HomeMy WebLinkAboutAPA3151CHAPTER V
AIRCRAFT DISTURBANCE TO MOULTING
SEA DUCKS, HERSCHEL ISLAND, YUKON
TERRITORY, AUGUST, 1972
M. A. GOLLOP
J. R. GOLDSBERRY
R. A. DAVIS
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TABLE OF CONTENTS
PAGE
INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . • . . . . • . . . . . . . . . . . . 202
SITE DESCRIPTION.......................................... 203
METHODS ...................................................
RESULTS
DISCUSSION ............................................... .
SUMMARY •••••••••••••••••••••••••••.•••••••••••••••••..••..
REFERENCES CITED ....................................•.....
TABLES
1 Population Counts of Molting Sea Ducks at Herschel
Island, Y.T.~ August, 1972 •.•.•••.•...••......•.•..•.•
FIGURES
1 Photograph of area used by molting sea ducks for
shelter .............................................. .
2 Map of the study area ................................ .
3 Photograph of the bluffs used as vantage points for
study ................................................ .
4 Total waterfowl counts~ observation post A, Herschel
Island, Y.T.~ 5 and 6 August, 1972 .......••..•........
5 Number of ducks on land~ observation post A, Herschel
Island,Y.T.~ 5 and 6 August, 1972 •...•....•.•.•.•••...
6 Number of ducks on land as a percentage of the total
ducks observed~ observation post A, Herschel Island,
Y.T.~ 5and6August, 1972 •••.••...•.•••...•..••...•..
7 Number of ducks on land, observation post B, Herschel
Island, Y.T.~ 5 and 6 August, 1972 ...••..••..........•
8 Number of ducks on land as a percentage of the total
ducks observed~ observation post B, Herschel Island,
Y .T. ~ 5 and 6 August, 1972 ............•.....••••......
xii
205
206
227
229
230
231
231
207
208
209
212
213
TABLE OF CONTENTS continued:
FIGURES continued.
9 Number of ducks on land; observation post D, Herschel
Island, Y.T.; 14 August, 1972 ...........•.......•.•...
10 Number of ducks resting or sleeping on water as a
percentage of the total ducks observed; observation
post B, Herschel Island, Y.T.; 5 and 6 August, 1972
ll Number of ducks resting or sleeping on water;
observation post B, Herschel Island, Y.T.; 5 and 6
August, 1972 ......................................... .
12 Number of oldsquaw resting or sleeping on water as a
percentage of the total oldsquaw observed; observation
post A, Herschel Island, Y.T.; 5 and 6 August, 1972
13 Number of surf scoters resting or sleeping on water as
a percentage of the total surf scoters observed;
observation post C, Herschel Island, Y.T.; 5 and 6
August, 1972 ......................................... .
14 Number of oldsquaw swimming or feeding as a percentage
of the total oldsquaw observed; observation post A,
Herschel Island, Y.T.; 5 and 6 August, 1972 .......... .
15 Number of surf scoters swimming or feeding as a
percentage of the total surf scoters observed;
observation post C, Herschel Island, Y.T.; 5 and 6
August, 1972 ......................................... .
16 Number of ducks swimming or feeding as a percentage of
the total ducks observed; observation post B, Herschel
Island, Y.T.; 5 and 6 August, 1972 ...........•........
17 Number of ducks in flocks as a percentage of the total
ducks on water; observation post A, Herschel Island,
Y .T.; 5 and 6 August, 1972 .................•..........
18 Average number of ducks in flocks; observation post E,
Herschel Island, Y.T.; 14 August, 1972 ...........•...•
Appendix
''A'' Photos -. . ,. . . . .. . . .......... ., ... ~ . . . . . . . . . . . .. . . ... -... ., . . ....... .
xiii
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214
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222
223
224
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231
INTRODUCTION
Each year, following the breeding season, ducks
and geese enter a molt period which renders them flight-
less for several weeks (Kortright 1942, Oring 1964).
During this period of flightlessness, they have high
energy requirements and are more vulnerable to predation,
and the effects of weather and other disturbances. In
certain species the energy demands of molting are suffi-
cient to reduce adult body weight (King and Farner 1963).
Blue geese (Chen caerulescens) do not regain weight lost
during nesting until after the molt period (Coach et al.
1960).
In southerly areas, the molt is not as critical
as in the arctic because the birds have less severe
weather to contend with and also have a longer period of
time, between molt and migration, to recover from body
energy depletions.
Areas with shelter and a good food supply probably
lessen the stress on molting birds and thus are selected
by them (Figure 1). Additional stress or disturbance
sufficient to drive the molting birds from these pro-
tected feeding and resting areas could have serious effects
on the more sensitive birds, increasing mortality rates
during the molting period, and possibly affecting mig-
ratory success as well.
