and interior Alaska .......... 111
3 Reproductive phenology of bald eagles and ospreys in
interior Alaska ...............•.......................... 112
:r
1. INTRODUCTION
Northwest Alaskan Pipeline Company (NWA) has proposed to build the
Alaskan portion of a large-diameter, chilled-gas pipeline from Prudhoe
Bay, Alaska, through Canada to the midwestern United States. The proposed
NWA gas pipeline alignment parallels the now-existing and functioning
Trans-Alaskan Pipeline System (TAPS) between Prudhoe Bay and Delta
Junction. At Delta Junction, the proposed gas pipeline alignment diverges
southeastward to follow the Alaska Highway and the nearby (currently
decommissioned) Ha~nes Products pipeline right-of-way (ROW) to the U.S.-
Canadian border.
In recent years, as large northern developments, particularly highwaY.t
.o;:,..-
and pipelines, have been proposed and in some cases constructed, concern 7i
~· has frequently been expressed about the potential impacts of such develop--
ments on the raptors (falcons, hawks, eagles, ospreys, etc.) that nest in
the vicinity of the developments (e.g., White and Streater 1970b; Hhite and
Cade 1975; Berger 1977). Concern has been most frequently expressed for
the peregrine falcon (Falco pePegrinus) because of its endangered status;
two subspecies (F. p. tundrius and F. p. anatum) are considered to be
endangered under the U.S. Endangered Species Act (1973). The concern for
nesting raptors led to government restrictions and the implementation of
protective measures in the case of the TAPS in an attempt to minimize its
impact on nesting raptors; and for the same reason, new government
restrictions are now being proposed with respect to the NWA pipeline.
The present study was conducted for N\·JA in order to deve 1 op protec-
-tion strategies to prevent or minimize the impacts of the proposed NWA
gas pipeline on nesting raptors. More specifically, the ohjectives of the
study were the following:
1. to review raptor nesting biology with respect to the information
needed for protection strategies,
'
;-
2.
3.
4.
5.
6.
2
to review the infonnation available on the impacts of develop-
ments on nesting raptors,
to review the various measures that have been proposed to
protect nesting raptors from the impacts of developments,
to criticaliy examine the government restrictions that are being
proposed to protect nesting raptors from the impacts of the
proposed NWA pipeline,
to delineate the potential conflicts under these restrictions
between raptor nest locations and the NWA pipeline alignment,
and
to make recommendations concerning the proposed government
restrictions and these potential confl i"cts that tiOL!l cl prevent or
minimize ~he impacts of the proposed NWA pipeline on nesting
raptors. l;r
Emphasis in this report has been placed on the peregrine falcon,
because of its endangered status and the consequent concern for this ~
-species. The other raptors for which protection strategies have been .
developed are those species whose nest locations are comparatively tradi-
tional, those species whose nest locations are fairly readily detectable,
those species whose nest sites are frequently used in subsequent years by
other raptor species (especially if they are used by peregrines), and/or
those species for whom concern has been expressed either because of their
population status or because of their sensitivity to impacts from develop-
ment. These are the species for which the development of protection
strategies is not only important but also practical. The other raptors
for which protection strategies are developed are the gyrfalcon (Falco
r>usticolus), rough-legged hawk (Buteo lagopus), golden .eagle (Aquila
l
j
l
{
3
ahrysaetos), bald eagle (Haliaeetus leuaoaephalus) and osprey (Pandion
:_haziaetus). Other raptor species, for which it was considered either not
~ important or not practical to develop protection strategies, have not
been treated in this report.
r
'I '· ,, ,;,
' .
4
2. PEREGRINE FALCON
~ 2.1 DISTRIBUTION, POPULATION SIZE AND PRODUCTIVITY
~
2.1.1 Throughout Alaska
It is not within the scope of this report to treat the statewide
population size and distribution of peregrine falcons in detail, nor to
reevaluate past estimates of numbers. It is appropriate, however, to
provide some perspective on these subjects before providing more detailed
information on the distribution, numbers and productivity of peregrines
in the vicinity of the proposed NWA gas· pipeline corridor.
2.1.1.1. Distribution
The distribution of peregrine falcon nesting habitat throughout
Alaska is now relatively well known (e.g., Fyfe et al. 1976; Alaska
Peregrine Falcon Recovery Team [APFRT] 1979). Scattered occasional
nesting habitat for one race, F. p. pealei, occurs along the coastline
of the Gulf of Alaska and southeastern Alaska, but the vast majority of
pairs of this race (which is not endangered) are found from the southern
Alaska Peninsula and associated islands westward throughout the Aleutian
Islands. Little nesting habitat for peregrines appears to occur along
the western coast of Alaska, where this race probably intergrades with
others.
One of the two endangered races, F. p. anatum, is found predomi-
nantly along the larger rivers of Alaska, in the region north of the
Alaska Range, northwest of the northern Aleutian Range and south of the
Brooks Range. Although occasional nesting habitat of F. p. anatum is
known to occur along some of the smaller tributaries of the Kuskokwim
and Yukon rivers (the principal drainages of this region) and even in a
5
~ few upland areas of interior Alaska, the vast majority of F. p. anatum
-~airs are restricted to seven important areas of excellent, relatively
cbncentrated nesting habitat that are found along the courses of the
upper Porcupine River (lower and upper ramparts), the upper Yukon River
(between the U.S.-Canada border and Circle}, the middle reaches of the
Charley River, the middle Yukon River (between Stevens Village and
Tanana) , the 1 ower Yukon River (between Ruby and St. r1arys) , the Tanana
River (between Tetlin Junction and Nenana) and the -Kuskokwim River (between
McGrath and Aniak).
The second of the two endangered races, F. p. tundrius, inhabits the
region north of the Brooks Ra~ge, and parts of northwestern Alaska, where
:a,.
the division between this race and F. p. anatzon is poorly understood.
the Arctic Slope between the U.S.-Canada border and the Sagavanirktok
River, nesting habitat is scattered and relatively limited in extent.
On~ -· ....
"' ~
The
best habitat 'concentrations' are small, and are found predominantly in
sections of the Canning and Kongakut rivers. A small, but more important
concentration of nesting habitat is found along the middle and lower
reaches of the Sagavanirktok River (Sagwon and Franklin bluffs). Between
the Sagavanirktok River and the Colville River drainage nesting habitat
is again scarce; only a few areas where peregrines have nested are known
to occur. The important 'center of distribution' _is the Colville River
drainage, where the majority of the nest locations and nesting pairs
occur. Small amounts of nesting habitat are scattered throughout many of
.the tributaries of this drainage (particularly along those flowing out of
the Brooks Range between and including the Etivluk and Nanushuk rivers),
-and a very important large concentration of nesting habitat ~ccurs along
·the Colville River course itself, between the Etivluk River a·nd Ocean
Point. Between the Chukchi Sea and the headwaters of the Colville River
drainage, the situation appears somewhat similar to that found east of
the Sagavanirktok River. The Utukok and Kukpowruk rivers appear to offer
the most important nesting habitat in the western portion of the Arctic
Slope.
6
~· ; 2.1.1.2 Population Size
~-· Cade (1960) estimated that not less than 600 nor more than 1200
breeding pairs of peregrines were present in Alaska. He suggested that
an estimate of 1000 breeding pairs was the proper order of·magnitude for
the number of peregrines present in the arctic, interior and coastal
regions (i.e., including all three currently recognized races). He
further divided his total estimate into the following regions: the
Arctic Slope,~ 200-250 pairs ('a reasonable figure'); the Yukon River
drainage,~ 250-300 pairs ('a conservative estimate'); the watersheds of
the Kuskokwim, Nushagak, Susitna and Copper rivers, ~ 100-200 pairs
·('likely'); southeastern Alaska,< 20 pairs; the Aleutian Islands,
~ 100 pairs ('certainly a minimum estimate'). Since the time of these \
estimates, a considerable amount of new information has been obtained on j·
the amount of available nesting habitat and the numbers of peregrines in ;£
many regions of Alaska. In general, these data suggest that, although
Cade's (1960) estimate of the total population was reasonable, the pro-
portions of the population he assigned to various regions of the state
were not as reasonable.
Cade's (1960) original estimates of the number of peregrines in the
Colville River drainage and the entire Arctic Slope may have been too
high. Cade and White (1976} recently contended that the original estimate
for the Colville watershed is still realistic, based on more recent data
and a review of past data; however, Haugh (1976a) disputed this figure,
· and contended that, in recent times, the Arctic Slope of Alaska never
supported more than ~ 100 pairs of peregrines. In view of what is now
:known about the amount and distribution of available nesting habitat
east of the Sagavanirktok River and the importance of the Colville
watershed to the population as a whole (Roseneau et al. 1976, 1980), this
latter figure (~ 100 pairs) appears more appropriate than the original
estimate. APFRT (1979) has recently suggested an upper limit of~ 150
l
l
l
1
~
l
l
1
I
l
[
7
<
~-
~ pairs based on known nesting locations, nesting densities on the Colville
.and Sagavanirktok rivers, and the physiography of the region.
, ..
It also appears that the original estimate by Cade (1960) of the
number of peregrines inhabiting the Yukon River drainage was too high.
Again, based on extensive survey efforts during the past 5-6 yr, consid-
erably more is now known about the occurrence and distribution of actual
available nesting habitat in this drainage. Many of the tributaries are
bereft of it. On the basis of the number of cliffs and bluffs now known
to occur (while still allowing for occasional nesting cliffs in less
well-known smaller tributaries and the odd tree-nesting pair), about one-
half of the original estimate seems a more appropriate number of peregrines
for this large region (APFRT 1979). ~ --i
~1ore r _ecent knowled~e of the drainage of the Kuskokwim, ~.
Nushagak, Susitna and Copper rivers indicates that the original estimate
of peregrine pairs in these areas was also quite high. Most of the
available nesting habitat is found in only one of these drainages, the
Kuskokwim River, for which few historical data are available. The number
of cliffs and bluffs along the Kuskokwim River is comparable to that found
on the Tanana River, and this information suggests the possibility that
similar numbers of peregrines could have occurred there in addition to a
smaller number of pairs scattered in various tributary drainages. Only a
few nest locations have been documented on the Nushagak River and nesting
, hab"itat comparab 1 e to that on the Yukon and Kuskokwim rivers does not
appear to exist there. The Susitna and Copper rivers both provide even
fewer potential nesting locations for peregrines.
The original estimate by Cade (1960) for southeastern Alaska appears
fairly accurate. A comparable small number of pairs is also known to
inhabit the northern coast of the Gulf of Alaska (e.g., White et aZ. 1976).
8
•• . ,
;. Cade (1960) offered what he considered to be a very minimum estimate
" for the Aleutian Islands; the amount of habitat there appeared substantial
·but very few data were available . ... New evidence suggests that the original
eStimate was indeed a minimum figure. It is now believed that four to six
times as many peregrines could inhabit this maritime region, which extends
westward from the southwestern Gulf of Alaska · (White 1975, 1976}.
The current total population size of peregrine falcons nesting in
Alaska is still difficult to ascertain, primarfly because so few data are
available on F. p. pealei in important coastal areas, particularly the
Alaska Peninsula and Aleutian Islands. However, the current status of
the two endangered races, F. p. -anatwn and F. p. tundroius, is now
relatively well known. During the last five years, a considerable amount\
of survey work has been conducted by various agencies and others in all ~ . ~
the areas of nesting habitat in Alaska important to these two races. 1
These d~ta, including _ comprehensive data obtained in 1900 (the year of
the third North American Peregrine Falcon Survey), indicate that an
upward trend has occurred in Alaska during the last four years in both
the numbers and the productivity of F. p. anatum and F. p. tundroius
(e.g., Curatolo and Ambrose 1978; Springer et al. l979b; Roseneau et al.
1980}. The number of F. p. anatun birds, in particular, has shown a
strong increase throughout most of the important nestinq habitat in
interior Alaska (and in north-central Yukon Territory). In 1980 the
vari·ous data indicate that"' 75 pairs and "' 10 single individuals occupied
~liffs and bluffs in the seven important habitat areas of interior Alaska.
_Dnly two of these important nesting areas, the Kuskokwim and Tanana River
drainages, were found to still contain only a few pairs each. A total
· estimate of "' 100 F. p. anatum pairs in Alaska in 1980 is probably not
unreasonable.
Increases in the population size of F. p. tu.ndroiu.s have not been as
large nor as widespread as those of F. p. anatum; however, data from the
9
.t
\ ~Colville River and Sagavanirktok River are indicative of such increases
(e.g., Springer et al. 1979b; Roseneau and Bente 1979; USFWS, unpubl.
ijqta). In 1980 additional data'were obtained from several drainages
between the Canning River and the U.S.-Canada border, and from the western
Arctic Slope. (Not all of the latter information has been received or
evaluated.) The information available to date suggests that~ 50 pairs
and several individuals may have been present in the region in 1980, and
that mos·t of them occupied nesting locations in the Colville River
drainage.
2. 1. 2 . Adjacent to Proposed NWA Gas Pipeline ROVI
The proposed N~~A gas pipeline route in Alaska runs parallel to majoJi
sections of the Sagavanirktok River and the Tanana River, and . crosses the i
Yukon River. The Sagavanirktok River drainage provides important nesting ~
habitat for F. p. tundrius. The Tanana and Yukon River drainages provide
important nesting habitat for F. p. anatL~. Two tributaries of the Tanana
River also provide nesting habitat. In addition, the proposed gas pipe-
line alignment passes near a small area of recently discovered nesting
habitat for F. p. anatum in the interior uplands of Alaska. Two adjacent
locations in that area were used by peregrines in 1979 and 19SO (Roseneau
and Bente 1979, 1980a). {There is no previous documentation of peregrine
use of this area.) Two other areas contain some potential nesting
habitat for peregrines.
2.1 .2.1 Sagavanirktok River
Numbers Present --Data on the number of peregrines nesting in the
Sdgavanirktok River drainage between the late 1950's and 1975 were
summarized by Roseneau et al. (1976). Two errors occurred in that compil-
ation (Table 9, p. 244). One lone adult peregrine occupying a nest
location on Franklin Bluffs in 1974 was omitted 'from the table, and five
10
· pairs of peregrines were listed in the table as being present in 1974,
~
when the correct n~mber, as stated in the text of that report, was four
~airs. These data, with appropriate corrections, additional data from ..
1964, and data from 1976-78 are listed in Table 1. Table 2 lists data
: obtained during NWA-sponsored surveys in 1979 and 1980.
These data suggest that peregrines were historically more numerous
in the Sagavanirktok Riv~r drainage than they have been in recent times.
Even though the Sagwon Bluffs vicinity and the Slope Mountain vicinity
were not checked in 1958, five of six known nesting locations on Franklin
Bluffs were occupied by pairs that year. Furthermore, it seems unlikely
that the other major section of prime nesting habitat, Sagwon Bluffs,
would have been totally unoccupied in 1958. Other data obtained on the
Arctic Slope of Alaska in the 1950's, 1960's, and 1970's also provide
evidence that peregrines were more numerous in the 1950's (Cade 1960;.
White and Cade 1971, 1975, 1977).
The incomplete nature of much of the data shown in Table 1 precludes
real comparisons among years. Complete or nearly complete survey coverage
of the drainage occurred only in 1970, 1972, 1974, 1975, 1979 and 1980.
Data from those years, and additional data obtained at Sagwon Bluffs since
1970 suggest that little change has occurred in the number of peregrines
inhabiting the Sagavanirktok River since the early 1970's. Since about
1970, the presence of about four pairs appears to be about average in this
Arctic Slope drainage.
All known nesting locations used by peregrines in the Sagavanirktok
River drainage have been reported by Roseneau and Bente (1979, 1980a). In
this report, data from the Sagavanirktok River drainage have not been
tabulated by specific nest locations. Instead, these data are reported by
specific sections of river drainage. The nearly continuous but frequently j
changing nesting habitat that is afforded by Sagwon Bluffs and Franklin
j
l
TASL£ I. !lumbers of peregrine falcons .(F. p. tundrit<s) occupyinCJ nestinq habitat in the ·sagavanirktok River drainage, Alaska, ljSB-78.1
t
Occupancy of !lest locations that 1·1ere Checked
Total fles~ locations tlumber Checked Unoccu[!ied lone Adult Pair
Fr,lnklin Saq1·10n Slope Franklin Saq1·10n Slope Franklin Sag1·10n Slope Franklin Sag1·1on Slope Franklin Sag1~on Slope
Year Bluffs Bluffs fltn. Bluffs Bluffs tltn. Bluffs Bluffs lltn. Bluffs Bluffs Htn. Bluffs Bluffs fltn.
1958 6 4 5 0 0 0 0 5
1963 6 4 4 0 2 0 0 0 0 1 2
1964 6 4 0 I 0 0 0 1
1970 6 4 3 4 1 3 0 0 0 2 1 0
1972 6 4 5 4 2 2 0 JJ't 0 3 tJ 0
1973 6 4 4 0 0 2 0 2
1974 6 4 5 4 1 2 2 0 2 I 2 0
1975 6 4 5 4 4 2 0 0 0 1 2 0
1976 6 4 0 4 0 3 0 1
1977 6 52 4 5 ? 3 3 ·o 0 23
1978 6 52 0 I 0 0 0 1
1 195i: and 1973 ddta are from J. Koranda (pers. comm. to C. II. I·Jhite); 1963 data are from r~. D. 11a?gus (pers. comm. to C. t1. White); 1964
data are from l·!hite and Cade (1975); 1970 data are from Hhite and Streater (1970a,b); 1972 data are from White and Ray (1972); 1974 data
arc from RosenCJu e~ al. (1976) and C. fl. Hhite (unpubl. data); J-975 data are from Roseneau o:t ul. (1976); 1976 data are from Capodice
(1976); 1977 data are from K. P. ~Jhitten and D. Roby (pers. co1nm.) and L. S01·1l {pers. comn1.); 1978 data are from C. 11. Hhite (pers. comm.).
2 Includes one site at the small bluffs on the east side of the r·iver opposite the no•·thern tenni fttl(. of Sagwon Bluffs, that has been
desiqnJted 'East Sagl'lon'.
1 Includes one pair that nested at the 'East Saqwon' location.
__, .....
.. "'•t' Jo•
TABLE 2. !lumbers of peregrine falcons ; (F. p. tw:w>-::~oa) occupying nestinq hal..litat in the Sagavanirktok River drainage, Alaska, .Jilll9-80.1
J
Occupancy of Nest Locations that ~1ere Checked
Total Nest Locations Number Checked Unoccupied Lone Adult .Pair
Frankl in Sdqi·IOn Slope
Bluffs~ Bluffs 1 Htn.
Frankl in Sag~son Slope
Bluffs 2 Bluffs 3 lltn.
Franklin Sagwon Slope
Bluffs Rl~ffs Htn.
Frank 1 in Sag1·10n S 1 ope Franklin Sagwon Sl~pe
Year Bluffs Bluffs Mtn. Dluffs Bluffs Htn.
1979
1980
6
7
5
5
6
7
5
5
4
5
3
4
0
0
0
( 1)~
0
0
2
2
0
0
I 1979 data are from Roseneau and Bente (1979), and B. Durtsche and R. Ambrose (pers. conm.); 19eO data are from Roseneau and Hente (1980a), and
Durtsche and Ambrose (pers. comn1.).
A pair made some attempt to nest at a ne1~ location in 1980 (Roseneau an(j Bente 19!l0a) that 1~as unoccupieel in 1979 . The location has been
incorporated into the data base for both survey years.
3 Includes one site at the small bluffs on the east side of the river opposite the northern terminus of Sagwon Bluffs, that has been
designated 'East Sagwon'.
" This single adult did not appear to actually occupy a location at Sag1·1on Bluffs. Instead it was observed several miles south of there,
but may have repr-esented one member of a pair that failed to nest successfully on the south end of Sag110n Bluffs in 1979 (Roseneau and
Bente 19SOa).
5 Includes one pair that nested at the 'East Sag~1on' location.
......
N
13
:r .,._
< ...
' Bluffs, and the characteristics of the nest sites chosen by arctic
peregrines at these nest locations are important reasons why these two
~eas should be treated as units rather than on the basis of the individual
nesting locations found on them.
PPOduativity --Data on the productivity of peregrine falcons nesting in
the Sagavanirktok River drainage are less complete than the data on the
numbers of pairs present over the years. Table 3 summarizes the available
productivity data for this drainage for those years when survey coverage
was complete or nearly complete. Appendix 5.1 provides more detailed
information on the nesting success during each ye~r.
The data indicate that the productivity of peregrines along the l
Sagavanirktok River in the mid 1970's had declined considerably from thatt
~
in the early 1970's. Productivity has apparently increased in the late •
1970's, but has not yet attained the levels of the early 1970's.
I
'I
2. 1.2. 2 Yukon Rive:f;
iII
Numbers Present -~ No data on the numbers of peregrine falcons inhabiting
the middle Yukon River prior to 1970 are available (APFRT 1979}. White
~nd Streater (1970a), White and Ray (1972) and C. M. White (unpubl. data}
report on a few nesting locations during partial surveys in 1970 and 1972.
The first complete survey of the peregrine falcon nesting habitat found
between Stevens Village and Tanana was conducted in 1974 (White 1974a,b) .
.. -Subsequent surveys were conducted in 1975, 1976, 1979 and 1980 (Haugh and
Halperin 1976; Springer et al. 1979b; Roseneau et al. 1980; R .. Ambrose,
-pers. corrm.). Springer et al. (1979b) compiled all the data on occupancy
of nesting locations in this section of the river for the years of
complete survey coverage (up to 1979). Data obtained in 1980 are reported
by Roseneau et al. (1980). Table 4 lists the data for the Yukon River.
-
TACLE 3. Productivity of peregrine falcons (F. p. tuncl,•ius) nesting along the Sagavanirktok River, Alaska, 1970-79.
!lumber of eggs per attempt
!lumber of chicl<.s hatched per attempt
Number of large chicks per attempt
Number of large chicks per successful dttempt
Number of failures
1 Data are from ~lhi te and Streater ( 1970b), Roseneau .:t ul. ( 1976).
2 Data are from l·lhite and Ray ( 1972), Roseneau .:t al. ( 1976).
Data are from Ro~·neau ..:tal. (1976), Roseneau (unpubl. data).
1' Data are from Ro~"neau and Bente (1979).
----
1970 1
?
(n=J)
?
(n=3)
1.7
(n=3)
2.5
(n=2)
1
(33%)
? 2.8 3.3
(n=4) (n=4) (n=3)
1.3 2.0 1.7
(n=4) (n=.,) (n=3)
1.0 0.8 0.3
(est., n=4) (n=4) (n•3)
2.0 1.5 1.0
(est., n=2) (n:2) (n=l)
2 2 2
(so~·:> (50:ro) (67~)
1979''
3.3
(n=4)
2.3
(n=4)
'1.1-1.3
(est., n'"4)
1.5-1.7
(est., n=3)
1
(25:';) .t:o
TABLE il. !lumbers of perel]rine falcons (F. p. anatum) occupying nesting habitat along the Yukon River between Stevens Vi_llage and Tanana. Alaska. 1974-80.
Occu nc
Springer .. : .~i. 1974 I 19752 19761 1979" 19805 i l97c;b)
Location 1lumber NWA Location number Pair Lone Adult Pair Lone Adult Pair Lone Adult Pair Lone Adult Pair Lone Adult
NY-2 P-92.1 0 0 1 0 0 0
I-IY-5 P-95a 0 0 0 0 0 0 0 0 0 0
HY-5.1 P-97 0 0 0 0 0 0 0 0 1 0
I-IY-6 P-97 .1 0 1 0 0 1 0 1 0
IIY-8 P-97.2 1 0 1 0 1 0 0 0
IIY-9 0 0 0 0 0 0 0 1 0 0
l-IY-12 1 0 0 0 0 0 0 0
lo!Y-14 1 0 0 0 0 0 0 0
_.
c.n
IIY-16 0 0 ? ? 1 0 0 0 1 0 -r -0--3--1----r () -,--1--r -0-
1 Data are from ~lhite (1974a,b), Hhite and Cade (1975) and liaugh and Halperin (1976).
D.1ta are from llaul)h and flalperin (1976) and R. Ambrose (pers. cor.1n.).
'~ Data are from Haugh and llalperin (1976).
'' Data are from Springer c:~ r1Z. (1979b).
·· u,.td arc from Hosert(!clU ut ul. ( 19UO).
• ~
16
~ During the five years that complete surveys were conducted, the number of
peregrines present has varied considerably; four to six nesting locations
~ve been occupied each year, and three to six pairs have been present.
White (1974a) suggested that more pairs may have occupied this section of
the Yukon River at some time in the past. Other potential cliffs are
present, and are spaced in a manner that could allow at least a few more
pairs to be present (Springer et at. 1979b; Roseneau et at. 1980).
The location numbers used in Table 4 follow the system developed by
Springer et at. (1979b). Corresponding NWA nest location numbers are
also listed where applicable. The locations in Table 4 that do not have
a corresponding NWA location number are more than 15 mi downstream from
the proposed NWA gas pipeline alignment.
Productivity --The productivity of peregrine falcons nesting along the
Yukon River between Stevens Village and Tanana also varied among years.
Productivity data from all five survey years are listed in Table 5, and
are described in more detail in Appendix 5.1.
2.1.2.3 Tanana River
Numbers Present --The numbers of peregrine falcons occupying nesting
locations along the Tanana River course previous to 1976 ~ere compiled
and summarized by Haugh (1976b}, White and Cade (1975, 1977) and Kessel
(1978). White and Cade (1975) suggested that as many as~ 20-21 pairs
could have been present along the river course until the early 1900's.
Haugh (1976b) indicated that at least 19 pairs could have been present prior
·to 1963. Fifteen of those pairs occupied locations between Fairbanks and
Tetlin Junction. Other data have been collected along this river since
1975 (Kessel 1978; R. Hemmen, unpubl. data; R. Ritchie and Ambrose,
unpubl. data). In 1979 these data and all previous data from Haugh (1976b)
were recompiled and reevaluated to determine which cliffs and bluffs in the
I
l
(
[
TABLE 5. Productivity of peregrine falcons (F. p. anatw~) nesting along the Yukon River between Stevens Village and Tanana, Alaska, 1974-80.
19741
tlumber of eggs per attempt ?
(n=6)
Number of chicks hatched per attempt ?
(n=6)
tlumber of large chicks per attempt 0.5
(n=6)
Number of large chicks per successful attempt 1.5
{n=2)
Number of failures 4
( 66'~)
1 Data are from l·lhite (1974a,b), \~hite and Cade (1975) and Haugh and Halperin
2 Data are from Haugh and Halperin (1976) and R. Ambrose (pers. comm.).
3 Data arc from Haugh and Halp•!rin (1976).
'• Data are from Springer· et at. ( 1979b).
s Data are from Roseneau e t al. ( 1930).
1975~
?
(n=4)
?
(n=4)
1.8
(n=4)
2.3
(n=3)
I
(25::)
( 1976).
1976 3 1979'' 1980 5
? ? ?
(n=6) (n=4) (n .. 6)
? ? ?
(n=6) (n=4) (n=6)
1.5 0.3 1.8
(n=6) (n=4) (n=6)
2.3 1.0 2.8
(n=4) (n=l) (n=4)
2 3 2
(33::) (75;,) (33'') ........
18
-Tanana River drainage upstream from Fairbanks represented historical
··Jleregrine falcon nesting locations. Part of that process included a
"' site-by-site discussion with J. R. Haugh. The locations that resulted
from that reevaluation, and the results of a 1979 NWA sponsored survey
of the Tanana River were reported by· Roseneau and Bente (1979). In 1980
the Tanana River upstream of Fairbanks was surveyed again for NWA
(Roseneau and Bente 1980a). Table 6 lists all known data on occupancy
of nesting cliffs along the Tanana River from the early 1960's to the
present .. Haugh's (1976b) location numbers and NWA nest location numbers
are both listed for purposes of reference.
The data in Table 6 indicate that a significant decline in numbers
of peregrines occurred in this nesting habitat after about 1968. The
lowest number of individuals was reached in 1974. Since about 1975, a
small increase has apparently occurred in the nu~bers of peregrines occupying
cliffs and bluffs along this river. This increase is quite small, however,
and may only reflect differences in survey techniques since 1975. Recently,
only three to four pairs and a few unpaired individuals have been accounted
for, even though the number of peregrines inhabiting most of the remainder
of the Yukon River drainage has increased substantially over the last
several years (Curatolo and Ambrose 1978; Ambrose 1979;-Curatolo and
Ritchie 1979; Springer et aZ. 1979a,b; Roseneau et aZ. 1980; D. Mossop,
pers. comm.). Because the decline in the number of peregrines nesting
along the Tanana River was so marked and nearly complete (unlike all
other areas in interior Alaska with the possible exception of the Kuskokwim
River), any recovery of this population is expected to occur slowly. Based
upo~ current data, it will take several more years to clarify any apparent
trends in this drainage.
Productivity --The productivity of peregrine falcons nesting along the
Tanana River prior to 1976 has been summarized by previous authors
l
I
]
I
j
~~ 'f"'.A, fl!ol!
•• li··~ .
fAilL( 6. tlumbers uf pt!reqrine falcons (P. p. an.rtMI) occupying nesting habitat alonq the Tanana River betl'leen Fairbanks and Tetlin Junction, Alaatc(;
prc-l'ioJ ~n•l 1963-<:0. I
• ~ ·-·--•• w --~--·---··
Occupancy
Hauoth's :a; A pre-1963.' 196Jl ~~ __]j•lQ_ 1971 1972 -~~-!1_ 1974 1975 1977 197li 1979 _IC!.!!Q__
$ i tr! Location lone lone Lone Lone lo~e lone lone lone lone Lone Lone
·i,ai'IUer-r~un:bl!r Pair Adult Pair Adult Pair Adult Pair lldult Pair lldult Pair Adult Pair Adult Pair Adult Pair Adult Pair Adult Pair Jldult --·· --·-----------·
P-
l6d yes tlC 15 0 _a!. IIC
19a( U~J'l) 5 possibly rK ? IS
2 21J yes tiC 0 0 0 0 0 0 0 0 0 0 0
25 possibly tiC
3 29b yes tiC 0 0 0 0 0 0 0 0 0
4~ p4ar [yes] [tiC] 0 0 0 0 0
3;la 0 0
35a 1 probably
'C' ? ? ? ? 0 Jli
4ld I probably ?
42a 7 probably ? ? [O I] _.
5 47a yes'1 \0 yes yes
6 4Ha yes yes 0 0 tiC iiC
50 0
( 7?)·• ~2 yes IIC 0 0
3 55 yes NC 0 yes 'IC tiC tiC
9 fiOa yes IIC 0 I 0 0 0 0
61 ? 0
10 63 yr:s yes 0 .;.
63.1 .: 1 ? IIC tiC IIC IIC tiC tiC IIC tiC
II [:::] [yes! (yes] [I 0] [I • 0] [--] (--] [--] [--] [one egg]16 [tiC]
12 70 tiC pair tiC tiC tiC ~IC IIC tiC NC NC ?
13 71b yes tiC 0 tiC
14 /4ol yes IIC 0 NC 0 0 0
( 15?) II .•.. yes NC _E!L. __ uc_ _r!f.._ __ IIC_ ~-__!!.L __ tiC _ _!!f_ _l!L ----
12 0 b 0 4 0 4 0 4 0 0 l 0 4 0 3 3 4 0 _ .......... --· ,. ---·---· -----·---· ··-·----------. ··-------·----·-----------. ·-
r~ ... ,llfrl I
I ' •• < -''K.) -~.( jll i •I If;)•,· '/' -;
I'"( ,_..f,.J • ~~ 7 V ~ -~ fpll.O
• (• () I• -~ 't 1/f(.# VII~! /'11/1 t" ... ' ~ttL
fAilLE 6 (continued)
l're-196] and 1963-75 ddta dre from llhite and Cade (1975), llauqh (1970, 1971. 1972, 1973, 1976b). White and Cade (1977), C. 1~.
R. ll<iu<Jh (per·s. couMn.); 1977 data are from Kessel ( 1978) and IL J. Ritchie (pers. conrn.); 197!1 data are from R. HeiiiiiCn (pers.
Roseneau und Bente ( 1979) ·dOd Ritchje (pers. con111.); 1980 data are from Roseneau and Bente (19!l0a).
White (pers. comn.) and J.
c011111.); I~~ data are from
"' • "'·"· 1' .. ,..
These location numne'rs 1·1ere assi!Jned by Hau(jh (1976b) and used by ~Illite dOd Cade (1975, 1977). Haugh developed
lj,•l 1
this number s.Y~~em from his own data and
trou1 other data he obtained (rom D. Grisco via l~hite (Hau!Jh,pers. COllin.).
II,IUqh ( 1976b) obtained pre-1%3, 1963 dnd l96!l datd from B. Kessel <1nd L. G. Swdr·tz (pers. COllin. to ltaugh), dod Grisco (pers. coon. to White).
l-lhite and Cade (1975, 1977) reported these data as being from 1967. llaugh (1976b) reported these data (excluding an obvious typo) as being fro111 196!3.
!laugh (pers. conrn.) stated that 1968 is the correct year.
Roscne<lu dnd Bente (1979) listed Location 19a as a historical peregrine nest location based on the possibility this location represented 'eyrie 112'
reported by Grisco (pers. comm. to White). If Grisco did indeed locate peregrines in this area, it is also possible that tiWA Location l8a could have
been iuvolved. Presently, there is no 1~ay to confirm thdt IIWA Locations 19a or 18a were used by peregrines in the past; however, both certainly appear
suitable for· that species, and are comparable to other ~~ell-documented nestin!J locations in Alaska (Roseneau and Bente,unpubl. data).
·· lluring 1970-74, H;:ugh found pairs occupying these biO cliffs in different years (Haugh 1970, 1971, 1972, 1973). Haugh (1973) states that 'eyrie sites
3 and 4 are probably occupied by the same pair in different years'. Haugh (1976b) and White and Cade (1975, 1977) combined these two locations into one
'site', number 4. Based on observations in other areas of Alaskd, including the lower Yukon River, and the distances between NWA Locations 34a and 38a,
it seems more likely that these dre distinct separate locations that can be used simultaneously or alternately by different pai!s in some years.
flo firm documentation of peregrines nesting at these locations appears to exist, with the exception of a single peregrine reported 'bet~1een eyrie 4 and
5' (lll-IA Locations 4la-42a) in 1975 (l-lhite and Cade 1975). In Hdugh (1976b) and ~lhite and Cade (Jg75, 1977) it appears this bird was reported at site
numt>er 2. All five locations (IIWA 35a,b; 4la,b; and 42a) appear suitable and c01nparable to other documented nest locations in Alaska. llaugh (pers.
cou1n.), 1·1hen reviel'ling this section of the Tanana River, also conmuented that ·peregrines could have 11sed these locations in the past, and could use them
again in the future.
" It has been confimaed that a single peregrine occupied this location in 1979 (Ritchie,pers. comn.). Roseneau and Bente (1979) reported this observation.
but did not have kno~lledge of an exact location at that time .
. , This location 1·1as occupied by d pair of peregrines in 1963 (~lhite, pers. con111.).
1'1Haugh (1976b) site number 7 is no1·1 believed to correspond ~lith miA Location 52, because NW\ Location 52 is the cliff that appears to have the greatest
poteutial betl·,een fll-IA Location 48a and IIWA Location 55; hOI~:!ver, some question as to the accuracy of this interpretation remains.
11 fii-IA Location 63.1 l·lil~ reported by Roseoeau and Bente (1979) as a cliff that should be treated as a historical peregrine nesting site. That determination
1·1ilS made on the I.Jasis of Al<i5kd Oepi.ll"tment of Fish and Game maps that indicated peregrines had been reported there by the USF\~S. No other back-up infor-
mation <ippcdrs dvdilable. !his nrt:a of rock outcr-ops is judged to offer some potential for nesting, and the proximity of N~IA Location 64. with documented
use by pereyri nes, suggests tha l it may have served as an a I ternate nesting c I iff to NWA Location 63 in some years.
1 :·Haugh ( 19761.J) site II uppears to correspond to IIWA Locations 68d and 69a. One abandoned peregrine egg 11as found in a nest in 1975 by White and Cade
(1975) ilt ••hat must almost certainly be either NWA Location 68a or 69a.
''·Haugh (1976b) site number 15 is now thought to represent riHA Location 'K', which offers some potential for nesting; however, some uncertainty as to the
accurucy of this ~~terpretation still exists.
1''Roseneau and llente (1979) repor-ted tMA Location 34a as a historical peregrine site, but inadvertently illustrated it as '34b' on th~ USGS topographic
map series that dccompanied their r·eport. The mdps should be corrected to show 34a as the peregrine site, and 34b should represent the reported raven
nest.
' IIC imp! ies location not chedc•J; -imp I ies location not occupied; ? in1pl ies not known if checked.
I'''~·~ -''"'fYJlo 14 "1\
1' This l!tJ!J indic.lles the presence of either" lone fenadle or a pair in <1ddition to the other birds listed for this year.
N
0
21
c
~ (White and Cade 1975, 1977; Haugh 1976b; Kessel 1978). These and more
' . recent data are listed in Table 7 and are described in more detail in
· ~ppend i x 5 . 1 •
"t
The productivity of peregrines inhabiting the Tanana drainage also
declined markedly after about 1968. By 1975 no nestlings were produced
by ·the few remaining birds (including only one confirmed pair). Since
1975, however, some nestlings have been produced by the few pairs that
have been found to be present. Although a few nestlings have been
fledged in each of the last few years. from nest sites along the Tanana
River, all available information on mortality and recruitment sug9est
that the number of nestlings successfully being produced is probably too
low to maintain the current level of the subpopulation. Recovery of thi~
subpopulation may depend on immigration from other Alaskan subpopulations~
2.1.2.4 Salcha River
A pair of peregrines occupied a cliff about 0.7 mi downstream from
the TAPS crossing (NWA Locations P-79 and P-80) in June 1970, but this
nesting attempt failed and only one adult was found at the cliff in July
(White and Streater 1970a). No 'peregrines have been observed there
during subsequent surveys (White and Ray 1972; White 1974b; White and
Cade 1975) or during recent surveys of the lower Salcha River in 1979 or
1980 (Roseneau and Bente 1979, 1980a). Development of recreational cabin
~ites and high levels of human activity, including sport fishing very
·near the potential nesting cliffs along this small narrow river, are
undoubtedly important factors that can be expected to limit the success
of nesting peregrines in this area.
2.1 . 2. 5 Chena River
Peregrines have nested at NWA Location P-84 in the past (L. G. Swartz
pers. comm.; White, pers. comm.), and some evidence of recent occupancy
.. ' ·~·~ ......
TABLE 7.
.,tJ •' ~· '
Productivity of peregrine falcons (F. p. anat,.,,,) nesting along the Tanana River between Fairbanks and Tetlin JuAcUon,
Alaskcl, 1968-80.)
1968 1970 1971 1972 1973 1974 1975 1977 2 1978 1979 1980
tlumber of eggs per attempt ? ? ? ? 7 ? ? 7 1 1 ?
(n=l2) (no:6) (n=:;) (n=4) ( n=4) (n=2) (n=J) (n=J) (n=4) (n=6) (n .. 4)
Number of chicks hatched per ? ? ? ? ? ? 1 1 1 ? 7
attempt (n=l2) (n=6) (n=-~ l (n=4) (n=4) (n=2) (n=J) (n=J) (n=4) (n=6) (n=4)
tlumber of large chicks per 1.9 2.7 2.3 1.8 2.0 0.5 0.0 >0.0 1.5 0.7 1.3
attempt (n=l2) (n=6) (n~·J) ( n=4) (n.:4) (n=2) (n=J) ( n=J) (n=4) (n=6) (n:o4)
~umber of large chicks per· 2.1 2.7 3.0 2.3 2.0 1.0 o.o >0.0 2.0 2.0 2.5
successful attempt (n=ll) (n=6) (lo J) (n=J) (n=4) (n=l) (n=O) (n=J) (n=J) (n=2) (n .. 2)
llumber of failures 1 0 1 1 0 1 3 est. 0 1 4 2
(8:'.?) ( o·~> ( 2~· :) (25~) (0':.) (50~~) ( 100~) (est. 0%) ( 25,;) (67%) (50~)
IJ968-74 data are from Haugh (l976b); 1975 data are from Hhite and Cade (1975) and Haugh (l976b); 1977 data are from Kessel (1978)
Jnd R. J. Ritchie (pers. conm.); 1978 data dre from R. Henwnen (pers. comn.); 1979 data are from Roseneau and Bente ( 1979) and
Ritchie (pers. comn.); 1930 data are from Roseneau and Bente (l980a).
2Qnly one do~my chick ~1as observed at one nest site during 14-16 July, but not all the ledge at that site could be seen. In July
a 11 three pairs ~/ere s t i 11 bringing food to the nest 1 edqes, and nest I i ngs 1·1ere heard; it 1 s thought that all three pairs
successfully fledged some nestlings (Ritchie,pers. conm.).
• ... 1: ~ 'f&
N
N
23
~ r by this species was found there in 1970 (White and Streater 1970a)~ No
.Peregrines were reported to have occupied ·the site in 1972, 1974 or 1975
"\~hite and Ray 1972; White 1974b; White and Cade 1975)~ In 1979 this
location was not checked (Roseneau and Bente 1979), and in ' 1980 only a
pair of ravens nested there (W. Tilton, pers, comm.). Although peregrines
have not used this nesting location for a number of years, it contains an
excellent nesting cliff that is surrounded by still relatively undeveloped .
land, and it apparently still provides prime nesting habitat for peregrines.
2. 1.2.6 Grapefruit Rocks, Mile 39 Elliott Highway
A small complex of rock outcroppings near mile 39 of the Elliott
Highway is the only other area adjacent to the praposed NWA gas pipeline
route in Alaska where the presence of peregrine falcon nest locations
has been documented. Prior to 1979, only golden eagles were observed to
nest there, and these interior upland rock outcrops did not have any
known previous history of use by peregrines (White, pers. comm.). In 1979
and 1980; however, one pair of peregrines nested there (Roseneau and
Bente 1979, 1980a). Two nest sites at two different locations (on two
different rock outcrops) were used in the two years.
In 1979, the pair of peregrines successfully fledged three nestlings
even though intense construction activities, including the regular
detonation of large amounts of explosives, took place about 0.4 mi away
(Roseneau and Bente 1979, 1980a). In 1980, what was probably the same
'pair of peregrines returned, nested at a new location about 0.7 mi
farther .from the highway, and again successfully fledged three nestlings
-(Roseneau and Bente 1980a).
2. 1.2.7 Jim River Canyon
This relatively well-defined ·randform lies several miles west of the
24
-~ -
; present TAPS alignment and the proposed. NWA gas pipeline route between
· the Yukon River and the Brooks Range. The area has no documented history
··'[ use by nesting peregrine falcons, but it does contain a series of
cffffs and rock outcrops that may be suitable for nesting peregrines
(Roseneau and Bente 1979; White, pers. comm.). This area may also have
been used by peregrines in the past (Roseneau and Bente 1979}. In any
event, with the increasing trend that has occurred in the numbers of
nesting peregrines in interior Alaska during the last several years, this
area should be considered as potential nesting habitat.
2.1.2.8 Koyukuk River
The Koyukuk River drainage to the west of both the present TAPS
alignment and the proposed NWA gas pipeline route, and between the Yukon
River and the Brooks Range has no documented history of use by nesting
peregrine falcons. For the same reasons mentioned in the discussion of
the Jim River Canyon area, however, some scattered river bluffs and cliffs
from the vicinity of Tramway Bar westward may provide potential nesting
habitat for this species.
.,_
2.2 NESTING HABITAT
25
U.A ~1\A R R~OURCES LTRRAltt
U.S. DEPT. OF. lNTEIUO&
-...
~ ...
' The nesting habitat of peregrine falcons can be defined as the land
forms and structures they nest on. Peregrines nest most often on cliffs,
bluffs or steep banks, but they have also nested on artificial structures
(such as man-made ledges and buildings), in trees and on level ground
(Cade 1960; Herbert and Herbert 1965; Hickey 1969; White and Cade 1971;
V.umari 1974; Newton 1976; Cugnasse 1980). No reports of nesting on level
ground or on artificial structures are known in Alaska (cf. White and
Cade 1971); almost all nest sites have been located on cliffs or bluffs,
and only a few instances of nesting in trees have been reported. A few
pairs have used unoccupied stick nests in spruce trees along Birch Creek
north of Fairbanks (White and Roseneau 1970), and there is one other
report of a pair that nested in a spruce snag in the Yukon River drainage
(Cade 1960). More recently, a few pairs have been found that were using
bald eagle nests in trees and the cavities of broken off trees along the
coast of southeastern Alaska (F. Robards, pers. comm.).
