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Susitna‐Watana Hydroelectric Project Document
ARLIS Uniform Cover Page
Title:
Surveys of eagles and other raptors, Study plan Section 10.14, 2014 Study
Implementation Report SuWa 289
Author(s) – Personal:
Author(s) – Corporate:
ABR, Inc. - Environmental Research & Services, [Office in] Fairbanks, Alaska
AEA‐identified category, if specified:
November 2015; Study Completion and 2014/2015 Implementation Reports
AEA‐identified series, if specified:
Series (ARLIS‐assigned report number):
Susitna-Watana Hydroelectric Project document number 289
Existing numbers on document:
Published by:
[Anchorage : Alaska Energy Authority, 2015]
Date published:
November 2015
Published for:
Alaska Energy Authority
Date or date range of report:
Volume and/or Part numbers:
Study plan Section 10.14
Final or Draft status, as indicated:
Document type:
Pagination:
51 pages in various pagings
Related works(s):
Pages added/changed by ARLIS:
Notes:
All reports in the Susitna‐Watana Hydroelectric Project Document series include an ARLIS‐
produced cover page and an ARLIS‐assigned number for uniformity and citability. All reports
are posted online at http://www.arlis.org/resources/susitna‐watana/
Susitna-Watana Hydroelectric Project
(FERC No. 14241)
Surveys of Eagles and Other Raptors
Study Plan Section 10.14
2014 Study Implementation Report
Prepared for
Alaska Energy Authority
Prepared by
ABR, Inc.—Environmental Research & Services
Fairbanks, Alaska
November 2015
STUDY IMPLEMENTATION REPORT SURVEYS OF EAGLES AND OTHER RAPTORS (STUDY 10.14)
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TABLE OF CONTENTS
1. Introduction ....................................................................................................................... 1
2. Study Objectives................................................................................................................ 1
3. Study Area ......................................................................................................................... 3
4. Methods and Variances in 2014 ....................................................................................... 4
4.1. Nesting-season Surveys .......................................................................................... 4
4.1.1. Territory Occupancy and Productivity Surveys .............................. 4
4.1.2. Nest Sightability Assessment .......................................................... 6
4.1.3. Variances ......................................................................................... 6
4.2. Foraging and Roost Surveys ................................................................................... 6
4.3. Migration Surveys ................................................................................................... 6
4.4. Mercury Assessment ............................................................................................... 6
4.5. Delineation of Eagle Nesting Habitat ..................................................................... 6
4.5.1. Variances ......................................................................................... 7
5. Results ................................................................................................................................ 7
5.1. Nesting-season Surveys .......................................................................................... 7
5.1.1. Territory Occupancy and Productivity Surveys .............................. 7
5.2. Delineation of Eagle Nesting Habitat ................................................................... 11
6. Discussion......................................................................................................................... 11
6.1. Territory Occupancy and Productivity Surveys .................................................... 12
6.2. Delineation of Eagle Nesting Habitat ................................................................... 15
7. Conclusion ....................................................................................................................... 16
7.1. Modifications to Study Plan.................................................................................. 16
8. Literature Cited .............................................................................................................. 16
9. Tables ............................................................................................................................... 20
10. Figures .............................................................................................................................. 29
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LIST OF TABLES
Table 2-1. Raptor Species Occurring in the Susitna-Watana Study Area (adapted from AEA 2011).
....................................................................................................................................................... 20
Table 5-1. Server Location and File Names for Field Data from the Surveys of Eagles and Other
Raptors Conducted in 2012–2014. ................................................................................................ 21
Table 5.1-1. Mean monthly temperatures at the Watana Dam Site and Cantwell 4E, 2013 and 2014.
....................................................................................................................................................... 21
Table 5.1-2. Eagle Nest Success and Territory Occupancy for Golden Eagles (in the Golden Eagle
Survey Area) and Bald Eagles (in the Raptor Survey Area), 2014. Numbers in parentheses indicate
additional possible territories or nests as a result of nests with an unknown occupancy status. .. 22
Table 5.1-3. Eagle Nest Number and Condition for Golden Eagles (in the Golden Eagle Survey
Area) and Bald Eagles (in the Raptor Survey Area), 2014. .......................................................... 23
Table 5.1-4. Raptor Nests Below 2,050 ft (predicted maximum pool) in the Reservoir Survey Area.
....................................................................................................................................................... 24
Table 5.1-5. Other Raptor Nest Success and Territory Occupancy for Gyrfalcon, Merlin, Peregrine
Falcon and Common Raven (in the Golden Eagle Survey Area) and Northern Goshawk (in the
Raptor Survey Area), 2014. Numbers in parentheses indicate additional possible territories or nests
as a result of nests with an unknown occupancy status. ............................................................... 26
Table 5.1-6. Other Raptor Nest Numbers and Condition for Gyrfalcon, and Common Raven (in
the Golden Eagle Survey Area) and Northern Goshawk (in the Raptor Survey Area), 2014. ..... 28
STUDY IMPLEMENTATION REPORT SURVEYS OF EAGLES AND OTHER RAPTORS (STUDY 10.14)
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LIST OF FIGURES
Figure 3-1. Raptor Study Area for the Susitna-Watana Hydroelectric Project, 2014. .................. 30
Figure 5.1-1. Distribution and Occupancy of Bald Eagle and Golden Eagle Nests, 2014. .......... 31
Figure 5.1-2. Eagle Nest Occupancy and Nesting Habitat in the Reservoir and Expanded Golden
Eagle Survey Areas, 2014. ............................................................................................................ 32
Figure 5.1-3. Eagle Nest Occupancy and Nesting Habitat in the Gold Creek Survey Area, 2014.
....................................................................................................................................................... 33
Figure 5.1-4. Eagle Nest Occupancy and Nesting Habitat in the Denali Survey Area, 2014. ...... 34
Figure 5.1-5. Distribution and Occupancy of Other Raptor Nests, 2014. .................................... 35
Figure 5.1-6. Distribution and Occupancy of Other Raptor Nests in the Reservoir Survey Area,
2014............................................................................................................................................... 36
Figure 5.1-7. Distribution and Occupancy of Other Raptor Nests in the Gold Creek Survey Area,
2014............................................................................................................................................... 37
Figure 5.1-8. Distribution and Occupancy of Other Raptor Nests in the Denali Survey Area, 2014.
....................................................................................................................................................... 38
APPENDICES
Appendix A: 2012 and 2013 Golden Eagle and Raptor Study Areas for the Susitna-Watana
Hydroelectric Project.
Appendix B: Nest Success and Territory Occupancy of Raptor Nests Found Outside of the Study
Area Boundaries, 2012–2014.
Appendix C: Number and Last Known Condition of Nests Built by Raptors Found Outside of the
Study Area Boundaries, 2012–2014.
Appendix D: Summary of Breeding Parameters of Eagles and Other Raptors, 2012–2014.
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LIST OF ACRONYMS, ABBREVIATIONS, AND DEFINITIONS
Abbreviation Definition
AEA Alaska Energy Authority
APA Alaska Power Authority
BLM Bureau of Land Management
DEM digital elevation model
DNPP Denali National Park and Preserve
FERC Federal Energy Regulatory Commission
ft foot, feet
GIS geographic information system
GPS global positioning system
ILP Integrated Licensing Process
ISR Initial Study Report
km kilometer(s)
kph kilometers per hour
m meter(s)
mi mile(s)
mph miles per hour
NDVI Normalized Difference Vegetation Index
NPS National Park Service
Project Susitna-Watana Hydroelectric Project
RSP Revised Study Plan
SPD Study Plan Determination
USFWS United States Fish and Wildlife Service
USR Updated Study Report
STUDY IMPLEMENTATION REPORT SURVEYS OF EAGLES AND OTHER RAPTORS (STUDY 10.14)
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1. INTRODUCTION
This study, Surveys of Eagles and Other Raptors, Section 10.14 of the Revised Study Plan (RSP;
AEA 2012) approved by the Federal Energy Regulatory Commission (FERC) for the Susitna-
Watana Hydroelectric Project, FERC Project No. 14241, focuses on characterizing the population
size, productivity, nesting phenology, habitat use, and migratory movements of raptor species in
the study area.
A summary of the development of this study, together with the Alaska Energy Authority’s (AEA)
implementation of it through the 2013 study season, appears in Part A, Section 1 of Initial Study
Report 10.14 (ISR) filed with FERC in June 2014 (ABR 2014a). As required under FERC’s
regulations for the Integrated Licensing Process (ILP), the ISR describes AEA’s “overall progress
in implementing the study plan and schedule and the data collected, including an explanation of
any variance from the study plan and schedule” (18 CFR 5.15(c)(1)).
Since filing the ISR in June 2014, AEA has continued to implement the FERC-approved plan for
Surveys of Eagles and Other Raptors. For example:
Occupancy and productivity surveys for nesting raptors were conducted to characterize
nests and nesting success.
The geospatially referenced relational database for raptor nests was updated.
Delineation of eagle nesting habitat was continued using data from field surveys and
remote sensing.
On October 21, 2014, AEA held an ISR meeting for the Surveys of Eagles and Other
Raptors along with meetings for each of the other wildlife studies.