Prior to the loss of flight feathers many water-
fowl species move into secluded, often traditional sites
-202 -
for molting (Oring 1964). Since the proposed pipeline,
if constructed, will create increased air traffic along
the arctic coast and thus over traditional molting
areas, it is important to test the effects of air
traffic on these molting birds.
The objectives of this study were: (1) to
determine if aircraft disturbance affects the normal
behavior of molting sea ducks; (2) to determine the
disturbance effects of aircraft flying at various
altitudes; (3) to determine whether intensive aircraft
activity would drive the sea ducks from the sheltered
areas.
SITE DESCRIPTION
The sheltered waters off the south side of
Herschel Island, located along the Yukon Arctic coast
approximately 40 miles east of the Alaska-Yukon border,
were selected as the site for this study (Figure 2).
Most of this area is protected from the pre-
vailing northwesterly winds by a series of sand and gra-
vel spits and islands running east off the Firth and
Malcolm river deltas and south from Herschel Island
(Avadlek Spit). The spit areas also provide good
resting spots for the molting birds.
The shore of Herschel Island is formed by moder-
ately high bluffs which provide excellent vantage points
for observing the molting birds with a minimum of
disturbance to them (Figure 3).
-203 -
WEATHER
Weather data from the Komakuk Beach D.E.W.
station, located 20 miles west of the study area, were
used in compiling this report.
On 5 August, winds were from the west at 3 - 4
m.p.h. and the temperature varied from 45°-49°.
On 14 August, winds were from the east at 12 -16
m.p.h. and temperatures varied from 460 -57° F.
AVIFAUNA OF THE SITE
Species of waterfowl present in large numbers
in the northern coastal waters during molting include
black brant (Branta bernicla), greater scaup (Aythya
marila), lesser scaup (Aythya affinis) (Bartonek 1969),
oldsquaw (Clangula hyemalis) (Anderson 1913, Dixon 1943,
Bartonek 1969), eider spp. (Somateria spp.) (Dixon 1943),
surf scoter (Melanitta perspicillata) (Anderson 1913),
and other species.
The species of primary concern in this study
were oldsquaw and surf scoters. Other waterfowl noted
in the area during the study were scaup spp., white-
winged scoter (Melanitta deglandi) and red-breasted
mergansers (Mergus serrator) . These other species were
present in very small numbers, probably using the area
mainly as a feeding ground rather than as a molting
area. The same may be said for four species of loon
also present: common loon (Gavia immer), yellow-billed
loon (Gavia adamsi), arctic loon (Gavia arctica), red-
throated loon (Gavia stellata) .
-204 -
45'
3
2
0
9
8
' I
!
!
!
I -t---
+I
I OBSERVATION POSTS
BASELINE DAY a FIRST DAY OF
DIS URBANCE ( AU(;UST 5 a 6)
DISTURBANCE
i
I
!
{ A,B,C)
( D,E)
-r--·-------··-·
I
~ ~ # ~--t;j--:
---~ _--~ ---!
HERSCHEL ISLAND
YUKON TERRITORY
Scale 1:250,000 Echelle
MAP OF THE STUDY
r ------
1
AREA
FIGURE 2.
-----£,;;;~~-
METHODS
Three observers were taken to the island in a
float-equipped Cessna 185 aircraft which landed at two
locations along the south shore. The observers then
positioned themselves so as to be able to observe as
much of the area from Osborn Point to Avadlek Spit
(Figure 3) as possible. It is believed that there was
probably very little overlap in the areas under obser-
vation by each observer.
The observers recorded, at 1/2 hour intervals,
the number of birds resting on the beaches, resting on
the water, swimming, feeding (diving), and sleeping.
Maps were made showing the locations of rafts of ducks
at one hour intervals.
On disturbance days, observations were also
made of the number of birds that dove from the path of
the aircraft, moved off the beach, swam away from the
aircraft's path, or showed erratic escape behavior. In
addition, observations were made on general behavior of
the birds during each disturbance. Since no birds were ob-
served to fly, all ducks under observation were assumed
to be molting.
On the first day of the study, 5 August, six
hours of observations were made under undisturbed
conditions in order to determine an index of the normal
behavior of the birds.
Aircraft disturbance was begun on the following
day (6 August) and observations as outlined above were
-205 -
made 1/2 hour before and 1/2 hour after each flight.
Flights were made at hourly intervals beginning two hours
after the observers were positioned on the island and
ending one hour before the observers were picked up. A
total of eight hours was spent observing on this day.
The helicopter flew a predetermined path over the sea
ducks approximately 100 yards from shore at altitudes
of 750 feet, 500 feet, 400 feet, 300 feet, 200 feet, and
100 feet.
On the second day of disturbance, 14 August,
observations were concentrated on a smaller area and
consisted of hourly flights at 100 foot altitudes, 100,
200, 300 and 400 yards from shore.
The delay between the first and second day of
disturbance was the result of a lack of available air-
craft for use in the study.