Most cliffs and bluffs used by peregrines in Alaska are associated
with the coast or with rivers (cf. Cade 1960, Section 2); only a few upland
rock outcrops away from rivers have been used (e.g., along the Elliott
Highway). In contrast, gyrfalcons, golden eagles and rough-legged hawks
(the three other raptor species that nest principally on cliffs and
bluffs in Alaska) use upland cliffs and rock outcroppings much more
-,frequently in these regions.
The elevations at which peregrines nest in Alaska are between sea
level and~ 2500-2600 ft asl (cf. Cade 1960). No documented nestings to
date have occurred in Alaska above that upper contour interval; most
nestings have occurred on cliffs or bluffs below~ 2000 ft asl. The
elevation (asl) at which peregrines will nest is higher in the central
26
" ~-Yukon Territory than in Alaska; some pairs in the central Yukon nest
.above 3000 ft asl (Mossop, pers. comm.). The upper elevation at which
\~regrines will nest is much greater in mountain mas.sifs at more southern
lat1tudes. For example, elevations of "' 11,000 ft asl are attained in
the Colorado region of the Rocky Mountains (J. Enderson, pers. comm.).
In arctic and interior Alaska, peregrines are clearly more restricted by
the elevation at which they can nest than are the other cliff-and bluff-
nesting raptors; gyrfalcons, golden eagles and rough-legged hawks are
often found at higher elevations than peregrines (cf. White and Cade
1971; Roseneau 1974).
Even though cliffs and bluffs may be closely associated with the
seacoast or riverways and may be below the upper elevational limit at
which peregrines will nest, they are not all suitable nesting habitat for
peregrines. Smooth rock faces without surface relief do not afford nest
sites for peregrines, nor do bare, unbroken or unstable dirt faces and
gravel slopes. The height, slope and aspect of a cliff are less important
than its micro-relief and the presence of a variety of potential nest
sites (cf. Cade 1960). Ledges, cavities, potholes and stick nests built
by other species are important features. Another important feature is
the .presence of vegetation on the cliffs and bluffs; it can provide slope
stability, create terraces and platforms, and provide some screening or
cover to the birds.
2.2.1 Arctic Slope
Cade (1960) and White and Cade (1971} discussed a variety of nest
locations and nest sites used by peregrines on the Arctic Slope of Alaska.
In general, nest sites are more frequently found on soft rock or soil
cliffs and bluffs than on hard rock cliffs or outcrops. No nests have
been found above"' 2200 ft asl in this region (White and Cade 1971).
Cliffs and bluffs used by peregrines on the Arctic Slope of Alaska have
j
l
I
~
t
~
;
27
ranged in height from~ 10-300 ft (Cade 1960).
~ ~ ~ _ The bluffs found along the lower Co)ville River and parts of the
Sagavanirktok River are typical of some of the best nesting habitat.
Nest sites chosen by these peregrines vary (cf. Cade 1960). Most nests
are cups scraped in the soil substrate at prominent breaks in the profile
of the cliff or bluff. They are often near the top of the bluffs, or
near the tops of predominant noses left by erosion, are sometimes at the
bases of small or large vertical faces, including the break between cliff
bottom and talus-soil slopes, and are sometimes in unoccupied rough-legged
hawk nests (cf. White and Cade 1971, p. 121 and 124).
Vegetation is usually an important component of the peregrine nest
sites that are located on soft, unstable Arctic Slope river bluffs.
Grasses and willows form terraces or platforms at and near the tops of
these bluffs, at prominent breaks on them, or on otherwise nearly bare
soil and gravel slopes. Many of the nest sites are closely associated
with these vegetated zones (cf. White a~d Cade 1971, p. 112 and 131). A
single willow bush and a clump of grass formed a nest site at Sagwon
Bluffs (NWA Location P-201), a single clump of grass~ 3ft in diameter
on a bare gravel slopeformed another important nest at Franklin Bluffs
tNWA Location P-220), and two similar points of vegetation have provided
the only stable structure to hold rough-legged hawk nests that have been
used subsequently by peregrines at another otherwise nearly unusable
·,barren gravel area along the northern section of Franklin Bluffs (NWA
Location P-223).
2.2.2 Interior Alaska
In the Yukon and Kuskokwim river drainages of interior Alaska, where
rocky cliffs are more prevalent, peregrines are associated with this type
of structure to a greater extent than they are on the Arctic Slope. As a
c \:.
28
~ consequence, many interior Alaska nest sites are more inaccessible than
~.those on the Arctic. Slope, and are better protected from marmnalian
-~ ~~dators, including humans (cf. Cade 1960). No nests have been found
above ~ 2500-2600 ft asl in this large region; the highest nesting
location known is in the Sheenjek River drainage (Roseneau 1974). Cliffs
used by peregrines in the interior have ranged from as low as ~ 30 ft to
more than 300 ft in height. Most cliffs found along the Tanana River and
in the middle section of the Yukon River are typical of excellent nesting
habitat.
An important feature of many interior Alaska nesting cliffs is the
presence of certain kinds of vegetation; terraced zones of Artemesia spp.
are particularly important (Roseneau and P. J. Bente, unpubl. data). Some
grasses and Epilobivm spp. also help create and stabilize ledges or
provide cover. Nest scrapes are commonly made in or behind these vegetated
areas against a protective backstop (e.g.-, firm soil or exposed rock
surface). Other features also occasionally provide nest sites. In a few
instances, unoccupied raven nests are used (P..g., NWA Location P-73b);
golden eagle nests usually provide a more stable substrate than raven
nests and they are also used on occasion, especially in the Porcupine
River drainage -(cf. Curatolo and Ritchie 1979). Within the distributional
range of rough-legged hawks along the lower Yukon River, their stick
nests are also used from time to time {Springer et aZ. 1979b; Roseneau
et al. 1980).
29
2.3 REPRODUCTIVE PHENOLOGY
•..
\ Figure 1 presents the reproductive phenology of peregrines on the
Arctic Slope and in interior Alaska. The figure is based on a compilation
of records from many locations and for many years; these observations are
presented in detail in Appendix 5.2. On the Arctic Slope, the main period
of arrival is ~ 25 April-15 May, of clutch initiation is ~ 15 May-10 June,
of hatching is~ 25 June-15 July, of fledging is ~ 1-20 August, and of
departure is ~ 15 August-10 September. In interior Alaska, the main period
of arrival is~ 2U April-10 May (early extreme of 29 March), of clutch
initiation is ~ 25 April-20 May, of hatching is ~ 10-30 June, of fledging
is~ 15 July-10 August, and of departure is~ 25 August-25 September. The
time required to lay a complete clutch of four eggs is ~ 7 d; ~ 34 d are
required for incubation and~ 40 d for the nestling period.
The tv1o races of peregrines, F. p. twulr•iun and F. r· anatum, in Alaska
exhibit shorter courtship _periods on their nesting grounds than F. p.
anatum birds do at more southern latitudes (Cade 1960). Cade (1960)
suggested that courtship activities of northern peregrines may commence
on the wintering grounds and continue during migration to the nesting
grounds, and recent evidence from wintering areas in South America supports
this suggestion (J. Albuquerque, in prep.; Roseneau, unpubl. data; A. M.
Springer, unpubl. data; C. Thelander, unpubl. data; White, unpubl. data).
Because some courtship activities may begin before peregrines reach Alaska,
·.and because of the relative)y short breeding season, the arrival of pere-
grines in interior and Arctic Slope regions is usually followed closely
-(i.e., within~ 2 wk) by the initiation of eg~laying. Cade (1960)
suggested that the interval between arrival and egg-laying could be
as short as 1 wk; however, recent data from captive falcons and some wild
pairs indicate that at least 13 d are necessary.
There is considerable variation in the reproductive phenology of
FIGURE 1. Reproductive phenology of peregrine falcons nesting in arctic and interior Alaska.,, '.,. 1:, .. , oL
Arctic Slope
Arrival
Clutch Initiation
Incubation
Hatching
Fledging
Departure
Interior Alaska
·" .,J.'
April May June July August September Oct.
1 1 2 2 3 1 1 2 2 3 1 1 2 2 3 1 1 2 2 3 1 1 2 2 3 1 1 2 2 3 1 1
5 0 5 0 5 0 5 0 5 0 5 1 5 0 5 0 5 0 5 0 5 0 5 1 5 0 5 0 5 1 5 0 5 0 5 0 5 0 5
----------
Arri va 1 -----------
Clutch Initiation
Incubation
Hatching
Fledging
Departure
------------
------------------
-------------
------------
---------------------
~""""!
w
0
i
\:
31
,. peregrines in Ala·ska, and the ranges of dates for various acti-vities in
:.Figure 1 are quite broad. The nesting phenology at individual nest sites
~Y-vary from year to year. In 1980, for example, nestling peregrines on
the-Colville River fledged~ 13-15 d earlier than they did in 1979. The
fledging schedule of peregrines on the upper Yukon River was similar in
1978 and 1979, but was 7-9 d earlier in 1980 (Ambrose 1979, pers. comm.).
Generally, in both interior Alaska and the Arctic Slope, nesting
phenologies in 1980 were earlier than average at most locations (Roseneau
e t a Z. 1980) .
Year-to-year variation is probably attributable to a large extent to
year-to-year differences in weather conditions, particularly annual
differences in snowfall and in average spring temperatures,and the
· occurrence ·of storms in May and early June. Year-to-year variations in
nesting phenology appear to be more prevalent on the Arctic Slope than in
interior Alaska. Arctic Slope weather conditions tend to vary more often
through a wider range of extremes. Arctic nesting peregrines tend to have
a narrower range within which portions of the nesting cycle must occur in
order to be successful; however, within those ranges, the peaks of the
phenological events tend to shift more often than the peaks of the same
events in interior Alaska.
The reproductive phenology also varies with location within Alaska
during a given year. Differences in average regional climates are probably
the cause. The average egg-laying, incubation, hatching, nestling and
fledging periods of F. p. tundrius on the Arctic Slope are generally
1-2 wk later than those of F. p. anatwn in interior Alaska. However, the
ranges of dates for these periods are usually greater for F. p. anatum,
so that the late extremes for these periods in interior Alaska are usually
comparable to those for the Arctic Slope. Phenological dates also vary
among locations within both the Arctic Slope and interior Alaska. In 1979,
for example, reproduction in peregrines on the Arctic Slope averaged
~
~
32
; ~ 10-12 d later on the Colville River than on the Sagavanirktok River
·_{Roseneau and Bente 1979; Springer and W. Walker II, unpubl. data}.
~ch variations ·were probably influenced by localized spring weather
conditions {e.g., storms) and local differences in snow accumulation.
The reproductive phenology in a given year will also vary with the
individual birds that nest in a general location. Pairs that occupy a
nest location for the first time are expected to arrive late at the nest
location {Enderson and Kirven 1979). Because there are no definite
records of peregrines having renested in Alaska after a nest failure
{although they may do so on rare occasions), individual variation in
nesting phenology at a general location is primarily a result of individual
variation in the commencement of nesting activity.
33
2.4 FOOD HABITS, HUNTING HABITAT AND HUNTING RANGE
"'~ 2.4.1 Food Habits .. .__ -
Tables 8 and 9 list the prey species that have been taken by
peregrines that nest on the Arctic Slope and in interior Alaska,
respectively. Observations on which these tables are based are presented
in more detail in Appendix 5.3.
In both regions of Alaska, the majority of the prey taken by peregrines
are birds. Although small mammals are regularly taken, they comprise only
"'6-10% by number, and even less by weight of the diet. The most signifi-
cant role played by microtines in the diet of these falcons may, in fact,
be a secondary one; an abundance of microtines can attract important avian
prey species such as jaegers (Cade 1960). Two species of fish have also
been recorded in the diet of peregrines, but these items should be
considered as only incidental and very occasional prey.
Peregrine falcons nesting on the Arctic Slope take slightly more than
half the number of prey species that peregrines nesting in Jnterior Alaska
take (47 vs. 79 species). This difference undoubtedly reflects the lower
number of species in arctic regions. Some important prey species are
commonly taken in both regions of Alaska.
On the Arctic Slope, the groups of birds that are most frequently
taken are shorebirds and passerines. Jaegers, particularly parasitic
-and long-tailed jaegers, are also very important. Although waterfowl
are taken less frequently, they are important food items because of their
larger bioma-ss per individual. In some years ptarmigan also play a
significant role in the diet of these peregrines. Some annual variation
occurs in the kinds of prey taken by peregrines in the Arctic. Variation
34
TABLE 8. Prey" sped e·s of peregrine fa 1 cons nesting on the Arctic Slope,
Alaska.*
Bf~ds (43 species)
arctic 1 oon
Cqnada-goose
pintail
green-winged teal
American wigeon
greater scaup
old squaw
red-breasted merganser
rough-legged hawk
ptarmigan spp.**
semipalmated plover
American golden plover**
black-bellied plover
oar-tailed godwit
lesser yellowlegs
spotted sandpiper**
northern phalarope**
red phalarope**
common snipe**
long-billed dowitcher**
semipalmated sandpiper
pectoral sandpiper
~1amma 1 s ( 3 species)
shrew spp. , Sor•ex spp.
pomarine jaeger
parasitic jaeger**
long-tailed jaeger**
Sabine's gull
arctic tern
short-eared owl
Say • s phoebe
gray jay
American robin
gray-cheeked thrush**
bluethroat
mountain bluebird
arctic warbler
yellow wagtail**
water pipit
northern shrike
yellow warbler
tree sparrow**
white-crowned sparrow
fox sparrow**
Lapland longspur**
arctic ground squirrel, Sparmophilus parryii
singing vole, Nie1•otus gr>egalis
vole spp., Micr>otus spp.
Fish (1 species)
arctic grayling, Thymallus arcticus
* Data are from Bee (1958), Kessel and Cade (1958), Cade (1960), Childs
(1969), White and Cade (1971), Springer ct al. (1979b), Roseneau
(unpubl. data), Roseneau and Bente (unpubl. data).
** A species that occurs commonly as prey of peregrine falcons in this
region.
35
TABLE~-Prey speci-es.o( peregrine falcons nesting in interior Alaska.*
,.
Birds (70 species)
red-nected grebe
horned gl-ebe
brant
pintail**
green-winged teal**
blue-winged teal
northern shoveler**
American wigeon**
canvasback
scaup spp.
common goldeneye
bufflehead
harlequin duck
white-winged seater
surf seater
sharp-shinned hawk
American kestrel
spruce grouse
ruffed grouse
willow ptarmigan
American golden plover
Hudsonian godwit
whimbrel
upland sandpiper**
Mammals (8 species)
dusky shrew, Sorex obscurus
shrew spp., Sorex spp.
greater yellowlegs
lesser yellowlegs**
solitary sandpiper
spotted sandpiper**
northern phalarope
common snipe**
long-billed dowitcher
semipalmated sandpiper
least sandpiper
Baird's sandpiper
pectoral sandpiper
mew gull**
Bonaparte's gull**
Sabine's gull
arctic tern
hawk owl
boreal owl
belted kingfisher
common flicker**
Say's phoebe
olive-sided flycatcher
bank swallow
cliff swallow
snowshoe hare, Lepus americanus
arctic ground squirrel, Spermophilus parryii
brown lenming, LeTTTrlus sibiricus
northern red-backed vole, Clethrionomys rutilis
tundra vole, Microtus oeconomus
singing ,vo 1 e, M_icrotus gregaUs
meadow vole, Microtus pennsylvanicus
vole spp., Microtus spp.
Fish (1 species)
whitefish spp., Coregonus spp.
gray jay**
black-capped chickadee
boreal chickadee
American robin**
varied thrush**
hermit thrush
Swainson's thrush**
gray-cheeked thrush**
wheatear
Townsend's solitaire
ruby-crowned kinglet
Bohemian waxwing**
orange-crowned warbler
yell ow warb 1 er
yellow-rumped warbler
rusty blackbird**
pine grosbeak
redpoll spp.
white-winged crossbill
dark-eyed junco**
tree sparrow
white-crowned sparrow
fox sparrow**
* Data are from Cade (1951, 1960, 1968), Cade et al. (1968), Enderson et al.
(1973), White and Roseneau (1970), Curatolo and Rit~hie (1979), Ritchie (1976),
Hayes (1977), Dotson and Mindell (1979), Springer et al. (1979b), Roseneau and
Springer (unpubl. data), Roseneau and Bente (unpubl. data).
** A species that occurs commonly as prey of peregrines in this region.
•·:
36
i
~ ; among pairs also occurs (i.e., some pairs take more passerines, some
pairs take more waterfowl), probably as a result of both individual prey
~eference and local prey availability.
In interior Alaska, shorebirds and passerines are again taken most
frequently. Waterfowl are also taken frequently (more so than in the
arctic), and they often constitute over 50% by weight of the diet of many
pairs. Woodpeckers also play an important role in the diet of these
peregrines. A high incidence of forest species can often be found in the
diets of interior peregrines; these species become vulnerable as they
cross rivers and open areas. As in the Arctic, some annual variation
probably occurs in the kinds of prey taken (although possibly not to such
a great degree). Variation among pairs also occurs.
The wide range of species taken as prey by both arctjc-nesting and
interior-nesting peregrines reflects their opportunistic feeding habits.
The ability to take such a wide variety and range in size of prey species
can be attributed in part to the marked sexual size dimorphism found in
peregrines. -The smaller male peregrines tend to take smaller prey than
do female peregrines. All other northern raptors, including the gyrfalcon,
exhibit various degrees of sexual size dimorphism; however, it appears to
be most developed in peregrines, and of the large northern raptors, only
peregrines reflect this size dimorphism so clearly in their feeding
habits (White and Cade 1971).
The fact that arctic-nesting and interior-nesting peregrines take
many individuals of a number of species also illustrates their less
. specialized nature. In contrast, the gyrfalcon, which nests in the same
regions, is also quite opportunistic and takes a relatively wide range of
prey species, but they are more dependent than peregrines on a few
species for the bulk of their diet, even in summer (e.g., Cade 1960;
White and Cade 1971; Roseneau 1972).
37
2.4.2 Hunting Habitat
~-In general, the preferred and most-used hunting habitats will depend
on such things as the relative abundance of vulnerable prey in the
various habitats within the falcon's hunting range, the species and sizes
of available prey, the vulnerability of the prey-laden peregrine to
pirating by other raptors, the prevailing winds, and the locations of
the various habitats relative to the nest cliff.
An important concept in dealing with peregrine hunting habitat is
that of a •gulf of air'; it is considered to be the airspace in front of
a nesting cliff over an open area that has comparatively little escape
cover and that is more or less confined by vertical boundaries (e.g., the
air over a river that has a cliff on one side and a forested bank on the
other). Peregrines take most of their prey in the air and do most of their
hunting either from perches on high points of land that overlook the
countryside, or from considerable heights in the air. The hunting strategy
employed by some peregrines is more often dependent on .waiting for
vulnerable prey species to enter their hunting area than it is on the
peregrines travelling -great distances to specifically seek out prey. As
a consequence, the gulf of air in front of the nesting cliffs is
important hunting habitat, particularly if it is associated with large
bodies of water (e.g., oceans, lakes, wide rivers) or open ground with
little vegetative cover (e.g., gravel bars, wide beaches).
Observations of the hunting habitats used by F. p. tundrius indicate
. that they hunt primarily over lakes, marshes and wetlands, and to a lesser
degree over upland tundra. In areas where riparian habitat is extensive,
they also hunt over this habitat. Observations of the hunting habitats
used by P. p. anatum in Alaska indicate that they hunt primarily in the
gulf of air over river valleys and over nearby lake and marsh areas. Their
prey include forest, wetland and riparian species that become vulnerable
38
f
~ ~
.... <
;. when they cross the open expanses of rivers, lakes or wetlands.
_Observation~ of hunting habitat are discussed in more detail in
Appendix 5.4.
2.4.3 Hunting Range
The distance from a nest site that peregrines will travel to hunt
depends largely on the type of prey and prey habitat available, the
initial abundance of the prey and any changes in prey abundance during
the nesting season, and the vulnerability of the prey. The gulf of air
above rivers and lakes in forested areas is often an important feature of
a nest location that may help to determine whether the falcon hunts in the
immediate vicinity of a nest site, or whether it travels to hunt at some
distant location.
Many peregrines appear to hunt relatively short distances from their
nest sites if prey are abundant nearby, or if the local land forms
and the gulf of air between and above these land forms provide sufficient
opportunities to obtain prey that are flying near the nesting area. Many
nest sites along major rivers in forested interior Alaska appear to fall
into this category; prey are either locally concentrated and abundant
(e.g. nearby wetlands or marshes) or are sufficiently abundant overall
in the surrounding river valley (including all habitat types) to provide
a nearly steady supply of exposed prey that pass along or across the
~·river in the vicinity of the nest location and nearby hunting perches
(cf. Cade 1960, p. 165 for a discussion of the importance of rivers to
. peregrines).
However, peregrines can and do travel much longer distances from
their nest sites if changes occur in prey composition or abundance, if
important concentrations of prey occur at a distance rather than nearby,
't
39
or if the gulf of air over coverless terrain near the nest location is
·~insufficiently large. In these instances the birds either travel and ..
hunt in distant areas that have vulnerable prey that are abundant or
concentrated, or they range over larger areas that have vulnerable prey
that are uniformly distributed but less abundant.
In treeless regions (e.g., the Arctic Slope of Alaska), the gulf of
air over exposed terrain in front of the nesting location appears to be
less important. Vast open spaces surround nest sites in all directions,
and much of the area has minimal escape cover for many of the prey
species. Although few data are available to substantiate this hypothesis,
it appears that in such regions (which often have a less diverse and ~~:
more patchily distributed prey base) peregrines may be more readily · .. -_
attracted greater distances to concentrations of prey or may r~nge over . · ·.
a broader area on a more regular basis to obtain their food.
There are few detailed observations of hunting ranges of individual
peregrines, and these observations are quite varied (Appendix 5.5). A
male on the Arctic Slope hunted over a territory that averaged ~ 7 mi
in radius, but that extended 9 mi in one direction but only 2.5 mi in
another direction (White 1974c). Several F. p. anatum birds in interior
Alaska and Canada hunted primarily within 1-3 mi of their nest sites,
but one such bird was recorded to have travelled 30 mi from its nest
cliff (J. Windsor, pers. comm.).
41
~
'iABLE 10.-General types of impacts to perearine falcons and other raptors.*
..
Oi stutbance
Construction and Operation Activities
sudden loud noises (e.g., blasting, gas venting, etc.) can lead
to panic flights and damage to nest contents
noise, human presence, etc. can lead to disruption of daily
activities
Aircraft Passage
sudden appearance and noise can lead to panic flights and damage
to nest contents
Human Presence Near Nests
inadvertent -chance occurrence of people (and dogs) near nests;
people may be unaware of nest, raptors or raptor alarm behavior
deliberate-curious passersby, naturalists, photog·raphers,
researchers can hav~ impacts if safeguards are not taken
Direct Impacts
Intentionally Destructive Acts (as a result of increased public access)
shooting
legal or illegal removal of eggs, young or adults
rolling of rocks off cliff tops
cutting of nest trees
Man-made Structures and Obstructions
raptors may be struck on roads where they may perch or feed
may strike wires, fences, etc.
may be electrocuted on power poles
raptors sometimes attack aircraft, or may accidentally strike aircraft
Environmental Contaminants
deliberate application and accidental release of insecticides,
herbicides, petrochemicals, and toxic industrial materials can
affect raptors and prey by affecting hormones, enzymes, shell
thickness, bird behavior, egg fertility and viabflity, and
survival rates of nestlings, fledglings, immatures and adults
,.
'
42
TABLE 10 (continued}
-...
""'· ..
Di reet_ Impacts
Changes in Prey Availability
decrease in prey abundance or loss of nearby hunting areas may
affect territory size, efficiency of hunting, nest occupancy,
nesting success, condition of adults and young
changes may result from aircraft overflights, construction and
maintenance activities, public access, etc.
Habitat Loss
abandonment of area due to destruction of nest, perch or important
hunting habitat
*Adapted from Nelson and Nelson (1978}.
r --_,..
·-·"·
.
43
~
rABLE 11. Factors that affect the sensitivity of peregrine falcons to
disturbances.* ..
~ . ...
1. Characteristics of the disturbance
a. type of disturbance
b. severity (speed, loudness, suddenness, persistence, etc.)
c. frequency of occurrence
2. Characteristics of the bird
a. the individual (individual differences in response)
b. sex
c. age
d. 'mood' (a factor of recent activities, weather)
e. territorial status (breeder, territorial non-breeder or
non-territorial floater)
f. stage of annual life cycle (winter, migration, courtship,
egg-laying, rearing young, etc.)
g. occurrence of other disturbances or natural stresses at the
same time
h. previous experience with this type of disturbance (habituation
may occur)
3. Topography
a. nearness of disturbance to raptor or nest
b. relative elevations (is nest or raptor above or below the
disturbance? by what distance?)
c. presence of screening features (trees, intervening hill)
d. direction faced by nest relative to sun, wind, disturbance
e. type of nest (exposed ledge, overhung ledge, cave)
f. distance of nest above foot of cliff and below lip of cliff
(i.e., 'security' of nest)
4.· Time of day
5. Weather at time of disturbance
6·. Potential predators nearby
7. Type of prey utilized by the bird (species, location, abundance)
*Based on published and unpublished sources and the experiences of the
authors.
r-.... _
• .
44
a disturbed bird. Consequently, each bird may differ to some degree in
its responses to disturbance, and in fact the same bird may react
-~differently to the same disturbance at different times (Cade 1960;
~
Ke?sel 1978). Herbert and Herbert (1965) noted that •perhaps the most
notable fact about them [peregrines] was that they varied greatly as
individuals. No two individuals nor pairs were the same in behavior. No
two pairs, it would seem, had the same problems. Each eyrie was a world
of its own, distinct in pattern.• Although there is a wide range of
variation in individual responses to disturbances, it seems likely that
the behavioral responses to a particular type of disturbance will follow a
general pattern, although they may differ in the degree of response.
The timing of the disturbance -relative to the time during the bird·~
breeding cycle is very important in determining the effect that it may Jr ·
have on the bird (Table 12). Peregrines are apparently most prone to 11
nesting failure that results from disturbance during their territory-
establishment, courtship, egg-laying, incubation, and early nestling
stages (Kessel 1978). They appear to be more tolerant of the effects of
disturbance (but also often more aggressive) in later stages of the -nesting cycle, particularly when they have large nestlings or fledglings
(Fyfe and Olendorff 1976).
Absence of adults from the nest site as a consequence of disturbance
leaves the eggs or young subject to predation or the effects of weather.
Adults can be away from eggs or small young for short periods (e.g., 5-
10 min) under reasonably good weather conditions without adverse effects
(e.g., Roseneau and Bente 1979). However, there appear to be no observations
that clearly indicate the maximum times for various temperatures that
falcons can safely be off their eggs or small nestlings. The careful
attendance of the nest contents by the parent birds during adverse weather
conditions, and the results of work with artificial incubation of peregrine
eggs and subsequent raising of young both suggest that the eggs and
..
.
'fABLE 12. ,.
....
•
Timi.ng
winter
arrival and
courtship
egg-laying
incubation
nestling
phase
fledgling
phase
night
general
45
Influence of timing of disturbance on the possible effects on
peregrine falcons and other raptors.*
Possible Effects of .Disturbance
raptor may abandon nest, roosting cliff or hunting area
(e.g., gyrfalcon)
migrant raptor may be forced to use alternate nest site
(if available), may remain but refuse to breed or may
abandon nest site
partial clutch may be abandoned and remainder (or full
clutch)laid at alternate nest; breeding effort may cease
or site may be abandoned
eggs may be chilled, overheated, or preyed upon if
parents are kept off nest too long; sudden flushing from
nest may destroy eggs; male may cease incubating; clutch
or site may be abandoned
chilling, overheating, or predation of young may occur
if adults are kept off nest; sudden flushing of parent
may injure or kill nestlings; malnutrition and death may
result from missed feedings; premature flying of nest-
lings from nest may cause injury or death; adults may
abandon nest or site
missed feedin~s may result in malnutrition or death;
fledglings may become lost if disturbed in high winds;
increased chance of injury due to extra moving about;
parents may abandon brood or site
panic flight may occur and birds may become lost or suffer
injury or death
undue expense of energy; increased risk of injury to
alarmed or defending birds.; missed hunting opportunities
*Adapted from Nelson and Nelson (1978) and Mossop et al. (1978).
r . .:-~· -·--· -
.....
46
.;
~ nestlings are susceptible to chilling and overheating (including
·dehydration) from rel~tively brief exposures. Serious consequences could
--~.,i!SUlt from repeated short absences due to human presence or from single
eveots of comparatively long duration, especially during inclement
weather. Even without human disturbance, small and large nestling gyr-
f~lcons have died from hypothermia during periods of especially bad
weather (when it is assumed that the adults could not attend to their
needs adequat"ely; Roseneau et al. 1980; Springer, unpubl. data; Bente,
unpubl. data).
Two factors must be remembered when considering the impacts of
developments on peregrines. Because most of the information is from
observations of very small sample sizes, the observations indicate the ~-
manner in which some birds will respond, but the observations may not be 1'-·-·-• conclusive with respect to the behavior of the species as a whole. Also,~
there may be a bias in the observations toward observations of birds
that successfully survive impacts of various types. Such cases are
lo
clearly evident, whereas in cases where nesting failures occur, the cause ;;
of the fa i 1 ure is frequently not obvious. ,:r
2.5.1.1 Construction and Operation Activities
Many of the activities associated with the construction and operation
of a natural gas pipeline have the potential to disturb peregrine falcons
(either visually or aurally) if the activities occur in the proximity of
nest sites during the nesting period. Construction activities that have
the potential to disturb nesting peregrines include pre-construction
. surveys; transportation of equipment and supplies; constructiorr and
operation of access roads, storage areas, and construction camps; operation
of material sites (including blasting); the various operations associated
with laying the pipe; testing the pipeline; clean-up and revegetation
activities; and construction of support facilities. Operational activities
47
• s
~
• that have the potential to disturb nesting peregrines include operation
~pf compressor stations (a continuous source of noise), servicing of
~pport facilities,and pipeline maintenance. There is probably some
le~way for delaying normal maintenance requirements that might disturb
peregrines; but emergency repairs, such as fixing a line break, would
require immediate action that might prove to be a disturbance to nesting
peregrines.
There appear to be no detailed studies of the effects of heavJ
construction on the behavior of raptors. The available observations
suggest that the responses of peregrines to construction activities are
variable. Blasting and other construction activities associated with the
building of the Palisades Parkway in 1950-56 in New Jersey and New York r~ -~~"
seriously disturbed the peregrines that nested on the adjacent cliffs _ ~
(Herbert and Herbert 1965, 1969). Some abandoned clutches and non-breeding
pairs were fairly clearly due to the effects of construction. Shooting,
poaching, increased hiking and picnicking, and insecticides also affected
the falcons in this area at this time, however, and the specific effects
of construction were difficult to ascertain in most cases. There appeared
to be •some sort of cumulative nervousness• in the falcons, such that
slight disturbances would cause them to abandon their clutches.
Blasting is one construction activity whose effects have the potential
to be felt at some distance from the construction site. Windsor (pers.
comm.} observed a peregrine to 'explode' from its nest ledge in response
to a blast; it bolted from the nest ledge in an extremely rapid and dis-
organized fashion. At some stages of the nesting cycle, this response
:could have damaged eggs or young.
A pair of peregrine falcons in Alaska provide evidence of a short-
term response to blasting without evident long-term effects. The birds
48
..:
~ established a nest site in 1979 about 0.5 mi in line of sight from, and
400ft above a highway (Roseneau and Bente 1979, 1980a). Normal peregrine
arrival dates suggest that. the pair should have arrived at the nest cliff
at" about the time that major reconstruction activities were initiated and
should have begun egg-laying at about the time blasting began (Roseneau
and Bente 1980a; Ambrose, USFWS memorandum to A. R. Crane, 24 July 1979).
In spite of heavy construction activities along the road bed, approximately
weekly detonations of 10,000-16,000 lb of dynamite in the road bed area,
and occasional rock climbing in the immediate vicinity, ~his pair fledged
three young. The nesting phenology of this pair was about 2 wk behind
that of other pairs that nested in interior Alaska in 1979 (Ambrose, pers.
comm.). In 1980 a pair of peregrines (presumably the same pair) returned
to this area and successfully fledged three young (in synchrony with many~-=-
other pairs) from a new nest site that was"' 0.7 mi farther from, and out¥ -:--. ~ -.
of sight of the highway (Roseneau and Bente 1980a). ·It can only be -~
speculated whether the disturbance in 1979 c·aused the delayed nesting
phenology in 1979 or the shift in nesting cliff in 1980. It is not known
if the nest location was first occupied in 1979, but if so, the peregrines
would have been expected to have arrived late (Enderson and Kirven 1979).
The response of the female peregrine to one blast was observed on
20 July 1979, when the nestlings were 18-20 d old (Ambrose, USFWS
memorandum to Crane, 24 July 1979; P. Reynolds, BLM memorandum to J. F.
Santora, 20 July 1979). Sixteen thousand pounds of dynamite were
exploded at a distance of "' 0.5 mi from the nest site (and also from the
··observer) when the adult female was perched on the cliff about 30 ft above
the nest site. (The adult male was not present.) At detonation, the
. female 'flinched away from the source', acted 'as if shot at', and
instantly dove from the cliff in rapid flight. The concussion wave may
have actually knocked the bird from her perch; one observer who was viewing
her through a telescope was knocked aside by the concussion wave and both
I
I
l
I
I
l
[
[
_.
>.: .,
49
i
observers were · showered with small rocks (Ambrose, pers. conm.). The
··"-female flew"' 0.1 mi away from the explosion, and then flew"' 0.2 mi
toward the blast site. In "' 40 sec she returned to her perch and watched
as a large dust cloud formed from the blast; she remained at the perch
for"' 1.5 h. A few minutes after a construction crew had begun to use
large hammers to break up rocks, she moved to another perch "' 100 yd
from the nest site. The adult male appeared "' 12 min later aDd joined
the female; a food exchange then occurred. Approximately 11 min later
food was brought to the nestlings. Apparently most blasts at this
construction site were of a somewhat more controlled nature than the
above blast, although they could still be classed as a major disturbance.
~·--
Mossop et aZ. (1978) suggested that blasting during high winds J ~~
might be less disturbing to raptors because of the loud background noise~
of the wind. Blasting at night could possibly cause abandonment of the
nest location or chilling of the eggs or nestlings. Blasting during
inclement weather could also cause chilling of the eggs or nestlings.
Reactions of peregrine falcons to other loud noises are also variable.
The birds have undoubtedly adapted to intense thunderstorms, which they .
experience at breeding sites (particularly in the Yukon River drainage)
or at wintering areas in some regions of eastern South America (Roseneau,
unpubl. data). Numerous observers have seen peregrines and other raptors
fly instantly in response to the relatively small explosions of firearms
"or firecrackers; the reaction in some instances, however, may also
involve the visual stimulus of first seeing the people and then associating
the loud noise with them. The emergency venting at compressor stations,
which might occur as often as once a year and which may create a sudden
noise in excess of 130 dB(A) at"' 110 yd (Foothills South Yukon 1979),
could possibly produce an effect similar to that of blasting.1
1 Equivalent to "' 100 dB(A) at 2 mi, or a power lawnmower at 1 yd
(Foothills South Yukon 1979).
50
White (1974c) commented on the effects of vehicular traffic along
;1he TAPS haul road on the hunting range of an adult male peregrine. The
' h\~1 road and a camp were~ 2 mi and~ 4 mi, respectively, in line of
sight from the nest site on Franklin Bluffs. The traffic and the noise
associated with it did not appear to influence the male's hunting range;
the bird made a stoop near the camp, and then started to stoop again when
a bird was flushed by a passing vehicle.
The effec~s of construction of the TAPS oil pipeline on nesting
peregrines were not clearly evident. White et al. (1977) concluded that
along the corridor there was, in general, 'no demonstrable negative impact
on raptors attributable to pipeline activity. Any impact that may have
occurred has been masked by the normal dynamics of the populations.'
Although this statement was in general true, specific effects may have
been noticeable for peregrines in one particular area --the Sagavanirktok
River. The productivity of peregrines in this drainage reached its lowest
level during the pipeline construction years of 1975 and 1976; productivity
was also low in 1974, the year the haul road was under construction
(Capodice 1976; Roseneau et al. 1976; Roseneau,unpubl. data). At Sagwon
Bluffs (the closest nests to the construction activities) productivity
declined to zero in 1976. However, in 1977 some productivity did occur
there (K. Whitten, pers. comm.), and by 1979 productivity in this drainage
appeared to be increasing (Roseneau and Bente 1979). Biocide contamination
of these birds must also be considered (see Section 2.5.2.3). The curves
generated by productivity data from the Sagavanirktok River generally
follow those calculated for the undisturbed Colville River (cf. Springer
et al. 1979b); both data sets had low points during~ 1974-76. These
data trends suggest that biocide contamination was responsible, at least
in part, for the decline. The possibility that pipeline-related impacts
were also involved cannot, however, be eliminated.
1
I
I
I
I
J
I
I
(
[
'
51
There is considerable evidence that at least some nesting peregrines
-~re capable of tolerating the activity associated with normal operation
o .. f.a pipeline or highway. Surveys to locate cliff-nesting raptors in the
TAPS corridor between Prudhoe Bay and Delta Junction in 1979 showed that
the numbers and productivities of peregrines that nested in and along the
corridor in 1979 were comparable to those reported by White et al. (1977)
for the period 1970-74 (Roseneau and Bente 1979). Raptor surveys 5-7
years after the construction of parts of the Dempster Highway in the Yukon
Territory showed a dense and apparently saturated population of golden
eagles and several active peregrine nests relatively near the highway.
The pre-construction populations are unknown, as is the status of the
peregrines with regard to biocide contamination and the overall peregrine~--~
decline, but some peregrines were present and producing satisfactorily in! & ....
. ~
1977, 1978 and more recently (Mossop et al. 1978; Mossop, pers. comm.). ~
A pair of peregrines may have up to six alternate nest ledges in
their territo~y that may be up to 4 mi apart (Ratcliffe 1962; Herbert and
Herbert 1965). If a particular pair does have alternate ledges available,
it may be able to avoid some types of disturbance by nesting at an
alternate ledge that is farther removed from the disturbance. For such an
event to occur, however, it is usually necessary that the disturbance be
occurring when the falcons return to the nest cliff in spring.
2.5.1.2 Aircraft Passage
A number of pipeline activities involve the use of aircraft, which
· have the potential to disturb nesting peregrines either visually or
aurally. Aircraft (fixed-wing or helicopter) will probably be required
for support of pre-construction surveys, for support and supply of
construction activities, for aerial re-seeding, for supply of operational
facilities (such as compressor stations), and for surveillance and repairs
of the operational pipeline.
.
'• ,
52
The sudden appearance of an aircraft from behind a nest cliff can
:.c;:ausean incubating or brooding falcon to flush quickly fr-om the nest .. scrape either in fear or in order to attack the plane. White and
Sherrod (1973) cautioned that eggs or nestlings could be damaged as a
result. Peregrines (Olsen and Olsen 1978) and prairie falcons (R. W.
Fyfe, pers. conm.) have been seen to knock nestlings almost from the
nest ledge when suddenly flushed; A peregrine that suddenly left her
nest scrape to attack an eagle that had suddenly appeared near the nest
flipped an egg out of the scrape; fortunately the falcon was able to roll
the undamaged egg back into the scrape (Nelson, unpubl. data). Peregrines
and gyrfalcons have been observed to attack light aircraft in the same
manner (Nelson, unpubl. data; Roseneau, unpubl. data), and eggs have been
observed to fall from a prairie falcon nest in similar circumstances when{ ~-:::-~
;,a.-
an aircraft surprised the bird (Fyfe, pers. comm.). Eggshells that are .t
thin as a result of biocides increase the risk of damage in such circum-
stances (Nelson 1976).
Windsor (1977) observed the effects on nesting peregrines of a
fixed-wing aircraft (Cessna 185) and a helicopter (Bell 206B). Both
types ' of aircraft flew past the nests at speeds of 90-100 mi/h and at
altitudes of 250, 500 and 1000 ft above ground level; they flew 500ft
in front of, and parallel to the nest cliff. The birds were acclimatized
to some degree to aircraft overflights because of their proKimity to an
airport. There was no significant difference in reproductive success
between tested pairs and control pairs. The birds showed the greatest
response to both types of aircraft at altitudes of 250 and 500 ft. Their
~ responses at 1000 ft were considerably less. The birds appeared to
·respond more during the nestling phase than during the incubation phase.
Instead of fleeing, some peregrines fly toward approaching aircraft
when the aircraft is as much as 1 mi from the nest. They may attack the
aircraft, presumably as a form of nest defense. Both helicopters and fixed-
53
••
"' ~ wing aircraft have been attacked very closely by peregrines, but as yet,
-there apparently have been no strikes. A peregrine (which may weigh
~
2--,l :b) could cause a fatal crash of a light fixed-wing aircraft or heli-
copter (Nelson 1979), or in the right circumstances, the crash of a much
larger aircraft.
In contrast to the panic response and the attack ·response is the
very tolerant response of some peregrines to aircraft that approach
relatively slowly and in view of the nest. Raptor biologists, who
purposely fly at low speeds, have often flown past an incubati~g or
brooding peregrine without causing the bird to rise from the nest scrape;
ground speed may be 50 mi/h or less and the aircraft may be as close as
25 yd from the falcon. White and Cade (1975) reported that •many peregri;es·:-._ ......... ·-:~ ..,.. .
could not be flushed from perches or nest sites by either fixed-wing or ~
it helicopter and often left only after we were on the ground and out of the
aircraft•. Peregrines have even continued to feed nestlings while a
helicqpter hovered less than 50 yd away (White and Sherrod 1973). The
abov~/observations suggest that the response of peregrines to aircraft may
be less at low air speeds than at high ones.
Near Inuvik, Northwest Territories, a pair of peregrines that was
apparently habituated to aircraft overflights raised young successfully
at a nest site located ~ 1 mi from an airport serving jet aircraft as
well as light planes (U. Banasch, pers. comm.).
Several raptor species (but not peregrines) have been tested during
the nestling phase in the American Southwest with military jets that
·approached at very high speed from generallyin front of the nest cliffs.
Even with jet fighters passing within ~ 100 yd and level with the nest,
the raptors (prairie falcons and red-tailed hawks at cliff nests,
Cooper•s hawks at tree nests), usually tolerated the intrusions; no
losses in productivity occurred (Ellis 1980). Habituation to low level
54
... · . ...
l jets in training areas probably occurs; the raptors cannot attack such
:.bigh speed aircraft, the aircraft do not linger near the nest, and air-....
cr~ft are regularly seen to fly past without any danger. In another
study of the effects of low-level jet aircraft on nesting raptors, White
(pers. comm.) felt that the birds possibly ignored the intense noise
because the visual stimulus of the aircraft had passed the birds before
the sound had reached them.
Under certain circumstances, however, larger aircraft may pose a
considerably greater danger to nesting peregrines than light aircraft.
In 1974, at Sagwon Bluffs, Alaska, unfavorable weather conditions during
July occasionally caused Lockheed Electras and Fairchild F-27s that were .. -:-~
servicing the TAPS construction camps (not equipped for IFR approaches) !l -
~
to fly the right-of-way between camps in that area at altitudes as low
as 300-500 ft above the tops of the bluffs. On a day immediately after
a period of heavy rain, vibrations from these multi-engine propeller-
driven aircraft (which were readily felt in nearby buildings) appeared to
have triggered 10-15 separate landslides in a short period of time. Land-
slides are relatively common along these inherently unstable bluffs during
the summer, but the number of slides following these flights was unusual.
One slide caused a peregrine nest with three young to slide into a river
(Roseneau, unpubl. data).
2.5.1.3 Human Presence Near Nests
Pipeline construction and operation has the potential to bring
· workers (or others by virtue of increased access) close to peregrine nest
·sites either inadvertently or purposely through curiosity. The occurrence
of humans near peregrine falcon nest sites has been shown to have widely
varying impacts on the birds. There are numerous cases where human
presence near nests has resulted in the birds abandoning nest sites. There
are also numerous cases where peregrines have nested successfully despite
the presence of humans nearby.
..
;
55
Some peregrine falcons are quite aggressive in defending their nest
_sites against humans. Some individuals have flown as far as ~ 1 mi from
··the nest cliff to dive at hikers and protest their presence (Harris and
~ .
Clement 1975; Windsor 1977). Other individuals have been observed to
fly as far as ~ 0.3 mi from their nests to defend against, and even
follow boats (Curatolo and Ambrose 1978; Roseneau and Bente,
unpubl. data). Other individuals do not respond by flushing or calling
unless the 'intruder• is within a few hundred feet of the nest cliff
(Roseneau and Bente, unpubl. data).