In furtherance of the next round of ISR meetings and FERC’s Study Plan Determination (SPD)
expected in 2016, this report describes AEA’s overall progress in implementing the Surveys of
Eagles and Other Raptors during calendar year 2014. Rather than a comprehensive reporting of all
field work, data collection, and data analysis since the beginning of AEA’s study program, this
report is intended to supplement and update the information presented in Part A of the ISR for
Surveys of Eagles and Other Raptors with data collected through the end of calendar year 2014. It
describes the methods and results of the 2014 effort and includes a discussion of the results
obtained to date.
2. STUDY OBJECTIVES
The goal of the Surveys of Eagles and Other Raptors is to characterize the population size,
productivity, nesting phenology, habitat use, and migratory movements of raptor species in the
study area. These data will inform the prediction and quantification of impacts that may result from
the proposed Project, and will provide information required for a possible application(s) for federal
eagle take (lethal or disturbance take, see below) and/or eagle nest take permits.
English and scientific names of raptors that are likely to occur in the Project area are listed in Table
2-1; bird names are capitalized throughout this report, in keeping with the standard practice of the
American Ornithologists’ Union (AOU 1998).
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Six objectives were identified for study in RSP Section 10.14.2:
1) Enumerate and identify the locations and status of raptor nests and territories that could be
affected by Project construction and operations. Four specific tasks are associated with this
objective:
a) Review and synthesize existing nest data for eagles and other raptors: Identify and assess
the status of previously recorded nest locations of various species, including geographic
coordinates, annual nest activity, descriptions of nest site characteristics, and general
descriptions of cliff habitat in the proximity of each site.
b) Conduct field surveys to locate and characterize nests: Locate and map Bald Eagle and
Golden Eagle nests in the Project study area, identifying all active and inactive nests and
alternative nest sites. Locate and map active and inactive nests of other tree- and cliff-
nesting raptor species (as well as Common Raven, a species whose nests often are used by
raptors) in the Project study area.
c) Create a geospatial database of all nests and territories: The database will be used to
calculate inter-nest distances, estimate local average territory size, and, with overlays of
Project footprint and habitats, determine the number of nests and territories potentially
affected by the Project.
d) Calculate local average territory size for Bald Eagles and Golden Eagles: Estimates of
average territory sizes (and mean inter-nest distance) are required for the applications for
federal eagle nest take permits.
2) Estimate Project effects on the productivity of raptors. This objective includes four tasks:
a) Review existing productivity data.
b) Determine the average and range of productivity of nests of each species (e.g., Bald Eagle,
Golden Eagle, other raptors).
c) Consider impacts on productivity at the local and larger population level using current and
historical data.
d) Establish the framework for comparisons of pre- and post-construction productivity to
evaluate whether realized take is consistent with the permitted take, and to ensure that the
level of take is compatible with the preservation of eagle populations.
3) Estimate effects on nesting and foraging habitats by delineating suitable habitat features in a
geospatial database (this work will be conducted in the Evaluation of Wildlife Habitat Use;
Study 10.19), These characterizations will be used to determine:
a) The percentage of local habitat lost.
b) Numbers of breeding pairs and productivity affected by development.
c) Whether or not a partial loss of a territory may functionally result in abandonment of the
entire territory.
d) Whether or not habitats adjacent to the Project area may be available for use by displaced
nesting birds.
4) Conduct field surveys and literature reviews to identify, map, and characterize the habitat-use
patterns at fall and winter communal roost sites and foraging sites of Bald and Golden eagles
and other raptor species. Describe seasonal habitat use, highlighting areas or conditions that
may result in impacts on raptors.
5) Assess the extent to which planned overhead transmission lines may pose a collision risk to
migrating or nesting raptors and identify migratory corridors (including altitudes of raptor
movements) in the Project transmission line corridors.
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6) Provide information on the distribution, abundance, food habits, and diet of piscivorous (fish-
eating) raptors; feather samples for characterization of mercury levels; and information on the
effects of methylmercury on piscivorous raptors, for use in the Mercury Assessment and
Potential for Bioaccumulation study (see Study 5.7).
3. STUDY AREA
As established by RSP Section 10.14.3, the study area for nesting raptors was subdivided using
two different criteria, depending on the species of interest and Project component. For Golden
Eagles, 10 mi (16 km) is the radial survey distance typically recommended by the U.S. Fish and
Wildlife Service (USFWS) (Pagel et al. 2010; M. de Zeeuw and J. Muir, USFWS, pers. comm.,
April 11, 2012) to determine mean inter-nest distances (i.e., representation of territory size) in
areas that contain suitable nesting habitat. For Bald and Golden eagles and other raptor species, a
radial distance of 2–3 mi around the proposed reservoir inundation zone, proposed facilities, and
centerlines of the potential access road and transmission line corridors was considered to be
sufficient (M. de Zeeuw and J. Muir, USFWS, pers. comm., April 11, 2012).
As described in the ISR Overview (Section 1.4) when the ISR was filed in June 2014, AEA
explained that it had decided to pursue the study of an additional alternative north–south corridor
alignment for transmission and access from the dam site to the Denali Highway. Referred to as the
“Denali East Corridor Option,” these areas were added to study areas, as appropriate, beginning in
2014. In addition, Section 1.4 of the ISR Overview noted that AEA was considering the possibility
of eliminating the Chulitna Corridor from further study. In September 2014, AEA filed with FERC
a formal proposal to implement this change. Thus, this report reflects a change in study areas, as
appropriate, to no longer include the Chulitna Corridor. These changes to the various study areas
affected the Eagle and Other Raptor Study as described below.
The study area for nesting raptors includes: (1) a 3-mi radius for both eagles and other raptors
around proposed facility areas and the centerlines of the potential access road and transmission
line corridors; (2) a 3-mi radius around the reservoir inundation zone for Bald Eagles and other
raptor species; and (3) a 10-mi radius around the reservoir inundation zone for Golden Eagles
(though all nests of cliff-nesting raptors were searched for and recorded in that area; Figure 3-1).
For the purposes of this report, the entire region encompassed by the 3-mi radius around the
corridors and reservoir inundation zone, in addition to the 10-mi expansion for Golden Eagles, is
defined as the Golden Eagle study area, whereas the region encompassed only within the 3-mi
radius of the corridors and reservoir inundation zone is defined as the raptor study area (Figure 3-
1). The Expanded Golden Eagle survey area is that portion of the 10-mi radius around the reservoir
that was not already included within the 3-mi radius of the other survey areas.
For comparison of survey results over such an expansive and varied landscape, the study area for
nesting raptors was subdivided into six survey areas: Denali West survey area (1,013 km² [391
mi²]), Denali East survey area (256 km² [99 mi²]), Gold Creek survey area (680 km² [263 mi²]),
Dam and Camp Facilities Area survey area (39 km² [14 mi²]), Reservoir survey area (883 km² [341
mi²]), and the Expanded Golden Eagle survey area (1,921 km² [741 mi²]) for a total of 4,792 km²
[1,850 mi²] (Figure 3-1). In 2014, the Denali East Corridor was added, the Denali Corridor was re-
named Denali West Corridor and the Chulitna Corridor was removed (see Appendix A for the
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2012 and 2013 study areas). The Reservoir survey area was defined by a 3-mi radius around the
reservoir inundation zone (93 km² [36 mi²]) and the Denali West, Denali East, and Gold Creek
survey areas were defined by a 3-mi radius around the three access road and transmission line
corridors. No radial buffer was applied around the Dam and Camp Facilities survey area.
The raptor study area differed slightly from the 2012 and 2013 raptor study areas due to changes
in the routing of access road and transmission line corridor alternatives between the two years, as
well as to facilitate implementation of USFWS recommendations for nesting surveys (see Shook
et al. 2013a). The width of proposed corridors for roads and transmission lines was reduced from
~0.7–2.0 mi wide in 2012 to ~0.5–1.0 mi wide in 2013. Additionally, the proposed maximum pool
elevation of the reservoir was reduced from 2,200 ft in 2012 to 2,050 ft in 2013. Because of these
changes in Project design, a 2-mi radial distance was applied to the wider 2012
corridors/inundation area and a 3-mi radial distance was applied to the narrower 2013 and 2014
corridors/inundation area to ensure that the study areas covered the required radial distance and
were similar among years.
All Bald and Golden eagle habitat within the relevant survey area boundaries was surveyed. For
Bald Eagles, surveys covered the area within a half-mile of the centers of all drainages with
suitable timber and within a half-mile of all shorelines of lakes with similar characteristics in the
reservoir inundation zone and wherever these habitats were crossed by potential road and
transmission line corridors. Information on other large tree-nesting birds was also collected during
those surveys. Survey routes for cliff-nesting raptors were flown in a cliff-to-cliff survey pattern,
focusing on cliffs suitable for Golden Eagle nests.
The survey methodology obtained information for an area larger than the 1980s survey coverage,
gathered information on key species in a more well-defined study impact area, and provided
information needed for eagle permitting and to develop avoidance areas and mitigation protocols
to reduce the potential disturbance of nesting raptors from Project construction and operations.