RESULTS
POPULATIONS
There were an estimated 10,000 ducks using the
south shore of Herschel Island as a molting area on 5
August. Nearly 1,400 of these were under observation
during the initial phases of the study. Population
counts on the control day (5 August) were almost the
same as those on the fir~t disturbance day (6 August)
(Table 1) • Counts on the second disturbance day (14
August) were much lower but, because of the eight-day
lapse between the first and second days of disturbance,
-206 -
TABLE 1. POPULATION COUNTS OF MOLTING SEA DUCKS AT HERSCHE[ ISLAND, AUGUST, 1972
AUGUST 5 -UNDISTURBED AUGUST 6 -DISTURBED AUGUST 14 -DISTURBED
OBSERVATION POST OBSERVATION POST OBSERVATION POST
SPECIES A B c A B c D E
Overall Overall Overall
Max Min Mean Max Min Mean ·Max Min Mean Mean Max Min Mean Max Min Mean Max Min Mean Mean Max Min Mean Max Min Mean Mean
Oldsquaw 360 116 194 21 4 12 206 485 190 327 80 20 46 373 450 250 363 363
Seater spp. 150 37 61 J60 90 147 208 90 12 61 170 100 132 193 150 12 31 31
Unidentified Ducks 888 710 815 315 177 236 946 700 320 572 400 128 199 771 425 120 239 239
TOTAL WATERFOWL 1,398 863 1 ,070 315 177 236 1~1 94 159 1,360 1,275 522 96(, 400 128 199 250 120 178 1,337 600 262 394 425 120 239 633
-1
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1200
1000
··t / __ ./
_.._./
600
400
200
FIGURE 4-TOTAL WATERFOWL COUNTS; OBSERVATION POST A,
HERSCHEL ISLAND, AUGUST 5 a 6, 1972.
/-"\
/ \
/'-..... ~ I '-..
I , I
I '\ I , \ ~
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1-;;0:-_.1._ __ -+---+ ---1----1
T 5oo' 400' 300' zoo' 100'
HEIGHT a TIMES OF HELICOPTER PASSES-AUG. 6
AUGUST 5 (Control Day)
AUGUST 6 (Disturbance Day)
o4------~-------L---------L--------~--------L-------~------~-----~
1800 1900 1100 1200 1300 1400 1500 1600 1700
TIME (A.D.S.T.)
F I G U R E 5 - N U M B E R 0 F 0 U C K S 0 N LA N 0 ; 0 B S E R VAT I 0 N POST A,
HERSCHEL ISLAND, AUGUST 5 a 6,1972.
600
500
z c
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400
I 0
N "TI
0 0
00 c
()
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z I I \ AUGUST 5 (Control day) 0 --··--
-------AUGUST 6 (Disturbance day)
I I \
200
100
.a HEIGHT a TIMES OF HELICOPTER PASSES -AUG. 6
• "'-750' 5oo' 4oo' 3oo' 2'oo' / ' P----r----f----t-----r~--
/ '
/ ' ---.... ""' / ' --.......... / / ' __ .....-' / ' ...._-.......... / ' ' ......... "" '
-t'oo'
o.~~-------L--------~---------~~-------L----------~-----------L----------~----------~ 1100 1200 1300 1400 1500 1600 1700 1800 1900
TIME ( A.D.S.T.)
TOTAL AUG 5
OBSERVED
AUG 6 20
100
"0 BO
I'T1 :u
n
N I'T1
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1.0 -t
0 I "'Tl
-t
601 0
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40
20 ._
0
1100
FIGURE 6-NUMBER OF DUCKS ON LAND AS A PERCENTAGE OF THE TOTAL
DUCKS OBSERVED ·, OBSERVATION POST A, HERSCHEL ISLAND,
AUGUST 5 8 6, 1972.
175 600 650 440 400 50
110 25 50 75 15 75 0
AUGUST 5 (Control day)
0
-------AUGUST 6 (Disturbance day)
8 TIMES OF HELICOPTER PASSES -AUG. 6
1750' I soo' 1400' 1 3oo' \ I zoo' jiOO'
,......__
/ ..........
/ ..........
/ .......... -__..._
......... ----~ ........ .....__ ____ ---............ -...... -
1200 1300 1400 1500 1600 1700 1800 1900
TIME (A D.S.T}
it is probably not valid to compare counts from these
days.
There was a great deal of fluctuation in counts
within a given day from a given observation post, but
even the pattern of these fluctuations did not appear to
be greatly altered by the disturbance (Figure 4).
Many visibility factors, especially sun location
and ground haze, affected the consistency of the counts
but since weather conditions on both 5 and 6 August were
very similar it is probable that these factors affected
both day's counts equally.
Table 1 summarizes population counts from the
three days of the study.