Peregrine fa 1 cons have a 1 so be·en observed to abandon nest sites as
a result of nearby human presence. Two pairs that had tolerated people
at distances of~ 100 yd for some time suddenly moved more than 0.3 mi ?' ·--
*" to alternate nest cliffs in response in one case to a visit to the cliff 7
top and in the other case to a visit to the prospective nest ledge duringjt
the week or so before egg-laying began (Nelson 1973, unpubl. data).
These and other observations suggest that peregrines are less tolerant of
activities at the top of their nest cliffs, whereas they may tolerate
people below their cliffs in the sensitive period if the cliff is
sufficiently high (e.g., Herbert and Herbert 1965).
In contrast to the above disturbances, peregrine falcons have
demonstrated an ability in many cases to tolerate the presence of humans
nearby when this presence has not been directly related to their nest
sites. Peregrines have successfully nested within 0.3 mi of major roads,
villages, fish camps and nets, and trapping cabins, and in the proximity
of regular boat traffic (Nethersole-Thompsen and Watson 1974; Cade and
White 1976; Curatolo and Ambrose 1978; Nelson and Nelson 1978; Ambrose
1979; Spr1nger et aZ. 1979a,b; Banasch, pers. comm.; L. Johnston-Beaver,
pers. comm.; Roseneau and Bente, unpubl. data; D. Weir, pers. comm.). At
a nest site on a high cliff~ 0.2 mi from a highway in the Yukon Territory,
peregrines courted, incubated and reared their young with very little
indication of their having noticed pedestrian or vehicular activities
..
-~-
56
(Nelson and Nelson 1978); peregrines also reoccupied the same site in
'"Subsequent years (Mossop, pers. cor.liTl.). Two other peregrine nest ..
s ftes occur above the same highway within "' 0. 2 mi of it (Mossop et aZ.
1978). Peregrines that nested along the Hudson River usually tolerated
people below their nest cliffs that were"' 135 yd high, but often became
alarmed at people on top of the cliffs (Herbert and Herbert 1965). In
Ecuador, a pair of peregrines of the South American subspecies (F. p.
aassini) that nested in a narrow high-walled gorge tolerated non-mechanical
farming activities"' 100 yd below the nest (Springer and Roseneau, unpubl.
data). Peregrines have also reared nestlings on the ledges of tall
·buildings in Montreal, New York, Philadelphia, and Baltimore (Hickey 1969;
Cade and Dague 1979).
..
Several pairs of peregrines on the Yukon River, Alaska, have success~
fully produced young at nest ledges that .were less than 20 yd directly
above a considerable amount of daily boat traffic, and above active fish-
wheels and fishing nets (Springer et aZ. 1979b; Roseneau and Bente,
unpubl. data). In one instance, a pair of peregrines successfully produced
young at a small river-front cliff in a narrow ("' 140 yd wide) slough
(Roseneau and Bente, unpub1. data). The nest site was"' 10 yd above the
water line, ~. 50 yd from an occasionally used fish camp, "' 250 yd from
another, regularly used fish camp, and"' 1.5 mi from a village of several
hundred people that used the slough for primary access to the Yukon River
(i.e., subject to considerable boat traffic and occasional barges from
late May until freeze-up). In another instance, a pair of peregrines
successfully nested "' 30 yd above fish nets and only"' 150 yd around the
corner and upstream from a village of over 100 people. Several pairs of
peregrines that successfully produced young on the Yukon River ignored
diesel-powered freight barges (with super structures nearly as high as
the nest ledges) as the barges passed close by the cliffs (Roseneau and
Bente, unpubl. data).
57
Some habituation to certain forms of disturbance has probably
occurred in connection with nesting attempts near man or his activities.
Several o~ the pairs that nest successfully near human activities on the
lower Yukon River, for example, are not as aggressively defensive or as
vocal as many other pairs; instead they appear to be 'quiet• bi-rds that
are relatively unobtrusive in their daily activities (Roseneau and Bente,
unpubl. data). Peregrines in wilderness areas have shown an ability to
become more tolerant of nearby observers if the observers follow a
standard procedure that is designed to minimize disturbance (Nelson 1973).
The height of a nest above humans, vehicles or other disturbances
appears to be an important factor that may permit falcons to nest in the
presence of disturbance. Height appears to place the birds in a 'superior -= ;·
position' that moderates threat. For instanci, pairs that regularly ~
tolerate daily human activities at fishwheels below them with minimal ~
response, react strongly to the pr.esence of humans on the bluff tops,
even though the humans are considerably farther away. Other factors that
may apparently contribute to successful nesting in the presence of
disturbance are the lack of sudden loud noises nearby, the lack of close
approaches by humans near the nest ledges, some ability to become h~bit
uatedto activities, and, most importantly, the lack of direct, overt
harassment aimed at the falcons. Absence of these conditions does not,
however, imply that a pair will be unable to nest successfully; birds that
have nested successfully in cities, for example, have done so in spite of
the noise levels of the cities.
In addition to inadvertent human presence near nest sites, some
. human activities may be directed specifically at nesting peregrines.
These 'nondestructive• activities may include the curious observations
of passersby, activities of naturalists and photographers, and scientific
studies of the birds. Such activities frequently cause disturbance.
Nelson (1973), White and Sherrod (1973), Fyfe and Olendorff (1976) and
Olsen and Olsen (1978) suggest methods for alleviating the potential
58
;
-"f'-
; impacts of disturbance from scientific studies. Fyfe and Olendorff
... (1976) list the following potential impacts (which apply to all types of
"' di~turbance, not only human presence near nests): desertion of the nest
site; damage to eggs or young by frightened adults; cooling, overheating,
or loss of moisture from eggs; chilling or heat prostration of nestlings;
missed feedings; premature fledging_; and predation.
2.5.2 Direct Impacts
There are several ways in which the construction and operation of a
natural gas pipeline could increase the direct impacts to peregrine
falcons (as opposed to the impacts of disturbance or habitat loss).
Because the proposed gas pipeline route follows already developed and ..
~ actively used transportation corridors, however, it seems doubtful that
i--direct impacts will be much increased over the low levels that probably
already exist. Direct impacts caused by previous oil pipeline construction
were, to our knowledge, minimal and we have no reason to anticipate a
significant change for the worse with a gas pipeline.
2.5.2.1 Intentionally Destructive Acts
These impacts may arise secondarily through the activities of the
general public that are able to visit raptor areas through increased
access (e.g., new roads or airfields), or through the activities of
construction or maintenance workers. White and Cade (1975) emphasize
the need to prevent deliberate harassment or shooting of peregrines in
connection with industrial developments. Shooting is still a significant
cause of peregrine marta 1 ity (Cade and Dague 1977} and poaching of
nestlings for purposes of falconry is also a continuing problem (A.
Breitkreutz, pers. comm.; USFWS, unpubl. rec.). However, we know of no
intentionally destructive acts that occurred during the construction or
operation (to date) of the TAPS.
·.
59
i
"T
2.5.2.2 Man-made Structures and Obstructions
.-.,.,_ .. Some species of raptors are attracted to .roads because of road-killed
prey in some areas, but it seems likely that peregrines (even inexperienced
young birds) would only scavenge from roads on rare occasions. Peregrines
may, however, be attracted to roads in some areas to take advantage of prey
that are flushed by passing vehicles (White 1974c) or that are crossing the
road. They may also be attracted to roads that, when clear of snow early
in the spring, attract large numbers of arriving and resting migrant prey.
(Gyrfa 1 cons, rough-1 egged hawks and short-eared O\t!l s v1ere attracted to such
roads on the Seward Peninsula in 1968 [Roseneau, unpub. data].) Vulnera-
bility of prey and availability of good perch points· along transportation
corridors may be among the reasons that various species of raptors are ; ~:.~.:
often observed in the north to perch near road or pipeline right-of-ways 5
~ throughout the breeding season. Peregrines, gyrfalcons and rough-legged
hawks have often been observed perched along the TAPS haul road or on
above-ground sections of the oil pipeline. Raptors may also be attracted
to roads for other reasons; a merlin, for example, was seen dust bathing
on the Dempster Highway. Peregrines that are attracted to roads may be
subject to collisions or near collisions with vehicles. A juvenile male
peregrine in Washington was observed to fly in a manner that suggested
that it had been caught and thrown by the slipstream of a passing truck;
the bird was stunned but uninjured (C. Anderson, pers. comm.) Raptors
perched along roads are obvious targets that are sometimes shot by
passersby (Ellis et aZ. 1969).
Peregrines may be killed in collisions with aircraft that they have
. struck either inadvertently or as the result of attacking the aircraft
(see Section 2.5.1.2).
Raptors may be injured by flying into guy wires, power lines, wire
fences, etc. Falcons are most likely to do so when they are in pursuit
60
,;
; of prey. F. Gudmundsson (pers. comm.) observed a gyrfalcon that was
.. killed when it flew at high speed into a wire fence in pursuit of a small
PaSSerine that flew through the fence. Enderson and Kirven (1979)
mentioned at least six collisions of peregrines with wires in California
and one in Colorado.
Some configurations of power poles, insulators and wires have led to
peregrines being electrocuted when they perched on power poles (J·. S.
Campbell, pers. comm.; Nelson, unpubl. data).
Camps for construction or maintenance workers often attract numbers
of common ravens because of the availability of garbage that they can
scavenge; the camps may thereby maintain larger populations of ravens in
an area than could otherwise survive. Ravens compete with raptors for
nest sites on cliffs, and this competition from artificially-maintained
ravens could have a serious effect on nesting peregrines (White et al.
1977). Although peregrines can attack and harm ravens (Roseneau, unpubl.
data), ravens are larger than peregrines and establish their nest terri-
tories before peregrines return in spring; it may thus be difficult for
peregrines to dislodge nesting ravens from favored nest sites (cf. White
and Cade 1971).
2.5.2.3 Environmental Contaminants
Peregrine falcon populations in Alaska are contaminated with organo-
chlorine residues such as ODE, and have shown various degrees of egg
shell thinning (Cade et al. 197lb; White et al. 1973; Peakall et al. 1975).
·DOE, a metabolite of DDT, is the major cause of the shell thinning that
has been observed in peregrines (Peakall et al. 1975; Peakall 1976). Eggs
from the two migratory races in Alaska (F. p. tu.ndrius and F. p. anatv.m)
have shown the greatest degree of eggshell thinning, and peregrines nesting
on the Arctic Slope and along the Tanana River appear to be the most
adversely affected. Shell thinning can increase the chance of egg loss by
61
."i accidental breakage during normal incubation behavior {Nelson 1976) . ...
; Other substances, most notably dieldrin and the polychlorinated biphenyl
:. compounds (Pes• s), are known to be more embryotoxic than DOE (Peakall et
~aZ. 1975; Peakall 1976), and can reach levels that can kill embryos out-
~~
right. Levels of dieldrin are very high in eggs from the Arctic Slope,
and appear to be sufficiently high to affect embryonic viability {Springer
et aZ. 1979b; Springer, unpubl. data). Pcs•s have also been linked with
possible behavioral changes, including changes in nest attentiveness
(Peakall et aZ. 1975; Peakall 1976). The presence of these harmful con-
taminants, and the fact that their levels may increase as a result of
changes in agricultural policies in Latin America, where many of the
migratory falcons and their prey winter, confounds the management of
peregrines in areas where they may also be subject to impacts from
developments.
The productivity of peregrines that nested along the Sagavanirktok
River was very poor during the years of road and pipeline construction
in 1974-76 (and probably 1977), in part because whole clutches failed to
hatch {Capodice 1976; Roseneau et aZ. 1976; Whitten, pers. comm.) --a
symptom recognized to be associated with biocide contamination {cf. Cade
and Fyfe 1970; Fyfe et aZ. 1976; Roseneau et aZ. 1976). Eggs collected
at that time for chemical contaminant analyses contained high levels of
DOE and dieldrin, and the shells were very thin (R. C. Stendell, memorandum
to Senior Agent, USFWS Div. of LE, Fairbanks, 4 January 1977; G. V. N.
Powell, memorandum to V. James, USFWS Div. of LE, Fairbanks, 24 January
1978). These contaminants probably caused, at least in part, the lower
productivity that was observed there in 1974-76 (see Section 2.5.1.1),
but the possibility that pipeline-related impacts were also involved
cannot be eliminated. Furthermore, the two possible causes may together
have produced more impact than either cause wouJd have produced separately.
The burning of some substances (e.g., discarded styrofoam or poly~
urethane) can release compounds such as Pcs•s, which can then become
incorporated into local food chains.
62
,.
_, The spilling of a toxic material into a major waterbody during
·pipeline construction or operation could affect large numbers of prey
\pecies (e.g., waterfowl or shorebirds downstream) on which nesting
pa·i:rs of peregrines may be largely or partially dependent.
2.5.2.4 Changes in Prey Availability
The size of peregrine faJcon territories, the distance between
adjacent pairs, and hence the number of nesting pairs in an area are all
dependent on the abundance of available prey. If the numbers of prey
decline, the territories of the falcons enlarge, and the area will have
fewer nesting pairs, or no pairs if the prey base becomes too small
(Ratcliffe 1962, 1969; Newton 1976; Nelson 1979). Ratcliffe described a~ -~
inland peregrine population that declined by 20%and then remained stable.•
The decline was apparently due to very extractive agricultural practices -
that diminished the prey of the falcons. Although such a change could be
the result of natural variation, there is evidence from Europe that
peregrine populations that are unaffected by man usually remain quite
stable with time and do not fluctuate by more than 15% (Newton 1976).
Nelson (1977) studied a coastal peregrine population that declined by
about 75% (the territories enlarged greatly) due to a drastic reduction
in the seabird prey of the falcons.
Any factors that significantly decrease the numbers or the availa-
bility of peregrine prey could reduce the productivity of the falcons in
the short term and cou1d reduce the number of nesting pairs in the long
term. Factors that could possibly cause such effects are 1oss of habitat,
, disturbance, and increased hunting pressure. Unless such changes are
large, however, they may be indistinguishable from natural fluctuations in
prey abundance and prey avai1ability. The food habits of peregrines
indicate that they are relatively well adapted ·to a wide variety of prey
species. Consequently, they are protected to some degree from perturbations
that could affect the numbers or availability of a particular prey species.
63
J ....
;;
; With the exception of large-scale habitat alterations (e.g., draining of
.. large marshes, clearing or burning of large areas), it seems unlikely
'<: •
fh,a.t the numbers and availability of a major portion of the prey base
would be affected by development activities. Arctic Slope peregrines
would probably be more prone than interior birds to impacts that affected
prey availability because the numbe~ of prey species on the Arctic Slope
is smaller and because these prey populations are more variable from
year to year.
Habitat 'improvements' that are sometimes associated with develop-
ments could lead in some cases to increased prey availability.
2.5.3 Habitat Loss
Because peregrine falcons nest on cliffs and bluffs, their nest
sites are unlikely to be physically lost to the pipeline right-of-way or
to support facilities. The perch points that they use for hunting and
for resting are also primarily on cliffs and bluffs. The one support
facility that could cause the loss of a nest site would be the operation
of a materials site that took material from the cliff or bluff. Because
the number of cliffs and bluffs that are suitable for nesting is limited
in any region, the loss of any nesting habitat could limit the number of
pairs that could nest within the region.
Hunting areas of nesting birds could be lost or disrupted through
construction of the pipeline, support facilities and materials sites or
through any drainage problems that might arise from their construction,
·but unless such habitat losses were large, they are unlikely to have
much impact on nesting peregrines (see Section 2.5.2.4).
In a few cases peregrines have accepted artificial nests that have
been constructed specifically for them (Olendorff et al. 1980). This
process might occasionally serve to compensate peregrines for the loss
of a nest site.
..
'.::· ..
-..
"'-..
64
·.
2.6 PROTECTIVE MEASURES
There are .essentially three methods of preventing pipeline activities
from affecting wildlife populations or of reducing the magnitude of these
effects. The location of the pipeline or support facilities can be altered
to avoid sensitive wildlife areas, the timing of pipeline activities can
be altered to avoid sensitive periods, and the methods of conducting
operations can be altered to avoid activities that may affect sensitive
wildlife species.
The information available on the impacts of developments on peregrine
falcons is insufficient to provide assured protection through mitigative
measures. In particular, there is no information available that will
provide the precise distances that are required for spatial and procedural
restrictions. Because of the lack of a basis that will guarantee the
safety of protective measures, the authors who have recommended protective
measures have often urged that a cautious approach be take~ and that a
. ~
safety margin be included in case of error. :1 ,;1 . '
A note of caution should be given concerning the formulation and
publication of protective measures for peregrines and other raptors.
Care should be taken to draw as little attention as possible to the birds
(Haugh and Halperin 1976). Restrictions to protect peregrine nest sites
can draw their existence to the attention of falconers who may take some
birds illegally. Curious people will often investigate wildlife areas
that have been posted to prevent their entry. Restrictions to protect
peregrines may also prove to be inconvenient, and some individuals may act
· illegally to remove the inconvenience. In one case in the Northwest
Territories, a materials site was temporarily closed to protect a nesting
pair of peregrines; however, someone then shot the birds, and the materials
site was thereafter allowed to operate again (Fyfe, pers. comm.). It is
probably best if restrictions to protect peregrines are simply labelled as
restrictions for 'sensitive wildlife'.
65
2.6.1 Spatial Restrictions
~ ~T: The d1stance from a peregrine falcon nest site at which operations
will not disturb the birds is poorly documented. There are consequently
a number of different distances from nest sites that have been proposed
as radii within which various activities should not be penmitted. Table
13 summarizes the various radii of avoidance that have been proposed in
the north for various activities.
Some of the distances by which nest sites should be avoided have
been proposed as year-round restrictions; other restrictions have been
proposed with specific time periods during which activities would be
prohibited within these avoidance radii~ This difference is particularly
important with respect to pipeline alignment. Construction could be
conducted closer to a peregrine nest site than the recommended radius of
avoidance if it were done during the non-sensitive period; however, when
the pipeline was operational, there would then be a need for surveillance
and possibly for emergency repairs during the sensitive period. Such a
situation does not arise with year-round restrictions.
The most commonly recommended distances to avoid peregrine nest sites
have been 2 mi and 1 mi. Some of the recommendations have called for a
2-mi buffer zone as the ideal distance to be implemented wherever
possible, with the further stipulation that a 1-mi distance was the
.minimum distance of avoidance that could be allowed (e.g., Hayes and
Mossop 1978). Generally, a 1-mi distance of avoidance is the minimum
such distance that has been proposed for most activities in recent years.
-Recommended distances of avoidance have often been greater for support
facilities that would involve permanent or frequent human use (e.g.,
compressor stations, access roads) and for sudden disturbing activities
(e.g., blasting} than they have been for other pipeline construction
activities.
lt'\IJL[ 13. l<econ1nended minimum distances for ')round activities to protect pere')rine fillcon nest sites in northern areas.
.~~ ... :.,, --------------------------------------------~--------~·~
Distance
of
Timing
ot
Type
of
Avoidance Avoiddnce Activiiy Location· Restriction Restriction
_(11~) -· ·-------------------. --·-·-----·----...• -----.. ------------------------·----· -·----·
15 general
5 15 April-highway
31 August (Mackenzie Valley)
5 gas pipeline
(Alaska ftighway)
5 gas pipeline
(Alaska Highway)
2.5 !)as pipeline
(Arctic Gas)
2.5 I April-highway
15 Au!]ust construction
2 I 1-la•·ch-high1·1ay
15 September (~lackenzie Valley)
2 !larch-gas pipeline
September (Arctic Gas)
2 gas pipeline
(Arctic Gas)
2a gas pipeline
(Arctic G.1s)
2 geological
field camps
2 gas pipeline
(Alaska lligh~1ay)
Alaska
N.W.T.
Yukon
Yukon
Yukon
N. ~1. T.
Yukon ·
ll.C.
N.W.T.
Yukon
tl.\-1. T.
Yukon
fUJ.T.
Yukon
tl.W. T.
tl.W. T.
Yukon
no land use practices and/or rec01nnendation
developments that could
detrimentally or significantly
alter or eliminate habitat or
food sources in major feeding
areas
no intensive, noisy or off right-recommendation
of-way activities
no blasting without special recommendation
approval
controlled blasting techniques recommendation
no pipeline or compressor
stations ·
no cons true t ion act i ·v ity
no construction
no ground activities
no roads or facilities without
specific approval
recou1nenda t ion
recontnenda t ion
recoumenda t ion
recommendation
recon1nenda t ion
no access to area without permitb proposed
requirement
should be beyond 2 mi from cliff government
face guideline
minimum distance pipeline to nest rec01nnendation
I
I I
' I!!
Reference
Alaska Peregrine Falcon
Recovery Team (1979)
Fyfe and Prescott (1973)
Alaska Highway Pipeline
Panel (1978)
Windsor (1979)
Gunn l11 Berger ( 1975)
lull (1979)
Fyfe and Prescott (1973)
Jacobson (1974)
Jacobson ( 1974)
Berger (1977)
Goodman ( 1977)
Mossop and Milligan
(1971)
0'1
0'1
TABLE 13. (continued)
' r'!, '·~ h .. , "·"'' Distance Timing Type ,.
of of of
Avoidance Avoidance Activity Location Restriction Restriction Reference
mi
2 gas pipeline Yukon will maintain minimum distance conmi tment by National Energy Board
(Alaska High1·1ay) whe•·e possible proponent (1977)
...• 2 1 l·larch-gas pipeline Yukon no construction, etc. without' recommendation Alaska Highway Pipeline
31 August (Alaska Highway) specific approval Panel (1978)
2 highway Yukon no camps, roads, quarries recomnaenda t ion Blood and Chutter ( 1978)
construction
2 1 May-highway Yukon no blasting recommendation Blood and Chutter (1978)
31 July construction
"' 2 15 April-gas pipeline Yukon no construction or related draft Northern Pipeline Agency
31 August (Alaska Highway) ac tivi ties requirement (1978)
any activities within radius
subject to site-specific
limitations
2 1 May-gas pipeline Yukon secondary zone recommenda t i·on Hayes and Hossop (1978)
31 July (Dempster Lateral) no construction activities 0'1
'-I
~1herever possible
2 oil pipeline Alaska buffer zone government Oldendorff and Zeedyck
(.Trans-A 1 askan) requirement (1978)
2 gas pipeline Yukon will consult agency for blasting commHment by Foothills South Yukon
(Alaska High1~ay) wi 11 monitor nests prior to and proponent (1979)
during construction
'· 2 oil pipeline Yukon wi 11 maintain distance from nest coannitment by Foothills Oil (1979)
(Alaska High1~ay) sites wherever possible proponent
2 1 May-gas pipeline Yukon no construction ~1herever possible recommendation Windsor (1979)
5 July (Alaska Highway) if construction must occur within
1-2 mi no activities during this
period
''• 2 during general Yukon given this disturbance-free suggestion. Mossop at al. (1978)
breeding radius, raptors can be expected
to t.rccd ~uccessfu1ly
1.2 durin9 general Yukon t~rc a ~1hich should remain suggestion l·lossop (:£ al. (197B)
breedinq unviolated
' l:~ ~ l • :~: ~ •
TABLE 13. (continued)
--------------------------------------------------~ ..... "·
Distance
of
Avoidance
Timing
of
Avoidance Activity Location Restriction
Type
of
Restriction
)i .~ j ,
Refereiice
~~-----------------------------------------------------------------------------------------------------------
1.2
0.5
0.5
15 April-
31 August
l f·lay-
15 r,ugus t
gas pipeline
(Alaska High1·1ay)
gas pipeline
(Arctic Gas)
15 April-human activity
15 September
l May-
31 July
15 April-
31 August
l 1\pril-
31 July
15 April-
1 September
15 1\pril-
30 August
geological
field camps
hiking trails
gas pipeline
(Uempster Lateral)
gas pipeline
(Northwest Alaskan)
oil and gas
drilling
human activities
general
( Sag~10n !ll uffs)
gas pipeline
(Alaska High1'1ay)
ga!; pipeline
(NortlMest Alaskan)
!JilS pipeline
(Alaska Hi(Jhway}
general
general
Yukon
Alaska
Alaska
N.W.T.
N.W. T.
Yukon
Alaska
no construction
no blasting, heavy equipment .or
access roads
no human activity
should be beyond l mi from
backside of uplift areas
no trails if visible from eyrie
no construction activities
requirement
reco111nenda t ion
recommendation
government
guideline
recommendation
reconvnenda t ion
safe distance for most activities discussion
Alaska no drilling government
requirement Colville R.
Alaska
Alaska
Yukon
Alaska
Yukon
general
U.S.A.
Alaska
no human activities unless
specifically authorized
no fire suppression
will attempt to schedule
construction outside period
no hun~n activities unless
·specifically authorized
if construction must occur within
l mi no activities during this
period
no permanent Iauman occupation or
disruptive land use
should ~e declared critical
h.Jhi tilt
recommendation
proposed
regulation
commitment by
proponent
reco111nenda t ion
reco111ncnda t ion
recommendation
reCOIIMIICIIda t i 011
Northern Pipeline Agency
( 1979)
Renewable Resources
Consulting Services
Ltd. (1973}
Ritchie (1976)
Goodman ( 1977}
Windsor (1977)
Hayes and Mossop (1978)
Kessel ( 1978)
Olendorff and Zeedyck
( 1978)
Alaska Peregrine Falcon
Recovery Team (1979)
Capodice (1979)
Foothills South Yukon
( 1979)
Roseneau (l979)d
Windsor (1979)
Cade (1974)
White and Cdde (1975)
......
TABLE 13. (continued)
-------....-----.---------------------------------------TT'--";..:..~ \'! 'T~
Distance
of
Avoidanc1·
ni
0.5
0.5
0.2
Timing
of
Avoidance Activity
general
hiking trails
1,1as pipeline
(Arctic Gas)
recreation
a Or of size required to protect nest site.
Location
Alaska
N.W.T.
Alaska
Alaska
Restriction
no permanent structures
no trails
no human presence
no recreational activity on any
nesting cliff
b Permit would require biological evidence that raptors would not be jeopardized.
c Tentative .
d As amended in letter to Fluor Northwest, Inc., 28 September 1979.
Type
of
Restriction
reco11111endation
reco11111endation
reco11111endation
reco11111endation
",n·;
Reference
Haugh and Halperin (1976)
Windsor ( 1977)
Renewable Resources
Consultin~ Services
Ltd. (1973)
Haugh and Halperin (1976)
70
·.
2.6.2 Temporal Restrictions
..
~ ~ The starting dates recommended for imposing restrictions near
per~grine nest sites in Alaska, Yukon and the Northwest Territories have
ranged from 1 March to 15 May; the dates recommended for terminating
these restrictions have ranged from 31 July to 15 September (Tables 13
and 14). Some of these time restrictions, particularly those in March,
are probably a result of blanket recommendations for all raptors (including
the early-nesting gyrfalcon}, rather than specific recommendations for
peregrine falcons. The most sensitive times for nesting peregrine falcons
are the early part of the nesting season (return to the nest site,
courtship, egg-laying, incubation, and early nestling stage; Kessel 1978}.
A conservative concensus of the various temporal restrictions that have
been proposed would provide for restrictions during the period 15 April-
31 August.
2.6.3 Procedural Restrictions
In some cases where it may be necessary to conduct activities that
contravene both spatial and temporal restrictions, restrictions have been
recommended for. the procedures of conducting these acti viti es. The
majority of such procedural restrictions have been with regard to aircraft
flights past nest sites. Such flights would be.needed during planning,
construction and operation of the pipeline. Table 14 lists the various
procedural restrictions that have been proposed for aircraft flights past
peregrine nest sites.
The minimum altitude of an aircraft above a peregrine falcon nest
site at which the nesting birds are not disturbed is poorly known.
Consequently, there is considerable variability in the minimum altitudes
that have been recommended in order to prevent disturbance. The most
commonly recommended minimum altitudes for aircraft overflights over
peregrine nest sites have been 2,000, 1,500 and 1,000 ft.
-.
TAOLE 14. Recommended minimum distances for aircraft activities to protect peregrine falcon nest sites in northern areas.
. ... ~ .. :.,., '• ~-...
------~--------------------~~------------------------------------------------------------------------~~'·-----... Minimum
Altitude
(ft)il
3300
3000
2700
2500
2000
'\. 2000
2000
2000
1500
1500
1500
1!JOO
1500
1500
Distance
of
Avoidance
(mi)
2
2.5
Timing
of
Avoidance
nesting
period
Activity
gas pipeline
(Alaska High1~ay)
gas pipeline
(Arctic Gas)
location
Yukon
Restriction
height above lowest suspected
elevation ~ithin 2 mi
Yukon maintain altitude near sites
N.W.T. no landings or takeoffs
Type
of
Restriction
Reference
recommendation Windsor (1979).
proposed
requirement
Berger (1977)
gas pipeline Yukon height above nearest ground level recommendation Windsor (1g79)
15 May -
31 August
1 March -
1 Sept.
(Alaska Highway)
gas pipeline
(Arctic Gas)
~as pipeline
(Arctic Gas)
Yukon only essential flights within recommendation LGL ltd. (1975)
N.W.T. radius
Yukon minimum altitude above ground recommendation Jacobson (1974)
N.W.T. level
airport near
nest sites
N.W.T. reroute low flying aircraft recommendation Windsor (1977)
1 f1a rch-
31 August
1 May -
31 July
gas pipeline
(Alaska Highway)
gas pipeline
(Dempster
Latera 1)
other aircraft maintain altitude
Yukon minimum altitude
Yukon ·rr-cannot avoid 1 mi radius,
maintain minimum altitude
wherever aud whenever safe
geological N.W.T. nun~rous gu1delines
(see Appendix 5.6) operations
1 April gas pipeline Alaska minimum altitude
30 August (North~1est Alaskan)
15 April -
1 Sept.
15 Ap.-i l -
15 August
15 April -
1 Sept.
general Alaska minimum altitude
general Ala~ka minimum altitude
(Sag~·on Bluffs) curtai I use of nearby airport
gas pipeline Alaska minimum altitude
(Northwc•; t
Alaskan)
qas pipeline Yukon
(Alaska lliqhway)
hei9ht abo•. ·! nest level far
sur-veill. .. ·~c of line
if rHH,JCruu!> ''"~ ls llh.JkC rout ina
complr~x. : 'flaS'i nests ~Y
miu imum o : 0.6 mi 'I) , . . ' '
recommendation Alaska Highway Pipeline
Panel (1978)
recommendation Hayes and Hossop (1978)
government Goodman (1977)
guide I ines
recommendation Kessel (1978)
reconPEndation Alaska Peregrine Falcon
Recovery Team (1979)
proposed Capodice (1979)
regulation
recommendation Roseneau (1979)b
recommendation Windsor (1979)
....... -
TABLE 14 (continued)
mnimum Distance Timing
A lt i tulle of of Activity Location Restriction
( ft)a Avoidance Avoidance
(mi)
1000 15 April -gas pipeline N.W. T. minimum altitude
15 Sept. (Mackenzie Valley)
1000 nesting oil pipeline Alaska minimum altitude
season (Trans-Alaskan)
1000 1 general Alaska minimum altitude and distancec
(aeronautical chart)
1000 nesting oil pipeline Alaska minimum altitude
season (Trans-Alaskan)
15 ~lay -oil pipeline Alaska no flights within 1 mi of nests
10 August (Trans-Alaskan)
(Sagavanirktok R.)
0.6 -gas pipeline
(Alaska Highway)
. Yukon no flights within 0.6 mi of nests
~as pipeline Alaska avoid use of aircraft in
Arctic Gas) immediate vicinity of nests
no helicopter landings near nests
a Metric altitudes have been converted and rounded to the nearest 100 ft.
b As amended in letter to Fluor llorthwest, Inc., 28 September 1979 .
.~· j
·~~ .: . ., .. ~ f
Type I•
of Reference
Restriction
co11111itment by National Energy Board
proponent (1977)
government Olendorff and Kochert
requirement ( 1977)
government Feder:1l Aviation
recommendation Admi nis tra ti on ( 1978)
government Olendorff and Zeedyck
requirement ( 1978)
recommendation White et aZ. (1977)
recommendation Schmidt (1977)
recommendation Renewable Resources
Consulting Services
Ltd. ( 1973) .
c Although the reconmendation is that minimum altitude and distance both he maintained, it undoubtedly means that one or the other
should be maintained.
.),J ·.. ·~·. '
.,
........
N
73
Minimum altitudes have usually been expressed in terms of the altitude
··~bove ground level. For a nest site on a cliff, however, these recoiTITienda-..
tto~s have frequently not specified whether the altitude referred to is the
height above the cliff top, the nest site, or the land at the base of the
cliff. Presumably, in order to protect the birds at the nest site, t~e
altitude should refer to the height·above either the cliff top or the nest
ledge.
Recommendations concerning m1n1mum altitudes for pipeline aircraft are
in practice often difficult to implenent. The pipeline airstrip and many
of the smaller pipeline aircraft are not equipped for IFR (instrument flight
rules) flights. Because of the relatively short distances between camps .
~--(e.g. ~50 mi) and the lack of IFR facilities, those aircraft that are ~~
equipped for IFR flights generally fly VFR (visual flight rules) at fairly
low altitudes between these airfields. Furthermore, low cloud ceilings or
fog are particularly frequent on the Arctic Slope of Alaska durinq the
spring, summer and fall, and it is common to have acceptable VFR conditions
beneath a low cloud base. Because of such conditions, restrictions con-
cerning minimum flight altitudes over important wildlife areas have usually
contained the phrase 'whenever possible'. Some recommendations (e.g.,
APFRT 1979) have suggested that a minimum distance of 1 mi from nest sites
be maintained whenever the minimum altitude over the nest sites could not
. be maintained.
-:.r-
0
74
2.7 PROPOSED PROTECTIVE MEASURES FOR NWA PIPELINE
-.. 2. 7.1 USFWS Recommended Protective Measures ~ ..
2.7.1.1 General Restrictions
Table 15 lists the September 1980 USFWS peregrine falcon protection
measures recommended for the Northwest Alaskan pipeline.
Restrictions 1, 2 and 3 concerning aircraft overflights and construc-
tion activities apply for the period from 15 April to 31 August. This
timing restriction generally agrees with most of the timing restrictions
that have been recommended for various developments in the north. In
particular, it agrees with the recommendation of the Alaska Peregrine
Falcon Recovery Team (AFPRT 1979), which carefully reviewed the nesting
phenology of peregrines in interio~ and arctic Alaska before making its
final recommendation. Peregrines rarely return to interior Alaska before
mid-April (Section 2.3); some arrive on the Arctic Slope by late April.
The final date of 31 August provides protection during the fledgling
period for peregrines whose nesting may be delayed for reasons such as
inclement weather (particularly on the Arctic Slope).
Restriction 1 prohibits aircraft flights during the sensitive period
(15 April-31 August) below an altitude of 1500 ft above nest levels and
~·
.. within 1 mi of peregrine nest sites. In this case no provision is made for
! any exceptions to this rule. This restriction falls roughly in the middle
of the various recommendations that have been proposed for aircraft over-
flights (Table 14). In particular, it is in agreement with the recommen-
dations of the APFRT (1979), with the exception of a one day difference in
the final date for which the restriction would apply, and the fact that
the recovery team would permit exceptions to the rule if specifically
authorized. We are in general agreement with restriction 1, but would
also permit specifically authorized exceptions on a case-by-case basis,
75
i
.:>-
.c
~ ;TABLE 15. September 1980 USHIS recorrrnendsd restrictions for protection of
...
<:. ..
peregrine falcons.*
A. Restrictions
1. Aircraft maintain 1500 feet altitude {above nest level) within
1 mile horizontal distance of nest sites {eyries) from April 15
through August 31.
2. Use of explosives and other activities or facilities, having
noise levels sufficiently high to disturb nesting efforts, is
prohibited within 2 miles of nest sites from April 15 through
August 31, unless specifically authorized.
3.
4.
All ground level activity is prohibited within 1 mile of nest
sites from April 15 through August 31 {except on the Haul Road -
Prudhoe to Livengood), unless specifically authorized.
Additional permanent facilities and long term habitat alterations
{such as material sites, roads, and airstrips) are prohibited
within 1 mile of nest sites, unless specifically authorized.
B. Application of Restrictions to Nest Sites Likely to be Occupied.
Our analysis of nesting records for peregrine falcons in the vicinity of
the proposed project indicates that the following nest sites have a
reasonable probability of occupancy in the near future. Therefore, all
of the above restrictions should apply to these nest sites and to others
where peregrine falcons are subsequently found to be present. Should
any of these nest sites not be occupied by June 1, they may, with U.S.
Fish and Wildlife Service concurrence, be considered inactive and subject
only to restriction {4) for the remainder of that nesting season.
P-21
P-29b
P-34b
P-42a
P-47a
P-50
P-86
Northwest Eyrie No•s.
P-95a
P-194
P-205
P-211
P-216
P-220
P-223
C. Application of Restrictions to Nest Sites Not Likely to be Occ~pied.
The following nest sites have a low probability of occupancy in the
•• $
-···~
TABLE 15 (continued)
76
't. ..
immediate future but will be essential in providing nesting habitat as
peregrine falcon populations recover. Consequently, until these sites
are again used by peregrine falcons, only Restriction (4) should apply.
Northwest Eyrie No's.
P-16a
P-19
P-25
P-38a
P-48a
P-60d
P-61
P-79
P-183a
*D. Money, USFWS, pers. comm., September 1980. --
"'
::
77
Restriction 2 concerns the use of explosives and other activities
or facilities that have noise levels that are sufficiently high to
·~isturb peregrine nesting efforts. The restriction prohibits such
"t
activities within 2 mi of nest sites during the sensitive period (15 April-
31 August). Provision is made for exceptions to this rule if specific
authorization is granted. This restriction is in agreement with many of
the recommendations that have been proposed (Table 13), but it is more
conservative than ma·ny other recommendations, including those of the
APFRT (1979). It seems in keeping with some recommendations concerning
activities near nest locations that call for an outer buffer zone in
which activities can be authorized after review and an inner 1 mi pro-
hibited zone (Hayes and Mossop 1978; Banasch, pers. comm.). Because this
restriction is directed at those particularly noisy activities that waul~
disturb nesting peregrines, we are in general agreement with it, but -~
believe it should be clarified. The restriction does not adeauately lisJI·.~
the activities that would be prohibited under this restriction (which was
partially done in the Oct. 1979 USFWS recoll1Tlended restrictions). In
particular, it is not clear whether compressor stations would be allowed
within 2 mi of nest sites. Presumably, discussion with USFWS will be
required to determine which specific activities are prohibited in the zone
between 1 mi and 2 mi from peregrine nest sites.
Restriction 3 prohibits all ground level activity within 1 mi of
nest sites during the sensitive period (15 April-31 Auaust). Provision
is again made for exceptions to this rule if specific authorization is
granted. Again this restriction is more liberal than many of the
recommendations that ha~e been proposed (Table 13), but is in keeoing
with many recommendations, including those of the APFRT (1979). One
exception to this restriction is specifically granted; ground activities
are permitted within 1 mi of nest sites on the Haul Road between Livengood
and Prudhoe. As we interpret this restriction, it pe·rmits only hauling
of goods (or any other activity) on the Haul Road, as opposed to any
activities beside the Haul Road.
.,
78
Restriction 4 prohibits permanent facilities and lonq-term habitat
.alterations such as materials ·sites, roads and airstrips within 1 mi of
·~st sites. (The meaning of the word 'additional' in the restriction is
not clear.) Provision is again made for exceptions to this rule if
specific authorization is granted. The prohibition of such activities is
year-round, rather than just for the sensitive period. Although this
restriction is more liberal than a number of the various soatial recommen-
dations that have been proposed (Table 13), it is in keeping with many of
these recommendations. It is more restrictive than the recommendations of
the APFRT (1979), which can be interpreted as permitting permanent .
facilities or long-term habitat alterations, provided that there is no
human activity at these areas during the sensitive period (15 April-31
August) unless specifically authorized. We feel that Restriction 4 is
justifiable and that it should generally provide adequate protection to
peregrine nest sftes.
Restriction 4 may be interpreted as prohibiting the pipeline right-
of-way from passing within 1 mi of peregrine nest sites. This interpre-
tation is arrived at by considering the pipeline per se as a permanent
facility. In pipeline parlance, however, the pipeline _is often referred
to separately from the support facilities, which are needed for
construction and operation of the pipeline; this parlance might permit an
interpretation of restriction 4 whereby the pipeline ri~ht-of-way was
permitted within 1 mi of nest sites because it was not considered a
'facility'. NWA should discuss with USFWS whether the pipeline right-of-
way is prohibited from passing within 1 mi of nest sites. In our discussion
we have assumed that restriction 4 includes "the pipeline right-of-way.
If the right-of-way is built within 1 mi of peregrine nest sites,
either through the second interpretation or through specific authorization,
we foresee two potential problems. Restriction 1 would limit surveillance
aircraft to a minimum altitude of 1500 ft above nest sites within 1 mi of
79
..
the sites {unless exemption by specific authorization is added
:~o restriction 1). NWA would have to determine whether they can in fact
~ mon)tor the line from such an altitude near nest sites. In particular,
und.er conditions of low ceiling (quite conmon on the Arctic Slope), they
would have to remain 1 mi from nest sites, which would probably preclude
their monitoring that portion of the line from the air. Restriction 3
would preclude any maintenance activities, including emergency repairs,
within 1 mi of peregrine nest sites during the sensitive period, unless
specific authorization to do so were granted.
The Sep. 1980 regulations provide two lists of nest sites. The lists
are of sites considered •likely• to be occupied and of sites considered
•not likely• to be occupied. For nest sites that are •likely• to be
occupied, and for any new sites at which peregines are found (including
finding them at any sites consi.dered •not likely• to be occupied), all
four of the restrictions · would apply. Sites that are considered •not
if ·.
.
-.
likely• to be occupied are still considered to be essential nest sites
"J
in order to protect them from permanen~!encroachment; this would permit
the site to be used in future years as · peregrine populations recover.
Any such sites that are occupied would be transferred to the •likely• to
be occupied category, and would be subject to all of the four restrictions.
We concur with this 9ivision of nest sites into the two categories,
because it permits much less strinqent restrictions at ·those peregrine
nest locations that have a low probability of occupancy at this time,
but sti 11 pro vi des 1 ong-tenn protection for these sites. Our specific
comments as to which sites are in which list are presented in Section
2.7.1.2.
The Sep. 1980 regulations provide a relaxation of restrictions 1, 2
and 3 after 1 June for nest sites that are not occupied during that year.
The term • occupied• is not defined. ~~e have interpreted the term to apply
to any nest sites for which either a pair of peregrine falcons or a single
80
~; bird demonstrates an affinity at any time during the nesting season
)15 April-31 August). Implementation of this provision to relax
lestrictions 1, 2 and 3 will require that a thorough program to monitor
th.e nest sites be conducted during construction years in order to determine
which sites are active. The date of 1 June appears to be a safe date; it
seems highly unlikely that peregrines would first occupy a nest cliff after
this date: Restriction 4, which applies to permanent facilities, would not
be affected by this relaxation provision. It is the only restriction that
could not be reimplemented if an unoccupied nest were to be occupied at
some future date.
Our 9efinition· of 'occupied' nest is derived from the definition in
the Oct. 1979 USFWS recommended restrictions (Table 16). The definition ~-·
includes considering a nest site to be occupied if it is occupied by a p--~
single bird. Although a single individual does not represent a breeding ]f~c
unit that can produce young, single individuals that occupy cliffs attempt
to nest; they make scra~pes, perform courtship flights and in the case of
females, occasionally rj[ay one or two infertile eggs. Some observations
suggest that subadult 'birds may establish themselves at an available cliff
for one or more breeding seasons prior to acquiring a mate and breeding.
Similarly, the reoccupation of former nest cliffs during a population
recovery may include single adults that occupy a location for one or more
years before they successfully attract a mate. Occupancy of cliffs by
single birds may thus play an important role in the recruitment process in
a given area.
The Sep. 1980 USFWS recommended restrictions should be considered in
conjunction with the Oct. 1979 USFWS recommended restrictions (Table 16).
Both sets of restrictions are intended to apply to the NWA pipeline
(D. Benfield, USFWS, pers. comm.). Sep. 1980 restrictions 1, 2 and 3 are
essentially modified from Oct. 1979 restriction I. .Restriction 4 of Sep.
1980 is new. The more recent set of restrictions (Sep. 1980) deal only with
81
TABLE 16. October 1979 USFHS recommended terms and conditions for protection
of the endangered peregrine falcon in Alaska.*
-·-~.
"-
I. -=-Recorrmended Protection Standards for Nesting Activities:
The following standards apply to all active peregrine falcon
nesting sites during the nesting season (April 15-August 31}.