The study area for migration route surveys was limited to specific locations along planned
transmission line routes that may pose risks to migrating birds (e.g., ridgelines). These study areas
were determined from review of USFWS documents (e.g., Pagel et al. 2010) and were based on
review of existing raptor migration data, topographical and wind current information, and other
relevant factors.
4. METHODS AND VARIANCES IN 2014
The methods employed for Surveys of Eagles and Other Raptors in 2014 were implemented as
described in RSP Section 10.14.4, with the exception of variances described below in Sections
4.1.2.
4.1. Nesting-season Surveys
4.1.1. Territory Occupancy and Productivity Surveys
Territory occupancy and productivity surveys were conducted in 2014 following the procedures
described in the RSP (Section 10.14.4) and incorporating the variances described in the ISR, Part
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A, Section 4.1.3 (ABR 2014a) and the Study Plan modifications proposed in ISR, Part C, Section
7.1.2 (ABR 2014b). Inventory and monitoring methods for nest occupancy and productivity
surveys followed established aerial and ground-based protocols for eagle nest surveys (USFWS
2007, Pagel et al. 2010), using helicopters and trained observers. Nests of cliff-nesting raptors
(including Golden Eagle, Peregrine Falcon, Gyrfalcon, and possibly Bald Eagle) and tree-nesting
raptors (including Bald Eagle, Great Horned Owl, Northern Goshawk, Red-Tailed Hawk, Osprey,
and possibly Golden Eagle) were inventoried and monitored, as were Common Raven nests.
Surveys for early and late-nesting raptors were conducted during two main time periods
(occupancy and productivity) in 2014, for a total of four surveys. Nest occupancy surveys for early
nesting species (primarily Golden Eagle, Gyrfalcon, and Common Raven) were conducted during
May 7–14. Nest occupancy surveys for late-nesting species (primarily Bald Eagle, Peregrine
Falcon), and resident species nesting in woodlands (e.g., Red-tailed Hawk, Northern Goshawk,
Great Horned Owl, and Great Gray Owl) were conducted during May 20–22.
Nest productivity surveys were conducted during July 13–15 for early nesting raptors and during
July 21–22 for late-nesting raptors to monitor nesting activity and to search for additional nests.
These dates were selected to best capture the intended range of nest phenology. Because of the
wide range of breeding dates for all raptors considered in the study (e.g., mid-February for resident
owls through September for dispersal of Bald Eagles from nesting areas), the surveys spanned a
broad timing window.
Remaining elements of the territory occupancy and productivity surveys were conducted as
described in ISR 10.14, Part A, Section 4.1.1 (ABR 2014a). Briefly:
A small, piston-engine helicopter (Robinson R-44) with two observers was used to fly
aerial surveys using slow (~10–40 mph) approaches and passes within ~100–300 ft from
cliffs and trees to search for nests.
Data recorded included GPS location, occupancy status, nest description, habitat
description, species, count of birds, age class, and behavior.
Historical locations of Bald and Golden eagle nests identified during Alaska Power
Authority (APA) studies in the 1980s (Kessel et al. 1982) were revisited even if they were
outside the raptor study area.
All Bald and Golden eagle habitat within the respective survey area boundaries was
surveyed.
Nest status was defined as occupied, unoccupied, or unknown.
Nests that were classified as occupied or unknown during occupancy surveys were
revisited during productivity surveys to evaluate the final status of the nests (e.g.,
successful, unsuccessful) and to record the number and age of young, if present.
The “Project-area mean inter-nest distance” was calculated for occupied nests (or
centroids), as described in the Eagle Conservation Plan Guidance (USFWS 2013). One half
of the mean inter-nest distance has been suggested as a coarse indication of mean territory
size (USFWS 2013).
Nest condition was classified as good, fair, poor, remnant, or unknown.
A geospatially referenced relational database was developed to incorporate historical and
current data, including: nest and roost locations for each species; occupancy, activity, and
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productivity data; nest type and characteristics; vegetation stand characteristics; and
photographs.
4.1.1.1. Woodland Raptor Surveys
Woodland raptor surveys were not conducted in 2014.
4.1.2. Nest Sightability Assessment
Nest sightability assessment surveys were not conducted in 2014.
4.1.3. Variances
In 2013, the study team implemented a variance (ISR 10.14, Part A, Section 4.1.3) that expanded
the survey area described in RSP Section 10.14.3 to include small extensions that had been
surveyed in 2012 (Shook et al. 2013a). This variance was continued in 2014. Resurveying these
extensions in 2013 and 2014 provided three years of comparative data in those areas. These
extensions will aid in accomplishing the study objectives by obtaining multi-year data on species
occupancy and productivity for annual comparisons.
4.2. Foraging and Roost Surveys
Foraging and roost surveys were not conducted in 2014.
4.3. Migration Surveys
Migration surveys were not conducted in 2014.
4.4. Mercury Assessment
Mercury assessment was not conducted for this study in 2014. RSP Sections 10.14.1 and 10.14.4.1
provide objectives and methods for the study team to review existing literature review on the food
habits and diets of piscivorous raptors as background for the Mercury Assessment and Potential
for Bioaccumulation Study (Study 5.7), and to collect feather samples for characterization of
mercury levels and provide information on the effects of methylmercury on piscivorous raptors.
The literature review was completed in 2013, as reported in ISR 10.14, Part A, Section 4.4 (ABR
2014a). After further consideration of all mercury studies for the proposed Project, AEA has
removed these objectives and methods related to mercury analysis of piscivorous raptors (RSP
Sections 10.14.1 and 10.14.4.1) from this study and consolidated this work under Study 5.7,
Mercury Assessment and Potential for Bioaccumulation, as outlined in ISR 10.14, Part C, Section
7.1.2 (ABR 2014b). Please see the Study Implementation Report for Study 5.7 for more
information.
4.5. Delineation of Eagle Nesting Habitat
The Delineation of Eagle Nesting Habitat was continued in 2014 following the procedures
described in the RSP (Section 10.14.4) and in the ISR Part A Section 4.5 (ABR 2014a). Preliminary
maps of nesting habitat for both species of eagles were generated in 2012 and 2013 using a
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combination of field observations, aerial photography, and GIS analysis that included a digital
elevation model (DEM) and data on vegetative biomass, as indicated by the Normalized Difference
Vegetation Index (NDVI) (Shook et al. 2013a, ABR 2014a). Additional mapping and a more
thorough evaluation of cliff habitats were completed in 2014. Methods were as described in ISR,
Part A, Section 4.1.1 (ABR 2014a); these methods are outlined briefly as follows:
Field-delineated notes on paper maps were digitized using a GIS.
An experienced raptor biologist ranked areas containing suitable cliffs with a qualitative
score from ‘A’ (high quality) to ‘C’ (low quality).
The study team analyzed remote-sensing imagery to map potential Golden Eagle cliff-
nesting habitat using DEM (slope and elevation) and NDVI raster data at the locations of
all Golden Eagle nests found during surveys 2012–2014 to define nesting habitat.
The study team mapped preferred nesting habitat for Bald Eagles using GIS by applying a
107 m buffer and, for a second less-conservative estimate, a 800 m buffer around all lakes
and perennial streams with adjacent large trees.
4.5.1. Variances
No variances from the methods described for delineation of eagle nesting habitat in the Study Plan
were implemented in 2014.
5. RESULTS
To protect sensitive resources, the location coordinates of raptor nests found during this study will
not be provided. Other data developed in support of the Eagle and Other Raptor Study are available
for download in the following files at http://gis.suhydro.org/SIR/10-Wildlife/10.14-
Raptors_Eagles/:
See Table 5-1 for details.
5.1. Nesting-season Surveys
Weather stations used in previous years (Cantwell 4E and Chulitna River; ABR 2014a) contained
discontinuous data in 2014 and could not be used for comparisons. Temperature data collected at
the dam site in 2013 and 2014 provides some insight into local conditions. Monthly temperature
averages for April and May 2014 were 9.3–10.1 degrees Fahrenheit warmer than 2013, which was
a colder than average spring (ABR 2014a; Table 5.1-1). Whereas monthly temperature averages
for June, July, and August 2014 were 1.0–11.1 degrees Fahrenheit cooler than in 2013. The 2014
temperatures at the proposed Watana Dam site appeared to have been near-normal when compared
to the Cantwell 30-yr mean (40 mi from the dam site). Precipitation data was not available in 2014.
5.1.1. Territory Occupancy and Productivity Surveys
5.1.1.1. Golden Eagle
In 2014, the study team located 37 Golden Eagle nest structures (17 percent of all nests located)
within the Golden Eagle study area that were occupied by Golden Eagles during at least one
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survey, and the occupancy status of another 9 (4 percent) nests was classified as unknown (Table
5.1-2, Figure 5.1-1). In addition, three Golden Eagle nests were occupied by other raptor species
(one by Gyrfalcons, one by Merlins, and one by Common Ravens). Although one nest structure
occupied by a Golden Eagle was 440 m (1,444 ft) outside the Golden Eagle study area, this territory
was considered to fall within the study area. Overall, the nests examined in 2014 represented 37
occupied territories and 6 territories of unknown occupancy, averaging 0.0082–0.0095
territories/km² (0.0211–0.0246 territories/mi²; Table 5.1-2). Breeding pairs were observed at 22
(59 percent) of the occupied Golden Eagle territories, averaging 0.0049 breeding pairs/km² (0.0126
breeding pairs/mi²). The mean inter-nest distance of the 37 occupied territories was 5.7 km (3.6
mi; using 36 nests and the centroid of two occupied nests within a territory), while the mean inter-
nest distance for breeding pairs was 9.7 km (6.0 mi). Only four of the 37 occupied territories (11
percent) were successful in rearing at least one young to ≥75 percent of fledging age, producing a
total of four young, for a mean brood size of 0.11 young/occupied territory (1.0 young/successful
territory; Table 5.1-2). Observers also confirmed occupancy at two successful nests outside of the
study area, each with one young by the end of surveys. (Appendix B).