BEHAVIOR
Ducks on land
The two most readily distinguishable
features of waterfowl behavior during the study were
the number of ducks on water and the number of ducks
on land.
The most favored resting spot for waterfowl
in the area was along the sheltered west bank of
Avadlek Spit. Counts were made of the numbers of water-
fowl resting on Avadlek Spit, from observation post A,
on 5 and 6 August (Figures 5 and 6). Despite the similar
weather conditions for the two days, the disturbance day
(6 August) had far fewer birds resting on the spit. It
should also be noted that on the control day, the
-210 -
numbers of birds on land reached a peak between 1300
and 1500 hours, the warmest part of the day, whereas
on the disturbance day no consistent pattern could be
observed.
The interruption in normal land-resting behavior
patterns was also evident at observation post B on the
same two days (Figures 7 and 8). Here, the number of birds
utilizing the south shoreline of Herschel Island was small,
but under control conditions they demonstrated a similar
pattern to those on Avadlek Spit. On the disturbance
day at post B the use of the beach became very erratic
and during the optimum period (13:00 -15:00 hours) no
birds were seen on land.
Observations on the second day of disturbance
(14 August) demonstrated the same erratic pattern (Figure
9), but on this day a moderate east wind may have been
partly responsible for keeping the birds away from the
beaches.
Resting and sleeping on water
Resting and sleeping behavior were noted
separately in the field, but have been combined for the
purposes of this report. As seen in Figures 10 and 11,
these types of behavior followed a rather erratic pattern
on both control and disturbance days. With only the one
control day on which to judge normal behavior it is
extremely difficult to determine whether any real dis-
ruption of the resting-sleeping behavior did occur.
At observation post A, only oldsquaws were near
-211 -
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CJ
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N "' Vl
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0
60
50
40
30
20
10
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)
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FIGURE 7-NUMBER OF DUCKS ON LAND; OBSERVATION POST B,
HERSCHEL ISLAND, AUGUST 5 S 6, 1972.
~
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\ lr5o'
\
\
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\
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HEIGHT a TIMES OF HELICOPTER /PASSES
I 5oo' l4oo' f l3oo'
I
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\
\
\
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AUGUST 5 (Control day)
-------AUGUST 6 (Disturbance
day)
l1oo'
ol •. J , ~ •. • •. ~ ' , .._ •' ...
1300 1400 1500 1600 1700 1800 1100 1200
TIME ( A.D.S T )
TOTAL
OBSERVED
-o
fT1
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N ("') f--1 fT1 VI z
-t
0 .,.,
-t
0
-t
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0
c
("')
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AUG 5
AUG 6
100
80
60
40
20 1-
.I
1100
0
9 14
FIGURE 8-NUMBER OF DUCKS ON LAND AS A PERCENTAGE OF THE
TOTAL DUCKS OBSERVED; OBSERVATION POST B,
HERSCHEL ISLAND, AUGUST 58 6, 1972.
0 20 25 26 26 30 20 30 30 4 5 15
26 0 0 0 0 0 0 14 34 60 0 0 0
AUGUS'I' 5 (Control day)
-------AUGUST 6 (Disturbance day)
HEIGHT a TIMES OF HELICOPTER PASSES-AUG.6
1750' l5oo' 14oo' I 3oo' I zoo' l1oo'
...... ~
~ ... ==~.\~-___ ,/X ..
• • •• 1900 1200 1300 1400 1500 1600 1700 1800
TIME ( A.D.S.T)
260
240
220
200
180
N 160
f-1
~
140
120
100
80
60
40
20
0
1200
FIGURE 9-NUMBER OF DUCKS ON LAND; OBSERVATION POST D,
HERSCHEL ISLAND, AUGUST 14, 1972.
TIMES OF HELICOPTER PASSES -ALL AT 100'
I I I I
1300 1400 1500 1600 1700 1800 1900
TOTAL
AUG. 5
OBSERVED
AUG 6 0
100 r
-u
fT1 80
;o
I n
fT1
N Z
~ -t
V1
0 ,
0 c 60
n
;>;;
lJl
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fT1
lJl
-t -z
Gl 40
0
;o
lJl
r
fT1
fT1
-u -z
Gl 20
I
I
I
' 0
1100
F I G U R E l{}-N U M 8 E R 0 F D U C K 5 R E 5 T I N G 0 R 5 L E E P I N G 0 N W AT E R AS A
PERCENTAGE OF THE TOTAL DUCKS OBSERVED·, OBSERVATION
POST B, HERSCHEL ISLAND, AUGUST 5 S 6,1972.
150 100 51 47 165 100 70 40 100 120 100 100 225
26 26 75 0 33 20 10 50 25 100 150 75 70
HEIGHT B Tl MES OF HELICOPTER PASSES-AUG 6
I I I I I I
400
r
I
I
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...... I
I '..J
I I I
I ,_-._.!
r---J I
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1200 1300 1400 1500 1600 1700 1800 t9C-:
AUGUST 5 (Control day)
TIME (ADST) -------AUGUST 6 (Disturbance day)
z
c
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OJ
fT1
;o
0
N Tl ......