All known nesting sites shall be considered active (whether or not
birds are present} between April 15 and June 1. Nesting sites not
having a peregrine falcon present by June 1 will be considered
inactive and, therefore, not subject to these restrictions.
A. Within one (1} mile lateral distance of peregrine falcon
nesting sites the following are prohibited unless specifically
authorized:
1. Aircraft flying lower than 1500 feet above nest level.
2. All other human activities.
B. Within two (2} miles of peregrine falcon nesting sites the
following are prohibited unless specifically authorized:
1. Major construction or other noise producing activities
such as mining, blasting, and operation of aggregate
grinders.
II. Recommended Protection Standards for Hunting Habitat:
The following standards apply to all peregrine falcon nesting
sites (active and historic} and at all times.
A. Within fifteen (15} miles of nesting sites the following
are prohibited unless specifically authorized:
1. Ground surface disturbance on a large scale which
could detrimentally and significantly alter peregrine
falcon prey habitat.
2. The use of pesticides or other environmental pollutants
which could be detrimental to the peregrine falcon or
its food source.
III. It is understood that the above standards may not be appropriate
in all situations and that a qualified biologist should review
specific cases and determine appropriate protective measures. It
is further understood that protection standards for hunting, as
listed above, do not preclude all development within a fifteen
(15) mile radius of a nesting site; rather, ·they are intended to
preclude major changes such as draining of marshes, or other
.extensive habitat alteration.
--•
82
TABLE 16. {continued)
-~
I~~ Yeregrine falcon surveys, studies and all variances to the above
··standards require prior approval of the Alaska Area Director,
U.S. Fish and Wildlife Service or his designated representative.
V. Definition:
A. Nesting Site -Any cliff, bluff, tree or other structure
which could reasonably be used as an eyrie by peregrine
falcons and for which a pair or single bird demonstrates, or
has in the past demonstrated, an affinity.
B. Active Nesting Site -All known peregrine falcon nesting
sites during the period April 15 -June 1 and those nesting
sites for which a pair or single bird demonstrates an affinity
at any time during the current nesting season (April 15 -
August 31).
* As given in letter from M. J. Sotak, FERC to Northwest Alaskan
Pipeline Co., 26 October 1979.
0.)
peregrine falcon nest sites •. The Oct. 1979 restrictions that deal with
hunting habitat (II), the need for consultation (III), and the need for
=i.USFWS approval (IV) were not included in the Sep. 1980 set, although they
"t a~e intended to apply. To avoid further confusion, there is a need to
consolidate the two sets of restrictions into an integrated document.
Restriction II of the Oct. 1979 recommendations prohibits large-scale
surface disturbances that could detrimentally and significantly alter
peregrine prey habitat within 15 mi of nest sites, and also prohibits the
use within 15 mi of nest sites of pesticides and other pollutants that
could harm peregrines or their prey. Provision is made for exceptions
to this rule if specific authorization is granted. Because the restriction
is concerned with long-term habitat changes, there is no provision for . _
relaxation of the restriction after 1 June if a 'likely' nest location i.::,
not occupied. This restriction is essentially in agreement with the ~-
recommendation of ·the APFRT (1979), who have made the only other recommen-
dation concerning protection of hunting habitat that we are aware of. As
mentioned in Restriction III, this restriction does not preclude develop-
ment within 15 mi of nest sites, but only major changes, such as draining
or filling in of wetlands or marshes, or other extensive habitat altera-
tions. In our opinion, the pipeline right-of-way and associated activities
and facilities should not be considered as major changes in that sense,
unless in some case the pipeline activities should have a major effect on
an important drainage system. Our interpretation is in general agreement
with the APFRT (1979), who considered that linear disturbances such as
roads probably do not cause sufficient damage to be of consequence to
hunting habitat. Restriction II does not specify the pesticides and
other pollutants that are prohibited within 15 mi of nest sites; presumably
the individual substances can be specified when NWA's plans concerning the
use of pesticides or other environmental pollutants are complete.
Restriction III of the Oct. 1979 recommendations requires that a
qualified biologist should review plans, activities, etc., near nest sites
to ensure that the restrictions or any modifications thereto are
84
~appropriate for protecting the birds. Because of the wide range of
r
possible biological experience that such a person could have, we would .
·~ecommend that the biologist assigned to this task be one who, among
~
hi~ qualifications, has had some experience with raptors. ·Such experi-
ence would permit him to make necessary decisions efficiently without
having to frequently refer to biologists experienced with raptors for
advice or assistance.
Restriction IV of the Oct. 1979 recommendations specifies that all
surveys and any exceptions to the restrictions must first be approved by
USFWS. I
One of the most important roles that protective measures can fill is~--·· .. · _ .. ~ I
to ensure that peregrine nest cliffs are protected. Although such pro-.
tection is not explicitly stated in the USFWS recommended restrictions, ~-I
it is, .in our interpretation, provided by restriction 4, which prohibits
long-term habitat alterations within 1 mi of nest sites. It would
probably be preferable if the protection of nest cliffs {i~~luding
alternate sites) were explicitly stated in restriction 4. ~·~here is not,
however, any protection for potential {as opposed to documented) nest
cl)ffs in drainages frequented by nesting peregrines. We recommend that
the physical integrity of such potential nest cliffs should be ensured.
In summary, we are in agreement with the recommended USFWS
restrictions (1) under the interpretations that we have made, (2) provided
that restrictions II, III and IV from the Oct. 1979 recommended restrictions
are included with the Sep. 1980 recommended restrictions, (3) with the
modification that we have suggested to Sep. 1980 restriction 1, and (4) with
the addition of a restriction to protect the physical integrity of potential
nest cliffs in drainages frequented by peregrines. While we are in agree-I
ment with these restrictions, we recognize that there are exceptions that
may be made at specific nest sites because of particular circumstances. (
I
(
85
;. The potentia 1 s i te-by-s 1 te conflicts and our recommendations concerning
.these conflicts are addressed in Section 2.8.
~-
"" 2.7~1.2 Specific Sites
The Sep. 1980 USFWS reco11111ended restrictions 1i st a number of 1 ocati ons
that are considered 'likely' to be occupied and a number of locations that
are 'not likely' to be occupied. The two lists are based on the usn~s
analysis of nesting records in the vicinity of the proposed pipeline.
Locations 'likely' to be occupied are those with a reasonable probability
of occupancy in the near future. Locations 'not likely' to be occupied
are those that have a low probability of occupancy in the immediate future,
but would be valuable for a future recovery of the peregrine population. J511t;
Our analysis of peregrine nest location histories (Section 2.1) in ~·
the vicinity of the pipeline corridor would suggest that some changes and
a number of additions should be made to the two lists. There appear to
be three typographical errors in the USFWS lists; Location P-21 would be
more correctly referred to as P-2la, Location P-19 as P-19a, and Location
P-60d as P-60a. Furthermore, there is a typographi ca 1 error in Roseneau
and Bente (1979) that affects the lists. In the text of that report,
Location P-34a was listed correctly as a historical peregrine location,
but on the USGS topographic maps accompanyinq the report the location was
shown as 'P-34b'. To maintain consistency with the text, the map should
be corrected to show the peregrine . location as P-34a, and the raven nest
at the same location should be designated as 34b (as it is in the text).
As a consequence it would be preferable for the USFWS to list this location
· as P-34a, not as P-34b.
We are aware of 53 documented or reported peregrine falcon nesting
locations within 15 mi of the pipeline corridor (as per the NWA Environ-
mental Master Guide alignment sheets dated April 1980). Of these, 32
86
~are within 2 mi of some facility or activity; 2 mi includes the distances with-
·_in which restrictions 1-4 apply, and is thus the only distance within
Wbich the categories of 1 likely 1 and 1 not likely 1 need be distinguished.
Eighteen of our 32 locations are listed on the two USFWS lists. Their
other 5 locations are 2-15 mi from pipeline activities or facilities.-
The designation of what constitutes a peregrine falcon nest site,
and hence which sites have been inc1uded in the two USFWS lists, is a
matter that is subject to several interpretations (in part because the
documentation of some historical sites is weak). The criteria that the
USFWS has used to select ·their locations and to assign them to the two
lists are not clear from their definitions. We feel that the other 14
locations within 2 mi of the corridor should be reconsidered for possible.
inclusion in their t\'10 lists. Some of these locations are currently acti -~~~-
or are, in our opinion, likely to be occupied in the near future. M'
In Section 2.8, in which we consider potential conflicts on a location-
by-location basis, we have done so for all of the 53 locations that we are
aware of within 15 mi of the corridor.
2.7.2 Other Recommended Restrictions
The Office of the Pipeline Coordinator, State of Alaska, has prepared
a preliminary list of sensitive wildlife areas along the proposed NWA
pipeline (C. E. Behlke, State Pipeline Coordinator, letter to E. A. Kuhn,
NWA, 15 July 1980). Included with the list is a series of protection
measures for sensitive wildlife species, including the peregrine falcon.
The protection measures for raptors are listed in Table · 49.
The state protection measures for peregrines are generally similar to
the USFWS recommended restrictions. In several respects, however, the
state measures are more restrictive than the USFWS measures. The state
87
·measures would prohibit major ground activity within 2 mi of nest
"locations during 15 April-31 August, whereas in the range 1-2 mi from ...
nest location, the USFWS measures would prohibit only blasting and other
activities making sufficient noise to disturb peregrines. The state
measures would prohibit permanent facility sites within 2 mi of nest
locations, whereas in the range 1-2 mi from nest locations, the USFWS
measures would prohibit only. those pennanent facilities that make
sufficient noise to disturb peregrines. The state measures would apply
to all peregrine nest locations during the period 15 April-1 June, after
which time they would apply only to oc~upied locations, whereas · the .
corresponding USFWS measures would apply only to nest locations considered
'lik:l~' to be occupie~ .. Unlike the ~SHIS restr~ctions, there is no ~
prov1s1on for any spec1f1cally-author1zed exempt1on to the state measures~-
i4: at a given nest location. -.... __
In recent years state authorities have normally followed USFWS
guidelines in dealing with endangered species. It is our unders~anding
that the state authorities were required to prepare their guidelines
before they had full input from the USFWS and that the state authorities
are likely to modify their protection measures to follow the USFWS
recommended restrictions (C. Yanagawa, State Pipeline Coordinator's
Office, pers. comm.). For these reasons, we have evaluated potential
conflicts between nest locations and the pipeline alignment on the
basis of the USFWS recommended restrictions. If the stricter state
measures remain in force, then the nest location conflicts should be
reevaluated.
Protection for the physical integrity of actual (and possibly
potential) nesting cliffs of peregrine falcons could be provided by two
pieces of legislation; one is a portion of the U.S. Endangered Species
Act (1973), and the other is a statute of the State of Alaska. Article
88
~ 402.04 (Consultation) of Section 7 of the U.S. Endangered Species Act
"_(1973) states that 'it is the responsibility of each federal agency to .
~~view its activities or programs and to identify any such activity or .
program that may affect listed species or their habitat'. Consultation
would then have to occur in order to ensure that the species and/or
habitat would be protected. Section 16.20.185 of Alaska Statutes Title
16 (p. 98) states that 'on land under their respective jurisdictions,
the Commissioner of Fish and Game and the Commissioner of Natural
Resources shall take measures to preserve ·natural habitat of species or
subspecies of fish and wildlife thatare recognized as threatened with
extinction'. Because nesting cliffs are ·the most important habitat to
preserve for present or future nesting peregrines, we recommend that
these two pieces of legislation be used to protect the physical integrit~
of actual and alternate nesting cliffs (both active and historical) of §:".
peregrine falcons, and that, if possible, these statutes should also be ·!_ ........ •
used to protect the physical integrity of potential nesting cliffs in
drainages frequented by peregrines.
[Sections 2.7 and 2.8, in which we discuss the USFl•IS recommended
restrictions and the potential conflicts that these restrictions would
generate between peregrine nest locations and the current NWA pipeline
alignment, were completed as a draft version of a portion of this report
on 6 October 1980 at the special request of Fluor Northwest, Inc. On
17 November 1980, the Office of the Federal Inspector, Alaska Natural
Gas Transportation System, Anchorage! completed a report entitled
'Biological Assessment of the Endangered Peregrine Falcon'. This report
contains a series of proposed protection measures for peregrine falcons.
These measures would modify some of the USFWS recommended restrictions
and would add some additional restrictions. The report also differs from
both the USFWS recommended restrictions and our designations as to
whether some peregrine nest locations are 'likely' or 'not likely' to be
occupied. Because our sections were completed prior to the publication
of this report, the proposed pl~otecti.on measures of OFI and the potentia 1
[
. [
[
89
conflicts under these protection measures are not discussed in this
·~eport. There is a need, however, to evaluate these proposed protection
~ .
measures and the potential conflicts that would arise under them.]
90
2.8 POTENiiAL PIPELINE CONFLICTS WITH NEST LOCATIONS
~~ This section discusses, on a site-by-site basis, nesting locations
tnat are found in the vicinity of the proposed Northwest Alaskan pipeline
alignment (NWA Environmental Master Guide alignment sheets, April 1980).
Potential conflicts between NWA plans and the USFWS restrictions (as we
have interpreted them in Section 2.7) are discussed, and we have made a
number of site-specific recommendations concerning these conflicts.
Because of the sensitive nature of this material we have placed it
in Volume II of this report. We have recommended that Volume II be
considered as confidential and be made available only on a need-to-know
basis.
91
= 2.9 RECOMMENDATIONS
~
~ The following recommendations, which have, for the most part, been ...
developed in Sections 2.7 and 2.8, are summarized here as a protection
strategy for peregrine falcons along the proposed NWA gas pipeline.
2.9.1 Recommendations re Restrictions
We are in general agreement \'lith restrictions 1, 2, 3 and 4 of the
Sep. 1980 USFWS recommended restrictions and restrictions II, III, IV and
V of the Oct. 1979 USFWS recommended restrictions. Accordingly, we
recommend that these restrictions be adopted provided that the following
changes are made. 11~--
The two sets of restrictions should be combined into a single -~4 1.
set of restrictions.
2. Restriction 1 should be modified to permit specifically-
authorized exemptions.
3. Restriction 2 should be modified to list the activities and
facilities that are included. In particular, compressor
stations should be included.
4. Restriction 4 should be modified to explicitly include the
pipeline per se as a permanent facility and to explicitly
include any alteration of nest cliffs under long-term habitat
alterations.
5. The term 'occupied' nest location should be defined consistent
with our interpretation of the term (i.e., it should include ·
occupancy of a nest location by a lone bird).
92
; ·.
6. The provision to relax the restrictions after 1 June for
unoccupied nest locations should include the requirement of
monitoring these locations prior to 1 June to determine if the
locations are occupied.
7. The nest locations to be protected should be those listed in
Table 38 and protection should be provided according to the
listed likelihood of occupancy.
8. Restriction II should be modified to list the pesticides and
other pollutants that are prohibited and this particular portion
of the restriction (pesticides and pollutants) should be
app.lied to the entire pipeline. In particular, the burn1ng ofif-'!!f~
substances that can produce PCB's should be prohibited, as ~F~
shoul d the use of any electrical transformers that may contain~-~~
them.
9. Restriction III should be modified to ensure that the responsible
biologist be someone who, among his qualifications, has had
some experience with raptors.
2.9.2 Recommendations re Potential Conflicts
This section is contained in Volume II of this report because of the
sensitive nature of the nest site information.
2.9.3 Other Recommendations
1. The U.S. Endangered Species Act of 1973 (Section 7, Article
402.04) and Alaska Statute 16.20.185 (Alaska Statutes Title 16) should be
used to protect the physical _integrity of actual and alternate peregrine
·nesting cliffs (both active and historical), and should, if possible, be
used to protect the physical integrity of potential nesting cliffs in
drainages frequented by peregrines.
-I
l
l
l
93
~. TABLE 38. RecoiTITiended status of peregrine falcon nest locations . ...
•..
' ~--------------------------------------------------------~
Nest locations within 2 mi
· 'Likely' to be occupied
P-21a P-196 1
P-86 P-2011
P-95a P-2051
P-97 P-2061
P-194 1 P-211
'Not likely'
P-19a
P-25
P-38a
to be occupied
P-41a
P-42a
P-47a
Nest locations between 2 and 51 mi
P-16a
P-29b
P-34a
P-35a
P-'C'
1 Sagwon Bluffs
2 Franklin Bluffs
P-50 ·
P-52
P-55
P-60a
P-68a
P-212 2
P-21Sa2
P-216 2
P-218.12
P-220 2
P-48a
P-61
P-63
P-22F
P-222 2
P-2232
P-224 2
P-2252
P-63.1
P-79
P-183a
(need not be classified as
or 'not likely')
P-69a
P-70
P-73b
P-74a
P-' K1
P-80
P-84
P~88~ 1
P-92. 1
P-97. 1
P-97.2
'likely'
94
~-2. If the above legislation cannot be used to provide protection ,.
for the physical integrity of potential nesting cliffs, then some other
provision should be made to protect the physical integrity of potential
nest cliffs in drainages frequented by peregrines.
3. During construction and ope~ation of the pipeline the restrictions
concerning peregrine falcons should be subject to a program of rigorous
scientific evaluation to determine how successful they have been in
reducing the actual impacts of the pipeline on nesting peregrines. Such
information would be invaluable in future years for any modifications to
the NWA pipeline and for the design of protective measures for other
development projects.
l
-I
I
95
3. OTHER RAPTORS
~ In addition to the peregrine falcon, five Alaskan raptor species
(gyrfalcon, rough-legged hawk, golden eagle, bald eagle and osprey) nest
at locations that are comparatively traditional and that can be comparatively
readily detected. The nest locations of some of these species (especially
the rough-legged hawk) are also important because they may be used in
later years by peregrine falcons or gyrfalcons. The nesting habits of
these five raptors make it practical to develop protection strategies
for them.
None of these five raptor species is considered to be endangered in
Alaska under the Endangered Species Act of 1973. All raptors are,
however, protected by federal and state law, and bald and golden eagles
are further protected under the Bald Eagle Act of 1940 (as subsequently
amended).
-
96
3.1 DISTRIBUTION AND POPULATION SIZE
~ . ... 3.1.1 Gyrfalcon
3.1.1.1 Throuahout Alaska
The gyrfalcon is a circumpolar arctic and subarctic species. Many
individuals winter in the breeding areas, but some migrate further south
in winter (Platt 1976). Gyrfalcons are distributed throughout most of
the tundra and alpine regions of Alaska (e.g., Cade 1960; Roseneau
1972). Small numbers of nesting gyrfalcons are found throughout parts of
the St. Elias Range, the Wrangell Mountains, the Talkeetna Mountains,
the Chugach Mountains, parts of the Alaska Peninsuli (including the
Aleutian Range), possibly parts of the Aleutian Islands, the Alaska
,;~·
~~-• Range, the Tanana Hills, the Whit~ Mountains, the Ray Mountains, and the: e
northern Kuskokwim Mountains. The largest concentrations are found in
western and northern Alaska, including the Ahklun Mountains -Kilbuck
Mountains region, the Nulato Hills,' the Seward Peninsula, the Brooks
Range (including the De Long and Baird Mountains), and the foothilis
province of the Arctic Slope from the Lisburne Peninsula to the U.S.-
Canada border (especially west of the Sagavanirktok River drainage).
Cade (1960) estimated the to.tal Alaskan population of gyrfalcons to
be~ 200-300 pairs (including breeders and non-breeders). This number
may be an underestimate (Roseneau 1972); however, it is doubtful whether
the population exceeds ~ 500 pairs. As much as ~ 70% of the total
population may occur in northwestern Alaska (including the Seward
Peninsula), the Brooks Range, and the foothills province of the Arctic
Slope.
3. 1.1.2 Adjacent to Proposed NWA Gas Pipeline ROW
The distribution and numbers of gyrfalcons in the vicinity of the
proposed NWA gas pipeline corridor have been reported by White et aZ.
{
l
l
[
l
97
·-
~ (1977) and Roseneau and Bente (1979). All known nest locations are
. north of the Yukon River; no nests occur between the Yukon River and the
'\.S.-Canada border in the general vicinity of the alignment. Five nest
locations that have or may have been used by gyrfalcons have been reported
within ~ 2-3 mi of the corridor between the Yukon River and the crest of
the Brooks Range and 11 locations (five of which were active in 1979)
have been reported from the continental divide to the northern terminus
of Sagwon Bluffs (including one by G. Elliott, USFWS, in 1980). To our
knowledge gyrfalcons have never been documented to nest on Franklin
Bluffs.
In general, the numbers of gyrfalcons nesting within the Sagavanirktok
drainage and in much of the region between the Anaktuvuk River and the ~
Canning River are ~mall relative to the Arctic Slope populations. -~
Within that region, gyrfalcons are somewhat more common east of the
Sagavanirktok River. (Greater concentrations are found east of the
Canning River and west of the Anaktuvuk River.) Similarly, on the south
side of the Brooks Range, gyrfalcons are more common in the eastern and
western Brooks Range than they are in the central section of the south
flanks of the Brooks Range.
3.1.2 Rough-legged Hawk
3. 1.2.1 Throughout Alaska
The rough-legged hawk is a migratory circumpolar species that
breeds in arctic and subarctic habitats. In Alaska, it nests throughout
much of the Aleutian Islands, portions of the Alaska Peninsula, western
Alaska, northwestern Alaska, and northern Alaska north of the crest of
the central and eastern Brooks Range (cf. Gabrielson and Lincoln 1959).
Although the rough-legged hawk is primarily associated with tundra and
alpine habitats, it does penetrate the forested valleys of western
98
~Alaska for a limited distance inland from the coast. It is found along
. the lower Kuskokwim River (Ritchie and Ambrose, unpubl. data; Weir,
-~npubl. data), and along the Yukon River as far upstream as the mouth of
' tne _Koyukuk River (Roseneau et aZ. 1980).
The rough-legged hawk has been incorrectly described as 'the most
common hawk of the interior of ~Alaska' (Gabrielson and Lincoln 1959).
Although rough-legged hawks are common in interior Alaska during migration,
particularly in spring, we know of no documented nests south of the
Brooks Range and east of 156° W.
No estimates are available of the population of rough-legged hawks
in Alaska. Rough-legged hawks are common throughout much of their range~
in the state. Over 80 active nests were found in one year on the Seward ~·
Peninsula (Roseneau and Walker, unpubl. data). Rough-legged hawks are ~
also very abundant along the Colville River in most years (cf. White and
Cade 1971, 1975; Springer et aZ. 1979b), and throughout the remainder of
the Colville region (cf. Ritchie 1978). The numbers of rough-legged
hawks in an area may fluctuate considerably from year to year.
3.1.2.2 Adjacent to Proposed NWA Gas Pipeline ROW
The distribution and numbers of rough-legged hawks in the vicinity
of the proposed NWA pipeline have been reported by White et aZ. (1977)
and Roseneau and Bente (1979). All known nest locations in the vicinity
of the alignment are north of the crest of the Brooks Range between the
Slope Mountain area and the Sagavanirktok River delta. Twenty-four
nesting locations were located and at least 18 of these were active in
1979.
99
3.1.3 Golden Eagle
~.1.3.1 . Throughout Alaska
The golden eagle is a migratory species that is widely distributed
throughout the mountainous and tundra regions of Alaska (e.g., Gabrielson
and Lincoln 1959). Territories are generally large (Brown and Amadon
1968), and although they are common in many regions (e.g., the Alaska
Range, the Aleutian Range, the Seward Peninsula, the Brooks Range),
golden eagles are not as abundant as either gyrfalcons or rough-legged
hawks.
The rolli~g uplands of the Seward Peninsula (west of~ 162° W)
usually supported at least 15-20 active nests and about the same number
of inactive nests during 1968-72 (Roseneau, Walker and Springer, unpubl.
data). The highest densities are probably reached in the Brooks Range
(cf. White et aZ. 1977; Roseneau and Bente 1979). Golden eagles also
nest north of the Brooks Range in the foothills zone of the Arctic Slope
(cf. White and Cade 1975); however, they appear to be uncommon north of
the Brooks Range between the Chandler River and the Canning River. Most
of the nests north of the Brooks Range occur east of the Canning River,
where the species reaches its northernmost limit in Alaska, and west of
the Chandler River in the uplands associated with the Colville, Utukok ·
and Kukpowruk river drainages (Roseneau 1974; Ritchie 1978).
The Arctic Slope is also important to a summer concentration of
subadult golden eagles --a phenomenon that is probably related to the
calving of the Porcupine, Central Arctic and Western Arctic caribou
herds on the Arctic Slope (Roseneau and Curatolo 1976; Ritchie 1978).
No estimate is available of the population size of golden eagles in
Alaska. North of the Arctic Circle, the papulation may be of the order
of 100-200 pairs.
100
~ 3.1.3.2 Adjacent to Proposed NWA Gas Pipeline ROW
~. The distribution and numbers of golden eagles in the vicinity of ..
the proposed NWA gas pipeline corridor have been reported by White et aZ.
(1977) and .Roseneau and Bente (1979). Nests occur in the general vicinity
of all segments of the alignment with the exception of the section on
the Arctic Slope between Prudhoe Bay and the Slope Mountain area. More
than 80 nest locations have been reported. At least 13 nests are known
in the Tanana Drainage (including one located at Tower Bluffs in 1980).
Two nest locations occur between Fairbanks and the Yukon River. At
least 35 nests have been located between the Yukon River and the crest
of the Brooks Range; and several more probably exist in this section.
At least seven more nests occur from the crest of the Brooks Range north ~~
to the vicinity of Slop~ Mountain. The greatest number of nests (and of r
active nests) occurs in the southern Brooks Range (White et aZ. 1977; ~.
Roseneau and Bente 1979).
3.1.4 Bald Eagle
3. 1.4.1 Throughout Alaska
The bald eagle is a North American species that has declined in
numbers over much of its range in the lower 48 states of the United
States. The northern subspecies of bald eagle (the subspecies that
breeds in Alaska) is not considered to be endangered, however, and bald
eagles are abundant and widely distributed throughout most of Alaska
(Gabrielson and Lincoln 1959; Brown and Amadon 1968). Large numbers
nest and winter in coa~tal areas of southeastern Alaska, along the coast
of the Gulf of Alaska and Bristol Bay, and in the Aleutian Islands.
Bald eagles also nest and sometimes winter in smaller numbers in
interior Alaska, where they are most often associated with rivers and
101
-~
~ wetland areas of lakes, streams and ponds (e.g., the Yukon and Kuskokwim
;_river drainages). The northern limits of their Alaskan nesting distribution
~cur in northwestern Alaska along portions of the Noatak River and in
~ ~-
central and northeastern Alaska in the river valleys on the south side
of the Brooks Range. A few nests in the East Fork Chandalar, Sheenjek
and Coleen rivers are among the known nests that are farthest north
(RRCS 1973). No nests have been reported from the Arctic Slope of
Alaska, and only occasional individuals have been seen there (D. D.
Gibson, pers. comm.).
In eastern interior Alaska most nesting bald eagles occur in two
important areas --the Tanana River drainage, where some wintering also
occurs (Ritchie, pers. comm.) and the Yukon Flats upstream from Stevens
Village. Surveys for nesting bald eagles have not, to our knowledge,
been conducted in the Yukon Flats. Casual observations suggest, however,
that this area may not be as important to nesting bald eagles as is the
Tanana drainage.
The popul~tion of bald eagles in Alaska is large. Lincer eta~.
(1979) estimated that~ 7500 pairs occur in the state. The estimated
breeding population of southeastern Alaska alone is ~ 4000 (King et a~.
1972). Isleib and Kessel (1973) reported~ 1800-2000 pairs in the north
gulf coast -Prince William .Sound region. Comparable data are generally
not available for other coastal regions of Alaska. White et at. (1977)
reported the presence of about 70 nests, of which ~ 70% had young, on
only one _ of the Aleutian Islands (Amchitka). His observations and
various other data suggest that a large population exists throughout the
western Gulf of Alaska, Bristol Bay and the Aleutian Islands.
In interior Alaska the number of breeding pairs is undoubtedly much
smaller.· Various observations suggest that concentrations of a similar
magnitude to that found in the Tanana drainage (i.e., between 20 and 100
···-~ ~--.
102
: pairs) occur in o·nly a few other areas (in particular the. Kuskokwim,
_Susitna, and Copper river drainages). Thus, although the bald eagles
~at nest in the Tanana drainage constitute only a ·relatively small
prdportion of the total state-wide population, they do constitute an
important segment of that portion of the Alaskan population that nests
inland from the southern coastal regions.
3.1.4.2 Adjacent to Proposed NWA Gas Pipeline ROW
The distribution and numbers of bald eagles in the vicinity of the
proposed NWA gas pipeline corridor have been reported by Roseneau and
Bente (1979, 1980b). Although a few individuals have been seen north of
the Yukon River, no nests have been documente _d in this section of the
corridor. A few pairs may nest along the Yukon River on either side of
the alignment, but the nearest reported nest location is downstream near
the mouth of Hess Creek. No nests have been found upstream as far as
Fort Hamlin, but some pairs m~y nest near Stevens Village. Between the
Yukon River and Fairbanks one nest (active in 1980) was found near the
Chatanika River crossing. Forty-four nests have been found in the
Tanana River valley between Fairbanks and the U.S.-Canada border. Pairs
were present at 25 of these nests in 1980.
3. 1 . 5 Osprey
3.1.5.1 Throughout Alaska
The osprey is a migratory species that is wid.ely but locally
distributed throughout Alaska south of the crest of the Brooks Range
(Gabrielson and Lincoln 1959). The two regions of Alaska that may have
more ospreys than other areas are portions of the Kuskokwim River
drainage and the upper Tanana-Tetlin Lake area.
l
)
I
. I
l
,..
103
No estimates of the population of ospreys in Alaska are available.
Their total numbers are probably relatively small, however, and the
·~roper order of magnitude is probably at most a few hundred pairs • ..
..
3.1.5.2 Adjacent to Proposed NWA Gas Pipeline ROW
The distribution and numbers of ospreys in the vicinity of the
proposed NWA gas pipeline corridor have been reported by Roseneau and
Bente (1979, 1980b). Ospreys are only occasional visitors north of the
Brooks Range. The osprey is a generally uncommon nesting species
throughout the upper Yukon River drainage, but appears to occur more
frequently in the Tanana River drainage. Only four nests have been
located near the proposed alignment; all occur in the Tanana drainage.
Two of the ~our nests fell down between the spring of 1979 and the
spring of 1980 (Roseneau and Bente 1980b). Other osprey nests also
occur in the Tanana drainage, but at greater distances from the proposed
alignment (e.g., the Tetlin Lake area).
•. -,-..
'-
\.
104
3.2 NESTING HABITAT
3. 2.1 Gyrfalcon
Gyrfalcons nest in a wide variety of habitat types in Alaska. They
are not as restricted to coastlines 9r river courses as are peregrines,
and are common in many upland areas. In northwestern Alaska and on the
Arctic Slope gyrfalcons prefer to nest in rolling upland areas or areas
along rivers, rather than in mountainous areas.
Gyrfalcons nest over a wide range of elevations. Most Alaskan nests
are found between sea 1 eve 1 and "'. 4000 ft as 1 ( ~Jhi te and Cad e. 1971 ) . The
greatest elevation
( Roseneau 1974).
known ("-4500 ft asl) is in the eastern Brooks Range ~, ...
-·. ·=-
In Alaska gyrfalcons nest almost exclusively on a wide variety of
cliffs and bluffs. Nesting cliffs have ranged from small ("' 15 ft high)
upland rock outcroppings to cliffs as high as "' 400-500 ft in mountainous
or coastal areas. Rocky cliffs or bluffs are preferred (cf. \~hite and
Cade 1971). Only a relatively small number of gyrfalcons have nested on
dirt/soil bluffs in northwestern Alaska and on the Arctic Slope (e.g.,
Sagwon Bluffs). In some regions of Alaska (e.g., the Alaska Range, south-
central Alaska) gyrfalcons construct typical falcon scrapes in soft
substrates that accumulate on ledges or in potholes on cliffs. However,
in most of subarctic and arctic Alaska, they prefer to scrape in and
utilize stick nests ~hat have been constructed by other cliff-nesting
raptors (rough-legged hawk, golden eagle) or ravens (cf. Cade 1960;
White and Cade 1971; Roseneau 1972). Common ravens provide the fewest
usable stick nests, because their nests are loosely constructed on small
ledges that provide marginal support; such nests have often fallen from
the cliffs by the following spring.
105
~ Although gyrfalcons have used stick nests in trees in other regions
.~f the world (cf._ Kuyt 1980), we know of only one reported instance in
~~?~a; a raven nest in a balsam poplar tree along a river on the Seward
Peninsula was used by gyrfalcons in 1967 (Roseneau 1979). In western
Alaska, gyrfalcons occasionally make use of the stick nests of other
species that have been built on man-made structures, such as gold dredges,
large sluice boxes, pile-drivers and wooden towers (White and Roseneau
1970; Roseneau, unpubl. data).
Gyrfalcons may shift in consecutive years from a nest site to a
nearby alternate nest site, or may shift to a new breeding area that is
a long distance from the original nest location. Long shifts, which may
involve many pairs moving out of an area, are undoubtedly in response to
reduced food availability (Roseneau 1972).
3.2.2 Rough-legged Hawk
Rough-legged hawks nest in a wide variety of habitat types in Alaska.
They nest in habitats similar to those used by gyrfalcons, along seacoasts
and rivers, and in upland areas. However, they do not nest over such a
wide range in elevations; most nests have been found below~ 2500 ft asl
(cf. Roseneau 1974; Ritchie 1978).
In Alaska rough-legged hawks nest almost exclusively on cliffs,
bluffs, rock outcrops and steep banks, but occasionally they nest on low
pingos and mounds. The size of the cliffs, outcrops and bluffs that they
will accept is smaller than that accepted by gyrfalcons. In some instances
rough-legged hawks have nested on the gravel shoulders of roads (Roseneau,
unpubl. data).
Although rough-legged hawks have been reported to nest in trees (cf.
Bent 1937; Brown and Amadon 1968), only one tree nest has been clearly
106
{
~ documented in Alaska in a balsam poplar tree along the Chandler River
(White and Cade 1975) --and a further possible tree nest has been
~weported from the lower Kuskokwim drainage (Weir, pers. comm.). Rough-
legged hawks also construct nests on a variety of man-made structures,
including gold dredges, sluice boxes, pile drivers, wooden towers, and
bridges (Roseneau, unpubl. data).
Although rough-legged hawks occasionally nest in old golden eagle
nests, they usually either build new nests each year or repair and reuse
old nests that they have built in earlier years. The numerous stick nests
built by rough-legged hawks within their nesting range are frequently
chosen as nest sites by peregrine falcons and gyrfalcons.
3.2.3 Golden Eagle
Although golden eagles nest in a wide variety of habitat types in
Alaska, they are generally most numerous in mountainous areas. Golden
eagles nest over a wide range of elevations from sea level ·to perhaps
5000 ft asl (cf. Mosher and White 1976). In the Alaska Range, we suspect
th~t some nests may be as high as ~ 6000-7000 ft asl. In the Brooks
Range in northern Alaska, nests have been found up to ~ 4400 ft asl
(Roseneau 1974; Roseneau and Bente 1979). Most nests in northern Alaska
have been found below~ 3500 ft asl.
In mountainous areas, nest locations are often well above the valley
floors (cf. Roseneau and Bente 1979). Nesting cliffs have ranged from
~ 20-25 ft high (upland rock outcroppings) to~ 500 ft high (mountains
and sea cliffs). A few Arctic Slope nests have been located near the
tops of rocky-soil bluffs.
Golden eagles typically construct large stick nests. Some of these
nests become immense; one nest in the Tanana drainage (not the largest
107
L
~ known) is ~ 6 ft in diameter and ~ 6 ft high. Even reindeer and caribou
-~ntlers may be incorporated into the nests (Roseneau, unpubl. data).
~
~
Although golden eagles commonly construct their nests in trees at
more southern latitudes, only~ 10 instances of nesting in trees are known
in Alaska --one in the Kuskokwim drainage, one in the Alaska Range, one
in the southern Brooks Range, and the remainder in the Yukon Drainage
(Gabrielson and lincoln 1959; J. McGowan, pers. comm.; Swartz, pers. comm.;
Weir, pers. comm.; Roseneau and Bente, unpubl. data; White, pers. comm.).
Golden eagles ~sually have 2-4 nests and alternate nests per pair,
but may have up to 14 nests per pair (Brown 1976). They may move 0.5-5 mi
to an alternate site in consecutive years (Nelson and Nelson 1978}. ~~-
Golden eagle nests are occasionally used by nesting peregrines in
interior Alaska and by rough-legged hawks in northern and western Alaska;
they are often used by gyrfalcons in norther~ and western Alaska (e.g.,
'•
Cade 1960; Roseneau 1972; Curatolo and Ritch~e 1979).
'i
3.2.4 Bald Eagle
In Alaska, bald eagles have constructed their· nests in a variety of
trees and on tundra mounds, cliffs, bluffs, sea stacks and the ridge tops
that connect sea stacks with larger islands, and the tops of small
islands (e.g., Gabrielson and Lincoln 1959; Murie 1959; Robards and Hodges
1977; White et aZ. 1977). Nests constructed in trees are used almost
exclusively when trees are available, even in coastal regions.
Nesting habitat is limited in interior Alaska. The principal tree
species available and most often used for nesting by bald eagles are balsam
poplar and white spruce; occasionally nests are constructed in large aspens
• ~
108
t (cf. Roseneau and Bente 1979). Nesting trees are usually closely associated
~ with river and stream courses, lake shores or large expanses of wetlands
.that contain lakes, ponds, streams, sloughs and marshes.
'>;:. ."t
-Stick nests are usually large and are added to each year. Only
some of the trees found within the general habitat favored by bald
eagles are suitable as structures on which the stick nests can be built.
The most frequently used trees are large mature trees that have tops
that are broken or deformed, or that are unusually bushy (a particularly
important feature of spruce trees that are used), or that have lost
sufficient limbs to have partially opened the canopy c~ver. The conformation
of the tree tops is an important feature because bald eagles require a
relatively open but solid platform on which to build. Trees of the
appropriate size and conformation are frequently uncommon in the interior.llr .
If a nest is 1 ost, some years may elapse before another tree is suitable :-·.
as a nest location. In some instances, however, human modification of ~
nearby trees can provide acceptable conditions.
Bald eagles may have up to 6 nests and alternate nests per pair
(Brown 1976). Alternate nests may be as much as 2 mi from the nest site
(Howell and Heinzman 1967).
3.2.5 Osprey
Ospreys are closely associated with water (e.g., Gabrielson and
Lincoln 1959; Brown and Amadon 1968). Nests are usually found along sea
coasts, rivers or lake shores, or in wetland areas of marshes, ponds and
streams. Nests may, however, be up to 2-3 mi from open water (Henny 1977).
Ospreys build large stick nests that with time can become so large
that the structures they are built on may eventually collapse. Osprey
nests have been built in a variety of alive or dead trees, on
109
~ cliffs, and on a variety of man-made structures, including telephone
poles, abandoned buildings, abandoned but still turning windmills, neon
~~iQnS on buildings, and artificially-constructed towers or platforms
pi~ced to provide nesting locations for them {Bent 1937; Gabrielson and
Lincoln 1959; Brown and Amadon 1968; B. Olendorff, pers. comm.). Ospreys
may have alternate nests that are as much as 4 mi away from the nest
(Green 1976).
In Alaska, relatively few nests have been located and described,
and all known nests have been in trees. In interior Alaska, the most
frequently used trees are white spruce and balsam poplar. The nests in
the Tanana River drainage have all been constructed in dead, dying or
·living spruce (Roseneau and Bente 1979). Only one of the four nests
near the pipeline corridor is a •classic• type --a large platform of
sticks atop a completely dead spruce that no longer has limbs. The
others, in partially alive spruce, have been smaller structures on top
. l -
~
or somewhat below the top of trees that have a somewhat bushy conformation.
Three of the four nests were found along the banks of the Tanana
River or on islands in it. Only one nest was on a lakeshore. The small
size of that nest and its location atop a living spruce in the •cup• of
a moderately bushy crown suggests that some nests could be difficult to
locate, especially if they are relatively new.
110
3.3 REPRODUCTIVE PHENOLOGY
Figures 2 and 3 present generalized nesting phenologies for gyrfalcons,
-~rough-legged hawks, golden eagles, bald eagles and ospreys in interior and ..
ar~tic Alaska. They are based on a compilation of records from many
locations and for many years. Gyrfalcons may be present at nest sites
during~ 1 March-30 September, rough-legged hawks ·during ~ 15 April-
10 September, golden eagles during ~ 10 March-15 September; bald eagles
during~ 10 March-30 September, and ospreys during~ 20 April-10 September.
Arctic Slope birds can be expected to be later in their breeding activities
than birds of the same species that breed in interior Alaska. Gyrfalcons
often remain in the vicinity of their nest locations throughout the year,
and some bald eagles also do so in portions of the Tanana River drainage.
I . .
.
~
FIGURE 2. Reproductive phenology of gyrfalcons, rough-legged hawks and golden eagles in
arctic and interior Alaska.
Gyrfalcon
March April May June July Aug. S~pt.
,·
1 2 . 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 . 1 2 3
0 0 1 0 0 0 0 0 1 0 0 0 0 0 1 0 0 1 0 0 0
Arrival/Courtship Rl ___ _
Egg-laying
Incubation to Hatching
Hatching to Fledging
Fledging to Dispersal R
Rough-legged Hawk
Arrival/Courtship
Egg-laying
Incubation to Hatching
Hatching to Fledging
Fledging to Dispersal
Golden Eagle
Arrival/Courtship
Egg-laying
Incubation to Hatching
Hatching to Fledging
Fledging to Dispersal
1 R = resident, M = migrant.
Ml ____ _
-----t~
M-------
------M
FIGURE 3. ~eproductive phenology of bald eagles
March A[!ri 1
1 2 3 1 2 3
0 0 1 0 0 0
Bald Eagle
Arrival/Cour~ship M/R 1 ------
Egg-laying
Incubation to Hatching
Hatching to Fledging
Fledging to Dispersal
and ospreys in
Ma~ June
1 2 3 1 2
0 0 1 0 0
Osprey
Arrival/Courtship
Egg-laying
M---
Incubation to Hatching
Hatching to Fledging
Fledging to Dispersal
1 R = resident, t·1 =migrant.
interior Alaska.
-! '
"'''l• ,.
·'I
Jul~ Aug. Se(!t.
3 1 2 3 1 2 3 ' 1 2 3
0 0 0 1 0 0 1 0 0 0
------M/R
----~1
--
..... .....
N
;;.
113
3.4 HUNTING HABITS
3.4.1 Gyrfalcon
Gyrfalcons, which are year-around residents of the arctic and
subarctic, are opportunistic hunters. During the summer their diets may
vary according to the prey availability and vulnerability (cf. Roseneau
1972}. However, their diet is not as varied as the diet of peregrines,
and they typically rely on only a few principal prey species for the
bulk of their food {cf. Cade 1960; White and Cade 1971; Roseneau 1972}.
The principal summer prey species include ptarmigan (often 70-90%
by weight of their diet}, arctic ground squirrels, and, in some regions,
long-tailed jaegers (cf. White and Cade 1971; Roseneau 1972). In some
regions of interior Alaska {e.g., the Alaska Range} ground squirrels
surpass ptarmigan in importance {cf. Cade 1960; Roseneau 1972}. Migratory
birds usually constitute no more than 15-20% by weight of their summer
diet. In the winter, gyrfalcons are almost solely dependent on ptarmigan
(cf. Platt 1976; Walker 1977}, although in some regions arctic hares are
also an important component of the diet (Muir 1973}.
Despite the reliance on a few principal prey species, gyrfalcons
are capable of shifting to other food sources during the breeding season
if the availability of a few prey species should change dramatically --
provided that other prey species are present (cf. White and Cade 1971;
Roseneau 1972}. It has also been suggested that gyrfalcons may not
breed in some years when prey availability .is low (cf. Hagen 1952; Cade
1960; Roseneau 1972}.
The reliance on ptarmigan, and the high utilization of small mammals,
particularly -ground squirrels, in the summer diet are important factors
that have helped gyrfalcons to avoid serious biocide contamination and thus
114
· maintain healthy, non-endangered populations in the arctic (cf. Cade ..
et aZ. 197lb; Walker 1977).
~ . ..
· Gyrfalcons may hunt up to at least 15 mi from their nest locations.
Nelson (1978) used a helicopter to follow a male that hunted as far as
15 mi from the nest. Another male hunted at or beyond 5.5 mi from a
nest in the Alaska Range, but the female hunted only within 1-2 mi of
the nest (Bente 1980).
3.4.2 Rough-legged Hawk
Rough-legged hawks, which generally catch their prey on the ground,
are largely dependent on small mammals as their source of prey (cf.