5.1.1.1.1. Nest Structures
Within the 2014 Golden Eagle study area, 218 Golden Eagle nest structures have been located,
one of which has since collapsed for a total of 217 standing nest structures at the end of the 2014
nesting season (Table 5.1-3). Based on finding whole nests that had fresh nesting materials (from
the current year), Golden Eagles did not likely construct any new nests in 2014.
Nest structure density in the 2014 Golden Eagle study area was 0.0478 nests/km² (0.1239
nests/mi²). In 2014, nest densities were relatively low in the Dam and Camp Facilities survey area
(0.0258 nests/km² [0.0668 nests/mi²]), Reservoir survey area (0.0294 nests/km² [0.0762
nests/mi²]), and the Denali East survey area (0.0273 nests/km² [0.0708 nests/mi²]; Figures 5.1-1–
5.1-4). Much (~60–70 percent) of the Expanded Golden Eagle survey area is flat tundra, which
decreases the overall density of nests over the entire area. Not surprisingly, Golden Eagles built
nests almost exclusively in the mountainous regions of the Expanded Golden Eagle survey area
(Figure 5.1-2). Nest densities were moderate in the Gold Creek (0.0474 nests/km² [0.1227
nests/mi²]) and Expanded Golden Eagle survey areas (0.0411 nests/km² [0.1065 nests/mi²]), while
highest in the Denali West survey area (0.0691 nests/km² [0.1790 nests/mi²]). Nests in the Gold
Creek and Reservoir survey areas were located primarily in the canyons of Susitna River tributaries
and on higher cliffs in the western portion of the Gold Creek survey area (Figures 5.1-2 and 5.1-
3). In the Denali West and East survey areas, Golden Eagle nests were primarily located along the
periphery of the survey areas, where mountainous terrain is more common (Figure 5.1-4).
Golden Eagle nests were found on cliffs at elevations between ~1,200 feet and 5,180 feet
throughout the Golden Eagle study area for all years; none were found in trees. A total of 147
Golden Eagle nests (68 percent) were in good or fair condition, 24 (11 percent) were in poor
condition, and 45 (21 percent) were remnant nests (Table 5.1-3). Three Golden Eagle nests were
found below the maximum-pool elevation of the proposed reservoir (2,050 ft; Table 5.1-4); one of
those nests was also occupied in 2012 and 2013. The other two nests have been unoccupied by
Golden Eagles and were remnant nests by 2014.
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Another 47 nest structures have been located outside of the 2014 Golden Eagle study area. Most
nests were within the 2013 Chulitna Corridor survey area or were found incidentally. Only 7 were
visited at least once during 2014 surveys (Appendix C).
5.1.1.2. Bald Eagle
Breeding-season surveys identified 14 occupied Bald Eagle nests (47 percent of all nests located)
within the 2014 raptor study area (Table 5.1-2). However, one additional nest structure was located
only 185 m (~600 ft) outside of the study area, so this territory was considered in the study area.
This resulted in 15 occupied territories with an average of 0.0057 territories/km² (0.0149
territories/mi²) within the study area. Breeding pairs were found in 11 (73 percent) of the occupied
territories with an average of 0.0042 breeding pairs/km² (0.0126 breeding pairs/mi²). The project-
area mean inter-nest distance of the 15 occupied territories was 8.8 km (5.4 mi), while the mean
inter-nest distance for breeding pairs was 12.2 km (7.6 mi). Bald Eagles in seven (47 percent) of
the occupied territories were successful in rearing at least one young to ≥75 percent of fledging
age. Those territories produced ten young for a mean brood size of 0.67 young/occupied territory
(1.4 young/successful territory).
5.1.1.2.1. Nest Structures
Within the 2014 raptor study area, 31 Bald Eagle nest structures were recorded, two of which have
since collapsed (one during spring breakup in 2014 and one during summer 2014) for a total of 29
standing nest structures at the end of the 2014 surveys (Table 5.1-3). Bald Eagles did not appear
to build any new nests within the raptor study area in 2014. Another 41 Bald Eagle nests have been
identified outside of the 2014 raptor study area. At least three of those have collapsed (one in 2013
and two in 2014) and one nest was newly built in the Expanded Golden Eagle survey area in 2014.
Twenty-one of those 41 nests were not surveyed in 2014 because the majority were located in the
Chulitna Corridor portion of the study area, so their status was unknown.
Nest structure density in the 2014 raptor study area was 0.0115 nests/km² (0.0297 nests/mi²). Nests
were most common along the Susitna River and its tributaries (Table 5.1-3, Figures 5.1-1–5.1-4).
Nest densities were highest in the Reservoir survey area (0.0215 nests/km² [0.0557 nests/mi²]),
moderate in the Gold Creek survey area (0.0084 nests/km² [0.0216 nests/mi²]), low in the Denali
West survey area (0.0049 nests/km² [0.0128 nests/mi²]), and there were no nests in the Dam and
Camp Facilities and Denali East survey areas. All but one Bald Eagle nest in the Gold Creek survey
area were located along the Susitna River. In the Reservoir survey area, 10 nests (53 percent
including the nest that collapsed in summer 2014) were located along major tributaries of the
Susitna River (Watana, Jay, and Kosina creeks and the Oshetna River), while nine were located
on the Susitna River (Figure 5.1-2). Only five nests were found in the Denali West survey area,
four on Deadman Creek and one on the Nenana River (Figure 5.1-4).
All of the Bald Eagle nests were located in trees and most (90 percent) of those found in the raptor
study area that were still standing at the end of 2014 were in good or fair condition. Two were in
poor condition, and only one was a remnant nest (Table 5.1-3). In the Reservoir survey area, seven
nests in good condition, one nest in poor condition and one nest that collapsed were below the
maximum-pool elevation of the proposed reservoir, six of which were occupied in 2012, 2013, or
2014 (Table 5.1-4).
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Outside the 2014 raptor study area, 41 Bald Eagle nest structures have been located
opportunistically (Appendices B and C), three of which have since collapsed. Only 20 of those
nests outside the study area were visited at least once during 2014 surveys. Of the 20 nests, 11
were occupied, representing 10 occupied territories. Two of the 10 known occupied territories
were successful and produced two nestlings.
5.1.1.3. Other Raptors
In 2014, five occupied Gyrfalcon territories were identified in the Golden Eagle study area (Table
5.1-5; Figures 5.1-5–5.1-8), none were below the maximum-pool elevation of the proposed
reservoir (Table 5.1-4). One pair used a nest originally constructed by Golden Eagles, two pairs
used Common Raven nests, and two pairs used natural rock/dirt ledges. Three of the territories
contained breeding pairs, one of which was successful with two young (≥75 percent of fledging
age). Four of the nests were in good condition and one (in a Common Raven nest structure) was
in poor condition (Table 5.1-6).
During the surveys in 2014, 11 occupied and 1 unknown occupancy Peregrine Falcon territories
were identified in the Golden Eagle study area, 6 occupied territories in the Reservoir survey area
and 4 occupied territories with 1 unknown occupancy territory in the Gold Creek survey area
(Figures 5.1-5–5.1-8). Breeding pairs of Peregrine Falcons were found in seven of the occupied
territories (64 percent; Table 5.1-5); however, we observed no pairs which successfully reared
young (to ≥75 percent of fledging age or to any age). Territories were located exclusively along
the Susitna River and in canyons of Susitna River tributaries (Table 5.1-5, Figures 5.1-6 and 5.1-
7). In the Reservoir survey area, ten occupied nests (five occupied territories) were below the
maximum-pool elevation of the proposed reservoir in 2012, 2013, or 2014 (Table 5.1-4).
In 2014, only 12 nest structures were occupied by Common Ravens within the Golden Eagle study
area, representing 12 occupied territories (Table 5.1-5, Figure 5.1-5). Breeding pairs were found
at 8 of the occupied nests. Because ravens fledged before the productivity surveys began, it was
not possible to accurately evaluate nest success or productivity for that species. Throughout
surveys in 2012–2014, 48 raven nest structures have been identified in the Golden Eagle study
area (Table 5.1-6, Figures 5.1-5–5.1-8); four nests have since collapsed, for a current total of 44
nests (two collapsed prior to 2013 studies and two collapsed prior to 2014 studies). All nests were
located on cliffs (none in trees). Most (77 percent) raven nests were in good or fair condition, three
(seven percent) were in poor condition, and seven (16 percent) were remnant nests (Table 5.1-6).