Q\ 0 c
n
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;o
fT1
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-t -z
Gl
0 ;o
(/)
r
fT1
fT1
-o -z
Gl
250
200
150
100
50
F I G U R E 11 - N U M 8 E R 0 F D U C K S R EST I N G 0 R S LEE P I N G 0 N W AT E R ;
OBSERVATION POST 8, HERSCHEL ISLAND, AUGUST 58 6,1972.
I 1so'
HEIGHT 8 TIMES OF HELICOPTER PASSES -AUG. 6
I soo' 14oo' l3oo'
f
!zoo'
~
I \
I \
I \
\
I .I
1001
I
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._ -.J
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r (400,
I
, ~ I \ ,...._ '\ I
/ --.J ' ' , / / 'v
/ \ / ~ ~ /
\
' 1100 1200 1300 1400 1500 1600 1700 1800 1900
TiME ( A.D.S T) AUGUST 5 (Control day)
-------AUGUST 6 (Disturbance day}
enough to the observer to allow a quantitative behav-
ioral description. This might help to explain the large
difference between observations from this post (Figure
12) and observations from post B where the birds under
observation included many scoters. The oldsquaws at post
A, slept and rested more on the disturbance day than
on the control day.
Figure 13 shows the sleeping and resting patterns
of surf scoters on the control and first disturbance
days at post C. Post C was the only post where scoters
were near enough to allow quantitative behavioral obser-
vations. Again because of the erratic pattern of the
control day it is difficult to draw positive conclusions.
It appears, however, that scoters spent much less time
sleeping and resting on the disturbance day.
It should be especially noted that the behav-
ioral responses of oldsquaws to the disturbance seem to be
quite different from those of scoter. If this is the
case, then combining the two species, as was done in the
field at post B and in some cases at post A, might yield
somewhat misleading results.
Swimming and feeding
These two types of behavior were also re-
corded separately in the field but have been combined
for the purposes of this report.
The normal feeding and swimming activities of
oldsquaws did not appear to change on the first distur-
bance day (Figure 14). Surf scoters, on the other hand,
-217 -
N .......
00
100
90
, 80
..., 1120
:tl
(") ...,
z
-1
0 10
""'
0
r
0
Vl
0
c 60
J>
~
:tl ...,
Vl
-1
z
G'l
0
:tl
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50
r 40 ..., ..., ,
z
G'l
30
20
10
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165
I
I
260
I
I
I
I
I
I
I
I
I
I
I
I
I
I
FIGURE 12-NUMBER OF OLD SQUAW REST lNG OR SLEEPING ON WATER
AS A PERCENTAGE OF THE TOTAL OLDSQUAW OBSERVED;.
OBSERVATION POST A, HERSCHEL ISLAND, AUGUST 5 a 6,1972.
~ I \HEIGHT 8 TIMES OF HELICOPTER PASSES-AUG 6
' I I I~ ' ' ~5~ _7 -~r.:..... __ ~0~ __ 1\o:...._ __ -t200 __ --tiOO
AUG.5 250 1 \300 100 I \ 200 150
140 I 4oo 5oo 230 3oo
I \ I \
375 4!10 AUG.6
TOTAL
OBSERVED
I
I
I
I \ I \
\ I \
\ I \
\ I \
\ I \
\ I \
\ I \
\ I \
\ I
\ I
\ I
\ I
\ I
\ /
~
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I
I
r
AUGUST 5 (Control day)
-------AUGUST 6 (Disturbance
o+-----------~----------L--~------~----------~~----------~----------~----------~-----------J day)
1100 1200 1300 1400 1500 1600 1700 1800 1900
TIME (A.D.S.T)
TOTAL AUG 5
OBSERVED AUG 6 170 170
100
1)
iTI 80
::0
(")
iTI z
N o-l
f-' ::oo
\.0 ,
VlVl rc
rrl;:o m,
1)
60
-Vl
Zo G)o
-i
iTI
::0
Vl
40
::0
iTI
Vl
~ -~
z G)
20
FIGURE 13-NUMBERS OF SURF SCOTERS RESTING OR SLEEPING ON WATER
AS A PERCENTAGE OF THE TOTAL SURF SCOTERS OBSERVED;
OBSERVATION POST C, HERSCHEL ISLAND, AUGUST 5 8 6, 1972.
90
170
" / '\ / v
140
170
/
/
140 140 140 140 160 160 160 160 160 160 160
150 150 150 100 100 100 100 120 120 120 120 120
HEIGHT a TIMES OF HELICOPTER PASSES-AUG. 6
1750' 1 5oo· l4oo' 13oo' 12oo' 1100'
/---.................