Bent 1937; Brown and Amadon 1968). Microtines constitute an important
part of their diet during the nesting season, and are very important
prey during the wjnter at more ~outhern latitudes (e.g., White and Cade
1971). ..
'I :I
Birds, particularly passeri~Js and ptarmigan (including fledglings),
may be more important in years of low microtine abundance, and may
generally constitute a greater proportion of the summer diet of rough-
legged hawks than had previously been thought {Springer 1975).
Although the importance of avian prey on the nesting grounds may
have been underestimated, rough-legged hawks are strongly dependent on
microtines. Their distribution, abundance and reproductive success
within a region can vary considerably from year to year in response to
fluctuations in the abundance and availability of these prey (cf. W~ite
and Cade 1971; Swartz et aZ. 1975; White et aZ. 1977). Only a few pairs
may be present in a region one year, but tens of pairs may be present in
the next year (White and Cade 1971; Roseneau, unpubl. data; Springer,
unpubl. data). When prey (microtines) are abundant, clutch sizes and
brood sizes are large, but when prey are not abundant, clutch and brood
sizes are smaller (Roseneau, unpubl. data; Springer, unpubl. data).
'(
115
i-
3.4.3 Golden Eagle
~ .. Golden ~ eagles are opportunistic hunters. When available, mammals
are · an important component of their diet (up to 70-98% by weight), but
bfrds and carrion can also be important" (cf. Brown and Amadon 1968).
In Alaska there are few reports of prey items found at nests.
Common i terns found in nests. have included ground squirrels, mannots,
snowshoe hares, ptarmigan, ducks and other waterfowl. Occasionally both
arctic and red foxes are taken; one pair on the Seward Peninsula took
possibly as many as 5-6 red foxes during the summer, and the fledgling
from that nest attacked a red fox ~ 1-2 wk after it had left the nest
(Roseneau and Springer, unpubl. data). Pairs nesting along sea coasts
also take a variety of seabirds (both alive and as carrion).
Carrion, often in the fonm of large game animals, is particularly
important during the early spring and the fall. Carrion also appears to
be very important to subadult golden eagles. Large numbers of subadults
frequent the calving and post-calving grounds of caribou herds. Up to
six subadults have been found feeding at one time on wolf-killed and bear-
killed caribou, and subadults also occasionally have been observed to
kill caribou calves (Roseneau and Curatolo 1976}.
Non-breeding of golden eagles occurs in some years, and there is
some evidence to suggest that prey availability may influence bre~ding
success (cf. Brown and ·Amadon 1968; Mosher ana White 1976).
3.4.4 Bald Eagle
Bald eagles are opportunistic in their feeding habits, and diets may
vary from region to region according to the availability and vulnerability
of prey species. Although they take a variety of live prey, bald eagles
116
often rely heavily on local sources of carrion (they may be attracted
~ to dumps)~ and they also pirate prey from other raptors, particularly
-~spreys (cf. Bent 1937; Brown and Amadon 1968; Sherrod et at. 1976).
~sh are a principal component of their diet in most regions.
. .
In Alaska, bald eagles rely heavily on dead or dying salmon when
they are available, and take other species of fish as they can in shallow
water or as carrion along shorelines. Waterfowi and seabirds (alcids
and larids) are also important components of their diet, particularly in
some co.astal regions (e.g., the Aleutian Islands). D~ad, dying or
injured birds are often taken from the water surface, but eagles are
also capable of surprising and taking uninjured waterfowl and seabirds
from the water surface or in the air. Geese may also occasionally be
taken in flights (Brown as:1d Amadon 1968), and swans and sandhill cranes •-·-
have sometimes been taken (D. Haynes, pers. comm.; Springer·, pers. corran.).l_
In the Tanana River valley salmon are undoubtedly important to bald
eagles in late summer, fall and winter. Earlier in the year, other fish
species (parti~ularly whitefish, suckers and grayling) and waterfowl
probably constitute the bulk of their diet. Snowshoe hares and muskrats
may also be taken on occasion.
3.4.5 Osprey
Ospreys prey almost exclusively on live fish (cf. Gabrielson and
Lincoln 1959; Brown and Amadon 1968), but occasionally may take birds
(usually waterfowl, shorebirds or alcids) and crustaceans. The principal
prey species in the Tanana drainage probably include whitefish, suckers
and grayling.
Ospreys may forage up to 7 mi from their nests (D. Weir, cited in
Newton 1976).
.:::-.-
J
~
l
(
(
·t .,.
~,._
117
3.5 IMPACTS OF PIPELINE ACTIVITIES
. .. The general types of impacts to rap tors that can result from
development -activities have been listed in Table 10. Construction and
operation of a natural gas pipeline could affect nesting gyrfalcons,
rough-legged hawks, golden and bald eagles, and ospreys in similar ways
to those described for peregrines. As in the case of peregrines,
disturbance from various pipeline activities is the most likely type of
impact to these birds.
3.5.1 Disturbance
The other raptor specfes have received as little in-depth study of
their responses to disturbances as have peregrines. Few studies have
directly investigated the responses of these species to disturbances .
Several authors (Mathisen 1968; Grier 1969; Juenemann and Frenzel 1972;
t, ;r Gerrard et aZ. 1973; and Fraser ep aZ. 1980) have studied the effects of
~:[ human presence and other activities (including recreational use of
resorts and campsites, construction of rice paddies, blasting of potholes,
and tree plantations) on the productivity of nesting bald eagles. Platt
(1975) and Platt and Tull (1977) conducted experimental overflights of
gyrfalcon nests in light helicopters. One of the few studies of the
effects of controlled disturbance {including noise, human presence and
vehicles) was conducted on ferruginous hawks (White et aZ. 1979). In
addition, there are other accounts of the effects of some disturbances
to various raptor species that c_an b-e related to the five species of
interest, and there are empirical observations of the responses of the
five species to individual cases of disturbance.
Responses of these raptors to various types of disturbance may
depend on the many factors that have been listed in Tables 11 and 12 and
discussed in Section 2.5.1. The ways in which disturbance can act to
lS-
I -.-
118
~· affect the reproductive success of these species may also be similar to
.~he ways disturbance can affect peregrines (Section 2.5.1). The
~utionary note concerning the interpretation of the information on
impacts (Section 2.5. 1) must also be considered for the other raptor
species.
3.5.1.1 Construction and Operation Activities
The various construction and operational activities that have the
potential to disturb nesting gyrfalcons, rough-legged hawks, golden and
ba 1 d eagles, and ospreys ar-e the same as those discussed with respect to
peregrines (Section 2.5.1 .1). As in the case of peregrines, the responses
of these species to construction activities are quite variable.
The construction of the TAPS oil line and haul road apparently did
not produce any demonstrable negative impact on nearby raptor populations
(White et al. 1977). Realignments to provide buffer zones around nest
locations no doubt contributed to minimizing the impact. However, one
gyrfalcon nest location and another probable nest location are unlikely
to be used again (White and Cade 1975; White et al. 1977; Roseneau
and Bente 1979).
In Ontario, a bald eagle pair that was relatively used to human
activities nearby tolerated the rather swift construction of a pipeline
within~ 100 yd of their nest tree (E. Baddaloo, pers. comm.). The
eagles were well into the nesting cycle when .the disturbance occurred,
and this may have contributed to their nesting success.
A 35-mi section of the Dempster highway was built through virtual
wilderness in the Yukon Territo,~y during the winter and spring of
1977-78. Two pairs of golden eagles and two ·pairs of gyrfalcons had
nested within~ 1.2 mi of the alignment in 1977. The construction of
l
I
f
119
...
i
~. the highway did not alter the occupancy or productivity of these four
pairs between 1977 and 1978, but it may have caused two pairs to shift
~
nest sites and it may have caused one brood to have a diminished chance
of survival (Nelson and Nelson 1978). One eagle nest that was within
~ 1 mi of and in view from the road was successfully reoccupied in 1978;
blasting occurred ~ 2-4 mi from the site until mid-March (by which time
the birds might have returned to the area) and construction occurred until
10 June. One gyrfalcon nest that was within ~ 0.5 mi but just oat of
sight of the road was reused in 1978; it was within~ 1.2 mi of the same
area of blasting. The three gyrfalcon nestlings were very underweight
when weighed in late June, and the adults were very nonaggressive toward
human intruders at the nest. The poor condition of the nestlings may
have been related to the adults• lack of aggressiveness, or the condition~
of the nestlings (and possibly the adults• behavior) may .have been related~"'~
to impacts from the nearby construction. The second pair of gyrfalcons
did not nest in 1978 at their 1977 sites (within ~ 275 yd of but out of
sight from the road); instead they moved~ 3.1 mi from the road and used
the 1977 nest site of the second golden eagle pair. The eagles
(presumably the same pair) nested in 1978 ~ 2.5 mi from the road.
Construction of a bridge during spring and summer of 1950 in Mount
McKinley National Park caused a pair of gyrfalcons in mid-season to
desert a regularly-used nest site that was ~ 500 yd from the bridge
(Cade, in Platt 19?5). The nest site has not been used since 1950, but
this may have been the result of continued disturbance along the nearby
road or it may have be2n due to a preference by birds in later years
for another nest site ~ 2 mi downstream of the abandoned location
(Roseneau, unpubl. data).
Other types of construction activity have also been tolerated in
some cases. A pair of bald eagles in Alaska apparently tolerated the
construction of an oil refinery ~ 2 mi from and in sight of the nest
120
,,
(L. Peet, pers. corrm.)." Nesting birds at this site have tolerated a ..
nearby gravel pit operation for a number of years and the construction
' of a 4000 ft runway~ 1.4 mi away.
The Seward Peninsula is an area that has been subjected to heavy
mining ac.tivity for many years. Although some impacts probably occurred
to gyrfalcons, golden eagles and rough-legged hawks in the course of
this activity, there is no evidence of any long-term imp~cts to these
species. The Seward Peninsula has one of the largest populations of
gyrfalcons, and in some large areas has some of the densest concentrations
of gyrfalcons in Alaska (Roseneau 1972; Swartz et al. 1975). Gyrfalcons
and rough-legged hawks nest in most years throughout the most intensively
mined districts, wherever suitable nesting habitat exists; they also nest
on at least one cliff that was created during a mining operation, on one
that was enlarged by road construction, and on several abandoned mining
structures. Gyrfalcons nested for a number of years on a gold dredge on
the Seward Peninsula. Nesting commenced before the mining operation
started each year, and in order for the operation to start, the large
young had to be removed from the dredge. The young were either placed
in a new location where they were reared by the adults or they were
partially hand-reared in the presence of the adults and were then returned
to the adults. The adults became relatively tame and would accept ground
squirrels that were thrown to them (Roseneau 1969; D. Tweet, pers. comm.).
The five raptor species have all nested near various types of
operating equipment, including vehicular traffic on roads. In addition
to the above examples, a pair of gyrfalcons nested regularly near a mining
camp where 6-8 people were living and working and where a 0-6 Caterpillar
tractor was being used (Roseneau, unpubl. data). A gyrfalcon nest in the
Yukon Territory was used in spite of its being.~ 300 yd from and in sight
of a highway; no behavioral responses were observed during the incubation,
nestling or fledgling periods that indicated the pair was alarmed by
-. .....
,,
'l
121
p:J.ssing vehicles {N.el son 1978). Gyrfalcons have also nested successfully .
on the Sewar~ Peninsula on cliffs that were only~ 0.2-0.5 mi from and in
~~ght of roads; one pair used a cliff that faced the road and was only
~ ~.3 mi from it during four successive years {Roseneau 1972, unpubl.
data). No responses to passing vehicles were seen that suggested that
the birds might have been disturbed.
Rough-legged hawks have nested close to roads along the Sagavanirktok
River and on the Seward Peninsula. In one case a pair nested successfully
on a road shoulder just below the surface of the road; the nest was
subject to human disturbance from people that stopped to see the bi-rds and
to weekly disturbance from a road grader that was forced to lift its
blade to avoid covering the nest (Roseneau and Bente 1979; Roseneau,
Walker and Springer, unpubl. data). Golden eagles have sometimes nested
near oil well pumps, farm facilities, roads and railroad tracks
{Olendorff 1975; Nelson 1980; Roseneau, unpubl. data).
Operation of heavy equipment has, however, proved detrimental to
nesting raptors in some cases. For example, a golden eagle nest in the
Yukon Territory that had been occupied in 1972 was found unoccupied in
1975, probably because of the heavy machinery at a placer mine operation
~ 30 yd below the nest. When rechecked in 1977, the mining had ceased
and the nest was reoccupied (Theberge and Gauthier 1978).
Operation of ~he TAPS oil line has in most cases also been tolerated
by raptors. Although no information is available as to whether a pair of
bald eagles nested at a location near(~ 0.3 mi) the TAPS oil line
crossing of the Chatanika River during construction, a pair did nest
there in 1980 ( Roseneau and Bente 1980a) .
tlogging activities in southeastern Alaska have temporarily caused
bald eagles to leave the vicinity of the activity (Carr 1974). Once the
. 122
activity ceased, however, eagles returned to the areas and bred there,
provided tha~ suitable nesting trees were still present. ·Some ospreys
~ve abandoned nests because of logging activity, but others have not
done so (French and Koplin 1977). In one instance, a pair of ospreys
that had previously been exposed to human activity nested successfully
even though logging activities had commenced in the late incubation
period and had occurred to within~ 100ft of the nest (Melo 1975).
3.5.1.2 Aircraft Passage
Aircraft activities associated with the construction·and operation of
a gas pipeline have the potentia~ to disturb nesting gyrfalcons, rough-
legged hawks, golden and bald eagles, and ospreys. As in the case of
peregrines, the sudden appearance of an aircraft near a raptor nest can
-J
cause ~n incubating or brooding bird to flush quickly and to possibly -i
thereby destroy the eggs or nestlings (White and Sherrod 1973).
The responses of raptors to aircraft disturbance are highly variable
and depend on the circumstances of the disturbance, the species, the
timing during the nesting cycle, the individual bird, and on various
other factors. The responses are of three general types --the birds
may flush from the nest and leave the area, the birds may remain at the
nest and more or less ignore the aircraft, or the birds may aggressively
attack the aircraft.
In the only detailed experimental study of the responses of these
raptors to aircraft overflights, Platt (1975) and Platt and Tull (1977)
noted the effects on nesting gyrfalcons of helicopter (Bell 2068) over-
flights. Overflights were made at 100 mi/h parallel to and~ 200ft in
front of nest cliffs at altitudes of 500, 1000, 1250 and 2000 ft above
the nests. No birds were disturbed by flights at 2000 ft, some birds
were disturbed at 1000 and 1250 ft, and all were disturbed at 500 ft. Of
the latter birds, 61% showed the most severe response--they flew from
123
perches in~ panic flight (low and weaving). No nest failures resulted
·~~from overflights (a maximum of two overflights in each of pre-laying,
laying, incubation, and nestling phases), and productivity of tested
nests did not differ significantly from that of control nests. A
statistically significant number of the overflown (vs. control) 1974
nests were unused in the following year; however, there was no significant
difference between the 1976 reoccupancies of nests that were overflown
or in 1975 (vs. control). These data · suggest that a factor other than
disturbance may have caused the difference in the 1975 reoccupancy
results.
Most of the other observations of the responses of raptors to air-
craft have been incidental observations made in 'the course of surveys of
nesting raptors. Repeated surveys by fixed-wing aircraft of nesting
. .
gyrfalcons on the Seward Peninsula did not cause any det~ctable loss of
productivity in the survey year or in successive years (Roseneau and
Springer, unpubl. data). These birds underwent some marked shifts in
the nests from one year to the next; thes~ shifts were apparently in
response to changes in prey availability and to some other factors.
On the Seward Peninsul~, helicopter flights near nesting gyrfalcons
in the late nesting stage have caused some birds to leave the nest
vicinity while the helicopter was present (Roseneau and Walker, unpubl.
data). White et aZ. (1979) suggested that ferruginous hawks might be
especially sensitive to disturbances when prey numbers were low; gyr-
falcons might similarly be quite sensitive when the numbers of ptarmigan
are low.
Golden eagles appear to be the most sensitive to aircraft. Windsor
(1979) noted an instance of premature fledging of a nestling golden
eagle in response to disturbance by a helicopter. Golden eagles may be
124
reluctant t{ flush during incubation, but they often flush from nests or
i~re either absent from nests or soaring above them when nests are flown
"ft. .
past during the nestling stage (Roseneau and Bente 1979; Roseneau, Walker
and Springer, unpubl. data}.
Although helicopters generally appear to have had little affect on
nesting ospreys, at least during incubation (Fyfe and Olendorff 1976),
incubating ospreys ·in Alaska have been observed to fly from a few nests
when a helicopter approached to within~ 150ft (Roseneau, unpubl. data}.
Bald eagles have also occasionally been frightened from nests, but we
suspect 'that this is an infrequent occurrence unless the birds are
purposely forced to leaye.
Hancock (1966) used a helicopter to flush bald eagles from nests in
order to obtain counts of eggs. He suggested (without presenting
supporting data) that those pairs had about 50% fewer young in the next
year and that about 45% of the pairs had moved to alternate nests. Fixed-
wing aircraft were said · to be much less disturbing. It is our view that
sufficient work has been done with aircraft on nesting bald eagles to
show that careful work with aircraft does not cause carry-over effects
into the following year. Helicopter counts of bald eagle eggs at Amchitka
Island may, however, have been the cause of relatively poor production of
young during the year of the disturbance (Sherrod et aZ. 1976).
There oave also been many occasions in which raptors did not flush
from nests in response to aircraft overflights, but instead either
assumed a stressed position, stood up on the nest, merely watched the
aircraft, or paid little or no attention to it. Some of these birds are
undoubtedli disturbed by the overflights, but it is not known what
effects this disturbance may have on the birds.
-·~
125
When overflown, some gyrfalcons on the Seward Peninsula and in
northeastern Alaska have watched as the ai~craft passed and then
·\ontinued to do whatever they were doing previously (Roseneau, unpubl.
data; Roseneau and Walker, unpubl. data). Others have flushed but
" remained in the nest area and either perched or circled. l~hite and Cade
(1975) observed some gyrfalcons that 'continued to feed their young
without looking up as we flew by to check the eyrie'.
Little information is available on the responses of rough-legged hawks
to aircraft, but we know of no attacks or strikes in several hundred hours
of aerial surveys (helicopter and fixed-wing). Rough-legged hawks that are
incubating eggs or small young have almost always refused to leave their
nests, and only the occasional bird has stood up (White and Cade 1975;
Roseneau, unpubl: data). Later in the nesting season, rough-legged hawks .
have remained perched or have flushed from perches to soar near the nest
when aircraft were nearby.
Incubating golden eagles in the Brooks Range have often been
reluctant to flush (Roseneau and Bente 1979), and golden eagles along the
Dempster highway in the Yukon Territory appeared to tolerate aircraft well,
particularly when their passage past the nest was slow (Mossop et aZ.
1978).
Bald eagles often do not leave their nests in response to aircraft
overflights. Sherrod et aZ .. (1976) noted that even in an unusually
aggressive population some bald eagles that were brooding small young
during periods of inclement weather would not leave their nests and would
allow the helicopter to approach as close as ~ 5-10 yd.
Most of the bald eagles in the Tanana River drainage that were over-
flown by fixed~wing aircraft or helicopters in the course of surveys during
the incubation period did not appear to be unduly disturbed. During heli-
copter surveys (Bell 206B to within~ 150 ft) of 17 bald eagle nests,
1~
jncubating adults did no more than look up~ and only two per~hed adults
. flushed and landed in nearby trees (Roseneau and Bente, unpubl. data}.
·~ ~imilar results were obtained during fixed-wing surveys (PA-18 Super Cub
to within~ 100 ft) of 26 nests.
On several occasions, ospreys along the Tanana River have remained
on nests when overflown, although some birds have stood up in response
to the aircraft (Roseneau, unpubl. data).
Instead of flushing and leaving or remaining at the nest, some .
raptors respond aggressively and attack aircraft as they fly past their
nest sites. Gyrfa~cons, which are very capable fliers~ can seemingly do
so with immunity; we know of no cases where gyrfalcons have actually
struck aircraft. Eagles and ospreys, which are less skillful fliers,
have occasionally collided with helicopters, fixed-wing aircraft and
gliders (Bruderer 1976; Scott and Surkan 1976; Nelson 1979).
,,
'I
Gyrfalcons are ~he most aggressive species, particularl i/against
light fixed-wing aircraft. Light fixed-wing aircraft were attacked at
as many as 50% of the nests visited on the Seward Peninsula (Roseneau
1969; 1970). In this and other studies, both sexes attacked aircraft
(occasionally together}, but males appeared to do so more commonly. On
subsequent visits several days later, the same birds usually attacked
the aircraft again. In most instances -the attacks occurred from above
(diving and passing just in front of or behind the wing}, or from a rear
quarter (flying under the outer portion of the strut or wheels to within
~ 1 yd), and then rolling and presenting the feet toward the fuselage or
tires. In one case, however, a female repeatedly attacked from directly
in front of the aircraft, then rolled and dove in an inverted position
under the aircraft when it was ~ 10 yd away. Another female attacked
repeatedly from above and to the side until the aircraft left the area.
Gyrfalcons were capable of overtaking the aircraft (which were flying at
j
-j
.I
I
127
~ 70-75 mi/h) from distances of up to~ 0.3 mi. Most attacks occurred
wheo the aircraft came within ~ 200 yd or closer to the nest, but in a
~~pmber of instances birds attacked aircraft from distances of ~ 0.5 mi
(Roseneau 1969, 1970, unpubl~ data). Several other authors have reported
attacks by gyrfalcons (White and Sherrod 1973; Mossop et aZ. 1978;
Nelson 1979). (Because gyrfalcons can outmaneuver light aircraft, the
best method of avoiding collisions appears to be to make no sudden
flight changes, and to let the gyrfalcon take evasive action.)
Golden eagles only rarely attack aircraft. We know of only one
instance of attack in Alaska, and in that case the aircraft had surprised
the birds by rounding a hill and then approaching the nest in a head-on
direction at a level slightly below the nest level (Roseneau, unpubl.
data).
Bald eagles are sometimes aggressive. They have attacked fixed-
wing aircraft and helicopters and have collided with them in a few
instances ~White and Sherrod 1973; Nelson 1979). Aggressive behavior
has occurred during helicopter surveys in the Yukon Territory (Mossop,
pers. comm.), and has been particularly common in the Aleutian Islands
(Sherrod et aZ. 1976).
Ospreys are often aggressive towards aircraft. They have attacked
and struck both fixed-wing aircraft and helicopters, and they have also
been struck by military aircraft (Nelson 1979).
3.5.1.3 Human Presence Near Nests
The occurrence of humans near raptor nests has been shown to have
widely varying impacts on the birds. There are cases where human
presence near nests has resulted in abandoned nest sites and there are
cases where raptors have nested successfully despite the presence of
128
humans nearby. Prolonged human presence near nests may result in poor
~parental care. Malnutrition may occur even though the parent birds are
,.n attendance _at the nest and may sometimes feed the young.
Gyrfa 1 cons, rough-1 egged hawks, go 1 den and ba 1 d eagles, a·nd ospreys
have all shown some tolerance of human presence near their nests in some
cases. They have also been disturbed by human presence near nests in
other cases.
Gyrfalcons usually vigorously protest human intrusions near nests,
although they occasionally slip away quietly when humans approach
(Roseneau and Nelson, unpubl. data). There is little evidence that gyr-
falcons may abandon their nests as a result of human disturbance, but
this may be due to the remoteness of most of the nesting areas. Fyfe and
Olendorff (1976) suggest that gyrfalcons may desert nests if human dis-
turbance occurs just prior to or during egg-laying. Four pairs that were
disturbed by the activities of trappers at the start of incubation (early
May) may ~ave deserted their nesting cliffs because of those activities
( Fyfe 1969).
Intensive geological sampling for several days around a small gyr-
falcon nest cliff resulted in the deaths (probably by starvation) of the
two almost-fledged young; the adults apparently f1edged young the next
year when there was no close disturbance (Nelson 1978). Under similar
circumstances on the Seward Peninsula, four nearly-fledged young died in
a nest from what appeared to oe starvation and/or abandonment (Roseneau
1970).
Because of the very low temperatures at which gyrfalcons lay and
incubate their eggs (well below 32° F), disturbance that causes the birds
to leave their nests could prove fatal to the embryos more quickly than
it would for most other raptors (cf. Platt and Tull 1977).
... ~-
·.:~
129
In contrast to the above observations, gyrfalcons have nested
-~uccessfully in many instances in spite of the activities of researchers
iho have each year made at least two visits to the nest ledges, once
during the late incubation or early nestling stage and once during the
late nestling period, when the young were banded (Roseneau 1972; Roseneau,
Walker and Springer, unpubl. data). Disturbance was even greater on some
visits when adults were trapped for banding and biopsies or chicks were
weighed. No nests were deserted as a consequence of these visits <~ 70
nestings), and only two cases occurred in which productivity was affected
by the visits.· In these cases, the small young were lost presumably from
chilling as a consequence of investigator error; the young were handled
for an excessively long period because of the sudden occurrence of incle-
ment .weather, and when they could be replaced in the nest they were not
attended sufficiently quickly by the adults. In some cases, identifiable
pairs that were visited on many occasions in one year returned to nest at
the same location during the next year (and in some cases for four ·suc-
cessive years). The shifts that occurred at some nest locations from one
year to the next appeared to have been in response to changes in prey
availability or other _natural factors rather than as a consequence of
human disturbance.
Platt and Tull (1977) observed five different gyrfalcon nests from
blinds that were~ 330 yd from the . nests for periods of one or more weeks.
Each of these nests was also subjected to helicopter disturbance. The
productivity at these nests did n·ot differ significantly from that at 11
undisturbed nests. Habituation to the coming and going of the observer
occurred at at least two of the five nests.
Rough-legged hawks almost always protest human intrusions. Although
they are rarely very aggressive, they will often leave perches or nests
to fly toward intruders when the intruder is still as much as ~ 0.3-0.5.
mi from the nest. (Females that are incubating eggs rarely leave their
130
nests until the intruder is~ 200 yd or closer from the nest.)
·-~\, Few data exist on the effects of human presence near rough-legged
hawK nests. Several birds have been trapped, banded and biopsied at
their nests during incubation without desertion or loss of productivity
occurring {Roseneau and Springer, unpubl. data), and many nests were
visited on the Seward Peninsula prior to hatching, shortly after hatching
and at other times during the nestling stage with again no desertion or
loss in productivity occurring (Roseneau, Walker and Springer, unpubl.
data). Many of the nest cliffs on the Seward Peninsula were successfully
occupied in successive years after the· visits.
It is not known how tolerant rough-legged hawks may be during the
egg-laying and early incubation stages. Other buteos are known to be
susceptible to disturbance at this time; some red-tailed hawks near
Fairbanks, for example, deserted their clutches after their nest trees
had been climbed once even though the experienced investigator was being
very careful to minimize disturbance (C. Lowe, unpubl. data).
The golden eagle is apparently the most sensitive species to human
presence near nests. Golden eagles often leave the nest area quickly
when people come into the area, and they often do so when people are at
considerable distances from the nest. Only rarely do they protest
intrusions, and people may often be unaware that they have caused a bird
to flush and stay off its nest.
Significant proportions of the golden eagle nest failures in some
areas have been blamed on human interference (cf. Brown 1969, 1976;
Boeker and Ray 1971; Kochert 1972; Snow 1973; Windsor 1979). Only one
in eight Scottish nests near houses was successful, whereas 6 of 12
nests that were remote from houses were successful (Brown 1969).
Boeker and Ray (1971) attributed~ 85% of the known nest losses in the
,.
131
Front Range of the Rocky Mountains during 1964-69 to human disturbance.
In Idaho, Kochert (1972) attributed 4-8 of 21 nest failures during
~\ncubation to human disturbance, including three failures that may have
resulted from his own activities.
A pair that had nested successfully for several years above a busy
highway near Anchorage deserted the nest after rock climbers visited the
nest ledge and removed the eggs for a short time (Roseneau and Tilton,
unpubl. data). A pair on the Seward Peninsula also abandoned a nest after
the incubating female was surprised at close range by an observer on the
cliff top (Roseneau, unpubl. data).
Golden eagle nestlings can suffer unusual weight losses due to the
prolonged intrusion of people at the nest. Ellis (1973) reported such a
case; the lengthy presence of people at the nest had caused the adult
eagles to remain away from the nest for an unusually long time after the
people had left the vicinity of the nest. The weight losses were regained,
however, before the young fledged.
In some cases golden eagles have habituated to or at least tolerated
human disturbance (Nelson 1980). Several nests, for example, were visited
on the Seward Peninsula prior to hatching without desertion occurrring
(Roseneau, unpubl. data). However, they do appear to be the most sensitive
species and the most susceptible to human interference of the five raptor
species treated here.
Bald eagles will sometimes protest the intrusions of people near their
nests. Nesting pairs that are disturbed usually remain in the vicinity of
the nest, either perched or flying around. They do not slip away from the
n~st vicinity in the manner of golden eagles, but they are usually much
less aggressive than falcons. In the Aleutian Islands, however, bald
eagles can be very aggressive towards people, and have struck them on at
least two occasion~ (Sherrod et al. 1976).
132
The removal of tree cover in order to plant crops and the visiting
_of nests by the public contributed to nest failures of bald eagles in
~"'outhern Ontario (Weekes 1974~ 197Sa). Nests in isolated trees may be .
especially vulnerable .to human disturbance, and fledgling eagles may be
more prone to leave the nest area earlier (Weekes 1975b).
Studies by Mathisen (1968), Grier {1969), Swenson {1975), Newman et aZ.
{1977) and Fraser et aZ. (1980) have indicated that nesting bald eagles
can be relatively tole~ant of human activity duri_ng the nestling stage.
In the Chippewa National Forest in Minnesota, there was no significant
difference in productivity between nests close to human ~ctivities and
those in isolated areas {Mathisen 1968). Most of the human activity in
this study occurred during the later stages of the nestling phase.
Fraser et al. {1980) compared disturbances within 1 mi of nests that had
failed in Chippewa National Forest with disturbances within 1 mi of
successful nests and found no evidence that disturbances were responsible
for the nest failures.
Grier (1969) compared the effects of climbing to nests to band
nestlings to that of counting nes~lings with bfnoculars from a di~tance.
He found n~ significant difference in the number of young produced in the
nest year from climbed vs. ·non-climbed nests. Although his sample sizes
were too small to be conclusive, his data suggested that climbing may have
caused an increased rate of nest changing. Eleven percent of the nests
that were climbed were not occupied in the following year. However,
Gerrard and Gerrard {1975) found that ~ 12% of bald eagle pairs would
shift nests between years without the trees being climbed, and it thus
appears that careful climbing to nests probably does not cause decreased
productivity or increased nest shifting.
Human presence can; however, change the behavior of nesting bald
eagles. Gerrard et aZ. (1973) found that adult behavior differed
significantly at nests that were observed from nearby blinds or time-lapse
133
cameras (< lOO _yd) from the behavior at nests that were observed at a
greater distance (> 275 yd). Adults spent much less time at the nest
~~nd did not visit the nest together. They rearranged the nest material
and shuffled on the eggs less often, and they spent more time alertly
watching.
Some studies have indicated that nesting densities of bald eagles
are lower in areas near disturbance than they are in areas farther
removed from disturbance (e.g., Juenemann 1973; Corr 1974). Fraser et al.
(1980) found that nest distribution was ~ffected by shoreline developments;
the eagles tended to select nest sites away from habitations.
Bald eagles have, however, nested near human disturbance in suburbs,
near hospitals and schools, and on golf courses (Braley 1952). A nesting
population in Washington increased from five to eight pairs in 1963-75,
during which time there was a considerable increase in the number of
roads and houses within 0.6 mi of active nests (Newman et al. 1977).
Ospreys sometimes protest human intrusions near nests, and they
have occasionally struck people. They appear to be relatively tolerant
of disturbance throughout their nesting cycle (Fyfe and Olendorff 1976;
Spitzer 1977), and they appear to be capable of accommodating or habitu-
ating to a wide variety of human activities (e.g., Melo 1975; French and
Koplin 1977; Grier et al. 1977). Ospreys have nested on bridges, near
houses, on highway medians, on telephone and power poles, and on a neon
sign above a hamburger stand (Zarn 1974; French and Koplin 1977; Olendorff
et al. 1980; Olendorff, pers. comm.). Reproductive success was not
significantly affected by climbing to the nests (Grier et al. 1977).
Some ospreys, however, have not accommodated to human presence and
disturbance. Increased levels of fishing, boating and hunting may have
partially been responsible for a population decline in Virginia (Kennedy
1977). High levels of boating activity may have affected the reproductive
success of some ospreys in -Chesapeake Bay (Reese 1977; Rhodes 1977).
134
The number of nesting locations on Yellowstone Lake, Wyoming, has
apparently declined since 1924 by~ 88% in heavy recreational use areas,
~\~t by only~ 19% in lightly used areas (Swenson 1975). The nesting
success and the number of young per nest were lower within ~ 0.6 mi of
centers of human activity. Most nesting failures were the result of eggs
failing to hatch,apparently because adults had spent too much time ·off
their eggs.
3.5.2 Direct Impacts
As in the case of the peregrine falcon (Section 2.5.2), there are
several ways in which the construction and operation of a natural gas
pipeline could increase the direct impacts to gyrfalcons, rough-legged .
hawks, golden and bald eagles, and ospreys (as opposed to the impacts of
disturbance or habitat loss). However, ·as with peregdnes, it seems
doubtful that these direct impacts will be much increased over the low
levels that probably already exist along the pipeline corridor.
3.5.2. 1 Intentionally Destructive Acts
These impacts may arise secondarily through the activities of the
general public who are able to visit raptor areas through increased
access, or through the activities of construction or maintenance ~orkers.
Newton (1979a,b) documented some of the impacts of human persecution
on raptor populations in Europe. Larger species with slower reproductive
rates (such as eagles) were more susceptible to population disruptions at
the hands of man than were smaller species. Direct persecution limits
the breeding distribution of golden eagles to about half of their poten-
tial breeding range in Britain .. Shooting and poisoning (both deliberate
and accidental) are the main decimating factors.
-W,
I'!
135
Illegal shooting of bald eagles continues despite potential ·fines
and jail terms (e.g., Coon et az.· 1970; Weekes 1974; Postupalsky 1978;
~~iser et aZ. 1980), and golden eagles have been shot in large numbers in
some of the westerry states in recent years. Eagles are large obvious
birds that scavenge at carcasses and that may take young livestock or game
animals; as such they are~probably more likely to be shot than the other
species. Gold~n eagles are often seen feeding on caribou carcasses on the
Arctic Slope, and as more people work in and visit the area, it is con-
ceivable that eagles could be subject to shooting.
One of the five species, the gyrfalcon, is more highly prized for
domestic and foreign falconry than even the peregrine. Some poaching of
nestlings may occur, and adults may be trapped in the winter. Gyrfalcons
• J
are also often attracted in winter to people hunting ptarmigan, and some
individuals have been shot under those circumstances (J. Burns, pers.
connn.).
' Rough-legged hawks have also been persecuted ~by man, and shot in
large numbers in some areas (cf. Bent 1937; Gabri~~son and Lincoln 1959).
They are conspicuous, relatively tame, and easy to approach.
3.5.2.2 Man-made Structures and Obstructions
As in the case of peregrines (Section 2.5.2.2), the other raptors
are also su.bject to collisions with vehicles, aircraft (see Section
3.5. 1.2}, and various structures. Bald eagles, which are the most likely
species to be attracted to camp dumps for scavenging (Sherrod et aZ.
1976}, are apparently quite susceptible to collisions with various
structures. Injuries from impacts with structures accounted for 18% of
the identifiable causes of death in one study (Kaiser et aZ. 1980).
Eagles that have:been attracted to dumps may starve if the dump is
then closed or they may become nuisances by attacking household pets,
etc. (Sherrod et aZ. 1976}.
.#.
136
Rough-legged hawks, particularly immatures, may be the most likely
_species to be attracted to roads in order to cat~h mic~otines that cross
\he roads. Young gyrfalcons have also been seen to perch near roads and
.to attempt to catch prey on them (Ros_eneau and Walker, unpubl. data).
These birds may be susceptible to collisions with vehicles.
Of the five raptor species, golden eagles (particularly immature
birds) are especially prone to electrocutions on power poles that have
particular configurations of wires (cf. Benson 1980; Howard and Gore
1980; Peacock 1~80). Bald eagles and ospreys are also occasionally killed
in this manner. This problem can be avoided by employing various . initial
design features or by altering the original configuration (Ansell and
Smith 1980).
Man-made structures may also supply nest sites for some raptor species.
For some tree-nesting raptors (especially ospreys) transmission line towers
and poles offer good opportunities for nest-building, and in some regions
specially bui 1t nest plat forms -have been i nsta 11 ed on transmission towers
for use by nesting raptors (Howard and Gore 1980; Van Daele 1980). Some
golden eagles have also accepted artificial structures on transmission
towers, and ospreys have _accepted a wide variety of other ~rtificial
nesting structures (cf. Olendorff et aZ. 1980). Rough-legged hawks have
also nested on a variety of man-made structures, and it is conceivable
that they may attempt to nest in the future on portions of the above
ground sections of the TAPS oil line.
3.5.2.3 Environmental Contaminants
All raptor species found in Alaska are contaminated to some degree
by various biocides, including organochlorine pesticides and PCB's, but
none appear to have been affected to the degree that peregrines have been
(Swartz, Walker and Springer, unpubl. data). The need to control the use
of these substances in development projects is thus of more concern for
peregrines than it is for the other species.
~
137
Migratory r.aptors are generally the species that are most affected
.. by biocide contamination. Of the five species treated in this section,
-~yrfalcons, which are year-round residents, are the least affected by
biocide contamination {cf. Cade et aZ. 197lb; Walker 1977).
The available data do not indicate that any of the four migratory
species are unduly endangered by environmental contaminants at this time.
Very little is known about the levels of biocide contamination in
Alaskan nesting populations of golden eagles, bald eagles or ospreys;
however, they are probably less contaminated than populations of these
species from more southern latitudes. Because of their food habits and
wintering areas, Alaskan bald eagles are unlikely to be in biocide-related
trouble. Golden eagles generally appear to be minimally affected at more
southern latitudes {e.g., Ellis 1979), and may be less affected in
Alaska.
Although rough-legged hawks are migratory, they apparently have .never
acquired dangerous levels of the more common contaminants (cf. Cade et al.
197lb), probably because their diet on their wintering grounds consists
principally of microtines. In recent years, a number of Alaskan rough-
legged hawk eggs have been analyzed; the level of contamination has
continued to remain well below levels that might be .considered dangerous
{Swartz, Walker and Springer, unpubl. data).
Within Alaska, the sources of chemical contamination to these raptor
species are primarily contaminated migratory prey _species that have become
contaminated on their. wintering grounds, and secondarily less contaminated
non-migratory species that have become contaminated via atmospheric
transport of the contaminants. As a general principle, the use of these
chemical contaminants should be avoided in development projects and other
activities, even in regions that are still relatively free of them.
138
The Spilling of a toxic material into a waterbody during construction
~~r operation of the .pipeline could affect 1arge numbers of fish, and
ithereby affect nesting bald eagles or ospreys that may be largely
dependent on these fish as their food source.
3.5.2.4 Changes in Prey Availability
As in the case of peregrines (Section 2.5.2.4), the numbers of the
other raptor species in an area are dependent on the numbers of their
available prey species. The dependence is more pronounced in species
such as gyrfa 1 cons, rough-·1 egged hawks and ospreys' which are dependent
on a comparatively small number of prey species. The prey bases of rough-
legged hawks and gyrfalcons both undergo large natural fluctuations, and
the numbers of these species nesting in an area will vary greatly from
year to year in response to these fluctuations (e.g., numbers of breeding
gyrfalcons in an area may decline by up to 75%, and numbers of rough-legged
hawks by up to 88% [Swartz et al. 1975; White and Cade 1975]). The numbers
of breeding golden eagles in northern areas may fluctuate in response to
prey availability as they have been shown to do in Idaho (USDI i979), but
there have been no studies to determine whether this does in fact occur.
Human impacts on gyrfalcons, rough-legged hawks and possibly golden eagles
through impacts on their prey bases would be very difficult to distinguish
from these natural fluctuations. The numbers of breeding bald eagles and
ospreys in an area apparently do not undergo these fluctuations from year
to year.
Human impacts are unlikely to affect .the microtine prey base of
rough-legged hawks. Ospreys, and to a lesser extent bald eagles, could
be affected if the fish were adversely affected at an important feeding
area. Gyrfalcons could also be impacted through impacts to their prey
base. Such an impact would be most likely to occur in winter, when they
are dependent almost entirely on ptarmigan (Roseneau 1972; Swartz et al.
1975; Platt 1976; Walker 1977), and would be adversely affected by any
development that affected the ability of ptarmigan to winter in areas of
shrub willow along streams and rivers.
.
--...::.
I
I
J .I
I
I
J
l
[
l
139
3.5.3 Habitat Loss
Materials sites are the only pipeline activity that are likely to
affect the actual cliff nests of gyrfalcons, rough-legged hawks and
golden eagles. Suitable cliff sites for nesting are usually limited, and
-
the loss of any such sites could limit the number of pairs that could
nest in the area. The tree nests of bald eagles and ospreys could be
destroyed by various construction activities. Because only trees with
certain characteristics are suitable for nesting, a lost nest tree may
not be easily replaced.
Hunting habitat could also be affected by pipeline construction, but
the only cases where it appears likely that raptors might be affected by
such impacts would be if construction were to affect an important fishing
area of ospreys or important shrub willow areas in river valleys where
ptarmigan overwinter and are a critical prey base for gyrfalcons.
The various raptor species have in some cases -accepted artificial
nests or platforms that have been specifically constructed for them on
cliffs, in tree tops or on man-made structures (Olendorff et al. 1980).
In conjunction with pipeline construction, it would be valuable if suitable
ledges for nesting were developed on any cliff faces that are created at
materials sites.
140
3.6 PROTECTIVE MEASURES
The measures· that have been proposed to protect the other species
-~f nesting raptors are of the same three basic types as those for
peregrines --spatial restrictions, temporal restrictions ~nd procedural
restrictions. Also, as in the case of peregrines, the information on the
impacts of developments on other nesting raptors is insufficient to
provide precise distances for spatial and procedural restrictions, and
consequently, the authors who have recommended protective measures have
often urged a cautious approach with the inclusion of a safety margin in
case of error.
Most of -the protective measures for the other raptor species have
been proposed in conjunction with protective measures for peregrines.
These restrictions have often been proposed as an overall set of restric-
tions for raptors generally or for several named species (in northern
areas usually peregrines, gyrfalcons, bald and golden eagles and some-
times ospreys}. As such, the same distance restrictions have often been
recommended for all species, rather than distances that reflect either
the sensitivities of the various species or the differing concerns for
each species. (In some cases, however, distance restrictions have been
separately specified for each species to reflect the differing sensitiv-
ities and concerns [e.g., Windsor 1979].} Some of the recommended
restrictions that provide a single distance for the various raptor
species specify separate time periods for each species during which the
restrictionswould apply; others have recommended a standard time period
for all raptors --something that is not in keeping with their various
reproductive phenologies.
The general characteristics of the various spatial, temporal and
procedural restrictions for the other raptor species and the differences
among them are similar to those of the peregrine restrictions, as dis-
cussed in Sections 2.6.1~ 2.6.2, and 2.6.3. The cautionary note in
j
f
.l
l
~
"J
(
I
(
I
[
141
Section 2.6 concerning the formulation and publication of peregrine
restrictions also applies to restrictions for the other raptor species.
~
-Tables 41, 42, 43 and 44 list the various restrictions ~hat have
been recommended for ground activities in the north near the nest
locations of gyrfalcons, golden eagles, bald eagles and ospreys, respec-
tively. The proposed restrictions are generally similar to those proposed
for peregrines, primarily because of the desire of the authors to provide
these species with the same degree of protection (with a comparable
safety margin). Tables 45, 46, 47 and 48 list the various restrictions
that have been recommended for aerial activities in the north in the
vicinities of nest locations of gyrfalcons, golden eagles, bald eagles and
ospreys, respectively. They are again similar to those for peregrines.
Protective measures for nesting rough-legged hawks have usually not -~~
. been proposed or else have been proposed in the form of general restric-
tions for nesting raptors. Five authors have provided specific recommen-
dations or requirements concerning rough-legged hawks. Four authors
(Renewable Resources Consulting Services Ltd. 1973; LGL Ltd. 1975;
Kessel 1978; Roseneau 1979, as amended in letter of 28 September 1979)
have provided recommendations for rough-legged hawks that are identical
to their recommendations for golden eagles (Tables 42 and 46). Olendorff
and Zeedyck (1978) indicate that government regulations concerning the
Trans-Alaskan pipeline provided a buffer zone of 0.5 mi around rough-
legged hawk nests, in comparison to zones of 1 mi for eagle nests and 2
mi for peregrine nests.