Raven nest structures were located primarily on the Susitna River and its tributaries. In the
Reservoir survey area, 23 nests (10 occupied in either 2012, 2013, or 2014) were below the
maximum-pool elevation (2,050 ft) of the proposed reservoir at the end of 2014 (Table 5.1-4).
Another 6 nests, representing two additional territories, have been located outside the study area
(Appendices B and C).
In 2014, one of the four Northern Goshawk nests (all in good condition) was occupied, but the
territorial pair did not appear to be breeding (Tables 5.1-5 and 5.1-6). Surveys in 2012 identified
one successful Red-tailed Hawk pair within the study area, but none were located in 2014 (Shook
et al. 2013a). Two cliff-nesting Merlin nests and territories were identified with breeding pairs
during surveys in 2014 (Table 5.1-5). Nests of this species are difficult to locate and their
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occupancy is difficult to assess from an aircraft; hence, extra effort was not expended to locate
Merlin nests.
Thirty nests constructed by unidentified raptors have been located within the Golden Eagle study
area. Two collapsed prior to 2014 studies, for a total of 28 current nests. One of these nests was
occupied by a Common Raven and three were unknown occupancy in 2014 (Table 5.1-5). Most
of the unidentified raptor nests were in poor or remnant condition (Table 5.1-6).
5.2. Delineation of Eagle Nesting Habitat
During survey flights in 2012, 2013, and 2014, observers identified and delineated 755 areas
containing cliffs suitable for Golden Eagle nesting within the Golden Eagle study area (Figures
5.1-2–5.1-4). Cliff area counts by quality were as follows:
high quality (A-ranked), 161 areas (21 percent),
medium quality (B-ranked), 270 areas (36 percent), and
low quality (C-ranked), 324 areas (43 percent).
Areas containing cliffs suitable for Golden Eagle nesting were concentrated in mountains and
along steep riparian slopes, but small cliff outcrops were also found throughout the study area. No
spatial patterns were evident in the distribution of cliffs of different quality.
Remote-sensing analyses identified potential habitat in which 94 percent of Golden Eagle nests
were located in 2013 (Figures 5.1-2–5.1-4). Delineation of potential and preferred Bald Eagle
nesting habitat was conducted in 2013 (ABR 2014a). Bald Eagle nesting habitat occurred primarily
along the Susitna River and its tributaries (Figures 5.1-2 through 5.1-4). Most lakes with forested
shorelines suitable for nesting were located near Stephan Lake and the lower Fog Lakes. Only
three Bald Eagle nests in the raptor study area were found outside of the preferred habitat that was
delineated. One of those nests was found in a tundra community with sparse small spruce trees
approximately 350 m (1,148 ft) from a small stream near Clarence Lake, another was found in
riparian habitat along Deadman Creek within 150 m (~500 ft) of water with two alternate nests
within the preferred habitat, and the final nest was found in a very small, isolated patch of
cottonwood trees in tundra habitat along upper Deadman Creek.
6. DISCUSSION
Surveys outlined in the RSP which were completed in 2014 included occupancy and productivity
surveys for Golden and Bald eagles and other raptors. Surveys not completed include woodland
raptor surveys, nest sightability surveys, and migration surveys. All 2014 field work for this study
was completed by late July. Data collection in this study was adequate to meet the first study
objective (identifying location and status of raptor nests and territories). Data collection was also
adequate to meet parts “a” and “b” of the second objective (estimating Project effects on
productivity), but parts “c” and “d” need to be completed after the final year of surveys and the
design of the Project is finalized. The third objective (estimating effects on nesting and foraging
habitats) cannot be completed until after the wildlife habitat map for Study 11.5, Vegetation and
Wildlife Habitat Mapping in the Middle and Upper Susitna River Basin, has been completed. The
fourth objective (characterizing use patterns of roosting eagles) was completed in 2013 and
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reported in the 2014 ISR (ABR 2014a). The fifth objective (assessing collision risk of transmission
lines on raptors) will be completed after the Project design (especially height) of said structures
has been determined. Additionally, data on migrating raptors to be collected in the next year of
study will bolster the relatively small sample size obtained in 2013, allowing more robust analysis
and discussion for that objective. The sixth objective (collecting feather samples from fish-eating
raptors for characterization of mercury levels) was transferred to Study 5.7.
Studies that are interrelated (Study 11.5, Vegetation and Wildlife Habitat Mapping Study in the
Upper and Middle Susitna Basin, and Study 10.19, Evaluation of Wildlife Habitat Use) are not yet
complete. The Updated Study Report (USR) for eagles and other raptors, to be completed after the
next year of study, will include more detailed delineation of raptor nesting and foraging habitat.
When completed, information produced by Study 9.5, Fish Distribution and Abundance in the
Upper Susitna River; Study 9.6, Fish Distribution and Abundance in the Middle and Lower Susitna
River; and Study 9.7, Salmon Escapement, will be included in the communal roosting and staging
section of the USR for this study.
6.1. Territory Occupancy and Productivity Surveys
All surveys were successfully completed as planned in 2014. Occupancy surveys were conducted
in May and productivity studies were conducted in July across the 2014 Golden Eagle and raptor
study areas.
Temperatures at the Cantwell 4E and Chulitna River weather stations in 2013 were cooler than
average in the spring and warmer than average in the summer (ABR 2014a). Weather data at these
stations were not available in 2014; however, temperatures at the proposed Watana dam site were
warmer in the spring and cooler in the summer than in 2013 and were similar to 30-year means for
the Cantwell 4E station.
Unfortunately, APA Project study reports from the 1980s did not include well-defined study area
boundaries (i.e., area surveyed), so direct comparisons of territory and breeding densities of raptors
cannot be made between that study and this one. Additionally, less survey effort was expended for
the 1980s APA Project studies than for the current study, further limiting comparisons of nesting
data. However, it is apparent that the Project studies in 2012–2014 located many more nests of
eagles and other raptors than did the previous studies, including breeding Peregrine Falcons, which
were not previously recorded in this area. This study obtained information for an area larger than
the area surveyed for the APA Project in the 1980s (Kessel et al. 1982). Furthermore, this study
gathered specific information on key species in a well-defined area to provide information needed
for eagle permitting and to develop avoidance areas/mitigation protocols to reduce the potential
disturbance of nesting raptors from Project construction and operations. The Bald Eagle nesting
survey also included nests upstream of the current study area, which were discovered during the
1980s surveys, for comparative purposes to evaluate trends in raptor populations and habitat use.
6.1.1.1. Golden Eagle
The density of occupied Golden Eagle territories in 2014 was similar to 2012 and 2013. The 2014
density of breeding pairs was similar to 2012, however it was 394 percent higher than 2013
(Appendix D). This suggests that while the occupancy of territories may be relatively stable, the
rate at which they breed is highly variable. Although the breeding rate (proportion of occupied
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territories that bred) was similar to 2012 and substantially higher (340 percent) than 2013, the
success rate (proportion of breeding pairs that were successful) in 2014 was moderately lower than
in 2012 and 2013 (61 and 55 percent respectively). Hence, in 2013 very few pairs attempted to
breed, but the ones that did were relatively successful at raising young, whereas in 2014 more pairs
attempted to breed, but very few were successful. Regardless, in all years, very few young were
produced. The number of young per occupied territory and density of young had high variability
among years, with 2012 being the most productive.
In all three years, densities of breeding Golden Eagles were lower than a nearby study in Denali
National Park and Preserve (DNPP; 120 km [75 mi] northwest of this study area) during the same
years and possibly under similar weather and prey conditions. In DNPP in 2014, the density of
occupied territories (0.0444 territories/km² [0.115 territories/mi²]) was 82 percent higher and the
density of breeding pairs (0.0133 pairs/km² [0.0345 pairs/mi²]) was 64 percent higher (C.
McIntyre, National Park Service [NPS], personal communication) than the Golden Eagle study
area. From 1988–1997 the average breeding pair density in DNPP (0.0185 pairs/km² [0.0479
pairs/mi²]) was 82 percent higher than the Golden Eagle study area in 2014 (McIntyre and Adams
1999). However, the lower density of breeding eagles in the Golden Eagle study area may be
skewed for two reasons: DNPP uses somewhat higher intensity surveys (often landing for
observations, for example) and the Golden Eagle study area includes large areas which are not
suitable nesting habitat. Even though the rate of occupancy and breeding pairs in 2012–2014 was
substantially higher in DNPP than this study, Golden Eagles in DNPP had some of the worst years
of productivity compared to the previous ~3 decades. In 2013, DNPP produced only 1.0 young
from 46 occupied territories and 12 young from 80 territories in 2014 (C. McIntyre, NPS, personal
communication). Snowshoe hare numbers were the lowest ever recorded in DNPP between 2012
and 2014, and were likely similarly low in the Golden Eagle study area. Overall population
productivity of Golden Eagles in DNPP has been significantly correlated with hare and ptarmigan
abundance during long-term monitoring studies (McIntyre 2002, McIntyre and Adams 1999).
Therefore, the 2012–2014 study years likely represent the Golden Eagle population only during
periods of low prey abundance.