/ '
I
_..._~-........._~ _ _J -
I
I
I
I
I
I
120
'
0+-----------~----------~----------~---------~----------~---------~----------~--------~
1100 1200 1300 1400 1500
TIME (A.DST)
1600 1700
AUGUST 5
AUGUST 6
1800 1900
(Control day)
(Disturbance day)
TOTAL NO. AUG.5
OBSERVED AUG. 6 120
100.
/
/
/ ., / ITI
:0 / 80
n
ITI z
-1
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N 0
0 ..,
0
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0 60
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0 c
)>
~
VI
~
s::: s::: 40 -z
G)
0
:0 ..,
ITI
ITI
0 -20 z
G)
0
1100
FIGURE 14-NUMBERS OF OLD SQUAW SWIM Ml NG OR FEEDING AS A
PERCENTAGE OF THE TOTAL OLDSQUAW OBSERVED;
OBSERVATION POST A, HERSCHEL ISLAND, AUGUST 58 6,1972.
260 250 300 100 200 150
165 140 400 500 230 300 375
-r-----,
\
\
\
\
~ \
\ I \ \ I \
I \ I
I \ I
I \ I
I \ I
I I \ I \ I I
I \ I \ I I I \
I \ I
\ HEIGHT/a TIMES OF HELICOPTER/ PASSES-AUG. 6
1750 ° \ l5oo' l4oo' \ l3oo' l2oo' 11oo'
\ I \ I
\ I \ I
\ I ~
"
1200 1300 1400 1500 1600 1700 1800
\
\
\
\
\
\
TIME (A.O.S.T.) AUGUST 5 (Control day)
480
\
\
1900
-------AUGUST 6 (Disturbance day)
spent more time swimming and feeding on the first distur-
bance day (Figure 15), possibly because their normal
sleeping and resting habits had been disrupted. At
post B, where oldsquaws and scoters were combined, no
real pattern is noticeable (Figure 16). Here again,this
may be due to the combining of the two major species
which, as has been previously noted, is probably not
justifiable.
Flocking activity
The observer at post A on 5 and 6 August
noted that, once disturbance began, the birds showed
a tendency to come together into close flocks on the
water rather than remaining in loose groups or scatter-
ings of single birds. On the control day at this post,
the number of birds in flocks remained relatively con-
stant at about 20% of the total birds on the water;
on the disturbance da~ the percentage of birds in flocks
rose steadily to 64% by the end of the day (Figure 17).
At post B, most of the ducks were in rafts on
the control day as well as on the disturbance day so
that no measurable difference could be detected. At
post A, many of the ducks under observation were
oldsquaws whose normal loose dispersal made it more ob-
vious when flocking began to occur. It is probable
that there were many more scoters at post B and our
observations seemed to indicate that these birds tended
to remain in fairly tight groups at all times. It should
be noted, however, that although the numbers of ducks
-221 -
TOTAL NO.
OBSERVED
AUG.5
AUG.6 170
100
"0
fT1
:0
n 80
fT1
z
-I
0 .,
N (/) N c N :0 .,
60
(/)
n
0
-I
fT1
:0
(/)
(/) :e
3: 40
3: -z
(;')
0
:0 .,
fT1
fT1
0 20 -z
(;')
170
F I G U R E 15 - N U M B E R S 0 F SUR F S C 0 T E R S S W I M M I N G 0 R FEE D I N G AS A
PERCENTAGE OF THE TOTAL SURF SCOTERS OBSERVED;
OBSERVATION POST C, HERSCHEL ISLAND, AUGUST 5 a 6, 1972.
90 140 140 140 140 140 160 160 160 160 160 160 160
170 170 "0 150 150 100 100 100 100 120 120 120 120 120
HEIGHT a TIMES OF HELICOPTER PASSES-AUG. 6
l75o' l5oo' I 4oo· I 3oo' 12oo' 1100'
1', ----/ '
/ '
--41' \ "
---.....-~ __ _...._....,_ __ ~
\ \.
\.
\. // -----...,...__....,.,
\
\
\
\
\
\
\
120
\ •
0+-------------~------------~----------~-------------L------------~------------~----------~~----------_j 1100 1200 1300 1400 1500 1600 1700 1800 1900
TIME ( A.D.S.T) AUGUS'I' 5 (Control day)
-------AUGUST 6 (Disturbance day)
TOTAL NO. AUG.5
OBSERVED
AUG.6 164
IOOr
\
'U \
fT1 \
::0 \
n \
fT1 80
z
--1
0
N "Tl
N
(.M 0 c n
"' (J} 60
(J}
~
~
~ -z
(;')
0 40 ::0
"Tl
fT1
fT1
~ z
(;')
20 1-
0
1100
177
190
~
I
FIG U R E l6 - N U M BE R S 0 F DUCK S S W I M M I N G 0 R F E E D I N G AS A
PERCENTAGE OF THE TOTAL DUCKS OBSERVED;
OBSERVATION POST B, HERSCHEL ISLAND, AUGUST 5 a 6,1972.