TABLE 41. Reconmended 1ninimum distances for ground activities to protect gyrfalcon nest sites in northern areas.
Distance
of
Avoidance
_ _(mi
5
5
2
2
2
2
2
2
2
2
Timing
of
Avoidance
N<1 rcha-
Septen1ber
1 February-
31 July
l February-
31 August
1 May-
31 July
February-
1 August
5 March-
15 June
Activity
gas pipeline
(Alaska Highway)
gas pipeline
(A 1 as ka High~1ay)
~as pipeline
(Arctic Gas)
gas pipeline
(Arctic Gas)
gas pipeline
(Alaska High1·1ay)
highway
construction
gas pipeline
(Alaska Highway)
gas pipeline
(Alaska High~1ay)
highway
construction
highway
construction
gas pipeline
(Alaska Highway)
gas pipeline
(Demster lateral)
--
location
Yukon
Yukon
Yukon
fLI.J.T.
Yukon
N.W. T.
Yukon
Yukon
B.C.
Yukon
Yukon
Yukon
Yukon
Yukon
Yukon
Restriction
no blasting 1~ithout special
~pproval
controlled blasting techniques
no ground activities
Type
of
Restriction
recommendation
recornnenda t ion
reconlDe.nda t ion
no roads or facilities 11ithout recomnendation
specific approval
minimum distance pipeline to nest reconvnendation
no construction activity
~1ill maintain minimum distance
where possibleb
no construction, etc. without
specific approval
no camps, roads, quarries
no blasting
no construction or related
acti viti es
any activities within radius
subject to site-specific
1 imitations
secondary zone
no construction activities
wherever possible
.-..
recon10enda t ion
co111ni tment by
proponent
reco~~~nendation
recommendation
recommendation
draft
requirement
reco1m1enda t ion
Reference
Alaska Highway Pipeline
Panel (1978)
Windsor (1979)
Jacobson (1974)
Jacobson (1974)
Mossop and Milligan (1977)
lull (1979)
National Energy Board
( 1977)
Alaska Highway Pipeline
Pane 1 (1978)
Blood and Chutter (1978)
Blood and Chutter (1978)
• Northern Pipeline Agency
(1978)
Hayes and Hossop (1978)
TABLE 41. (continued)
'-' Di!>tance Timing Type
of of of
Avoidance Avoidance Activity location Restriction Restriction Reference
llli
2 gas pipeline Yukon will. consult agency for bla!>ting convnitment by Foothills South Yukon
(Alaska Hi gh1~ay) will monitor nests prior to and proponent (1979)
during construction
'" 2 oil pipeline Yukon will maintain distance from nest conmitment by Foothills Oil (1979)
(Alaska High1·1ay) sites wherever possible proponent
2 l April-gas pipeline Yukon no construction 1·1herever possible recorrrnenda t ion Windsor (1979)
5 July (Alaska Highway) if construction must occur within
l-2 mi no activities during
this period
"' 2 during general Yukon given this disturbance-free suggestion Hossop et al. ( 197S)
breeding radius, raptors can be expected
to breed successfully
' ~ 1.2 during general Yukon area which should remain suggestion Hossop et al. ( 1978) w
breeding unviolated
l c l March-gas pipeline Alaska , no blastinll, heavy equipment or recommendation Renewable Resources
l August (Arctic: Gas) access roads Consulting Services
ltd. ( 1973)
5 !>larch-gas pipeline Yukon no construction activities recoutnenda t ion Hayes and Mossop (1978)
15 June (Oempster Lateral)
gas pipeline Alaska safe distance for most attivities discussion Kessel (1978)
(llorthwest Alaskan)
general Alaska no fire suppression proposed Capodice ( 1979)
( Sag~1on Bluffs) regulation
l April-gas pipeline Yukon ~1i ll at tempt to schedu 1 e conmi tment by Foothills South Yukon
31 July (Alaska High~1ay) construction outside period proponent ( 1979)
I 1-!ji'Ch-gas pipeline Alaska no human activities unlr.ss reconanenda t ion Roscneau (1979)d
l ~.ptember (llor·thwest Alaskan) specifically authorized
15 .l.Htuary-gas pipeline Yukon if construction must occur within recon•nenda t ion Windsor (1979)
30 J'oJqust (Alaska lligh~1ay) l mi no activities durin') this
periotl
1L .·,;, I··
-
T/\UL£ Ill. (conliuuc:d)
Di'itilncc
of
Avoidance
rni
0.5
0.5
0.2
Timing
of
/\voic!Jnce
a Possibly earlier.
Activity
genera 1
general
gas pipeline
(Arctic Gas)
recreation
b for rare or endangered rap tors.
c Tentative.
Location
Alaska
Alaska
Alaska
Alaska
Restriction
should be declared critical
halli tclt
no rermanent structures
no human presence
no recreational activity on any
·. _::nr,~·Ung c l i f f
d As amended in letter to Fluor Northwest, Inc., 26 September 1979.
-
Type
of
Restriction
recon1nenda t ion
recor.menda t ion
recommend at 1 on
rec011111enda t ion
...
it4''
Refertmce
White and Cade (1975)
Haugh and Halperin (1976)
Rene~1ab le Resources
Consulting Services
Ltd. (1973)
Haugh and Halperin (1976)
TABLE 42. Reconrnended minimum distances for ground activit.ies to protect golden eagle nest sites in northern areas.
Distance
of
Avoidance
(mi
5
5
2.5
2
2
2
2
''· 2
2
2
... 2
2
Timing
of
Avoidance
1 May-
15 August
March-
September
1 ~larch-
31 August
1 ~lay-
31 July
1 March-
31 Augu.st
7 flpril-
31 July
Activity
gas pipeline
(Alaska High1·1ay)
gas pipeline
(Alaska Highway)
park
development
~as pipeline
(Arctic Gas)
gas pipeline
(Arctic Gas)
gas pipeline
(Alaska Hi gh1·1ay)
gas pipeline
(Alaska High1~ay)
gas pipeline
(Alaska High~1ay)
hi gh~1ay
construction
high1-1ay
construction
gas pipeline
(Alaska Highway)
gas pipeline
(Dempster Lateral)
Location
Yukon
Yukon
Yukon
Yukon
N.W. T.
Yukon
N.W. T.
Yukon
Yukon
Yukon
Yukon
Yukon
Yukon
Yukon
Restriction
no blasting without special
approval
controlled blasting techniques
no quarries, blasting, heavy
equipment
no ground activities
no roads or facilities without
specific approval
Type
of
Restriction
reconrnendation
reconrnenda t i on
reconrnendation
reconrnendation
reconrnendation
minimum distance pipeline to nest · reconrnendation
will maintain migimum distance
where possible
no construction, etc. without
specific approval
no camps, roads, quarries
no blasting
no construction or related
activities
any activities within radius
subject to site-specific
1 imitation$
secondary zone
no construction 11ctivities
~lht!rever possihle
:~: i
"•II' 'I"," .1 I ~.
colll!d tment by
proponent
reconrnendation
recornnendation
reconrnenda t ion
draft
requirement
rccon111enda t ion
Reference
Alaska Highway Pipeline
Panel (1978)
Windsor (197g)
Theberge and Gauthier
( 1 g78)
Jacobson (lg74)
Jacobson ( 1 g74)
Mossop and Milligan
( 1977)
National Energy Board
(1 g77)
Alaska Highway Pipeline
Panel (1978)
Blood and Chutter (1978)
3lood and Chutter (lg7C)
Northern Pipelin~ Agency
( 1978)
Hayes and Mossop (1978)
TA il LE 42. (continued) ...
iF''
Distance Timing Type
of of of
Avoidance Avoid.lnce Activity Location Restriction Restriction Refet·ence
mi
2 gas pipeline Yukon will consult agency for blasting c011111i tment by Foothills South Yukon
(Alaska Highway) will monitor nests prior to and proponent ( 1 g79)
during construction
.,, 2 oil pipeline Yukon will maintain distance from nest conmitment by Foothills Oil ( 1979)
(Alaska Hi gh~tay) sites wherever possible proponent
2 1 April-highway Yukon no construction activity reconmenda t ion Tull ( 1979)
31 July construction B.C.
2 1-15 August highway Yukon no· particularly disturbing reconmendation Tull ( 1979)
construction B.C. activities
"' 2 during general Yukon given this disturbance-free suggestion Ho:;sop at aZ. ( 1978)
breeding radius, raptors can be expected _,.
to breed successfully m
1.7 18 March-gas pipeline Yukon no construction wherever possible reconmendation Windsor (1979)
30 June (Alaska High~1ay) if construction must occur within
1-2 mi no activities during
this period
1.2 during general Yukon area which should remain suggestion Hossop et aZ. (1978)
breeding unviolated
lb 1 May-gas pipeline Alaska no blasting, heavy equipment or reconrnenda t ion Renewable Resources
15 August (Arctic Gas) dccess r·oads Consulting Services
Ltd. ( 1973)
7 April-gas pipeline Yukon no construction activities recomnenda t ion Hayes and Hossop {1978)
31 July (Dempster Lateral)
gas pipeline Alaska safe distance for most activities discussion Kessel ( 1978)
(Northwest Alaskdn)
oil pi pe 1 i ne Alaska buffer zone government Oldendorff and Zeedyck
(Trans-Alaskan) requirement ( 1 978)
---
TABLE 42. (continued)
Distance Timin!J
of of
Avoidance Avoidance Activity
mi
l April-gas pipeline
31 July (Alaska High1-1ay)
15 April-gas pipeline
1 SeptE·.uber (Northwest Alaskan)
18 r~arc:.-gas pipeline
29 Augu·t (Alaska Highway)
0.5 general
0.2 1as pipeline
Arctic Gas)
recreation
a For rare or endan!)ered rap tors.
b Tentative .
Location Restriction
Yukon will attempt to schedule
construction outside period,
Alaska no human activities unless
specifically authorized
Yukon if construction must occur within
l mi no activities during this
period
Alaska no permanent structures
Alaska no human presence
Alaska no recreational activity on any
nesting cl i f f
c As amended in letter to Fluor North1·1est, Inc., 28 September 1979.
-~ ·-........
·-~----~
• •• ,,
Type
of
Restriction Reference
~onvnitment by Foothilh South Yukon
proponent (1979)
reconvnendation Roseneau (1979)c
reconmenda t ion Windsor (1979)
recommendation Haugh and Halperin (1976)
recommendation Renewable Resources
Consulting Services
Ltd. (1973) .....
recommendation Haugh and Halperin (1976) ~ ......
TABLE 43. Reco111nended minimum distances for ground activities to protect bald eagle nest sites in northern areas.
Distance Timing Type
of of of
Avoidance Avoidance Activity Location Restriction Restriction Reference
{mi..~-l __________________ -:--------------------~------------
5
5
2
2
2
2
2
2
2
2
"' 2
2
2
~-larch
September
1 t1arch-
3.1 August
1 Nay-
31 July
7 April-
31 July
I /\pril-
31 July
1-15
Au<JUS t
gas pipeline
(Alaska High~tay)
gas pipeline
(Alaska Highway)
gas pipeline
(Arctic Gas)
gas pipeline
( AI'C tic Gil s )
gas pipeline
(Alaska Highvtay)
gas pipeline
(Alaska ltigh11ay)
gas pipeline
(Alaska High~1ay)
highvtay
construction
highway
construction
gas pipeline
(Dempster Lateral)
gas pipeline
(Alaska lligh~tay)
o i l pipe l i ne
(Alaska IIi ghway)
flil]h~l•lY
cons true.. t i oi1
higlll·tay
con~truction
Yukon
Yukon
Yukon
ti.W. T.
Yukon
ILW. T.
Yukon
Yukon
Yukon
Yukon
Yukon
Yukon
Yukon
Yukon
Yukon
B.C.
Yukon
ru:.
no blasting without special
approval
controlled blasting techniques
no ground activities
no roads or facilities without
specific approval
minimum distance pipeline to
nest
1·till maintain minimum distance
where possihlea
no construction, etc. without
specific approval
no camps, roads, quarries
no blasting
secondary zone
no construction activities
wherever possible
will consult agency for blasting
will monitor nests prior to and
during construction
will maintain distance from nest
sites ~thcrr!ver pass ible
no conslructinn activity
no pdrticularly di5lurbing
<Jr:tivitii'S
recomendation
recOillllendation
recommendation
reco11111endation
recommendation
commitment by
proponent
reco11111endation
reconunendation
reco11111endation
reco111nenda t ion
conmi tment by
proponent
commitment by
proponent
recon•ncnda t ion
recou1uenda ti on
Alaska Highway Pipeline
Pane 1 ( 1978).
Windsor (1979)
Jacobson (1974)
Jacobson (1974)
Mossop and Milligan
( 1977)
National Energy Board
(1977)
Alaska Highway Pipeline
Panel (1978)
Blood and Chutter (1978)
Blood and Chutter (1978)
Hayes and ~~ssop (1978)
Foothills South Yukon (1979)
Foothills Oils (1979)
lull (1979)
lull (197'.1)
TABLE 43. (continued)
Distance
of
Avoidance
(mi
1'
Timing
of
Avoidance
7 April-
31 July
1 April-
31 July
15 April-
1 September
1 April-
15 September
Activity
gas pipeline
(Dempster Lateral)
gas pipeline
(North1-1est Alaskan)
oil pipeline
(Trans-A 1 askan)
gas pipeline
(Alaska Highway).
gas pipeline
(Northwest Alaskan)
gas pipeline
(Alaska Highway)
a For rare or endangered raptors.
Location
Yukon
Alaska
Alaska
Yukon
Alaska
Yukon
Restriction
no construction activities
Type
of
Restriction
recoi!Jnendation
safe distance for most activities discussion
buffer zone government
will attempt to schedule
construction outside period
no human activities unless
specifically authorized
if construction must occur within
1 mi no activities during this
period
requirement
coi!Jnitment by
proponent
reconnenda t ion
recoi!Jnendation
bAs amended in letter to Fluor North1·1est, Inc., 28 Ser1tember 1979.
Reference
Hayes and Mossop (1978)
Kessel (1978)
Oldendorff and Zeedyck
( 1978)
Foothills South Yukon
(1979)
Roseneau (19l9)b
Windsor (1979)
TABLE 44. Recontnended minimum distances for ground activities to protect osp.-ey nest sites in northern areas. ~:, til'' c.
Dl stance 1 iming Type
of of of
Avoidance Avoidance Activity Location Restriction Restriction Reference
1:11
5 gas pipeline Yukon no blasting without ':ipecial recontnendation Alaska Highway Pipeline
(Alaska Highway) , approval Panel (1978)
5 gas pipeline Yukon controlled blasting techniques recommendation Windsor (1979)
(Alaskan Highway)
2 Harch-~as pipeline Yukon no ground activities reconxnenda t 1 on Jacobson ( 1974)
September Arctic Gas) N.W. T.
2 gas pipeline Yukon no roads or facilities without recon111en\ia t ion Jacobson ( 1974)
(Arctic Gas) N.W.T. specific approval
2 gas pipeline Yukon minimum distance pipeline to nest reco111nenda t ion Mossop'and Milligan
(Alaska Highway) ( 1977) __.
U1
2 gas pipeline Yukon will maintain minimum distance conmi tment by National Energy Board 0
(Alaska Highway) where possibltf proponent · ( 1977)
'I· 2 1 Harch-gas pipeline Yu~on no construction, etc. without recommend~tion Alaska Highway Pipeline
31 August (Alaska Highway) specific approval Panel (1978)
2 high1'1ay Yukon no camps, roads, quarries recon111enda t ion Blood and Chutter (1978)
construction
2 l ~lay-highway Yukon no blasting recon111enda t ion Blood and Chutter (1978)
31 July construction
.... 2 l t·larch gas pipeline Yukon no construction or related draft Northern Pipeline Agency
31 August (Alaska Highway) activities requ frement ( 1978)
any activities within radius
subject to site-specific
limitations
2 gas pipeline Yukon will consult aqency for blasting conxni tment by footh 111 s South Yukon
(Alaska lliuhway) will.monitor nc!its prior to and proponent (1979)
during construction
'" 2 oil pipeline Yukon ~1ill maintain distance from nest COIIIIIi tment by Foothills Oil (1979)
(A 1 aska II i!thway) sites wllcn~VI!r po!.sihlc JlrO[IOIICilt
-
TABLE 44. (continued)
Distance ·Timing
of of
Avoidance Avoidance Activity
(mi)
gas pipeline
(Northwest Alaskan)
l April-gas pipeline
31 ,July (Alaska IIi ghway)
15 April-gas pipeline
l September (Northwest Alaskan)
l April-gas pipeline
15 September (Alaska llighway)
a For rare or endangered raptors.
Location Restriction
Alaska safe distance for most activities
Yukon will attempt to schedule
construction outside period
Alaska no human activities unless
specifically authorized
Yukon if construction must occur within
l mi no activities during this
period
b As amended in letter to Fluor Northwest, Inc. , 28 September 1979.
Type
of
Restriction
discussion
co11111itment by
proponent
reco11111endation
reco11111endation
Reference
Kessel (1978)
~· I
Foothills South Yukon
( 1979)
Roseneau (l979)b
Windsor (1979)
__.
Ul __.
TAilll 45. Recommended minimum distances fot· aircraft activities to protect gyrfalcon nest sites in northern areas.
.. ... I
lf1''
1·1inimum Distance Timing Type ·•
Altitude of of of
(ft)a Avoidance Avoidance Activity Location Restriction Restriction Reference
(mi)
3300 gas pipeline Yukon height above lowest suspected reconvnendation Windsor (1979)
(Alaska ttigh11ay) elevation within 2 mi
2700 gas pipeline Yukon height above nearest ground recommendat·ion Windsor (1979)
(Alaska High~1ay) level
2500 2.5 1 February-gas pipeline Yukon only essential flights 1~ithin reconvnendation LGL Ltd, ( 1975)
Jl July (Arctic Gas) N.W. T. radius
2000 I March-{as pipeline Yukc.n minimum altitude above ground recorflllenda t ion Jacobson (1974)
I September Arctic Gas) N.LJ.T. level
2000 I February-gas pipeline Yukon minimum altitude recorr•nenda t ion Alaska Highwa~ Pipeline
31 August (Alaska Highway) Panel (1978 __.
(.11
2000 5 Narch-gas pipeline Yukon if cannot avoid I mi radius, reconunenda t ion Hayes and Mossop (1978) N
15 June (Oempster Lateral) maintain minimum altitude
~therever and whenever safe
1500 I April-gas pipeline Alaska minimum altitude rccoiTinenda t ion Kessel ( 1978)
30 August (Northwest Alaskan)
1500 15 April-general Alaska minimum altitude proposed Capodice (1979)
15 August ( Sag~1on 0 I uffs) curtail use of nearby airport regulation
1500 March-gas pipeline Alaska nrinimum altitude reconwenda t ion Roseneau ( 1979 )b
S.;ptember (t1orth~1est
Alaskan)
1500 gas pipeline Yukon height above nest level for recon1nenda t ion Windsor (1979)
(Alaska Highway) surveillance of line
If, numerous nests rna ke routing
complex, bypass nests by
minimum of 0.6 mi
1000 15 April-gas pipeline N.~I.T. minimum alti.tude coiTiui tment by National Energy Board
15 Septembet· (t·lackenz i e proponent ( 1977)
Vall1~y)
- -
TABLE 45. (continued)
Minimum
AI t i tude
( ft)a
1000
1000
Distance
of
Avoidance
(mi)
0.6
Timing
of
Avoidance
nesting
season
nesting
season
Activity
oil pipeline
(Trans-Alaskan)
oil pipeline
(Trans-Alaskan)
gas pipeline
(Alaska Highway)
gas pipeline
(Arctic Gas)
Location Restriction
Alaska minimum altitude
Alaska minimum altitude
Yukon no flights within 0.6 mi of
nests
Alaska avoid use of aircraft in
i.nmediate vicinity of nests
no ,,el icopter landings near nests
a 11etri c a 1 t itudes have been converted and rounded to the nearest 100 ft.
b As amended in letter to Fluor Northwest, Inc., 28 September 1979.
Type
of
Restriction
government
requirement
government
requirement
reco11111endation
recommendation
.... ,r.
Reference
Olendorff and Kochert
( 1977)
Olendorff and Zeedyck
(1978)
Schmidt (1977)
Renewable Resources
Consulting Services
Ltd. (1973)
TABLE 46. Recommended minimum distances for aircraft activities to pt·otect golden eagle nest sites in northern areas.
11i n imum
Altitude
( ft)il
3300
2700
2500
2000
2000
2000
1500
1500
1000
1000
1000
Distance
of
Avoidance
(mi)
2.5
Timing
of
Avoidance
15 May-
31 August
l March-
I September
l ~1a rch-
31 August
7 April-
31 July
l April-
30 August
Activity
gas pipeline
(Alaska Highway)
gas pipeline
(Alaska Highway)
~as pipeline
(Arctic Gas)
gas pipeline
(Arctic Gas)
gas pipeline
(Alaska High1'1ay)
gas pipeline
(Dempster Lateral)
gas pipeline
(Northwest Alaskan)
gas pipeline
(Alaska High1·1ay}
15 Aprfl-gas pipeline
15 September (Mackenzie Valley)
nesting
season
nesting
season
oil pipeline
(Trans-Alaskan)
o i I pi pe 1 i ne
(Trans-Alaskan)
Location Restriction
Yukon·_-::: -he-i-ght above l o~1es t suspected
-----~elevation within 2 mi
Yukon height above nearest ground
level
Yukon only essential flights within
N.W.T. radius
Yukon
fl. w. T.
Yukon
Yukon
Alaska
Yukon
tUI. T.
minimum altitude above ground
level
minimum altitude
if cannot avoid l mi radius~
maintain minimum altitude
wherever and whenever safe
minimum.altitude
height above nest level fpr·
surveillance of line
if numerous nests make routing
complex, bypass nests by
minimum 6f 0.6 mi
mini111um altitude
Alaska minimum altitude
Alaska minimum altitude
Type
of
Restriction Reference
recommendation \Hndsor (1979)
recommendation ~lindsor (1979)
reconmendation LGL Ltd. (1975)
r~commendation
recommendation
Jacobson (1974)
Alaska Highway Pipeline
Panel. ( 1978)
recommend'a t ion Hayes and ~los sop ( 19 78)
recommendation
rec01m1enda t ion
commitment by
proponent
government
requirement
government
requirement
Kessel (19711)
Windsor (1979)
National Energy Board
(1977)
Olendorff and Kochert
( 1977)
Olendorff and Zeedyck
( 1978)
TABlE 46. (continued)
Minimum
AI titude
( ft)a
Distance
of
Avoidance
(mi)
0.6
Timing
of
Avoidance Activity
gas pipeline
(Alaska High1·1ay)
Location
Yukon
Restriction
no flights within 0.6 mi of
nests
Type
of
Restriction Reference
recommendation Schmidt (1977)
gas pipeline
(Arctic Gas)
Alaska avoid use of aircraft in recommendation Renewable Resources
Consulting Services
Ltd. ( 1973)
immediate vicinity of nests
no helicopter landings near nests
aMetric altitudes have been converted and rounded to the nearest 100 ft.
bAs amended in letter to Fluor Northwest. Inc .• 28 September 1979.
........
01
01
TABLE 47. Recor.mended minimum distances for aircraft activities to protect bald eagle nest sites in northern areas. ·t·· .,,..., ..
-1.·
Minimum Distance Timing Type
Altitude of of of
( ft}a Avoidance Avoidance Activity Location Restriction Restriction Reference ,•
(mi )
3300 gas pipeline Yukon height above lowest suspected reco11111endation L-lindsor ( 1979)
(Alaska Highway) elevation within 2 mi
2700 gas pipeline Yukon height above nearest ground recommendation Windsor (1979)
(Alaska Highway) level
2500 2.5 15 t·lay-gas pipeline Yukon only essential flights within reconmenda t ion LGL Ltd. ( 1975)
31 August (Arctic Gas) N.H. T. radius
2000 ~larch-~as pipeline Yukon minimum altitude above ground re~.:o111nenda t ion Jacobson (1974)
September Arctic Gas) N.W. T. level
2000 ~larch-gas pipeline Yukon minimum altitude reco11111endation Alaska Highway Pipeline
31 August (Alaska Highway) Panel ( 1978) U1
Ol
2000 1 April-gas pipeline Yukon if cannot avoid l mi radius. recon1nenda t ion liayes and Mossop ( 1978)
31 July (Dempster Lateral) maintain minimum altitude
wherever and ~1henever safe
1500 l April-gas pipeline Alaska minimum altitude recorrmenda t ion Kessel (1978)
30 August (Northwest Alaskan)
1500 15 April-gas pipeline Alaska minimum altitude reconmenda t ion Roseneau (l979)b
l September (Noothwest
Alaskan)
1500 gas pipeline Yukon height above nest level for recoJrunenda t ion ~lindsor (19!9)
(Alask3 lligh~1ay) surveillance of line
if numerous nests ma~e routing
complex. bypass nests hy
minimum of 0.6 mi
1000 15 April-gas pipeline ti.W.T. minimum altitude couijni tment hy National Energy Board
15 September (t~ackenz i c !Jroponent ( 1977)
Valley)
1000 nestinl] oil pipeline Alaska minimum altitude government Olendorff and Kochert
se<Json (Trans-A l ilsi;un) requirement ( 1977)
TABLE 47. (continued)
Minimum
Altitude
( ft )a
1000
Distance
of
Avoidance
(mi)
0.6
Timing
of.
Avoidance
nesting
season
Activity
oil pipeline
(Trans-Alaskan)
gas pipeline
(Alaska Highway)
Location Res tri c t1 on
Alaska minimum altitude
Yukon no flights within 0.6 mi of
ne·s ts
a .~1etric altitudes have been converted and rounded to the nearest 100 ft.
bAs amended in letter to Fluor Northwest, Inc., 28 September 1979.
Type
of
Restriction
government
requirement
Reference
Olendorff and Zeedyck
( 1978)
recommendation Schmidt (1977)
TABLE 48. Reconmended minimum distances for aircraft activities to protect osprey nest sites in northern areas.
14i nimum
Altitude
(ft)a
3300
2700
2000
1500
1500
1500
1000
1000
1000
Distance
of
Avoidance
(mi)
0.6
Timing
of
Avoidance
1 March-
31 August
1 April-
3D August
Activity
gas pipeline
(Alaska Highway)
gas pipeline
(Alaska Highway)
location
Yukon
Yukon
Restriction
height above lowest suspected
elevation within 2 mi
height above nearest ground
level
gas pipeline Yukon minimum altitude
(Alaska Highway)
gas pipeline Alaska minimum altitude
(Northwest Alaskan)
15 April-gas pipeline Alaska minimum altitude
1 September (North1·1es t fd askan)
15 April-
15 September
nestinq
SedS.On
nesting
season
gas pipeline
(Alaska High1•ay)
gas pipeline
(1-lackenzie
Valley)
oil pipeline
(Trans-11 l askan)
oil pipeline
(Trans-Alaskan)
9as pipeline
(Alaska llighway)
Yukon
N.W.T.
Alaska
Alaska
Yukon
height above nest level for
surveillance of line
if numerous nests make routing
complex, bypass nests by
minimum of 0.6 mi
minimum altitude
minimum altitude
minimum altitude
no fliqhts within 0.6 rni of ,
nests
a ~1etric altitudes have been converted and rounded to the nearest 100 ft.
bAs dlnended in letter to rluor t1orth~1cst, Inc., 28 Scptcmhcr 1979.
Type
of
Restriction
.I
Reference
·recommendation Windsor (1979)
recommendation IHndsor (1979)
recommendation Alaska Highway Pipeline
Panel (1978)
recommendation Kessel (1978)
recommendation Roseneau (l979)b
recommendation Windsor (1979)
commitment by
proponent
government
requirement
government
requirement
National Energy Soard
(1977)
Olendorff and Kochert
(1977)
Olendorff and Zeedyck
( 1978)
recon•nendation Schmidt (\977)
159
3.7 PROPOSED PROTECTIVE MEASURES FOR NWA PIPELINE
3. 7.1 State of Alaska Protective Measures
3.7.1.1 General Restrictions
Table 49 lists the State of Alaska temporal and spatial protection
criteria for nesting raptors that are currently in force for the N~lA
pipeline. The state measures apply to other species as well as nesting
raptors, but the raptor measures are the only ones discussed here. The
protection measures for peregrines are discussed in Section 2.7.2.
The protection measures consist of spatial criteria around nest
locations, within which various pipeline activities are prohibited during
sensitive periods. In addition to the peregrine falcon, protection
measures are applied to the nest locations of five other raptor species
. (gyrfalcon, rough-legged hawk, golden eagle, bald eagle and osprey). The
spatial and temporal protecti~n criteria differ for the various raptor
species. The general restrictions are discussed in this section; the
temporal and spatial criteria for the individual species are discussed
in Sections 3.7.2 and 3.7.3, respectively.
The aerial activity restriction prohibits flights of fixed-wing
aircraft and helicopters nelr nest locations. It restricts aircraft so
that they maintain either a specified distance .from the nest location or
a specified altitude above the nest location during a specified time
period. The radii of avoidance, altitudes, ·and time periods are separately
specified for each raptor species. The restriction does not specify
whether the altitude to be maintained is the altitude above nest level,
cliff (or tree) top or base of the cliff (or tree). The restriction should
state that the altitude is the height above either the nest level or the
cliff (or tree) top.
TABLE 49. State of Alaska .temporal and spatial protection criteria for nesting rap tors. 1
··:
Protection Criteria
Minor Major
Sensitive Aerial Ground Ground Faci 1 ity Habitat
Species Time Period Acti vity 2 Activity Activity Siting Disturbance
Peregrine 15 April-1 mi h 1 mi 2 mi 2 mi 2 mi falcon 31 August or 1500 ft v
Gyrfa leon 15 February-1/4 mi h l/4 mi 1/4 mi 1/2 mi · 15 August or 1000 ft v
Golden eagle 1 S April-1/2 mi h 1/4 mi 1/2 mi 1/2 mi 31 August or 1000 ft v
Rough-legged 15 Apri 1-l/4 mi h 1/4 mi 1/4 mi 1/2 mi hawk 31 August or 1000 ft v
Bald eagle 15 MarchL l/4 mi h 1/8 mi 1/4 mi l/2 mi 1/8 mi 15 August or 1000 ft v
Osprey 15 f-1arch-1/4 mi h 1/8 mi 1/4 mi 1/2 mi l/8 mi 15 August or 1000 ft v
l Extracted from 'Sensitive wildlife areas of the Northwest Alaskan gas pipeline corridor', C. E.
Behlke, State Pipeline Coordinator, letter to E. A. Kuhn,.NWA, 15 July 1980.
2 h =horizontal; v =vertical.
3 l March for areas between mileposts 472 and 573 (Tanana River from near North Pole to near
Gerstle River).
_.
0'\
0
I MDLI:. '"t::1. \ I..UII L IIIUI:!U 1
Explanatory Notes ~·fl;~ t· .1.
Raptor nest sites are assumed occupied until June l each year. After that date, protection. measures
for a specific nest site can be withdrawn for the remainder of the year if the nest is documented to
be non-active.
It should be noted that any activity, disturbance, or habitat alteration that may affect historic or
currently active peregrine falcon nest sites must be reviewed by the U.S. Fish and Wildlife Office,
Office of Endangered Species, to evaluate the potential for detrimental impacts to the welfare of
this endangered species.
Restrictions -The restriction columns provide temporal and spatial protection measures necessary to
minimize disturbance to sensitive wildlife areas from aerial activity, minor ground activity, major
ground ac t ivity, and the siting and operation of facilities.
Aerial activities include the potential disturbance effects from both fixed-wing aircraft and heli-
copters. The disturbance and •startling• impacts of low-level aircraft activity are of particular
concern during ... raptor nesting ....
Minor ground activity is characterized by limited, short-term, reconnaissance and exploration-type
programs that ~o not involve significant amounts of personnel, equipment, surface disturbance, or
noise. Examples of minor ground activity include foot reconnaissance, field inventories, topographic
surveys, resistivity surveys, and some borehole/test pit exploration activities.
Major ground activity is characterized by extensive construction-related disturbance involving sig-
nificant amounts of personnel, equipment, surface disturbance, noise, or vehicular activity. The
duration of this disturbance may be either short-term or long-term, but the magnitude of overall
activity is such that sensitive wildlife areas could be adversely affected. Typical major ground
activities include clearing, pad construction, blasting, ditching, pipe laying,.materials site ·
development, and facility construction.
Facility Siting_-The concerns of facility siting in proximity to sensitive wildlife areas include
the long-term impacts of facility operation during duration of the project and the effects of habitat
alteration on the integrity of wildlife use areas. Continuously occupied or uperating facilities may
generate noise or activity disturbance that could preclude wildlife occupation of a sensitive use
area for the duration of the project. Alteration of adjacent habitats beyond the boundary of a
defined wildlife use area may also discourage or preclude continued use of a sensitive area by
wildlife.
162
The minor ground activity restriction proh~bits minor ground activity
within a specified radius of a nest location during a specified time
-~eriod. The radii of avoidance and time periods are separately
sp~cified for'each raptor species. Minor ground activities are considered
to be those characterized by '1 imi ted, short-term reconnaissance and
exploration-type programs that do not involve significant amounts of
personnel, equipment, surface -disturbance, or noise'.
The major ground activity restriction similarly prohibits major
ground activity within a s"pecified radius of a nest location during a
specified time period. T_he radii of avoidance and time periods are again
separately specified for each raptor species. Major ground activity is
considered to be 'characterized by extensive construction-related distur-
bance involving significant amounts of personnel, equipment, surface
disturbance, noise, or vehicular activity•. Its duration may be short-or
long-term, but 'the magnitude of overall activity is such that sensitive
wildlife areas could be adversely affected'. We disagree with this
definition because there is a possibility that some ground activities
might not fit the definitions of either 'minor' or 'major' ground
activities and would then not be subject to any restrictions. We would
suggest instead that the definition of major ground activity be any ground
activity th~t does not fit the definition of minor ground activity.
The facility siti·ng restriction would prohibit the location of
pipeline facilities within a specified distance (separately specified for
each raptor species) of nesting locations. Because the restriction
applies to permanent facilities, there is no temporal criteria for this
restriction. The restriction is primarily to prevent long-term impacts
from the operation of facilities near nest locations.
The facilities that are prohibited are not listed for the general
restriction, but the table of site-specific restrictions lists compressor
and metering stations and camps. From the activities listed under major
163
ground activities, the pipeline ROW is not included as a permanent
_facility and can be built within the radius of avoidance for pennanent
;o-
"'-acilities. Two operational problems arise_ if the ROW is within various
radii of avoidance. If the pipeline ROW is built within the radii of
avoidance for aerial activity, then operational surveillance flights must
maintain the avoidance altitudes within the radii of avoidance during the
sensitive periods. Similarly, if the ROW is built within the radii of
avoidance for major ground activity, then maintenance activities of a
major nature, particularly emergency repairs, could not be conducted
within the radii of avoidance during sensitive periods.
There is also a habitat alteration restriction that prohibits habitat
alterations within a specified distance of nesting locations. The distance
is again specified separately for each species. There is also no temporal
criteria for this restriction; it applies year-round. Unfortunately, the
term 'habitat alteration' is not defined and the meaning of this
restriction is not clear. We have interpreted this habitat alteration
restriction to prohibit major ground activity within the radii of
avoidance throughout the year.
Although it is not so stated under the general restriction, the
habitat alteration restriction is evidently intended to apply only to bald
eagle and osprey nest locations (as well as peregrine falcons). This
interpretation is evident from the table of site-specific restrictions
that accompany the general restrictions. This restriction thus provides
protection for the nest trees of bald eagles and ospreys and their
immediate vicinities. There is not, however, any protection for the
actual nesting cliffs of gyrfalcons, rough-legged hawks and golden
eagles.
Unlike the USFWS recommended restrictions, there is no provision in
the state protective measures whereby an exemption to a restriction can be
-~,
~-·-.......... __
-10'-::-:
164
granted at a particular location if specific authorization is obtained.
~Jhere will undoubtedly be instances at specific locations where exemptions
ire requested and .where it is judged that the exemption can be granted -.
without harming the nesting raptors. Accordingly, we recommend that
provision be made in these restrictions .for exemptions, provided that
specific authorization is granted for each exemption on a site-by-site
basis.
The state protection measures include the provision to relax the
aerial~ minor ground and major ground activity restrictions after 1 June
at nest locations that are non-active. Documentation of non-activity at
a -nest location would require that monitoring of the nest locations be
conducted each year. The term 'non-active' is not defined; we recommend
that nest locations with either a pair of birds or a single bird in
attendance be considered as active (as in the definition for peregrines).
The date of 1 June for the relaxation of these restrictions appears
. to be reasonable in view of the nesting phenologies of the various species;
all should be in attendance at nest sites by 1 June (Section 3.3). The
restrictions could possibly be relaxed at an earlier date for at least one
earlier-nesting species, the gyrfalcon. But because later-arriving species
(rough-legged hawks, and in come cases golden eagles) may use the same
nest site if it is not in use, it is desirable to use .the date of 1 June
in all cases. It may also be desired by the State to have a single date
whereby all monitoring has been completed and relaxations can be granted
on a site-specific basis.
Unlike the USFWS recommended restrictions, there is no provision for
further relaxation of the restrictions according to whether the nest
location is 'likely' or 'not likely' to be occupied. The nesting
histories at the nest locations of these species are more poorly known
than the histories of peregrine nest locations, and consequently there is
little basis for determining likelihood of occupancy. Because the nests
·-=c-T--• .... __ _
~
~ --~--
165
are 'likelyr to be occupied and because the radii of avoidance are less
than those for peregrines, there is probably less likelihood of exemptions
~ito the restrictions for the other raptors than there is to the restrictions · ... ,;
for peregrines.
Unlike the USFWS recommended restrictions, the state protection
measures contain no measure to prohibit the use of pesticides and other
pollutants in the vicinity of nest locations, no measure to ensure that
plans, activities, etc .. near nest locat.ions are reviewed by a biologist,
and no measure to ensure that all surveys and any exemptions to the
protection measures are first approved by the state. We recommend that
such restrictions should be added to the state protection measures.
3.7.1.2 Temporal Criteria
The state protective measures concerning aerial activities and minor
and major ground activities apply during sensitive time periods that are
defined for each species. Our comments on these time periods are based on
the breeding phenologies of these species as outlined in Section 3.3
The provision for gyrfalcons precludes these activities in the
vicinity of nest locations between 15 February and 15 August. We are in
agreement with this timing. Gyrfalcons are often resident at nest cliffs
during the winter and may begin their courtship activities during late
February. Although their young have often fledged by the latter part of
July, some do not fledge until mid-August.
We recommend that two time periods be established for rough-legged
hawk nest locations, according to whether the nest site is likely to be
taken over by gyrfalcons. Some rough-legged hawk nests are very likely
to be occupied in later years by gyrfalcons. These nests can usually be
identified from their nest characteristics, and we have designated them
as rough-legged hawk (gyrfalcon) nests -in Section 3.8. These particular
.i~'::
166
·.
rough-legged hawk nest locations should receive the same temporal
io-ifrotection a_s gyrfalcons {i.e., beginning 15 February). This protection
would then assure that gyrfalcons nesting at these sites {which they are
quite likely to do) would receive protection from· the impacts of the
various procedures during their sensitive period •. The monitoring surveys
would determine by 1 June the species occupying the site and the corres-
ponding termination time for the restrictions (1 June if unoccupied}.
For rough-legged hawk nest locations that are unlikely to be occupied by
gyrfalcons, we are in agreement with a _starting date for restrictions of
15 April. We are also in agreement with a termination date of 31 August
for restrictions at all occupied rough-legged hawk nests.
The commencement _ date for restrictions at golden eagle nest locations
is too late. Golden eagles often arrive at their nest locations and
begin courtship activities in March or early April. we · recommend that
the commencement date for restrictions be 1 April. We are in agreement
with the termination date for restrictions of 31 August; most young
golden eagles have fledged by this date.
We are in agreement with the commencement dates for restrictions
near bald eagle nest locations. Bald eagles are early migrants, and the
restrictions should be in place by 15 March. Bald eagles may also be
resident along parts of the Tanana River in some years, and they could
be in attendance at nests in that area at an earlier date. It is for
this reason that restrictions on the Tanana between North Pole and the
Gerstle River commence on 1 March. We .disagree, however, with the
termination· date for bald eagle restrictions. Some young bald eagles do
not fledge until late August or even early September, and we recommend a
termination date for these restrictions of 31 August.
The commencement and termination dates for restrictions at osprey nest
sites are too early. Ospreys arrive considerably later than bald eagles,
167
and the restrictions need not apply until 15 April. The restrictions
.. should, however, extend until 31 August, by which time most young ospreys
r~ill have fledged.
3.7.1.3 Spatial Criteria
The state protective measures prohibtt the various activities within
various distances of the nest locations. These distances are defined for
each species. necause there is no information available that will provide
·the precise distances at which nesting raptors will not be affected by
pipeline activities, the distances in the restrictions are judgements as
to the distances needed to ensure that impacts are at . levels that can be
tolerated by the various species.
The distances of avoidance that are provided in the state protective
measures are generally considerably less than the various distances of
avoidance that have been recommended for northern projects (Tables 41-48).
The various recommended distances have usually not reflected the lessened
concern for the other species in comparison with the concern for peregrines;
they have consequently included as large a safety margin for the other
species as they have for peregrines. We feel that the state protective
measures represent a good compromise between the sensitivity of the other
raptor species and the lessened concern for them relative to peregrines.
We are consequently in general agreement with the distances of avoidance
in the state protective measures.
The restrictions prohibit aircraft overflights at altitudes less than
1000 ft over nest locations (presumably 1000 ft above the nest level or
cliff top). This restriction applies within a specified distance from the
nest location; the distance varies according to the species. The altitude
restriction of 1000 ft applies for the five raptor species that are
considered. It is a less severe restriction than that for peregrines
(1500 ft). The only detailed study of aircraft overflights of these
168
species indicated that some gyrfalcons were disturbed at overflights of
__ 1000 and 1200 ft (Platt and Tull 1977). These were gyrfalcons that were
--. ·1bomparatively unhabituated to aircraft; gyrfalcons and other raptors along ..
the NWA pipeline would probably be more habituated. For this reason,
and because there is more concern for peregrines than for these species,
we are in agreement with a 1000 ft altitude restriction above .nest levels
(or cliff tops) within the various radii of avoidance.
The restrictions provide that permanent facilities be located at least
1/2 mi from the ne'st locations of all of the five other raptor species.
This restriction is to ensure that the birds do not suffer long-term
disturbance impacts from the day-to-day human activities at these facilities,
and hopefully, to ensure that the birds are not molested by personnel at ~---
......-..;::
-~ the facilities. We are in a·greement with this restriction; l/2 mi should
ensure that the facilities are not visible from most nests in trees, and
the distance plus the probable higher altitude of ·nests on cliffs should
ensure that clif~-nesting ·species are comparatively little affected.
The radii of avoidance are greatest for the golden eagle (1/2 mi for
aerial and major ground activity; 1/4 mi for minor g-round activity).
Golden eagles are the most sensitive of the other raptor species to both
aerial and ground activities. A distance of avoidance of 1/2 mi is
probably the best possible compromise between the concern for the sensi-
tivity of this species and the lesser concern for golden eagles than for
peregrines. We agree with the spatial restriction of l/2 mi for aerial
and major ground activity; we also agree with the restriction of 1/4 mi
for minor ground activity, provided that the included activities (e.g.,
some borehole/test pit exploration activities) are short-term, quiet,
well below (at least 100 ft) the nest level, and do not occur during
incubation.
.:..1!r;:.;
4 ~
169
The spati?l restrictions are identical for gyrfalcons and rough-legged
hawks (1/4 mi for aerial activity and for major and minor ground activities).
~~pth species are less sensitive than golden eagles, and the restrictions
a're accordingly less strict. We agree that all ground activity (both minor
and major) should be prohibited within l/4 mi of the nest locati.ons during
the sensitive periods, because of the open ·terrain that these species
usually inhabit. It is also good that the protective measures are identical
for the two .species, because of the likelihood that gyrfalcons will occupy
rough-legged hawk nests in successive years.
...