Additionally, the three-year average density of breeding pairs for this study was 73 percent lower
than at Eva Creek in 2011 (87 mi north of this study area; 0.0127 breeding pairs/km² [0.0329 mi²]);
however, those were lower intensity surveys (Shook et al. 2013b). Furthermore, a 2010 Borough
of Land Management (BLM) study along the Dalton Highway Corridor reported an average
occupied territory density (0.0100 occupied territories/km² [0.259 occupied territories/mi²]; BLM,
unpublished data from the Central Yukon Field Office) 21 percent higher than the three-year
average in the Golden Eagle study area. In contrast, the average density of occupied territories for
this study was 2,295 percent higher than what the BLM recorded when they conducted surveys in
north-central Alaska in 2007 (0.0003 territories/km² [0.0009 mi²]; BLM, unpublished data). The
2007 BLM inventory area included large expanses without Golden Eagle nesting habitat and both
BLM surveys were conducted at lower intensity than in this study. Therefore, the BLM data
represent a minimum number of occupied territories rather than an estimate of total occupied
territories. However, this difference highlights the extreme variability that occurs in Golden Eagle
breeding densities, even within interior Alaska.
A number of characteristics of breeding raptors, especially Golden Eagles, complicate assessment
of the total number of occupied territories in an area. Territories may not be occupied in a given
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year. Weather, prey abundance (noted above), and winter mortality of adults can influence the
number of nesting adults each year (Kochert et al. 2002). For example, during six consecutive
survey years in DNPP, only 43 of 74 (58 percent) Golden Eagle territories have been occupied
every year (McIntyre 1995).
Due to the dynamic nature of territory occupancy, it is reasonable to assume that the maximum
number of Golden Eagle territories in the study area will continue to fluctuate widely among years.
Like many other raptors, Golden Eagles normally construct alternate, or supernumerary, nests
(Kochert et al. 2002). The number of alternate nests per territory has ranged from 1 to 14, but 2 or
3 nests are more typical in a territory (Kochert et al. 2002). Alternate nests often occur in closely
spaced clusters, but also can be separated by several kilometers (>5.0 km [>3.1 mi]; McGa han
1968). Territorial eagles also may improve more than one alternate nest in a breeding season,
further complicating an estimate of territorial pairs in an area (Kochert et al. 2002). Based on a
positive relationship between the number of nesting Golden Eagles and the population of snowshoe
hares in Denali National Park and Preserve (McIntyre and Adams 1999, McIntyre 2002), more
territories may be identified in the study area if surveys are conducted when prey densities are
higher than they were 2012–2014.
Only 2.1 percent of the Golden Eagle study area is within the proposed reservoir inundation zone.
Correspondingly, a relatively low proportion of Golden Eagle nests (1.4 percent), occupied
territories (2.7 percent), and breeding pairs (0.0 percent) were below the maximum pool elevation
of the proposed reservoir in 2014.
6.1.1.2. Bald Eagle
The density of occupied territories and breeding pairs was similar from 2012–2014 (Appendix D).
The success rate in 2014 was also similar to 2012, but 65 percent higher than 2013, and the number
of young per occupied territory was the highest out of all three years of the study (Appendix D).
Possible explanations for the annual differences in productivity may include weather, prey
abundance, and/or other environmental factors (Buehler 2000). Unfortunately, there are no known
diet studies for Bald Eagles in this part of the state, so it is difficult to surmise a nutritional link.
Also, there are no nearby populations of Bald Eagles with which to compare the productivity data.
However, substantial annual variability in productivity has occurred elsewhere in Alaska (e.g.,
Zwiefelhofer 2007) so the amount of variability found in the study area from 2012–2014 is not
unexpected.
Only 4 percent of the raptor study area is within the reservoir inundation zone. However, a
relatively high proportion of Bald Eagle nests (30 percent), occupied territories (33 percent), and
breeding pairs (36 percent) were below the maximum pool elevation of the proposed reservoir in
2014.
6.1.1.3. Other Nesting Raptors
Nesting Peregrine Falcons were not recorded during surveys conducted in the 1970s and 1980s
(White 1974, LGL 1984), a period when the population was low or only beginning to recover from
physiological impacts of the pesticide, DDT (Ambrose et al. 1988, Enderson et al. 1995).
Furthermore, before the impacts of DDT, Cade (1960) noted that there were only a few interior
Alaska regions with very little use by breeding Peregrine Falcons (i.e., Copper, Susitna, and
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Kuskokwim drainages), even though suitable habitat was present. Hence, the presence of this
species in 2012–2014 may represent recovery of the breeding population and/or an expansion of
their pre-pesticide range, similar to what has been recorded elsewhere in interior Alaska (e.g.,
Ritchie and Shook 2011).
All Peregrine Falcons nested on cliffs along or in close proximity to the Susitna River. This
dendritic pattern of nesting is consistent with most nesting records of Peregrine Falcons in interior
Alaska (Cade 1960). They occupied the same number of territories in 2014 as they did in 2013.
However, in 2014 no nests were successful (Appendix D). Seven occupied territories (64 percent
of occupied territories) occupied in 2014 had the nest and majority of the territory below the
maximum pool elevation of the proposed reservoir.
Common Ravens were found distributed widely across the study area, but primarily along the
Susitna River. A high proportion of nest structures (50 percent) were found in the Reservoir survey
area. Ravens appear to prefer the cliffs along the Susitna River and there is an abundance of cliff
habitat within the proposed reservoir. In 2014, five occupied territories (42 percent of all occupied
territories) had the nest and majority of the territory below the maximum pool elevation of the
proposed reservoir.
Only three to five Gyrfalcon nests/year were occupied during 2012–2014 and evidence of
historical Gyrfalcon use (e.g., distinctive guano-covered nest ledges) was limited at other cliffs,
suggesting the possible rarity of this species in the study area. The occupancy of Gyrfalcon nests
is difficult to determine because they either nest on ledges with dirt scrapes or regularly use nests
of other species (e.g., Golden Eagles and Common Ravens; Swem et al. 1994). So, unlike other
stick-nesting raptors, one cannot use newly constructed, refurbished, or decorated nests as clues to
occupancy status. Additionally, their breeding and survival can be tied closely to their prey (Booms
et. al 2008). Therefore, it is suspected that annual variation will continue to be considerable in the
study area for years to come. Studies of Gyrfalcons elsewhere in the Alaska Range have noted
relatively high densities (Swem et al. 1994), but substantial annual variability in the occupancy
and success is normal for Gyrfalcons (White and Cade 1971).
The low number of nests of other raptors found in this study disallows most discussion on their
occupancy and productivity in the study area. For example, only one nesting pair of Red-tailed
Hawks was found during 2012–2014 and only three nesting pairs of Merlins were confirmed (one
in 2012 and two in 2014). Considering the intensive survey protocols, it may be that other nesting
raptors are not common in the region or are currently at lower numbers because of environmental
factors, such as prey abundance.
6.2. Delineation of Eagle Nesting Habitat
Areas containing cliffs suitable for Golden Eagle nesting within the Golden Eagle study area have
been thoroughly delineated using both field and remote sensing techniques. In 2013, slope,
elevation, and NDVI values at nest sites were used to identify potential nesting habitat at 5 m
resolution. This potential nesting habitat is useful for planning and conducting field surveys. The
field delineated areas represent coarse mappings of ground-truthed areas where suitable cliff
nesting habitat is present. When used in concert with the remote-sensing analysis, one can identify
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the habitat that is suitable for Golden Eagle nesting at a finer scale than can be achieved with just
field delineation alone (Figures 5.1-2 through 5.1-4).
The buffer distance for the preferred Bald Eagle nesting habitat was calculated by measuring the
distance from water at which 95 percent of all nests were found from 2012–2013 (ABR 2014a).
This habitat delineation will be refined further after the wildlife habitat map is completed (Study
11.5) and accurate delineations of forested habitats can be overlaid with the buffer, thus identifying
and eliminating much non-nesting habitat.
7. CONCLUSION
To further the progress of addressing the Study Plan objectives in 2014, the raptor study completed
occupancy and productivity surveys in the six survey areas: the Dam and Camp Facilities Area,
Denali East, Denali West, Expanded Golden Eagle, Gold Creek, and Reservoir areas. A
geospatially referenced database of raptor nests was created and eagle nesting habitat was
delineated further. These data were collected to advance the objective of estimating the Project
effects on nesting raptors.
The field work to be conducted in the final year of the study will be similar to that conducted in
2013 and 2014, continuing the variances described above and in ISR, Part C, Section 7.1.2).
Future field efforts for this study will include occupancy and productivity surveys, as well as
woodland raptor surveys (including sightability surveys for each of these), which will provide
raptor nest avoidance information to limit disturbance as well as data to address the Study Plan
objectives. To fulfill the relevant Study Plan objective, a second year of raptor migration surveys
should be conducted. Estimation of Project effects on eagles and other raptors using the occupancy,
productivity, and migration survey data collected for this study will need to be conducted after
completion of Study 10.19, Evaluation of Wildlife Habitat Use.