201 195 225 266 236 200 195 230 260 264 305 315
202 210 130 183 128 96 150 139 209 260 250 270 400
" HEIGHT S. TIMES OF HELICOPTER PASSES-AUG. 6
115o' I
\
\ I 5oo' l4oo' 1300' 12oo' 1100'
I
I \
I \
\ _....,_
I .... -
\
....... \ .......
" \ ,......-1
' \ ~
' ..__
\ r I
' \ \
\ \
\ \
\ \
\
\
\
\
\
\
\ I \ \ I \
\ \ I \
-.J \
\
\
\
\
1200 1300 1400 1500 1600 1700 1800
TIME (A.D.S.T.) AUGUST 5 (Control day)
-------AUGUST 6 (Disturbance
1900
day)
TOTAL NO.
DUCKS
ON WATER
AUG. 5
AUG-6
-u
fT1
::tl
()
N fT1
N z
.j;>. --4
0 ......
0 c
()
" tn
-z
......
r
0
()
" tn
80
70
60
50
40
30
20
10
665
......
/
-......
535
644
/
/ _....,
FIGURE 17-NUMBERS OF DUCKS IN FLOCKS AS A PERCENTAGE
OF THE TOTAL DUCKS ON WATER; OBSERVATION
POST A, HERSCHEL ISLAND, AUGUST 5 a 6, 1972.
/
/
/
/
555 547 597 643 1115
832 600 860 919 815 965
HEIGHT 6 TIME OF HELICOPTER PASSES-AUG.6
750' 500' 400' . 300' 200' 100' ~-----+----r:----F-----F------1
, I
I
I
I
I
I
,......_ ,_.-
/ ~--/ , --, /
// ' /
/ ' / y ' /
I ' /
I ' /
/ '~
1115
__ ....
AUGUST 5 (Control day)
------AUGUST 6 (Disturbance day)
0~------------~------------._ __________ ~~----------_. ____________ ~------------~----------~~----------~
1100 1200 1300 1400 1500 1600 1700 1800 1900
Tl ME ( A.D.S.T.)
in flocks as a percentage of the total ducks observed
did not differ greatly between the control and the first
disturbance day, there was a tendency on the disturbance
day for the flock size to increase as disturbance
continued. On the last count on 6 August, all the birds
from posts B and c joined together in one large flock
(400 birds). This tendency towards increased flock
size was again noted on 14 August at post E (Figure 18).
Immediate response to aircraft
Firstly it was noted that escape reactions
were more acute on low level helicopter passes but that
in all cases normal behavior was quickly resumed.
At post A, ducks moved off the land into the
water as early as the first pass at 750 feet on 6 August.
This exit from land areas increased as disturbance con-
tinued. Ducks on the water became very alert to the
movements of the aircraft at about the 300 foot level
but none dove in response to the aircraft until the pass
at 200 feet. At 100 fee~entire rafts of ducks dove
when the helicopter came overhead. All ducks attempted
to swim away from the path of the plane at flights
below 300 feet.
At post B, birds swam away as early as the
750 foot pass and first dove from the path of the plane
at 500 feet. The same responses were noted at post C.
It is possible that these earlier reactions at posts
B and C were because of the larger number of scoters in
those areas. Throughout the study, scoters seemed to be
-225 -
NO.
FIGURE 18-AVERAGE NUMBER OF DUCKS IN FLOCKS, OBSERVATION POST E,
HERSCHEL ISLAND, AUGUST 14,1972
4 3 3 2
FLOCKS 3 2 2
l>
<
fT1
;o
,l>
Gl
NfTl
N
0\.,
r
0
n
;o;;
Vl
N
fT1
450
375
300
225
TIMES OF HELICOPTER PASSES -ALL AT 100'
I I 1 I
150
75
04-----------L---------~-----------L----------J-----------~--------~~--------~
1200 1300 1400 1500 1600 1700 1800 1900
TIME ( A.D.S T.)
more sensitive to the disturbances.
Finally, all observers noted that birds became
aware of the aircraft long before it could be seen by
the birds or the observers. This reaction in some in-
stances was noted as a general awareness, with birds
looking toward the direction of the aircraft, a general
restlessness and in some instances, a movement away
from shore. These reactions were noted while the aircraft
was one-half to one mile away. Since the physiography of
Herschel Island in many instances did not allow the birds
to see the aircraft, these reactions must have been in
response to the sound of the aircraft.
DISCUSSION
Helicopter disturbance apparently did not affect
the populations of molting sea ducks at Herschel Island.
That is, no detectable numbers were driven away from
the area. However, since the birds were flightless they
could not travel far. Continued harassment over a
period of several days might have caused the birds to
reach a threshold level of tolerance which would not
be obvious with 2 separated days of disturbance, but it
was not possible to test this possibility within the
framework of the present experiment.