The state protective measures contain no provision to protect the .
actual nest location~ of the cliff-nesting golden eagle, gyrfalcon or
rough-legged hawk. Materials sites or other activities that could destroy
a nest cliff or bluff could be permitted under the state restrictions,
provided that the activity occurred during the non-sensitive period. We
recommend that the restriction that prohibits habitat disturbance within
1/8 mi of bald eagle and osprey nest locations be extended to the nest
~ ' locations of golden eagles, gyrfalcons and rough-legged hawKs. This
measure would protect the nest cliff and immediate vici~ity;!(to a distance
of 1/8 mi) from all habitat alt.eration; the additional distance from l/8 mi
to 1/4 mi (gyrfalcon, rough-legged hawk) or 1/2 mi (golden eagle) would be
protected during the sensitive periods.
The spatial restrictions are identical for the tree-nesting bald
eagle and osprey (1/4 mi for aerial and major ground activity and l/8 mi
for minor ground activity and habitat disturbance). These species are
sensitive to disturbance, but less so that golden eagles; the radii of
avoidance are accordingly smaller. We are in agreement with the distance
of l/4 mi ·for aerial and major ground activity and l/8 mi for habitat
disturbance, but we recommend that the distance for minor ground activity
be extended to prohibit minor ground activity within l/4 mi Guring the
sensitive period. This change would prohibit all activity within l/4 mi
170
·.
of nest locations during the sensitive periods a distance that we
1i[eel is necessary to protect these birds from human presence near the
'Cf •
nest sites during nesting activities.
Although the radii of avoidance for aerial activity near nest
locations (1/2 mi for golden eagle; 1/4 mi for other species) are probably
sufficient to prevent major disturbance to the birds, they are insuffi-
cient to prevent agressive gyrfalcons, ospreys or bald eagles from
attacking aircraft. All of these species have been known to attack air-
craft.. Pilots may consequently prefer to remain farther than the radii
of avoidance from these nests. Gyrfalcons are highly maneuverable and
can probably avoid· collisions provided the aircraft does not change
course suddenly, but eagles and ospreys are less maneuverable and there
is more likelihood of collisions with these species. Cautious flying
near nest locations should be practiced during the appropria~e sensitive
periods and throughout the year near gyrfalcon nest locations. ,,
'f ;,
3 . .7.1.4 Specific Sites ,;,
The State of Alaska general protective measures are accompanied by
a list of sensitive wildlife areas along the NWA gas pipeline corridor.
The list of raptor nest locations that they have included is·taken from
Roseneau and Bente (1979) but is not complete. It apparently lists only
the nest locations that were active in 1979 in a corridor of several miles
in width. However, it is only those raptor nest locations (other than
peregrines) that are within l/2 mi of the current pipeline alignment (NHA .
Environmental Master Guide alignment sheets dated April 1980) or facility
or materials sites that may possibly be in conflict with the state
protective measures. (The other locations must be considered in the
event of any realignment.) There are also a few additional nest locations
that were found in 1980 within 1/2 mi of the current pipeline ·alignment or
materials sites.
171
In Section 3.8 we discuss the potential conflicts between the
proposed pipeline and facilities and all the nest locations (of gyr-
~it~lcon, rough-legged hawk, golden eagle, bald eagle, and osprey} that we
are aware of within 1/2 mi of the current pi~eline alignment or any
facility sites. In Section 3.8 we also make recommendations on a site-
by-site basis as to any exemptions that should be granted for any of the
specific conflicts between the nest locations and the pipeline alignment.
3.7.2 Other Protective Measures
Bald eagles and golden eagles are specifically protected under the
U.S. Bald Eagle Act of 1940 (as subsequently amended). A part of this
act prohibits the 'taking' of any bald or golden eagle or the nests or
eggs of such birds without a permit. 'Take' is defined to include
molest or disturb. There are also state laws that provide similar
protection for these and the other raptor species.
It is not clear to what extent such laws will apply to the NWA
pipeline with respect to disturbance to raptors, because it may be a
matter of opinion whether raptors are still being disturbed in spite of
compliance with the state protective measures. It may hence be necessary
to obtain additional permits under these laws so that any disturbance at
distances greater than those under ' the state protective measures would
be 1 egal.
·~~
~
~
172
3.8 POTENTIAL PIPELINE CONFLICTS WITH NEST LOCATIONS
~ib This section discusses, on a site-by-site basis, the nest locations
o~ the other rapto~s that are found . within 1/2 mi of the proposed Northwest
Alaskan pipeline alignment or any material _or -facility sites (according
to the NWA Environmental Master Guide alignment sheets dated April 1980).
Potential conflicts between NWA plans and the State of Alaska protective
measures (as modified according to our recommendations in Section 3.7) are .
discussed, and we have made a number of site-specific recommendations
concerning these conflicts.
This section is contained in Volume II because of the sensitive nature
of the nest .site information.
173
3.9 RECOMMENDATIONS
' ~\ The following recommendations7 which have, for the most part, been
deVeloped in Sections 3.7. and 3.8, are summarized here as a protection
strategy for gyrfalcons, rough-legged hawks, ·golden eagles, bald eagles
and ospreys along the proposed NWA gas pipeline.
3.9.1 Recommendations re Restrictions
We are in general agreement with the State of Alaska protective
measures,.but there are a number of changes to these protective measures
that we recommend.
1. The state restrictions concerning peregrines should be changed
to agree with the USFWS peregrine restrictions (as modified by
our recommendations in Section 2.9).
2. Provision should be made in the state -protective measures for
the granting of exemptions to the restrictions, provided that
specific authorization is granted for each exemption on a
site-by-site basis.
3. Protection should be supplied for the actual nesting cliffs of
gyrfalcons, rough-legged hawks and golden eagles.
4. The altitude specified in the aircraft activity restriction
should be the altitude above either the nest leve·l or the top
of the cliff or tree.
5. Major ground activity should be defined as any ground activity
that does not fit. the definition of minor ground activity.
6.
174
A!specific exemption permitting ground activity on the Haul . ~
Rhad should be permitted under the major ground activity
restriction, as · in the case of the USFWS peregrine restrictions.
7. Habitat alteration (as employed in the habitat alteration
r~striction) shoul~ be defined to be those alterations that
occur in the course of major ground activity.
8. The term •active• nest location should be defined to be
consistent with the USFWS term •occupied• as per our recommen-
dation in Section 2.9.1 {i:e., it should include occupancy of a
·nest location by a lone bird).
9. The provision to relax the restrictions after 1 June for non-
active nest locations should include the requirement of
monitoring these locations prior to 1 June to determine if the
locations are active. If the sites are not monitored,
relaxation should not be permitted.
10. The list of sensitive wildlife areas should include all of the
nest locations listed in Table 78. Each of these nest locations
is within 1/2 mi of the ROW or any facility or material site.
We are also aware of other nest locations {in Roseneau-and Bente
[1979] or discovered in 1980) that are within a corridor along
the pipeline of several miles in width, but that are more than
1/2 mi from the current alignment or any materials or facility
sites. These locations should also be added to the state list
of sensitive wildlife areas, in order that they will be
considered in the event of any pipeline realignment or reloca-
tion of facilities or materials sites.
11. The temporal and spatial protection criteria should be those
listed in Table 79 {as per our discussion in Sections 3.7.1.2
and 3.7.1.3).
-~
.1~
175
TABLE 78. Recommended nest locations for State of Alaska list of
sensitive wildlife areas.
Go~-~ eagle:
Gyrfalcon:
Rough-legged hawk:
Bald eagle:
*
NWA-78
NWA-87
NWA-98
NWA.:.11J8
NWA-109
NWA-151
NWA-175
NWA-102
NWA-183d
Nl~A-187b
NWA-190b
NWA-183b*
NWA-•vv• (new)
NWA-186
NWA-187a*
NWA-188*
NWA-189
NWA-190a*
NWA-193
NWA-202.1*
NWA-214
NWA-216.1 (new)
NWA-218.1 (new)
NWA-223
NWA-1
NWA-64 and 64.1
NWA-85.1 (new)
Rough-legged hawk nests that are likely to be occupied in future years
by gyrfalcons.
TABLE 79. Recommended temporal and spatial protection criteria for nesting gyrfalcons, rough-legged
hawks, golden eagles, bald eagles and ospreys.
Sensitive
Species Time Period
Gyrfalcon 15 February-
15 August
Golden eagle 1 April-
31 August
2
Rough-legged 15 April -
hawk 31 August
3
Bald eagle 15 March -
Osprey
1
31 August
15 April-
31 August
Aerial 1 Activity
1/4 mi h
or 1000 ft v
1/2 mi h
or 1000 ft v
1/4 mi h
or 1000 ft v
1/4 mi h
or 1000 ft v
1/4 mi h
or 1000 ft v
h = horizontal; v = vertical.
2
Protection Criteria
mnor
Ground
Activity
1/4 mi
...
1/4 mi
1/4 mi
1/4'mi
1/4 mi
Major
Ground
Activity
1/4 mi
1/2 mi
1/4 mi
1/4 mi
1/4 rni
Faci 1 i ty
Siting
1/2 mi
1/2 mi
1/2 mi
1/2 mi
1/2 mi
,.
Habitat
Disturbance
1/8 mi
1/8 mi
1/8 mi
1/8 mi
1/8 mi
15 February for .rough-legged hawk nests that are likely to be occupied by gyrfalcons.
3
1 March for areas between mileposts 472 and 573 (Tanana River from near North Pole to near
Gerstle River).
4 Provided that these activities are short-term, quiet and at least 100 ft below the nest level
and provided that they do not occur during incubation.
177
12. The USFWS restrictions a) to prohibit the use of pesticides
and other pollutants in the vicinity of nest locations; b)
to ensure that plans, activities, etc. near nest locations
are reviewed by a biologist; and c) to ensure that all surveys -and any exemptions to the protection measures are first
approved by the responsible agency should be added to the
state protection measures, with the changes to these restric-
tions that we have recommended in Section 2.9.
3.9.2 Recommendations re Potential Conflicts
This section is contained in Volume II because of the sensitive
nature of the nest site information.
3.9.3 Other Recommendations
•
During construction and operation of the pipeline the state restric-
tions concerning gyrfalcons, rough-legged hawks, golden eagles, bald
eagles and ospreys should be subject to a program of rigorous scientific
evaluation to determine their effectiveness in reducing the actual impacts
of the pipeline on these nesting birds.
~ -~ ~
178
4. REFERENCES
4.1 LITERATURE CITED
Alaska Highway Pipeline Panel. 1978. ·Environmental and socio-economic
code for the Yukon portion of the Alaska Highway Gas Pipeline.
Winnipeg, Manitoba.
Alaska Peregr·ine Falcon Recovery Team (APFRT). 1979. Peregrine falcon-
Alaska population (FaZao peregrinus tzmdrius, FaZao peregrinus
anatum): agency review draft recovery plan. U.S. Fish Wildl.
Serv., Anchorages Alaska. 84 p. and appendices.
Alliston, vl.G. and L.A. P.atterson. 1978. A preliminary study of
peregrine falcon populations in t .he Polar Gas area, Districts of
Franklin and Keewatin, N.W.T. Unpubl. rep. by LGL ltd., Toronto,
Ontario, for Polar Gas Project. 112 p.
Ambrose, R.E. 1979. Combined reports of the Yukon River peregrine
falcon surveillance program, 1979. Unpubl. rep., U.S. Fish Wildl.
Serv., Fairbanks, Alaska. 10 p.
Ansell, A. and W. Smith. 1980. Raptor protection activities of the
Idaho Power Company. p. 56-70 in R.P. Howard and J.F. Gore
(eds.). A workshop on raptors and energy developments. Idaho Chap.
Wildl. Soc. Rep. No. 1. Boise, Idaho. 125 p.
Bee, J.W. 1958. Birds found on the Arctic Slope of northern Alaska.
Univ. Kansas Publ., Mus. Nat. Hist. 10(5): 163-211.
Benson, P.C. 1980. A study of large raptor electrocution and powerpole
utilization in six western states. p. 34-40 in R.P. Howard and
J.F. Gore (eds.). A workshop on raptors and energy developments.
Idaho Chap. Wildl. Soc. Rep. No. 1. Boise, Idaho. 125 p.
Bent, A. C. 1937. Life histories of North American birds of prey. Part
1. U.S. Natl. Mus. Bull. No. 167.
Bente, P.J. 1980. Nesting behavior and hunting activity of the gyrfalcon,
FaZoo rusticoZus, in south-central Alaska. Unpubl. M.S. thesis,
Univ. Alaska, Fairbanks. 103 p.
Berger, T. R.
Inquiry:
1975. Transcripts of the Mackenzie Valley Pipeline
formal hearings. Vol. 93. Ottawa, Ontario.
Berger, T.R. 1977. Northern frontier, northern homeland: the report
of the ~·1ackenzi e ·va 11 ey, Pipe 1 i ne Inquiry. Vo 1 . 2, terms and
conditions. Can. Dep. Supply a_nd Services, Ottawa, Ontario. 268 p.
Blood, D.A. and M. Chutter. 1978. 1978 raptor nesting survey for
Shakwak Highway Improvement Project. Unpubl. rep. by Donald. A. Blood
& Assoc. for Thurber Consultants Ltd., Victoria, ·s.c. 70 p.
Boeker, E.L. and T.D. Ray. 1971. Golden eagle population studies in
the southwest. Condor 73: 463-467.
w ~
--·-
179
Braley, J.J-~ 1952. Eagle man. Pellegrini and Cudahy, New York. 210 p.
Brown, L.H.~ 1969. Status and breeding success of golden eagles in
~ north-west Sutherland in 1967. Brit. Birds 62: 345-363. ,_
BrOwn, L.H~ 1976.
224 p.
Eagles of the world. David and Charles, Vancouver.
Brown, L.H. and D. Amadon. 1968. Eagles, hawks and falcons of the
world. 2 vols. Country Life Books, London.
Bruderer, B. 1976. Unter welchen Umstanden greifen Steinadler AquiZa
chrycaetos Flugzeuge an? [Under what circumstances will Golden
Eagles A. crysaetos attack aircraft?] Orn. Beob. 73: 29-30.
Cade, T.J. 1951. Food of the peregrine falcon, FaZco peregrinus in
interior Alaska. Auk 68: 373-374.
Cade, T.J. 1960. Ecology of the peregrine and gyrfalcon populations in
Alaska. Univ. California Publ~ Zool. 63: 151-290.
Cade, T. J. 1968. Ecology of raptor populations in arctic Alaska.
Project Code ONR 409. Unpubl. rep. to Arctic Inst. N. Am. 22 p.
Cade, T.J. 1974. Plans for manag1ng the survival of the peregrine
ftalcon. P. 89-104.in F.N. Hamerstrom, B.E. Harrell and R.R.
Olendorff (eds.). Management of raptors: .proceedings of the
1donference on raptor conservation techniques, Fort Collins, Colo.,
'1'973. Raptor Research Foundation, Inc., Vermillion, South Dakota.
Cade T.J. and P.R. Dague (eds.). 1977. The Peregrine Fund Newsletter,
No.5: 1-12. Cornell Univ. Lab. of Ornithology, Ithaca, N.Y.
Cade,·T.J. and P.R. Dague (eds.). 1979. The Peregrine Fund Newsletter,
.No. 7; 1-12. Cornell Univ. Lab. of Ornithology, Ithaca, N.Y.
Cade, T.J. and R. Fyfe. 1970. The North American peregrine survey,
1970. Can. Field-Nat. 84: 231-245.
Cade, T.J., J. Haugh and C.M. White. 197la. Ecology and current status
of cliff-nesting raptors in arctic Alaska. Project Code 5342.
Unpubl. Manuscript. 22 p.
Cade, T.J., J.L. Lincer, C.M. White, D. G. Roseneau and L.G. Swartz.
197lb. DOE residues and egg shell changes in Alaskan hawks and
falcons. Science 172{3986): 955-957.
Cade, T.J. and C.M. White. 1976. Colville River watershed, Alaska.
P. 245-248 in R.W. Fyfe, S.A. Temple and T.J. Cade. The 1975
North American peregrine falcon survey. Can. Field-Nat. 90: 228-273.
~ •
180
..
t, Cade, T.J.,~ C.M. White and J.R. Haugh~ 1968. Peregrines and pesticides
in Alaska. Condor 70~ 170-178 . •
~-apodice, J.A. 1976. Sagwon Bluff peregrine falcon habitat management
~~~ plan. Bureau of Land Management, Arctic-Kobuk Resource Area,
Fairbanks, Alaska. 53 p. -
Capodice, J.A. 1979. Sagwon Bluffs peregrine falcon habitat management
plan. Bureau of Land Management, Fairbanks, Alaska. 25 p.
Childs, H.E., Jr. 1969. Birds and mammals _ of the Pitmegea River region,
Cape Sabine, Northwestern Alaska. Biol. Pap. Univ. Alaska No. 10.
74 p.
Coon, N.C., L.N. Locke, E. Cromartie and W.L. Reichel. 1970. Causes of
bald eagle mortality, 1960-1965. J. Wildl. Dis. 6: 72-76.
Carr, P.O. 1974. Bald eagle (HaZiaeetus ZeucocephaZus aZaskanus) nesting
related to forestry in southeastern Alaska. Unpubl. M.S. Thesis,
Univ. Alaska, Fairbanks. 144 p.
Cugnasse, J.-M. 1980. Adoption d'une aire artificielle par un couple de
faucons pelerins et note sur la maturite sexuelle de la femelle.
Nos Oiseaux 35(5): 238-242.
Curatolo, J.A. and R. Ambrose. 1978. A final report of the peregrine
· falcon surveillance program between Circle, Alaska, and the Alaska-
Yukon border, 1973. Unpubl. rep. to U.S. Fish Wildl. Ser., Div. of
Law Enforcement, Fairbanks, Alaska. 40 p.
Curatolo, J.A. and R.J. Ritchie. 1979. Peregrine falcon banding on the
Porcupine River, Alaska·, T979. Unpubl. rep. to U.S. Fish Wildl.
Serv., Office ·of Endangered Species. Contract No. 14-16-0007-7~-0016.
28 p.
Dotson, R.A. and D.P. Mindell. 1979. Raptor surveys and river profiles
in the Kuskokwim, Unalakleet and Yukon River drainages, Alaska.
U.S. Dep. Interior, Bureau Land Management, Anchorage, Alaska. 63 p.
Ellis, D.H. 1973. Behavior of the golden eagle, an ontogenic study.
Unpubl. Ph.D. dissertation, Univ. Montana. 416 p.
Ellis, D.H. 1979. Development of behavior in the golden eagle. Wildl.
Monogr. 70. 94 p.
Ellis, D.H. 1980. Presentation at aircraft-raptor interaction workshop.
Raptor Res. Found. Annual Meeting, 10-13 Oct. 1980, Duluth, Minn.
~
li
..
181
Ellis, O.H., O.G. Smith and J.R. Murphy. 1969. Studies in raptor
mortality in western Utah. Great Basin Nat. 29: 165-167 .
·~ ~derson, J.H., J. Craig and W. Burnham. 1977. Peregrines in the Rocky
--Mountains: status, biological assessment, and management.
Abstract and paper presented at the Raptor Res. Found. Annu.
Meeting, 11-14 Nov., Arizona State Univ., Tempe.
Enderson, J.H. and M.N. Kirven. 1979. Peregrine falcon foraging study
in the Geysers-Calistoga Known Geothermal Resource Area, Sonoma
County, California-1979. Unpubl. rep. to Bureau of Land
Management, Sacramento, Calif. 83 p.
Enderson, J.H., D.G. Roseneau and L.G. Swartz. 1968. Nesting performance
and pesticide residues in Alaskan and Yukon peregrines in 1967.
Auk 85: 683-684.
Enderson, J.H., S.A. Temple and L.G. Swartz. 1973.
graphic records of nesting peregrine falcons.
113-128.
Time-lapse photo-
Living Bird II:
·Federal Aviation Administration. 1978. Sectional aeronautic chart:
Pt. Barrow. 15th Edition. U.S. Dep. Commerce, Nat. Ocean.
Atmosph. Admin., Nat. Ocean Survey, Washington, D.C.
Foothills Oil Pipe Line Ltd. 1979. Before the National Energy Board and
to the Department of Indian Affairs and Northern Development. Vol.
3, Part E -Environment. Calgary, Alberta.
Foothills Pipe Line (South Yukon) Ltd. 1979. Environmental impact
statement for the Alaska Highway Gas Pipeline Project. Calgary,
Alberta.
Fraser, J.D., L.D. Frenzel, J.E. Mathisen and N.S. Fraser. 1980. Human
activities near successful and unsuccessful bald eagle nests on
Chippewa National Forest. Paper presented at the Raptor Res. Found.
Annu. Meeting, 10-13 Oct., Duluth, Minn.
French, J.M. and J.R. Koplin. 1977. Distribution, abundance and
breeding status of ospreys in northwestern California. P. 223-240
in J.C. Ogden (ed.). Trans. N. Am. Osprey Res. Conf.,
Williamsburg, Virginia. 258 p.
Fyfe, R.W. 1969. Reactions of nesting raptors to intrusion. P. 421-422.
in J.J. Hickey (ed.). Peregrine falcon populations: their biology
and decline. Univ. Wisconsin Press, Madison. 596 p.
·-· ........
i --:
182 .
Fyfe, R.W. and R.R. Olendorff. 1976. Minimizing the dangers of nesting
~ studies to raptors and other sensitive species. Can. Wildl. Serv.
"\,_ Occ. Pap. 23. 16 p.
Fyfe, R.W. and W.H. Prescott. 1973. Endangered raptor breeding terri-
tories near the Mackenzie Highway route and their protection.
Unpubl. Can. Wildl. Serv. rep., Edmonton, Alberta.
Fyfe, R.W., S.A. Temple and T.J. Cade. 1976. The 1975 North American
peregrine falcon survey. Can. Field-Nat. 90: 228-273.
Gabrielson, I.N. and F.C. Lincoln. 1959. The birds of Alaska. Stackpole
Co., and Wildl. Mgmt. Inst.
Gerrard, J.M. and P.N. Gerrard. 1975. Ecological road planning in
[
[
[
[
[
[
northern Saskatchewan. Blue Jay ~3:.131-139. . _..(
Gerrard, J.M., P.N. Gerrard, O.W.A. Wh1tf1eld and W.J. Maher •. 1973. Bald If·~
eagle behaviour study. Part II. Unpubl. rep. to Can. W1ldl. Serv. . .. ·
90 p. { ~
Goodman, A.S. 1977. Northwest Territories guidelines for geological
operations in areas frequented by peregrine falcons. Unpubl. Can.
Wildl. Serv. guidelines, Yellowknife, Northwest Territories. 2 p.
Green, R. 1976. Breeding behavior of Ospreys Pandion haZiaetus in
Scotland. Ibis 118: 475-490.
Grier, J.W. 1969. Bald eagle behavior and productivity responses to
climbing to nests. J. Wildl. Manage. 33: 961-966.
Grier, J.W., C.S. Sindelar, Jr. and D.L. Evans. 1977. Reproduction and
toxicants in Lake of the Woods ospreys. P. 181-192 in J.C. Ogden
(ed.). Trans. N. Am. Osprey Res. Conf., Williamsburg, Virginia.
258 p.
Hagen, Y. 1952. The gyrfalcon (FaZao rustiaoZus L.) in Dovre, Norway.
Skrifter Utigitt av Det Norske Videnskaps-Akademi. I. Mat-Naturv.
Klasse, No. 3. 37 p.
Hancock, D. 1966. David Hancock reports on the bald eagle research
project. Can. Audubon 28(3): 88-92.
Harris, J.T. 1979. The peregrine falcon in Greenland: observing an
endangered species. Univ. Missouri Press, Columbia. 255 p.
Harris, J.T. and D.M. Clement. 1975. Greenland peregrines at their
eyries: a behavioral study of the peregrine falcon. Meddelelser
om Gr0nland 205(3)~ 1-28.
1-83
Haugh, J.R •. 1970. Peregrine falcon survey on the Tanana and Colville
rivers. Unpubl. rep. to Alaska Dep. Fish Game, Fairbanks. 12 p.
~~augh, J.R. 1971. Ecology and present status of cliff-nesting raptors
'i-_ and other birds in arctic Alaska. Unpubl. rep. to Alaska Dep. Fish
!: Game, Fairbanks. 34 p.
Haugh, J.R. 1972. Ecqlogy and present status of birds and mammals in
interior and arctic Alaska. Unpubl. rep. to Alaska Dep. Fish Game,
Fairbanks. 24 p.
Haugh, J.R. 1973. Ecology and present status of cliff-nesting raptors
in arctic and interior Alaska. Unpubl. rep. to Alaska Dep. Fish
Game, Fairbanks. 20 p.
Haugh, J.R. 1976a. Populations and reproductive changes in Alaskan
arctic peregrines. Can. Field-Nat. 90: 359-361.
Haugh, J.R. 1976b. Tanana River of Alaska. P. 254-256 in: R. Fyfe,
S.A. Temple and T.J. Cade. The 1975 North American peregrine
falcon survey. Can. Field-Nat. 90: 228-273.
Haugh, J.R. and K.C. Halperin. 1976. Evaluation of raptor populations:
Portage Glacier area, Denali Highway area, Yukon River pipeline
crossing area, and Yukon River and Porcupine River tributaries.
Unpubl. rep. to Bureau Land Management, Anchorage, Alaska. 58 p.
Hayes, R. 1977. Food habits of northern Yukon peregrines. Unpubl.
rep. to Biol. 400. Trent Univ. and the Yukon Game Branch,
Whitehorse. 24 p.
Hayes, R. and D. Mossop. 1978. The nesting raptor populations located
along the proposed Dempster Lateral gas pipeline corridor. Unpubl.
Yukon Wildlife Branch rep. to Foothills (Yukon) Pipe Line Ltd.,
Calgary, Alberta. 39 p.
Henny, C.J. 1977. California ospreys begin incubation at a frozen
mountain lake. Bird-Banding 48: 274.
Herbert, R.A. and K.G.S. Herbert. 1965. Behavior of peregrine falcons
in the New York City region. Auk 82: 62-94.
Herbert, R.A. and K.G.S. Herbert. 1969. The extirpation of the Hudson
River peregrine falcon population. P. 133-153 in J.J. Hickey (ed.).
Peregrine falc~n populations: their biology and decline. Univ.
Wisconsin Press, Madison.
Hickey, J.J. (ed.). 1969. Peregrine falcon populations: their biology
and decline. Univ. Wisconsin Press, Madison. 596 p.
~ -iiiE
~~-
184
Howard, R.P. and .J.F. Gore (eds.). 1980. A workshop on raptors and
energy developments. Idaho Chap. Wildl. Soc. Rep. No. 1. Boise,
Idaho. 125 p . ...
~
lkowell, J.C. and G.M. Heinzman. 1967. Comparison of nesting sites of
~ bald eagles in central Florida from 1930· to 1965. Auk 84: 602-603.
Hurit, H.E. 1~79. Behavioral patterns of breeding peregrine falcons.
Unpubl. M.S. thesis. Humboldt State Univ., Arcata, Calif. 51 p.
Isleib, M.E. and B. Kessel. 1973. Birds of the North gulf coast -
Prince William Sound region, Alaska. Biol. Pap. Univ. Alaska, No.
14. 149 p.
Jacobson, J.O. 1974. ~Birds. p. 120-176 in Environment Protection Board.
Environmental impact assessment of the portion of the Mackenzie gas
pipeline from Alaska to Alberta. Vol. IV, research reports. Winnipeg.
Juenemann, B.G. 1973. Habitat evaluations of selectert bald eagle nest
sites on the Chippewa National Forest. Unpubl. M.S. Thesis, Univ.
Minnesota, Minneapolis.
Juenemann, B.G. and L.D. Frenzel. 1972. Habitat evaluations of selected
bald eagle nest sites on the Chippewa National Forest. Paper
presented at the 34th Annu. Midwest Fish Wildl. Cenf., Dec. 10-13,
Des Moines, Iowa. 4 p.
Kaiser, T.E., W.L. Reichel, L.N. Locke, E. Cromartie, A.J. Krynitsky,
T.G. Lamont, B.M. Mulhern, R.M. Prouty, C.J. Stafford and D.M:
Swineford. 1980. Organochlorine pesticide, PCR, and PBB residues
and necropsy data for bald eagles from 29 states --1975-1977.
Pest. ~1on. J . 13 ( 4) : 145-149.
Kennedy, R.S. 1977. The status of the osprey in Tidewater, Virginia,
1970-71. P. 121-133 in J.C. Ogden (ed.). Trans. N. Am. Osprey
Res. Conf., Williamsburg, Virginia. 258 p.
Kessel, B. 1978. Raptors and rapto~ habitat along ~he Alaska portion
of the Northwest Alaskan gas pipeline corridor. Unpubl. Univ.
Alaska rep. for Northwest Alaskan Pipeline Co., Salt Lake City,
Utah. 21 p. ·
Kessel, B. and T.J. Cade. 1958. Birds of the Colville River, Northern
Alaska. Biol. Pap. Univ. Alaska, No. 2. 83 p.
King, J.G., F.C. Robards and C.J. Lensink. 1972. Census of the bald
eagle breeding population in southeast Alaska. J. Wildl. Manage.
36(4): 1292-1295.
Kochert, M.N. 1972. Population status and chemical contamination in
golden ea9les in southwestern Idaho. Unpubl. M.S. Thesis, Univ.
Idaho, Moscow. 115 p.
I
j
~
[
[
185
: Kumari, E. 1974. Past and present of the peregrine falcon in Estonia.
.... In: Estonian wetlands and their life. Valgus. Tallinn. P. 230-253 .
~ ~t, E. 1980. Distribution and breeding biology of raptors in th~
-Thelen River area, Northwest Territories, 1957-1969. Can. Field-
Nat. 94: 121-130.
Lincer, J.L., W~S. Clark and M.N. LeFranc, Jr. 1979. Working biblio-
graphy of the bald eagle. Nat1. Wildl. Fed. Sci. & Tech. Series,
No. 2. 344 p.
LGL Ltd. 1975. A summary of ornithological recommendations in regard
to the proposed gas pipeline route. Unpubl. rep. by LGL Ltd.,
Edmonton, Alberta, to Canadian Arctic Gas Study Ltd. 37 p.
Mathisen, J.E. 1968. Effects of human disturbance on nesting of bald
eagles. J. Wildl. Manage. 32: 1-6.
Melo, J. 1975. Logging around an osprey nest site -an observation.
J. Forest. 73: 724-725.
Mosher, J.A. and C.M. White. 1976. "Directional exposure of golden
eagle nests. Can. Field-Nat. 90: 356-359.
Mossop, D. and P. Milligan. 1977. Alcan pipeline proposal in relation
to non-migratory birds. P. 97-112 in Alaska Highway gas pipeline
project: environmental concerns and recommendations of the Yukon
Wildlife Branch. Yukon Wildlife Branch, Whitehorse.·
Mossop, D., R.W. ·Nelson, A.L. ~elson and R. Hayes. 1978. Birds of
prey and the Dempster Highway transportation corridor. Yukon
Wildlife Branch, Whitehorse. 87 p.
Muir, R.D. 1973. A study of the breeding biology of arctic gyrfalcons.
Unpubl. Rep., Can. ~1-ildl. Serv., Ottawa, Ontario. 81 p.
Murie, O.J. 1959. Fauna of the Aleutian Islands and Alaska Peninsula.
N. Am. Fauna No. 61.
National Energy Board. 1977. Reasons for decision, northern pipelines.
Vol. 3. Ottawa, Ontario.
Nelson, M. 1980. Historic overview of raptor-powerline problems and
raptor management priorities. P. 6-8 in R.P. Howard and J.F. Gore
(eds.). A workshop on raptors and energy developments. Idaho
Chap. Wildl. Soc. Rep. No. 1. Boise, Idaho. 125 p.
·-·_,-_-:_·~_--
--"
186
Nelson, R.W. 1973. Field techniques in a study of the behavior of
peregrine falcons. Raptor Res. 7{3/4): 78-96.
~~elson, R.W. 1976. Behavioral aspects of egg breakage in peregrine
~-falcons. Can. Field-Nat. 90: 320-329.
·~
Nelson, R.W. 1977. Behavioral ecology of coastal peregrines (FaZao
peregrinus peaZei). Unpubl. Ph.D. Thesis, Univ. Calgary, Calgary,
Alberta. 490 p.
Nelson, R.W. 1978. Gyrfalcon ecology and behavior in the north central
Yukon, 1978. Progress Rep. No. 1 to World Wildlife Fund {Canada),
Toronto, Ontario. 36 p.
Nelson, R.W. 1979. Flying with raptors: dangers and discoveries. .
Paper presented at the Raptor Res. Found. Annu. Meeting, 8-12 Nov.,
Davis, Cal if.
Nelson, R.~. and A.L. Nelson. 1978. Effects of the Dempster Highway on
nesting falcons and eagles. ·unpubl.-rep. for Yukon Wildlife Branch,
Whitehorse. 88 p. ·
Nethersole-Thompsen, D. and A. Watson. 1974. The Cairngorms: their
natural history and scenery. Collins, London. 286 p.
Newman, J.R., W.H. Brennan and L.M. Smith. 1977. Twelve-year changes
in nesting patterns of bald eagles (HaZiaeetus ZeuaoaephaZus) on
San Juan Island, Washington. Murrelet 58: 37-39.
Newton, I. 1976. Population limitation in diurnal raptors. Can. Field-
Nat. 90: 274-300.
Newton, I. 1979a. Effects of human persecution on European raptors.
Raptor Res. 13{3): 65-78.
Newton, I. 1979b. Population ecology of raptors. Buteo Books,
Vermillion, South Dakota. 399 p.
Northern Pipeline Agency. 1978. Environmental requirements for the
pipeline for the transmission of natural gas from Alaska across
Canada. Initial draft. Ottawa, Ontario.
Northern Pipeline Agency. 1979. Yukon environmental terms, conditions
'
f
j
and related guidelines, Alaska Highway gas pipeline. Draft II. j
Ottawa, Ontario.
Olendorff, R.R. 1975. Golden eagle country. Alfred A. Knopf, New York.
202 p. J
l
187
Olendorff, R.R. and M.N. Kochert. 1977. Land management and conservation
of birds of prey. Proc. ICBP World Conf. Birds of Prey, Vienna, 1975.
P. 294-306.
~~ndorff, R.R., R.S. Motroni and M.W. Call. 1980. Raptor management
-the state of the art in 1980. USDI-BLM Tech. note No. 345, Sup. Doc.
U.S. Gov. Printing Off., Washington, D.C. 56 p.
Olendorff, R.R. and W.O. Zeedyk. 1978. Land management for the conserva-
tion of endangered birds. P. 419-428 in S.A. Temple (ed.).
Endangered birds: management techniques for preserving threatened
species. Univ. Wisconsin Press, Madison. ·
Olsen, P. and J. Olsen. 1978. Alleviating the impact of human disturbance
on the breeding peregrine falcon: 1. ornithologists. Corella 2(1):
1-7.
Peacock, E. 1980. Powerline electrocution of raptors.
Howard and J.F. Gore (eds.). A·workshop on raptors
developments. Idaho Chap. Wildl. Soc. Rep. No. 1.
125 p.
P. 2-5 in R.P.
and energy
Boise, Idaho. -.
-
Peakall, D. B. 1976. The peregrine falcon (PaZao peregrinus) and pesti-
cides. Can. Field-Nat. 90: 301-307.
Peakall, D.B., T.J. Cade, C.M. White and J.R. Haugh. 1975. Organochlorine
residues in Alaskan peregrines. Pestic. Manit. J. 8(4): 255-260.
Platt, J.B. 1975. A study of diurnal raptors that nest on the Yukon
North Slope with special emphasis on the behaviour of gyrfalcons
during experimental overflights by aircraft. Arctic Gas Biol. Rep.
Ser. 30(2). 40 p. ·
Platt, J.B. 1976. Gyrfalcon nest site selection and winter activity in
the western Canadian arctic. Can. Field-Nat. 90: 338-345.
Platt, J.B. and C. E. Tull. 1977. A study of wintering and nesting
gyrfalcons on the Yukon North Slope during 1975 with emphasis on
their behaviour during experimental overflights by helicopter.
Arctic Gas Biol. Rep. Ser. 35(1). 90 p.
Porter, R.D. and C.M. White. 1973. The peregrine falcon in Utah,
emphasizing ecology and competition with the prairie falcon.
Brigham Young Univ. Sci. Bull., Biol. Ser. 18(1): 1-74.
Postupalsky, S. 1978. The bald eagles return. Nat. Hist. 87(7): 62-63.
.-
188
·-
Ratcliffe, D.A. 1962. Breeding density in the peregrine (Falco
pePegrinus) and raven (Corvus corax). Ibis 104: 13-39.
~tcliffe, D.A. 1969. Population trends of the peregrine falcon in
=-~ Great Britain. P. 239-2 _69 in J.J. Hickey (ed.). Peregrine falcon
populations: their biology and decline. Univ. Wisconsin Press,
Madison.
Reese, J.G. 1977. Reproductive success of ospreys in central Chesapeake
Bay. Auk 94: 202-221.
Renewable Resources Consulting Services Ltd. (RRCS). 1973. Raptorial
bird nesting sites along proposed pipeline routes in Alaska. Unpubl.
rep. for Northern Engineering Services Ltd., Calgary, -Alberta. 40 p.
R.hodes, L.I. 1977. An osprey population aided by nest structures. P.
77-83 in J.C. Ogden (ed.). Trans. N. Am. Osprey Res. Conf.,
Williamsburg, Virginia. 258 p.
Ritchie, R.J. 1976. A suggested approach to resource planning for the
upper Yukon River. Unpub1. M.S. Thesis, Univ. Alaska, Fairbanks.
113 p.
Ritchie, R.J. 1978. Inventory and evaluation of, and recommendations
for, cliff-nesting raptor habitat in Naval Petroleum Reserve-Alaska
(NPR-A). Unpubl. rep. U.S. Fish Wildl. Serv., Anchorage, Alaska.
88 P.
Robards, F.C. and J.I. Hodges. 1977. Observations from 2760 bald eagle
nests in southeast Alaska. Unpubl. progress rep., U.S. Fish Wildl.
Serv., Juneau, Alaska. 27 p.
Roseneau, O.G. 1969. Numbers and productivity in gyrfalcons on the
Seward Peninsula, Alaska .. rn J.D. McGowan and R.B. Weeden (eds.).
Game Bird Proj. Annu. Segment Rep. Vol. 10, Alaska Dep. Fish Game.
Fed. Aid in Wild1. Restoration, Proj. Rep. W-13-R-3 and W-17-1.
Juneau, Alaska. 44 p.
Roseneau, D.G. 1970. Density and productivity of gyrfalcons on the
Seward Peninsula, Alaska. In R.B. ~~eeden and O.G. Roseneau (eds.).
Game Bird Proj. Annu. Segment Rep. Vol. 11, Alaska Dep. Fish Game.
Fed. Aid in Wild1. Restoration, Proj. Rep. W-17-1 and 2. Juneau,
Alaska. 25 p.
Roseneau, O.G. 1972. Summer distribution, numbers, and feeding habits
of the gyrfalcons (Falco rusticolus L.) on the Seward Peninsula,
Alaska. Unpubl. M.S. Thesis, Univ. Alaska, Fairbanks. 124 p.
j
J
189
Roseneau, D.G. 1974. A continuation of studies of raptorial bird
nesting sites along proposed pipeline routes in Alaska. Unpubl.
rep. to Canadian Arctic Gas Study Ltd., Calgary, Alberta. 69 p.
Roseneau, D. G. 1979. Raptor restrictions · statement. Unpubl. rep. by
LGL Ecol. Res. Assoc., Inc., Fairbanks, Alaska, to Fluor Northwest,
Inc. 11 p.
Roseneau, D.G. and P.J. Bente. 1979. A raptor survey of the proposed
Northwest Alaskan Pipeline Company gas pipeline route: the U.S.-
Canada border to Prudhoe Bay, Alaska. Unpubl. rep. by LGL Ecol.
Res. Assoc. Inc., Fairbanks, Alaska, to Fluor Northwest, Inc. 82 p.
Roseneau, D.G. and P.J. Bente. 1980a. Peregrine falcon surveys in
selected areas of nesting habitat along the proposed Northwest
Alaskan Pipeline Company route in Alaska, 1980. Interim rep. by
LGL Ecol. Res. Assoc. Inc., Fairbanks, Alaska, to Fluor Northwest,
Inc. 26 p.
Roseneau, D.G. and P.J. Bente. 1980b. Aerial surveys of tree-nesting
raptors along the proposed Northwest Alaskan Pipeline Company pipe-
line route: U.S.-Canada border to the Chandalar Shelf, 18 April-
10 May 1980. Interim rep. by LGL Ecol. Res. Assoc. Inc., Fairbanks,
Alaska, to Fluor Northwest, Inc. 31 p.
Roseneau, O.G., P.J. Bente and A.M. Springer. 1980. Numbers and status
of peregrine falcons . on the middle Yukon River, lower Yukon River
and in the Arctic National Wildlife Range. Unpubl. rep. by FALCO
to U.S. Fish Wildl. Serv., Office of Endangered Species, Anchorage,
A 1 aska. 53 p.
Roseneau, O.G. and J.A. Curatolo. 1976. Distribution and movements of
the Porcupine caribou herd in northeastern Alaska and Yukon
Territory, 1975. Arctic Gas Biol. Rep. Ser. 36(1). 82 p.
Roseneau, D. G., H. Reynolds III and C.M. White. 1976. Northeastern
Alaska. P. 243-245 in R.W. Fyfe, S.A. Temple and T.J. Cade. The
1975 North American peregrine falcon survey. Can. Field-Nat. 90:
228-273.
Schmidt, R.K. 1977. Birds. P. 315-404 in Alaska Highway Pipeline
Panel. Initial environmental evaluation of th.e proposed Alaska
Highway gas pipeline, Yukon Territory. Winnipeg, Manitoba.
Scott, F. and D.L. Surkan. 1976 .. An unsuspected osprey concentration
in west-central Saskatchewan. Blue Jay 34: 98-99.
-. .
!-:
190
Sherrod, S.K., C.M! White and F.S.L. Williamson. 1976. Biology of the
bald eagle on Amchitka Island, Alaska. Living Bird 15: 143-182.
~now, C. 1973. Golden eagle Aquila ahrysaetos. Habitat Management
~~~ Series for Unique or Endangered Species. Rep. No. 7. Bureau Land
Management Tech. Note. 52 p.
Spitzer, P.R. 1977. Osprey egg and nestling transfers their value
as ecological experiments and as management procedures. P. 171-182
in S.A. Temple (ed.) Management techniques for preserving threatened
species. Univ. Wisconsin Press, Madison. 466 p.
Springer, A.M. 1975. Observations on the summer diet of rough-legged
hawks from Alaska. Condor 77: 338-339.
Springer, A.M., D.G. Roseneau and P.J. Bente. 1979a. Numbers and status
of peregrine falcons on portions of the Colville River and Yukon
River, Alaska. Unpubl. rep. by LGL Ecol. Res. Assoc. Inc., Fairbanks,
Alaska, to u.s. Fish Wildl. Serv., Office of Endangered Species,
Anchorage, Alaska. 36 p.
Springer, A.M., D.G. Roseneau, P.J. Bente, W. Walker II and R.G. Clarke.
1979b. Numbers and status of peregrine falcons on the Colville
River, middle Yukon River and lower Yukon River, Alaska, 1979.
Unpubl. rep. by LGL Ecol. Res. Assoc. Inc., Fairbanks, Alaska, to
U.S. Fish Wildl. Serv., Office of Endangered Species, Anchorage,
Alaska. 69 p.
Swartz, L.G., W. Walker II, D.G. Roseneau and A.M. Springer. 1975.
Populations of gyrfalcons on the Seward Peninsula, Alaska, 1968-
1972. P. 71-75 in J.R. Murphy, C.M. White and B.E. Harrel (eds.).
Population status of raptors. Raptor Res. Rep. No. 3, Raptor
Res. Found., Vermillion, South Dakota.
Swenson, J.E. 1975.
National Park.
146 p.
Ecology of the bald eagle and osprey in Yellowstone
Unpubl. M.S. Thesis, Montana State Univ., Bozeman.
Theberge, J.B. and D. Gauthier. 1978. Inventory of raptors in the
Slims River drainage, Kluane National Park. Unpubl. rep. to
Parks Canada, Prairie Region, Winnipeg, Manitoba. 54 p._
Tull, C.E. 1979. Raptor nest sites along segments 2-6, Shakwak Highway,
British Columbia-Yukon, May-June 1979. Unpubl. rep. by LGL Ltd.,
Edmonton, Alberta, to Public Works Canada, Shakwak Project,
Whitehorse, Yukon. 66 p.
J
I
J
191
_U.S. Dep. Interior (USDI). 1979. Snake River birds of prey special
~ report to the Secretary of the Interior. Bureau Land Management,
"\_,._ Boise, Idaho. 142 p.