7.1. Modifications to Study Plan
As was discussed in the ISR meeting on October 21, 2014, the two years of surveys conducted in
2012 and 2013 did not find any indications of fall and winter communal roosts and foraging sites
used by Bald Eagles or other raptors in the Study Area. Hence, AEA proposes that further surveys
for this study task not be conducted. Therefore, the work needed to fulfill Study Plan Objective 4
(in Section 2 above) is considered to be completed.
8. LITERATURE CITED
ABR. 2014a. Surveys of Eagles and Other Raptors Study Plan Section 10.14; Initial Study Report
Part A: Sections 1–6, 8–10; Susitna–Watana Hydroelectric Project (FERC Project No.
14241). Report for the Alaska Energy Authority by ABR Inc., Fairbanks, Alaska. Available
online: http://www.susitna-watanahydro.org/.
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Susitna–Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 17 November 2015
ABR. 2014b. Surveys of Eagle and Other Raptors Study Plan Section 10.14; Initial Study Report
Part C: Executive Summary and Section 7; Susitna–Watana Hydroelectric Project (FERC
Project No. 14241). Report for the Alaska Energy Authority by ABR Inc., Fairbanks,
Alaska. Available online: http://www.susitna-watanahydro.org/.
AEA (Alaska Energy Authority). 2011. Pre-application document: Susitna–Watana Hydroelectric
Project, FERC Project No. 14241. December 29, 2011. Report for the Federal Energy
Regulatory Commission, Washington, DC.
AEA. 2012. Revised Study Plan: Susitna–Watana Hydroelectric Project FERC Project No. 14241.
December 2012. Report for the Federal Energy Regulatory Commission by the Alaska
Energy Authority, Anchorage, Alaska. Available online: http://www.susitna-
watanahydro.org/study-plan.
APA (Alaska Power Authority). 1985. Before the Federal Energy Regulatory Commission: Draft
amended application for license for major project—Susitna Hydroelectric Project. Volume
11, Exhibit E – Chapter 3: Fish, wildlife, and botanical resources. 702 pp. [APA Doc. No.
3435]
Ambrose, R. E. , R. J. Ritchie, C. M. White, P. F. Schempf, T. Swem, and R. Dittrick. 1988.
Changes in the status of Peregrine Falcon populations in Alaska. Pages 73–82 in T. J. Cade,
J. H. Enderson, C. G. Thelander, and C. M. White (eds.). Peregrine Falcon Populations:
Their Management and Recovery. The Peregrine Fund, Inc., Boise, ID.
AOU (American Ornithologists’ Union). 1998. Check-list of North American Birds. 7th ed.
American Ornithologists’ Union, Washington, DC.
Booms, T. L., T. J. Cade, and N. J. Clum. 2008. Gyrfalcon (Falco rusticolus). Account 117 in A.
Poole, editor. The Birds of North America online. Cornell Lab of Ornithology, Ithaca, NY.
<http://bna.birds.cornell.edu/bna/species/114.> Accessed 12 October 2015.
BPIFWG (Boreal Partners in Flight Working Group). 1999. Landbird conservation plan for Alaska
biogeographic regions. Version 1.0. U.S. Fish and Wildlife Service, Anchorage.
BLM (Bureau of Land Management). 2010. BLM–Alaska sensitive animal and plant lists. Alaska
State Office, Anchorage.
Buehler, D. A. 2000. Bald Eagle (Haliaeetus leucocephalus). Account 506 in A. Poole, editor .
The Birds of North America online. Cornell Lab of Ornithology, Ithaca, NY. Available
online: http://bna.birds.cornell.edu/bna/species/506 (accessed October 12, 2015).
Cade, T. J. 1960. Ecology of the Peregrine and Gyrfalcon populations in Alaska. University of
California Publications in Zoology 63: 151–290.
Enderson, J. H., W. Heinrich, L. Kiff, and C. M. White. 1995. Population changes in North
American peregrines. Transactions of the North American Wildlife and Natural Resources
Conference 60: 142–161.
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FERC Project No. 14241 Page 18 November 2015
Kessel, B., S. O. MacDonald, D. D. Gibson, B. A. Cooper, and B. A. Anderson. 1982. Susitna
Hydroelectric Project environmental studies, Phase I final report—Subtask 7.11: Birds and
non-game mammals. Report by University of Alaska Museum, Fairbanks, and Terrestrial
Environmental Specialists, Inc., Phoenix, NY for Alaska Power Authority, Anchorage. 149
pp.
Kochert, M. N., K. Steenoff, L. B., C. L. McIntyre, and E. H. Craig. 2002. Golden Eagle (Aquila
chrysaetos). Account 684 in A. Poole, editor. The Birds of North America online. Cornell
Lab of Ornithology, Ithaca, NY. Available online:
http://bna.birds.cornell.edu/bna/species/684 (accessed 12 October 2015).
LGL (LGL Alaska Research Associates, Inc.) 1984. Susitna Hydroelectric Project, update and
refinement of Bald and Golden eagle impact assessments and mitigation plans. FERC
Project No. 7114. Report for the Alaska Power Authority, Anchorage. 66 pp.
McGahan, J. 1968. Ecology of the Golden Eagle. Auk 85: 1–12.
McIntyre, C. L. 1995. Nesting ecology of migratory Golden Eagles (Aquila chrysaetos) in Denali
National Park, Alaska. M.S. thesis, University of Alaska, Fairbanks. 57 pp.
McIntyre, C. L. 2002. Patterns of nesting area occupancy and reproductive success of Golden
Eagles (Aquila chrysaetos) in Denali National Park and Preserve, Alaska, 1988–99.
Journal of Raptor Research 36 (supplement): 50–54.
McIntyre, C. L., and L. G. Adams. 1999. Reproductive characteristics of migratory Golden Eagles
in Denali National Park, Alaska. Condor 101: 115–123.
Pagel, J. E., D. M. Whittington, and G. T. Allen. 2010. Interim Golden Eagle technical guidance:
inventory and monitoring protocols; and other recommendations in support of eagle
management and permit issuance. U.S. Fish and Wildlife Service, Division of Migratory
Bird Management. 30 pp.
Ritchie, R. J., and J. E. Shook. 2011. Recovery and trends of Peregrine Falcons breeding in the
Yukon–Tanana uplands, east-central Alaska, 1995–2003. Journal of Raptor Research 45:
150–159.
Shook, J. E., J. H. Welch, and R. J. Ritchie. 2013a. Susitna–Watana Hydroelectric Project (FERC
No. 14241), Surveys of Eagles and Other Raptors, 2012 technical memorandum. Report
for Alaska Energy Authority, Anchorage, by ABR, Inc.—Environmental Research &
Services, Fairbanks.
Shook, J. E., R. J. Ritchie, and T. J. Mabee. 2013b. Eagle conservation plan for the Eva Creek
wind energy project, Alaska. Unpublished report by ABR, Inc.—Environmental Research
& Services, Fairbanks, AK, and Forest Grove, OR, for Golden Valley Electric Association
Inc., Fairbanks, and SAIC Energy, Environment & Infrastructure LLC, Denver, CO. 26 pp.
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Swem, T., C. McIntyre, R. J. Ritchie, P. J. Bente, and D. G. Roseneau. 1994. Distribution,
abundance, and notes on the breeding biology of Gyrfalcons (Falco rusticolus) in Alaska.
Pages 437–446 in B. U. Meyburg and R. D. Chancellor (eds.). Raptor Conservation Today,
Proceedings of the IV World Conference on Birds of Prey and Owls. Helm Information
Ltd., East Sussex. 799 pp.
USFWS (U.S. Fish and Wildlife Service). 2007. National Bald Eagle management guidelines.
Washington, D.C. 25 pp.
USFWS. 2008. Birds of Conservation Concern 2008. U.S. Department of Interior, Fish and
Wildlife Service, Division of Migratory Bird Management, Arlington, Virginia. 85 pp.
Available online: http://www.fws.gov/migratorybirds/.
USFWS. 2013. Eagle Conservation Plan Guidance, Module 1—Land-based Wind Energy, Version
2. 103 pp. Available online: http://www.fws.gov/windenergy/eagle_guidance.html.
White, C. M. 1974. Survey of the Peregrine Falcon and other raptors in the proposed Susitna River
reservoir impoundment areas. Report for Brigham Young University, Provo, Utah, and
U.S. Fish and Wildlife Service, Anchorage, Alaska. 3 pp.
White, C. M., and T. J. Cade. 1971. Cliff-nesting raptors and ravens along the Colville River in
arctic Alaska. The Living Bird 10: 107–150.
Zwiefelhofer, D. 2007. Comparison of Bald Eagle (Haliaeetus leucocephalus) nesting and
productivity at Kodiak National Wildlife Refuge, Alaska, 1963–2002. Journal of Raptor
Research 41: 1–9.
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9. TABLES
Table 2-1. Raptor Species Occurring in the Susitna-Watana Study Area (adapted from AEA 2011).