Several forms of behavior appear to have been
altered by the disturbances. However, the reactions
of the two principal species, oldsquaws and surf scoters,
to the disturbances were very different and, for this
-227 -
reason, those field data which combined the two species
are likely not of great value.
It is also necessary to understand the implications
of weather disturbances on behavior of molting birds.
The sheltered molting areas probably serve their greatest
purpose during times of turbulent weather; should dis-
turbance provoke evacuation of these areas during critical
times, stress on the birds is likely to be increased.
The importance of molting areas to waterfowl
is illustrated by the fact that some species migrate
hundreds or even thousands of miles to reach them (Sterling
and Dzubin 1967; Salomonsen 1968). The sole purpose of
these migrations is to reach undisturbed areas which are
free from predation (because waterfowl are flightless
during molt) and provide adequate food supplies. Some
species vacated traditional molting areas if subjected
to human disturbance (Sterling and Dzubin 1967). However,
this abandonment of traditional areas occurred in years
subsequent to the disturbance.
Prime molting areas along the Yukon Arctic
coast are few in number and relatively small in size,
yet they are vital to the welfare of thousands of sea
ducks (10,000 along the south shore of Herschel Island).
Our study showed that the passage of aircraft caused
molting waterfowl to alter normal behavior, and it is
reasonable to assume from these changes that re-
peated exposure to aircraft disturbance would have a
detrimental effect on these birds. Slight deviations
in aircraft routing and altitudes during the molting
-228 -
period could help greatly in preserving the importance of
these areas traditional to molting waterfowl.
1.
2.
3.
4.
5.
6.
7.
SUMMARY
Population levels of molting sea ducks did not
appear to be affected by disturbance.
Ducks were driven from land by the aircraft.
Oldsquaws rested and slept (on water) more on
disturbance days; surf scoters rested less.
Swimming and feeding activities of oldsquaws
appeared to be unaffected by disturbance. Surf
scoters swam and fed more, probably because
their normal sleeping and resting habits had
been disrupted.
Flock sizes and number of birds in flocks (as
a percentage of the total birds) increased as
disturbance continued.
The first responses to the helicopter were
shown at 750 feet when birds began moving off
land and out from shore.
Surf scoters appeared to be more sensitive than
oldsquaws to the disturbances.
-229 -
REFERENCES CITED
Anderson, R. M. 1913.
collections of
V. Stefansson,
Macmillan Co.,
Report on the natural history
the expedition. Pages 436-527.
My life with the Eskimos.
New York. 538pp.
In
Bartonek, J. c. Arctic Slope and Trans-Alaska Pipeline
Task Force Report: the Bird Resources of Alaska's
Arctic Slope and Petroleum Development. Mimeo
report on file at Northern Prairie Wildl.
Resources Center, Jamestown, North Dakota. 33pp.
Cooch, F. G., G. M. Stirrett and D. F. Boyer. 1960.
Autumn weights of blue geese (Chen caerulescens).
Auk 77:460-465. --
Dixon, J. S. 1943. Birds observed between Point Barrow
and Herschel Island on the arctic coast of Alaska.
Condor 45:49-57.
King, J. R. and D. S. Farner. 1963. The relationship of
fat deposition to zugunruhe and migration. Condor
65: 201)-211.
Kortright, F. H.
America.
1942. Ducks, geese and swans of North
Wildl. Mgmt. Inst., Washington. 476pp.
Oring, L. W. 1964. Behavior and ecology of certain ducks
during the postbreeding period. J. Wildl. Mgmt.
2 8 ( 2 ) : 2 2 3-2 3 3 .
Salomonsen, F. lq68. The molt migration. Waterfowl 19:5-24.
Sterling, T. and A. Dzubin. 1967. Canada goose molt migra-
tions to the Northwest Territories. Trans. N. Am.
Wildl. and Nat. Resources Conf. 32:355-373.
-230 -
-T£?: -
SHdW~O.LOHd
FIGURE 1-Area used by Molting Sea Ducks for shelter.
FIGURE 3-Bluffs used as vantage points for study.
BIOLOGICAL REPORT SERIES
VOLUME FOURTEEN
DISTURBANCE TO BIRDS BY GAS COMPRESSOR
NOISE SIMULATORS, AIRCRAFT AND HUMAN
ACTIVITY IN THE MACKENZIE VALLEY AND
THE NORTH SLOPE, 1972
Edited by
W. W. H. GUNN, JOHN A. LIVINGSTON
Prepared by
L.G.L. LIMITED, ENVIRONMENTAL RESEARCH ASSOCIATES
FEBRUARY, 1974
CANADIAN ARCTIC GAS STUDY LIMITED
ALASKAN ARCTIC GAS STUDY COMPANY