Van Daele, L.J. 1980. Osprey and power poles in Idaho. P. 104-116 in
R.P. Howard and J.F. Gore (eds.}. A workshop on raptors and energy
developments. Idaho Chap. Wildl. Soc. Rep. No. 1. Boise, Idaho.
125 p.
Walker, W. 1977. Chlorinated hydrocarbon pollutants in Alaska gyrfalcons
and their prey. Auk 94: 442-447.
Weekes, F. 1974. A survey of bald eagle nesting attempts in southern
Ontario, 1969-1973. Can. Field-Nat. 88: 415-419.
Weekes, F.M. 1975a. Bald eagle nesting attempts in southern Ontario in
1974. Can. Field-Nat. 89: 438-444.
Weekes, F.M. 1975b. Behavior of a young bald eagle at a southern
Ontario nest. Can. Field-Nat. 89(1}: 35-40.
White, C.M. 1974a. The peregrine falcon in the region of the Alaska
Pipeline Yukon River crossing --Stevens Village to Tanana, Yukon
River. Interim rep. to U.S. Fish Wildl. Ser., Anchorage, Alaska. 6
p.
White, C.M. 1974b. The 1974 raptor survey of the Alaska pipeline
between Franklin Bluffs and B"ig Delta. Interim rep. to U.S. Fish
Wildl. Serv., Anchorage, Alaska. 10 p.
White, C.M. 1974c .. Hunting range of a breeding peregrine falcon on
Franklin Bluffs, Sagavanirktok River. Interim rep. to U.S. Fish
Wildl. Serv., Anchorage, Alaska. 5 p.
White, C.M. 1975. Studies on peregrine falcons in the Aleutian Islands.
P. 33-50 in J.R. Murphy, C.M. White and B.E. Harrell (eds.).
Population status of raptors. Raptor Res. Rep. No. 3. Raptor Res.
Found., Verm·illion, South Dakota.
White, c.r-1. 1976. Aleutian Islands. P. 262-263 in R.H. Fyfe, S.A.
· Temple and T.J. Cade. The 1975 North American peregrine falcon
survey. Can. Field-Nat. 90: 228-273.
White, C.M. and T.J. Cade. 1971. Cliff-nesting raptors and ravens along
the Colville River in arctic Alaska. Living Bird 10: 107-150.
192
White, C.M. and T.J. Cade. 1975. Raptor studies along the proposed
Sustina powerline corridors, oil pipeline and in the Yukon and
Colville River regions of Alaska. Unpubl. combined report for U.S. ~-Fish Wildl. Serv., Bureau Land Management, Natl. Park Serv.,
Arctic Inst. N. Am., and Am. Mus. Nat. Hist. 28 p. !
White, C.M. and T.J. Cade. 1977. Long term trends of peregrine popula-
tions in Alaska. ·p, 63-72 Proc. ICBP World Conf. on Birds on Prey.
Vienna, 1975~
White, C.M., W.B. Emison and F.S.L. Williamson. 1973. DOE in a resident
Aleutian Island peregrine population. Condor 75: 306-311.
White, C.M. and T.D. Ray. 1972. Survey of cliff-nesting raptors along
the Trans-Alaskan pipeline corridor, Alaska. Interim rep. to Bur.
Sport Fish. Wildl., Anchorage, Alaska. 9 p.
White, C.M., T.D. Ray and L.W. Sowl. 1977. The 1970-1972-1974 raptor
surveys along the Trans-Alaskan Oil Pipeline. Proc. ICBP World
Conf. on Birds of Prey. Vienna, 1975. P. 222-227.
White, C.M. and D.G·. Roseneau. 1970. Observations on food, nesting,
and winter populations of large North American falcons. Condor 72:
113-115.
White, C.M., D.G. Roseneau and M. Hehnke. 1976. Gulf coast of Alaska.
P. 259-261 in R. Fyfe, S. Temple and T.J. Cade. The 1975 North
American peregrine falcon survey. Can. Field-Nat. 90: 259-261.
White, C.M. and S.K. Sherrod. 1973. Advantages and disadvantages of
the use of rotor-winged aircraft in raptor surveys. Raptor Res.
7(3/4): 97-104.
White, C.M. and J.H. Streater. 1970a. Survey of cliff-nesting raptors
along the Trans-Alaskan pipeline corridor, Alaska. Interim rep. to
Bur. Sport Fish. Wildl., Anchorage, Alaska. 8 p.
White, C.M. and J.H. Streater. 1970b. The oil pipeline and peregrines
in Alaska. P. 241 in T.J. Cade and R. Fyfe. The North American
peregrine survey, 1970. Can. Field-Nat. 84: 231-245.
White, C.M., T. Thurow and J.F. Sullivan. 1979. Effects of controlled
disturbance on ferruginous hawks as may occur du~ing geothermal
energy development. P. 777-780 in Expanding the Geothermal Frontier,
Transactions. Vol. 3. Geothermal Resources Counc., Davis,
California.
l
J
193
-, Windsor, J. 1977. The response of peregrine fa 1 cons (Fa teo peregl'inus)
~ to aircraft and human disturbance. Can. Wildl. Serv., Mackenzie -~ ~-Valley Pipeline Investigations, Ottawa, Ontario. 87 p. ·
i:
Windsor, J. 1979. Birds of prey in the
the Alaska Highway and proposed gas
Yukon Wildlife Branch, Whitehorse.
southern Yukon in relation to
pipeline. Unpubl. rep. to
173 p.
Zarn, M. 1974. Osprey Pandion hatiaetus carotinensis. Habitat Manage-
ment Series for Unique or Endangered Species, Rep. No. 12. Bureau
Land Management Tech·. Note. 41 p.
~ •
194
4.2 PERSONAL COMMUNICATIONS AND UNPUBLISHED DATA
~ J. L. B. Albuquerque, Parai ba, Brazi 1
~~E. Ambrose, US~WS, Office of Endangered Species, Fairbanks, Alaska ..
C. Anderson, Kirkland, Washing~on
E. Baddaloo, Foothills Pipe Line {Yukon) Ltd., Calgary, Alberta
U. Banasch, Canadian Wildlife Service, Edmonton, Alberta
T. Bendock, Alaska Department of Fish and Game, Fairbanks, Alaska
D~ Benfield, USFWS, Office of Endangered Species, Anchorage, Alaska
P.J. ·Bente, University of Alaska, Fairbanks, Alaska
A. Breitkreutz, B.C. Fish and Wildlife Branch, Smithers, British Columbia
J. Burns, Alaska Department of Fish and Game, Fairbanks, Alaska
J.S. Campbell, Black Diamond, Alberta
B. Durtsche, Bureau of Land Management, Fairbanks, Alaska
G. Elliott, USFWS, Office of Special Studies, Anchorage, Alaska
J. Enderson, Colorado College, Colorado Springs, Colorado --. .
R.W. Fyfe, Canadian Wildlife Service, Edmonton, Alberta
D.O. Gibson, University of Alaska Museum, Fairbanks, Alaska ' . ~
D. Grisco, address unknown :1 1:/
F. Gudmundsson, Museum of Natural History, Reykjavik, Iceland' {deceased)
J.R. Haugh, U.S. Geological Survey, Anchorage, Alaska
D. Haynes(Barnard), student, University of Alaska, Fairbanks, Alaska
R. Hemmen, Alaska Department of Transportation and Public Safety, Fish
and Wildlife Protection, Fairbanks, Al"aska
L. Johnston-Beaver, Canadian Wildlife Service, Edmonton, Alberta
B. Kessel, University of Alaska ~1useum, Fairbanks, Alaska
J. Koranda, address unknown
C. Lowe, graduate student, University of Alaska, Fairbanks, Alaska (deceased)
M.D. Mangus, address unknown
J. McGowan, Alaska Department of Fish and Game, Fairbanks, Alaska
D. Money, USFWS, Office of Endangered Species, Anchorage, Alaska
D. Mossop, Yukon Game Branch, Whitehorse, Yukon
B. Olendorff, Bureau af Land Management, Sacramento, California
L. Peet, North Pole Air Service, North Pole, Alaska
195
., K. Persons, Arctic Project Office, University of Alaska, Fairbanks, Alaska
;.P. Reynolds, Bureau of Land Management, Fairbanks, Alaska
~.J. Ritchie, Alaska Biological Research, Fairbanks, Alaska ..
F. -Robards, USFWS, Juneau, Alaska (retired)
D. Roby, graduate student, University of Alaska, Fairbanks, Ala-ska
L. Sowl, USFWS, Anchorage, Alaska
A.M. Springer, Bodega Bay Institute of Pollution Ecology, Berkeley, California
H. Springer, Alaska Department of Transportation and Public Safety, Fairbanks,
Alaska
t.G. Swartz, University of Alaska, Fairbanks, Alaska
C. Thelander, Biosystems Analysis Inc., San Francisco, California
W. Tilton, North Pole, Alaska
D. Tweet, address unknown
W. Walker II, Lawrence Berkeley Radiation Laboratory, University of Califo
Berkeley, California
D. Weir, Newtonmore, Invernesshire, Scotland
C.M. White, Brigham Young University, Provo, Utah
K.P . Whitten, Alaska Department of Fish and Game, Fairbanks, Alaska
J. Windsor, graduate student, University of Saskatche\A/an, Saskatoon,
Saskatchewan
C. Yanagawa, Alaska Department of Fish and Game, State Pipeline Coordinator's
Office, Fairbanks, Alaska
196
5. APPENDICES
5.1 PRODUCTIVITY OF PEREGRINE FALCONS
~ The data that have been summarized to prepare Tables 3, 5 and l are
presented in detail in the following sections.
5.1.1 Sagavanirktok River
In 1970, two pairs that nested on Franklin Bluffs produced five
nestlings of advanced age. A third pair that nested on Sagwon Bluffs
may have failed in its attempt to ne~t (White and Streater 1970a,b).
In 1972, two pairs that nested on Franklin . Bluffs hatched five
nestlings, and a third pair failed in its attempt to nest there. A
fourth pair occupied Sagwon Bluffs that ·year, but failed in its attempt
to nest at that location (White and Ray 1972).
Two pairs nested on Sagwon Bluffs and two pairs nested on Franklin
Bluffs in '1974. A total of 11 eggs were produced, eight of which hatched
(Roseneau et al. 1976). Both pairs that nested on Franklin Bluffs failed
to fledge any young. One pair that nested on Sagwon Bluffs fledged one
young and a second pair at that location fledged two nestlings (Reynolds,
unpubl. data; Roseneau, unpubl. data).
In 1975, three pairs of peregrines nested along the Sagavanirktok
River, one on Franklin Bluffs and two on Sagwon Bluffs. These pairs
produced 10 eggs, five of which hatched, but only one nestling is known
to have eventually fledged from these nesting attempts (Roseneau et al.
1976). Both nesting attempts on Sagwon Bluffs failed that year (Reynolds,
unpubl. data; Roseneau, unpubl. data).
No productivity data were obtained at Franklin Bluffs in 1976. Only
one nest site was occupied at Sagwon Bluffs in 1976; it was not success-
ful (Capodice 1976).
--.-~~ ' ' -< --
197
The productivity of peregrines nesting al~ng the Sagavanirktok River
;_may have improved in 1979. That year two pairs nested on Franklin
"P~ iij~ffs, one pair n~sted on Sagwon Bluffs and one pair .nested on the east
siJe of the river at a series of small bluffs ('East Sagwon') about 1 mi
southeast of TAPS Pump Station No. 2. At least 13 eggs were produced by
the four pairs. Nine of the eggs at three of the nests successfully
hatched, but the one pair on Sagwon Bluffs abandoned its clutch previous
to 7 July (Roseneau and Bente 1979). Data on fledging success were not
obtained in 1979; however, it is known that at least one nestling did
fledge from the nest site at 'East Sagwon• (Roseneau and Bente 1979, 1980a).
If it is assumed that up to 50% of all .successfully hatched chicks died
(a relatively high estimate, especially considering the favorable weather
conditions in 1979}, then at least four or five nestlings may possbi ly
have fledged in the drainage in 1979. That same year 2.5 nestlings of
advanced age per successful pair (n = 6) were found at Colville River
nest sites at a comparable latitude (Springer et al. 1979b). --
.
' ,f
Some productivity data were also obtained in 1980. At Fra!rl.klin ,;T
Bluffs one pair .probably did not lay eggs at all, but the second pair in
this section of the river produced a clutch of four eggs and eventually
fledged two nestlings (Roseneau and Bente 1980a). Peregrines did not
occupy Sagwon Bluffs in 1980; however, one individual was present a few
miles south of the bluffs (Durtsche, pers. comm.). A pair did nest
at 'East Sagwon•, but productivity data were not collected from that
location (Durtsche, pers. comm.). Without data from the 'East Sagwon•
nest site, we can only speculate that total productivity in the
Sagavanirktok drainage may have been lower in 1980 than in 1979.
5. 1. 2 Yukon River
In 1974 only two of the five pairs of peregrines present in this
section of nesting habitat apparently produced nestlings that may have
fledged (White 1974a,b; Haugh and Halperin 1976). In 1975, when one
198
single individual and three pairs were present, the three pairs
._successfully produced seven large nestlings {Haugh and Halperin 1976;
,~brose, pers. comm.). In 1976, four of the six pairs present produced
a total of nine nestlings (Haugh and Halperin 1976; Ambrose, pers. comm.).
The lowest known productivity occurred in 1979, when only one single
adult and three pairs were present. Only one of the three pairs was
successful that year, and that pair produced only one nestling to near
fledging age (Springer et aZ. 1979b). In 1980, productivity rebounded,
and attained the highest level ever recorded. Four of the six pairs
present successfully produced 11 nestlings to near fledging age that
year {Roseneau et aZ. 1980).
5.1.3 Tanana River
The productivity of peregrines inhabiting the Tanana drainage
declined markedly after about 1968. By 1975 no nestlings were produced
by the few remaining birds, but since 1975, some nestlings have been
produced by the few pairs that have been found to be present. In 1977
the three pairs present were thought to have successfully fledged
nestlings (Kessel 1978; Ritchie, pers. comm.). Only one pair was confirmed
to have at least one chick that year (Kessel 1978); however, all three
pairs were still bringing food to their respective nest ledges during
July, and nestlings were heard begging for food (Ritchie, pers. comm.).
In 1978 four pairs of peregrines were present along this river
course (Hemmen, pers. comm.). Two pairs probably fledged one young each,
one pair probably fledged four young, and one pair reared three large
young (from four eggs), all of which died previous to fledging. In 1979,
of three pairs present, two successfully fledged two nestlings each
{Roseneau and Bente 1979; Ritchie, pers. comm). Two of four pairs present
in 1980 successfully fledged a total of five nestlings, two at one nest
site and three at another (Roseneau and Bente 1980a).
-----...
199
5.2 NESTING PHENOLOGY OF PEREGRINE FALCONS
~. The data that have been used to prepare Figure 1 are presented in
~-
detail in this section. Phenological data reported here from Cade (1960)
for arctic and interior regions in Alaska were determined using 7 d as
the time required to lay a complete clutch of four eggs, 29 d for
incubation and 35-40 d for the nestling period between hatching and
fledging. All other data reported here are based on 7 d to lay a complete
clutch of four eggs, 34 d for incubation to allow for the last egg
(usually a female) to hatch, and 40 d for the nestling period to allow
the last female to fledge. These new intervals reflect information from
recent literature, from field observations and from observations of
captive-bred peregrines. Calculations of dates of phenological events
are based on the estimated ages of nestlings at the time nest sites were
visited; in general, experienced observers can usually estimate the age
of broods to within ± 2 d.
5.2.1 Arctic Slope
Cade (1960) gave some information on arrival dates of peregrines on
the Arctic Slope of Ala~ka. He reported that birds were not seen on the
Colville River between 25 March and 19 April 1953, but that a pair was
present on the nearby Anaktuvuk River on 4 May. That pair had apparently
been there since 1 May of that year (Kessel and Cade 1958). Cade (1960)
also reported that between 4-10 May 1953, several other pairs became
established along the lower Colville River. He suggested that the peak
of arrival on the Arctic Slope probably occurred after mid-r1ay, based on
comparisons of the other reproductive events in the nesting cycle of
arctic and interior Alaskan peregrines.
For the Colville River in 1952, and for other Arctic Slope localities
in other years, the peak of egg-laying occurred during about the first
week of June (Cade 1960). Cade (1960) reported that a few pairs completed
~ •
200
clutches as early as the third week of May, most pairs completed clutches
in the first week of June, some pairs completed egg-laying in the second ·-·ieek of June, and a few pairs occasionally completed clutches as late -·-as the third week of June. These data suggested that the earliest
clutches laid were initiated in the second week of May, and that the
latest clutches were not initiated until sometime in the second week of
June. Cade (1960) also reported that the egg-laying schedule was somewhat
later in 1959 th~n in previous study years. In 19o9 one pair began
laying in the last week of May, 12 pairs began in the first week of June
and six pairs began in the second week of June. That year, the earliest
clutches to be laid were not completed until about the first week of June,
and the latest clutches were not completed until about the third week of
June.
Cade (1960) did not give actual dates of observed hatching or
fledging. Instead, he generalized Arctic Slope and 1nterior data to
describe the following phenological event periods for peregrines breeding
in northern Alaska: egg-laying~ 15 May-21 June, hatching~ 21 June-
21 July, fledging ~ 28 July-1 September, and independence ~ 1 September-
1 October. Kessel and Cade (1958) reported that there were 25 fledged or
nearly fledged young at nest sites in the Colville River drainage between
26 July and 15 August 1952.
In recent years, new observations have been made that can be added
to the data base on the reproductive phenology of peregrines nesting on
the Arctic Slope of Alaska. A few observations from the Colville River
drainage suggest that some peregrines may arrive as early as mid-April
(APFRT 1979; T. Bendock, pers. comm.; Kessel, unpubl. data). The possibility
of mid-April arrival dates on the Arctic Slope in some years is also
suggested by the dates that peregrines start migrating from their South
American wintering grounds (Roseneau, unpubl. data; Springer, unpubl.
data; Thelander, unpubl. data; White, unpubl. data). The peak of arrival
201
probably does not commence until near the end of the first week of-May in
-
~most years, and as late as the third week of May in some years • . ~ ~-~-
~ In 1974, one member of a pair of peregrines attending a nest site at
Sagwon Bluffs was incubating on 13 May (Roseneau, unpubl. data). That
pair had probably arrived at least 2 wk prior to that date. On 4 May
1980 a single peregrine was observed north of Franklin Bluffs, and a
pair of peregrines was observed at a nest site near Sagwon Bluffs (NWA
Location P-211; K. Persons, pers. con~.).
White and . Ray (1972) commented on the late reproductive phenology of
raptors nesting on the Arctic Slope ·in 1972. They found several 5-9-d-old
nestling peregrines along the Sagavanirktok River on 21 July of that year. 111111
By back calculation, these ages indicated that egg-laying began~ 4-8 June,\ ~
clutches were probably completed ~ 10-14 June, and hatching occurred · --· ~
~ 13-17 July. Fledging would probably have occurred~ 17-24 August.
In 1974, a brood of peregrine nestlings at Sagwon Bluffs was estimated
to be~ 18-21 d old on 19 July (Roseneau, unpubl. data). Egg-laying had
probably commenced ~ 21-24 May, the clutch was probably completed ~ 27-30
May, hatching probably occurred during ~ 29 June-2 July, and fledging
would probably have occurred~ 10-13 August.
Nine nestling peregrines, ranging in age from 2-9 d, were found in
three nests along the Sagavanirktok River on 7 July 1979 (Roseneau and
Bente 1979}. Egg-laying was probably initiated~ 20-27 May, and clutches
were probably completed during ~ 26 May-3 June. Hatching probably occurred
during~ 28 June-S July, and fledging should have occurred~ 7-14 August.
At the nest that contained the oldest chicks on 7 July, at least one
nestling was observed flying on ~.12-15 August (White, pers. comm.).
Farther to the west in the Colville River drainage, 15 nestlings were
2~2
. estimated to be between ~ 14-23 d old on 28-31 July 1979 (Springer and
~ . -
~~alker, unpubl. data). These clutches were probably initiated~ 29 May-
-~-June and completed~ 4-13 June. Eggs probably hatched~ 7-16 July,
and fledging probably occurred~ 17-21 August. Reproduction in Colville
River peregrines averaged~ 10-12 d later than reproduction in
Sagavanirktok River peregrines in 1979.
On 2 August 1980, two nestlings estimated to be~ 36-38 d old were
close to fledging age at a nest site on Franklin Bluffs along the
Sagavanirktok River (Roseneau and Bente 1980a). The clutch was probably
initiated on ~ 18 May, and completed by~ 24 May. Hatching probably
occurred ~ 26 June, and fledging was probably complete by 4 August.
Peregrine nestlings on the Colville River had started to fledge at about
the same time as the Sagavanirktok nestlings. During 26 July-4 August,
19 of 29 Colville River nestlings were estimated to be between 35 and 40
d old, and a few were capable of flight (Ambrose, pers. comm.). Nine
other nestlings appeared to be~ 30-32 d old, and one was only~ 20 d
old. Most Colville River nestlings probably fledged during~ 2-12 August,
and one nestling may have fledged as late as~ 17 August. In 1980,
Colville River nestling peregrines fledged~ 13-15 d earlier than they
did in 1979.
These recent data help to illustrate variation among years in the
reproductive phenology of Arctic Slope peregrines. They also help to
illustrate phenological differences among different areas of nesting
habitat within the same region. The recent data also fit within Cade's
(1960) original generalized summary of phenological events for northern
peregrines.
-. ~
·;
203
5.2.2 Interior Alaska
~-Interior Alaskan peregrines (F. p. anatum) initiate and complete
---fneir annual reproductive cycle earlier than Arctic Slope peregrines
(F. p. tundrius)._ Cade (1960) specified the last week of April and the
first week of May for the arrival of peregrines in interior Alaska.
Those t\-10 weeks were when nearly all of the first spring observations
of peregrines were reported in interior Alaska for the years 1950-59
(B. Kessel; unpubl. rec.). The arrival of peregrines in the Tanana and Yukon
river drainages coincided with the arrival of waterfowl and shorebirds,
which are both important groups of peregrine prey species (Cade 1960). -
Cade (1960) further commented that nesting cliffs were immediately
occupied by arriving birds. He gave 6 May 1951 and 3 May 1952 as dates
when mates appeared to arrive simultaneously at Chena Bluffs, near
Fairbanks.
A small sample of records for interior Alaska in the 1950's
suggested that a few pairs of peregrines completed their clutches in the
second week of May, that most clutches were-completed during the third
week of May, and that a few were not completed until the last week of
May (Cade 1960).
In recent years earlier arrival dates have been obtained in interior
Alaska. Data from the Tanana and Yukon river drainages suggest that
some peregrines may arrive as early as late March in some years (APFRT
1979; Roseneau et al. 1980; Bente, unpubl. data; Kessel, unpubl. rec.).
During the period 1960-77, the two earliest arrival dates on record are
1 February 1964, near Clear, Alaska, and 27 February 1965, near Eielson
Air Force Base (Kessel, unpubl. rec.). Both these dates must be con-
sidered unusual. The earliest annual arrival records from 1950-77 include
one on 29 March 1968, near Fairbanks, but the rest (n = 23) fall between
20 April-10 May, and most center around 27 April-6 May (Kessel, unpubl.
rec.). These early arrival dates may include sightings of some peregrines
---
204
·.that are passing through on their way to the Arctic Slope. The records
;t~ first sightings in interior Alaska are probably also biased toward
tl\e:_ latter part of the arrival period, because few represent specific
regular checks of peregrine nesting locations. However, these records
do not appear to be at great variance with the expected effects of normal
variation among years, or from recently calculated periods of egg-laying
for nesting areas in the Yukon River drainage.
A few early records for the arrival of peregrines in interior Alaska
were also obtained during 1978-80. In both 1978 and 1979, a pair of
peregrines nesting along the Tanana River opposite the mouth of the
Robertson River (NWA Location P-21a) was first observed at the cliff on
20 April (Ambrose and Ritchie, pers .. corrm.). In both years this cliff
had been checked a few days prior to that date, and no peregrines were
found. On 24 April 1980, two adult male peregrines were observed
migrating separately into the Tanana River drainage near Tok, Alaska, on ,,
the fr~t of a large influx of waterfowl and sho:ebirds (Roseneau, unpubl.
data) d
The peak arrival date of peregrines in interior Alaska also appears
to vary between years, just as it does on the Arctic Slop~ of Alaska. In
most years, the majority of the peregrines nesting in the Yukon River
system probably do not begin to arrive until about the last week of April,
whereas in some years they may not begin to arrive in large numbers until
the first week of May.
Some information is available on the approximate ages of nestling
peregrines from several interior Alaskan dra1nages. On the upper Yukon
River between Circle, Alaska, and the U.S.-Canada border, 14 young at 10
nest sites were flying strongly by 2-3 August 1967 (Enderson et al. 1968;
Roseneau, unpubl. data). These young had probably fledged ~ 20-26 July,
but at least one 14-15-d-old nestling was found at another nest site on
--"-----.,_ ~
-.:-;"'0:
205
·.
; 5 August 1967. That nestling would not have hatched until ~ 21-23 July,
~and could not have fledged until ~ 28-31 August. That egg_ was probably
.\ot laid until ~ 19 June, but most clutches were probably initiated
~
~ 3-9 May and completed by ~ 10-15 May, and most hatching probably
occurred during ~ 11-17 June.
In the same study area, 21 nestling peregrines were estimated to
have fledged from nest sites during ~ 22-30 July, and six other nestlings
fledged during~ 6-11 August 1978 (Curatolo and Ambrose 1978). In 1979,
the fledging schedule for upper Yukon River peregrines was similar to
that of the previous year (Ambrose 1979, pers. comm.). In 1980, nestling
peregrines fledged an estimated 7-9 d earlier in this section of the
Yukon River (Ambrose, pers. comm.). Most eggs were probably laid~ 4-12
May and most hatching probably occurred~ 13-21 June in 1978 and 1979;
the corresponding 1980 dates were~ 27 April-4 May and~ 5-13 June,
respectively.
Farther north, in the Porcupine River drainage, 13 large nestlings
that were~ 25-28 d old were found at nest _ sites on 11-13 July 1976
(Springer and Walker, unpubl. data). Fledging probably occurred~ 23-28
July. Back calculations suggested that clutches were initiated~ 6-12
May and completed~ 12-17 May, and that hatching probably occurred~
14-19 June. In 1979, 19 nestlings from the same study area probalby
fledged during late July and the first few days of August (Curatolo and
Ritchie 1979; Ritchie, pers. comm.). In 1980, a smaller group of
nestlings from the Porcupine River drainage probably fledged~ 1 wk
earlier (Ritchie, pers. comm.).
Along the lower Yukon River in 1979, the following approximate
phenological sequence of events for nesting peregrines were
reported by Roseneau et aZ. (1980): initiation of clutches, 6-20 May
(:X = 13 May); clutch completion and beginning of incubation, 13-27 Hay
(x = 20 May); hatching, 16-30 June (x = 23 June);~nd fledging, 26 July-
~.:
206
9 August (x = 2 August). These data were based on back calculations for
~39 nestlings with a mean age of 13.3 d (s.d. = 5.4 d) on 5 July. In
;~]8, Springer et aZ. (1979a,b) reported that the schedule of the nesting
cycle was essentially the same. In 1980~ however, laying began during
26 Aprfl-17 May (I= 6 May), clutches were completed and incubation began
during 3-24 May (x = 13 May), hatching occurred during 6-27 June (x =
16 June) and fledging occurred during 15 July-6 August {x = 26 July)
{Roseneau et aZ. 1980). These dates, -which are~ 7 d ahead of the 1978-79
schedules, were based on back calculations for 69 nestlings with a mean
age of 20.5 d (s.d. = 8.8 d) on 5 July.
In the middle section of the Yukon River, three nestlings in one
brood were only~ 15 d old on 20 July 1976. That clutch was probably
initiated ~ 26-27 May, completed·~ 2-3 June and hatched ~ 5-6 July. The
nestlings could not have fledged until ~ 13-14 August. In 1979 the
single nestling found in this section of the river was about 21 d old on
12 July (Springer et al. 1979b; Roseneau, unpubl. data). That chick
probably hatched on ~ 22 June from an egg laid ~ 20 May. Fledging
probably occurred~ 31 July. In 1980, 11 nestlings with a mean age of
21.2 (s.d. = 3.3 d) on 5 July were observed in the same study area
(Roseneau et al. 1980). These data suggested that clutches were initiated
during 30 April-9 May (x = 2 May), completed during 7-16 May (x = 9 May)
and hatched during 10-19 June (x = 12 June). Fledging was calculated to
have occurred during 20-29 July (x = 22 July).
In the Tanana River drainage, hatching at one nest site occurred on
22 June 1978 {Hemmen, pers. comm.). That clutch was probably initiated
on ~ 14 May and completed by ~ 20 May. Fledging probably occurred on
~ 1 August. In 1980, five nestlings were estimated to have fledged
·-v 14-16 July (Roseneau and Bente 1980a). Clutches were probably
initiated~ 23-29 April and completed~ 29 April-S May, and hatching
probably occurred about 1-7 June.
207
At a nest site along the Elliott Highway, north of Fairbanks, three
d8-20-d-old nestlings were found on 20 July 1970 (Ambrose, USFWS
~prandum of 24 July 1979 to A. Crane, FWS/LE, District 1). That clutch
was probably initiated ~ 24 May and completed ~ 30 May. Hatching probably
occurred ~ 2 July and the nestlings probably fledged ~ 10 August. In
1980, three nestlings fledged ~ 26-28 July from this location (Roseneau
and Bente 1980a); the clutch was probably initiated on~ 8-10 May and
completed by~ 15-17 May. Hatching was calculated to have occured
~ 17-19 June. The nesting cycle at this location was~ 12-14 d earlier
in 1980 than it was in 1979.
208
5.3 FOOD HABITS OF PEREGRINE FALCONS
a_
~-~-The sources that have been used to prepare Tables 8 and 9 are discussed
'!
in more detail in Sections 5.3.1 and 5.3.2, respectively.
5.3.1 Arctic Slope
A few studies list -prey or discuss the food habits of peregrines on
the Arctic Slope of Alaska (e.g., Bee 1958; Kessel and Cade 1958; Cade
1960, 1968; Childs 1969; White and Cade 1971; Springer et aZ. 19i9b). The
two principal sources of information on the prey taken by peregrines nesting
north of the Brooks Range are ~ade (1960) and White and Cade (1971); both
reported data collected on the Colville River. -~ • Some other unpublished data have been obtained since ~~hite and Cade
(1971). In 1974 a few prey items were collected and identified from a nest
site o~ Sagwon Bluffs along the Sagavanirktok River (Roseneau,unpubl.
data) .. The most interesting item in that collection was a shrew (Sorex
spp.), which has not been reported in other Arctic Slope collections.
During 1979 and 1980, additional small collections of prey items were
obtained from a few nest sites at Franklin and Sagwon bluffs on the
Sagavanirktok River (Roseneau and Bente, unpubl. data). Although these
prey items have not yet been subjected to detailed analysis, they appear
to be generally consistent with previous findings; most items appear to
be common Arctic Slope passerines and shorebirds. Only one new prey
species was found --mountain bluebird, a scarce vagrant in the region.
Collections of peregrine prey remains were made in the Colville
River drainage in 1980 by the USFWS; however, this material has not yet
been completely identified (Ambrose, pers. comm.). A considerable number
of other prey items were also collected on the Colville River in 1979.
A brief summary of these data is given by Springer et aZ. (1979b). These
l
209
prey remains also have not undergone detailed analysis; however, the
,species present appear to be generally consistent with previous findings • . ,
~ringer et aZ. (1979b) reported that jaegers, shorebirds (particularly
common snipe, American golden plover, spotted sandpiper, and other
small sandpipers), ptarmigan, and one passerine (Lapland longspur) were
taken frequently that year. Some passerine species were apparently not
as abundant in the prey remains as in the previous collections made by
Cade (1960) and White and Cade (1971). Some annual variation in the prey
taken by Arctic Slope peregrines must be expected to occur because of
annual variations in prey species abundance and vulnerability in this
arctic area:
5.3.2 Interior Alaska
A somewhat greater body of information is available on the food
habits of peregrines that nest in interior Alaska (e.g., Cade 1951, 1960,
1968; Cade et al. 1968; White and Roseneau 1970; Enderson et al. i973;
Ritchie 1976; Hayes 1977; Curatolo and Ritchie 1979; Dotson and Mindell
1979; Springer 'et al. 1979b; Roseneau et al. 1980). Some other data are
also available or becoming available (e.g., Ritchie, unpubl. data;
Roseneau and Bente, unpubl. data; Roseneau and Springer, unpubl. data;
USFWS, unpubl. data). The majority of the information is from collections
made at nest sites along the upper and lower Yukon River and along the
Porcupine River. A large proportion of the more recent collections are
still undergoing detailed·analysis; however, all data obtained to date
are generally consistent with previ·ously published or reported findings.
210
5.4 HUNTING HABITAT OF PEREGRINE FALCONS
~ ~ 5.4.1 F. p. tundrius
Franklin Bluffs and Sagavanirktok River--The male of a pair with small
young in a nest was followed by hel~copter on his hunting flights, and
was observed to make 39 stoops at prey or actual kills (White 1974c).
The male hunted especially over lakes and marshes; 97% of the hunting
attempts were in this habitat type. Only 13% of the hunts occurred in
tussock tundra habitat. Riparian habitat, which is comparatively uncommon
in this area, was infrequently used (3 stoops).
Sagwon Bluffs and Sagavanirktok River --The few data available suggest
that lakes, marshes and wetlands are most important (Roseneau, unpubl.
data; Ambrose, pers. comm.). Adults have been observed bringing prey
·from the northeast, and flying toward and returning from the small lakes
and wetlands to the east. However, some prey remains indicate that some
use is made of tundra uplands (e.g., American golden plover).
Colville River--This drainage has much more extensive riparian habitat;
over 25% of the prey species and approximately 23% of the prey items are
normally associated with riparian habitats (White and Cade 1971; White
1974c). The remaining prey species indicate important use of both lake-
marsh areas and upland tundra habitat. Springer et al. (1979b) obtained
similar data.
Northern Keewatin, Canada --Two pairs with large downy young were
observed from distant blinds; birds were seen returning from 70 hunting
flights (Alliston and Patterson 1978). Hunting occurred mainly in
•
•••• ~
upland areas within l/4 mi of the nesting escarpments; it occurred infre-
quently in the wet lowland areas that extended away from the foot of the es-
carpments. Other studies showed that the densities of nesting passerines were
211
highest in the area near the foot of the escarpment, somewhat lower in
the uplands, and lowest in wet lowlands away from the cliffs. In the 5-d
~bservation period, many recently fledged passerines were present. Their
-·-. presence may have made the suggested hunting habitat preferenc~ atypical
of the overall season.
GreenZand --Falcons apparently hunted over tundra with scattered small
_ lakes --the only habitat available {Harris 1979).
5.4.2 F. p. anatwn
Yukon River --All prey remains from the Yukon River nest sites suggest
that hunting habitat is predominantly the river valley, including the
gulf of air over it (Cade 1960; Cade et aZ. 1968; Springer et aZ. 1979b;
Roseneau, Bente and Springer, unpubl. data). Prey include forest,
wetland and riparian species, most of which become very vulnerable as
they pass by the cliffs along the river, cross over the river, or cross
open non-vegetated areas. Adjacent expanses of lake-marsh wetlands are
more important downstream of Tanana, Alaska. A few prey items suggest
that occasional use is made of nearby upland areas.
Grapefruit Roaks, EZZiott Hightt1a7J --At this interior upland nest site,
prey remains have consisted primarily of wetland, upland and forest
species (Ambrose, pers. comm.; Roseneau, unpubl. data). Several hunting
flights were observed in 1979; when birds flew toward the Tatalina River
wetlands.
Tanana River--Cade (1951, 1960) reported that prey remains from Tanana
River nest sites suggested that hunting habitat is predominantly the
river valley, associated wetlands, and the gulf of air over the river.
Prey included forest, riparian and wetland species that become vulnerable
as they pass along the river, cross the river, or leave, enter or cross
open wetlands and lakes. Observations at Round Lake indicate that
li .
-
---
212
important use is made of the gulf of air over the river, expanses of
~~pen gravel bars and mud flats in the vicinity of the nest site, and
T~ke-marsh wetlands along the north side of the Tanana River that extend
from the nest cliff for several miles to the southeast {Roseneau, Bente
and Springer, unpubl. data). Falcons appear to favor hunting from
perches on top of the nesting cliff or from hilltops to the southeast. ·
Observations at Tower Bluffs indicate important use of the gulf of air
over the Tanana and Robertson rivers, and of the expanses of open gravel
floodplain of the Robertson River (Ambrose and Ritchie, pers. comm.;
Roseneau, Bente and Springer, unpubl. data). Lake-marsh wetlands (north
of the Tanana River) that extend from near the nest cliff for several
miles northw~st toward . Round Lake are probably also hunted. Several
hunting attempts were observed as prey species crossed from one side of
the Robertson River to the other.
Poraurine River --Prey remains consist primarily of wetland, riparian
or woodland species that become vulnerable as they cross the river or
follow it (Curatolo and Ritchie 1979; Roseneau and Springer, unpubl.
data). Some prey species (e.g., singing vole and upland sandpiper)
suggest that upland areas at some distance to either side of the river
are also used to some extent. It is important to note that many of the
nest sites along this smaller, narrower river are in canyons, and that
the over-look and the gulf of air in front of the nests are more
restricted. The local topography may accordingly dictate a greater use
of uplands in comparison to the use at nest sites on the Yukon or Tanana
rivers.
North-aentraZ Yukon Territory~ Canada --Two pairs of peregrines that
nested on mountain sides overlooking a mostly-forested, 0.5-1.0-km-wide
river valley were observed on 62 hunting attempts (Nelson and Nelson 1978).
Most hunts were into the valley and were initiated from cliff perches.
Prey were attacked over the river, among treetops, over meadows, and at
213
several hundred meters above the valley floor. Some hunts apparently
·;took place at higher elevations, where sparse forests and meadows occurred;
~
Jp1and sandpiper remains were found in nests and some flights to and
from such habitats were recorded. In general, the s~me area was used by
the hunting falcons during the spring migration of prey {May) and during
the subsequent summer months {until early August).
CoLorado --A radio-tagged adult female with a recently-fledged young
foraged over varied habitat types, but tended to prefer river drainages
and mixed forest/brushland/meadow habitat. Transition forests were
hunted frequently {Enderson et aZ. 1977; Enderson and Kirven 1979).
214
5.5 HUNTING RANGE OF PEREGRINE FALCONS
5. 5.1 F. p. tundz>ius
FrankZin BZuffs and Sagavanirktok River--Data were obtained by 'shadowing•
a hunting male with a Bell 2068 Jet Ranger helicopter (White 1974c).
The male (at a nest with one egg and two just-hatched young) had a
hunting range of slightly over 120 mi2 in the approximate shape of 3/4
of a circle. The longest distance travelled was 9.1 mi to the southwest
to hunt over tundra. The southeastern quarter of the circle was used
the most; 51% of the 39 kills or attempted kills occurred there. Only
about 13% of the 39 kills or attempted kills occurred in the northeastern
quarter.
5.5.2 F. p. anatum (Alaska and Northern Canada)
Round Lake, Tanana River--Several observations of hunts, a _small
sample of prey remains, and observations of abundant nearby ~rey and
prey habitat suggested that this pair did most of its huntin~! from the
nest cliff or from perches on nearby hills (Roseneau, Bente and Springer,
unpubl. data). Most hunts appeared to occur within 1-2 mi to the east
and southeast of the nest site. Abundant local waterfowl and shorebirds
appeared to be the primary prey. Severa 1 "stoops from the cliff at
American wigeon resulted in near misses, and a stoop at a sandpiper was
successful. Another stoop into the local march after a duck from a
hilltop about 1 mi away was successful.
Mackenzie River~ Canada --A radio-tagged adult was located as much as
30 mi from the nest c 1 iff (~li ndsor, per~. comm. } .
North-aentraZ Yukon Territory, Canada --At two nests on mountain sides
overlooking a river valley, many hunts from perches on the cliffs
·---·-""'"
. . -
-~ ·--
215
·.
went up, down or across ~he river to the maximum observable distance
~(using a telescope) of 2 mi from the cliff (measured on a map; Nelson
~d Nelson 1978).
Lake Athabasca, Northern Alberta~ Canada --A pair hunted a maximum
distance of.,_ 4-5 mi from their nes~ site; mos:t often they flew only
about 1.5-2.5 mi from the nest (Johnston-Beaver, pers. corrm.). _ .
5.5.3 Other Peregrines
Pacific NoPthwes~ --During the breeding season, a radio-tagged adult
female hunted predominantly within a few miles of her nest site (Anderson,
pers. corrm.). In the winter, at a separate locality, the adult female .
hunted over a coastal waterfowl area of.,_ 64 mi2. Several radio-tagged
immature peregrines have ranged over and hunted over an area about four
times as large during winter.
:.
~
NoPthern California --A radio-tagged pai rl hunted regularly within
1•1
.,_ 2 mi of the nest, but sometimes hunted ·o'ut to distances of .,_ 5. 5 mi
(Enderson and Kirven 1979).
Utah --Peregrines hunted up 17 mi from their nests (Porter and White
1973, cited in Newton 1976).
ColoPado --'An instrumented female with fledged young ranged most
frequently within 5 km of the eyrie, but 10-15 sorties included excursions
more distant than 9 km, and up to 18.4 km' (Enderson et al. 1977).
Estonia --Peregrines hunted up to 12.5 mi from their nests (Kumari
1974, cited in Newton 1976).
216
5.6 NORTHWEST TERRITORIES GUIDELINES FOR GEOLOGICAL OPERATIONS ~
~ ·~-IN AREAS FREQUENTED BY PEREGRINE FALCONS
~·-
The following is relevant to camp site selection, air tr~nsport of
personnel from camps to ground work locations, random air reconnaissance
flights, and on-ground activity.
1. Camp sites should be beyond 3.2 kilometers (2 miles) from the cliff
face or 1.6 kilometers (1 mile) from the backside of an uplift area.
This should avoid conflicts with active nest sites, known or
undiscovered. Mode of air support, fixed-wing or helicopter, and
their required takeoff and approach~s could further restrict camp
site selection.
2. Camp sites using fixed-wing air support should be selected so that
approach/takeoff paths would not result in low level flights (less
than 457 meters (1500 feet] above ground level) over cliff areas
from the backside to the cliff face.
3. Helicopter flights to and from a camp site near an uplift area
should descend from and ascend to 457 meters (1500 feet) AGL as
quickly as feasible and avoid low level activity about cliff areas
as above.
4. Aircraft activity within a region should be above 457 meters (1500
feet) AGL whenever possible within safe aircraft operation guide-
lines.
5. Low level reconnaissance should avoid passing from the backside to
the cliff side of an uplift area. Activity should be by approaches
toward the cliff face or along the backside 'paralleling' the
217
'
orientation of the cliff face. This mode of operation is particularly ;
important prior to July 16, the time by when the young should be 2 ~i..
~--~ weeks old, due to the incubating and brooding behavior of the falcon.
6. Prolonged helicopter or fixed-wing activity about a nest site should
be avoided as falcons are aggressive defenders of nest sites and have
been known to make swoops at aircraft. An approach to an area and
then on-foot reconnaissance would be more appropriate.
7. On-ground reconnaissance activity within view (1.6 kilometers [ 1 mile])
of a nest site should be limited to as short a time as possible on any
day with a two to four day interval between repeated activity. Activity
in the vicinity but obscured from the nest site can continue for a ~
longer period of time, however, once your presence has attracted the _;_ 4
bird, so it sits on a perch watching you, flies about sounding alarm
or swoops at you, then activity should be restricted for that day as
above. A definite time per day cannot be given as local weather
conditions and orientation of the nest site to those conditions will
affect the net impact, from prolonged exposure, on eggs or young (up
to 7 weeks of age).
8. Sightings of peregrine falcons should be recorded, plotted on a
1:250,000 scale map if possible, and the birds• reaction to your
presence documented. Location, data and behavior response information
should be forwarded to NJLT. Gar.1e Granch, Yellowknife, H.W.T., and Canadian
Wildlife Service, P.O. Box 2310, Yellowknife, N.W.T.
Diamond drilling, blasting and intensive airborne reconnaissance transects
within a region necessitate specific program discussions to account for
site specific problems and individual operation peculiarities.
by A. S. Goodman
Canadian Wildlife Service,
Yellowknife, N.W.T.
24 February 1977
218
5.7 CHARACTERISTICS OF PEREGRINE FALCON NEST LOCATIONS BETWEEN
2 AND 15 MILES FROM THE ROW
This section is contained in Volume II of this report because of the
sensitive nature of the nest site information.