English
Name
Scientific
Name
Conservation
Status1
Seasonal
Status2
Relative
Abundance3
Osprey Pandion haliaetus FS M rare
Bald Eagle Haliaeetus leucocephalus FS B uncommon
Northern Harrier Circus cyaneus FS B fairly common
Sharp-shinned Hawk Accipiter striatus FS B uncommon
Northern Goshawk Accipiter gentilis FS B uncommon
Red-tailed Hawk Buteo jamaicensis FS B uncommon
Golden Eagle Aquila chrysaetos BLM, FS B fairly common
Merlin Falco columbarius FS B uncommon
Gyrfalcon Falco rusticolus PIF, FS R uncommon
Peregrine Falcon Falco peregrinus anatum BCC, FS M unknown
Great-horned Owl Bubo virginianus FS R uncommon
Northern Hawk Owl Surnia ulula FS R uncommon
Great Gray Owl Strix nebulosa PIF, FS ? rare
Short-eared Owl Asio flammeus BLM, FS B?, M, S uncommon
Boreal Owl Aegolius funereus PIF, FS R rare
1. Conservation Status: FS = Featured Species (ADF&G 2006); BCC = Birds of Conservation Concern (USFWS 2008); BLM = BLM
Sensitive Species (BLM 2010); PIF = Boreal Partners in Flight Working Group (BPIFWG 1999).
2. Seasonal Status: M = migrant (transient); B = breeding; S = summering; R = resident; ? = uncertain (Kessel et al. 1982; APA 1985:
Appendices E5.3 and E6.3).
3. From Kessel et al. (1982) and APA (1985: Appendices E5.3 and E6.3).
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Table 5-1. Server Location and File Names for Field Data from the Surveys of Eagles and Other Raptors Conducted in
2012–2014.
Server Pathway or File/Folder Name Description
http://gis.suhydro.org/SIR/10-Wildlife/10.14-Raptors_Eagles/
Pathway to data files
RPTR_10_14_PublicData_2012_2014_ABR.gdb
Geodatabase file containing spatial layers of the Eagle and
Other Raptor Study, including nest habitat suitability raster,
2012–2014 study areas, and Golden Eagle nest habitats.
RPTR_10_14_RPTR_Nests_2012_2014_NoCoordinates_ABR.xlsx Microsoft Excel file containing raptor nest occupancy and
productivity data, 2012–2014. Geographic coordinates are
omitted due to the sensitive nature of nest location data.
Table 5.1-1. Mean monthly temperatures at the Watana Dam Site and Cantwell 4E, 2013 and 2014.
Month Watana Dam Site Mean Air Temperature (°F) Cantwell 4E Mean Air Temperature (°F)
2013 2014 2013 30-yr Mean
April 17.5 27.6 11.6 27.2
May 36.8 46.1 35.7 41.4
June 58.7 47.6 56.8 51.3
July 56.7 53.7 56.6 55.2
August 52.8 51.8 53.2 50.6
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Table 5.1-2. Eagle Nest Success and Territory Occupancy for Golden Eagles (in the Golden Eagle Survey Area) and Bald
Eagles (in the Raptor Survey Area), 2014. Numbers in parentheses indicate additional possible territories or nests as a
result of nests with an unknown occupancy status.
Species Survey Area
No. of
Occupied
Nests
No. of
Occupied
Territories1
No. of
Breeding
Pairs
No. of
Successful
Pairs2
No. of Young2
Golden
Eagle
Dam and Camp Facility Area 0 0 0 0 0
Denali East 2 2 1 0 0
Denali West 8 (1) 8 5 0 0
Expanded Golden Eagle 14 (4) 14 (4) 8 2 2
Gold Creek 6 (3) 7 3 (2) 3 3 1 3 1 3
Reservoir 7 (1) 6 5 1 1
Total Golden Eagle 37 (9) 37 3 (6) 22 3 4 3 4 3
Bald
Eagle
Dam and Camp Facility Area 0 0 0 0 0
Denali East 0 0 0 0 0
Denali West 2 2 1 1 1
Gold Creek 4 5 4 3 4 2 3
Reservoir 8 8 7 4 6
Total Bald Eagle 14 15 4 11 4 7 10
1. Some occupied territories contain more than one occupied nest.
2. Young ≥75% of fledging age (estimated by comparing with known-age photos).
3. One nest (172GOEA) with an incubating adult was located 440 m outside of the study area, it is not included in Occupied Nests, but
the occupied territory was included in all other calculations because of its proximity to the study area..
4. One nest (050BAEA) with an incubating adult was located 185 m outside of the study area, it is not included in Occupied Nests, but
the occupied territory was included in all other calculations because of its proximity to the study area.
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Table 5.1-3. Eagle Nest Number and Condition for Golden Eagles (in the Golden Eagle Survey Area) and Bald Eagles (in
the Raptor Survey Area), 2014.
Species Survey Area
Nest Condition
Total1
Collapsed or
Degraded
Beyond
Recognition
in 2014 Good Fair Poor Remnant Unknown
Golden
Eagle
Dam and Camp Facility Area 0 0 1 0 0 1 0
Denali East 3 2 1 1 0 7 0
Denali West 35 2 12 8 15 0 70 1
Expanded Golden Eagle 40 3 16 5 17 1 79 0
Gold Creek 19 4 4 3 8 0 34 0
Reservoir 15 1 6 4 0 26 0
Total Golden Eagles 112 35 24 45 1 217 1
Bald
Eagle
Dam and Camp Facility Area 0 0 0 0 0 0 0
Denali East 0 0 0 0 0 0 0
Denali West 3 2 0 0 0 5 0
Gold Creek 5 0 0 1 0 6 1
Reservoir 14 2 2 0 0 18 1
Total Bald Eagles 22 4 2 1 0 29 2
1. Total nests located does not include collapsed nests.
2. One nest was occupied by a Gyrfalcon in 2014.
3. One nest was occupied by a Common Raven in 2014.
4. One nest was occupied by Merlins in 2014
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Table 5.1-4. Raptor Nests Below 2,050 ft (predicted maximum pool) in the Reservoir Survey Area.
Species Nest ID 2012 Maximum Nest
Occupancy
2013 Maximum
Nest
Occupancy
2014 Maximum
Nest
Occupancy
2014 Nest
Condition
Golden Eagle SU015GOEA Occupied Occupied Occupied Good
SU092GOEA Occupied 1 Unoccupied Unoccupied Remnant
SU098GOEA Unoccupied Unoccupied Unoccupied Remnant
Bald Eagle SU001BAEA Occupied Occupied Occupied Good
SU002BAEA Occupied Occupied Occupied Collapsed
SU020BAEA Occupied Unknown Unoccupied Good
SU021BAEA Unknown Unoccupied Unoccupied Poor
SU030BAEA Occupied Occupied Occupied Good
SU031BAEA Unoccupied Unoccupied Unoccupied Good
SU032BAEA Occupied Occupied Occupied Good
SU045BAEA Unoccupied Unoccupied Unoccupied Good
SU063BAEA – Occupied Occupied Good
Northern Goshawk SU001NOGO – Occupied Unoccupied Good
SU002NOGO – Unoccupied Unoccupied Good
SU003NOGO – Unoccupied Occupied Good
SU004NOGO – Unoccupied Unoccupied Good
Peregrine Falcon SU003PEFA 2 Occupied Unknown Occupied Good
SU004PEFA 2 Occupied Unknown Unoccupied Unknown
SU005PEFA 3 Occupied Occupied Unoccupied Good
SU006PEFA 3 Occupied Unoccupied Occupied Good
SU009PEFA 4 Occupied Unknown Occupied Good
SU011PEFA 2 Occupied Unoccupied Unknown Unknown
SU014PEFA 4 – Occupied Occupied Good
SU015PEFA 5 – Occupied Occupied Good
SU017PEFA – Occupied Occupied Good
SU022PEFA 5 – – Occupied Good
Common Raven SU001CORA Unoccupied Unoccupied Unoccupied Good
SU002CORA Occupied Unoccupied Unoccupied Good
SU003CORA Unoccupied Unoccupied Unoccupied Good
SU004CORA Occupied Unoccupied Unoccupied Good
SU005CORA Unoccupied Collapsed Collapsed Collapsed
SU006CORA Occupied Unoccupied Unoccupied Good
SU007CORA Occupied Unoccupied Unoccupied Remnant
SU008CORA Unoccupied Occupied Unoccupied Good
SU009CORA Unoccupied Unoccupied Nest Collapsed Collapsed
SU010CORA Unoccupied Unoccupied Unoccupied Good
SU011CORA Unoccupied Unoccupied Unoccupied Good
SU023CORA Unoccupied Unoccupied Unoccupied Good
SU027CORA Unoccupied Unoccupied Unoccupied Remnant
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Species Nest ID 2012 Maximum Nest
Occupancy
2013 Maximum
Nest
Occupancy
2014 Maximum
Nest
Occupancy
2014 Nest
Condition
SU029CORA – Unoccupied Unoccupied Poor
SU030CORA – Unoccupied Unoccupied Good
SU031CORA – Unoccupied Unoccupied Remnant
SU041CORA – Unoccupied Unoccupied Good
SU043CORA – – Unoccupied Good
SU044CORA – – Unoccupied Good
SU045CORA – – Occupied Good
SU046CORA – – Occupied Good
SU047CORA – – Unoccupied Good
SU048CORA – – Occupied Good
SU049CORA – – Occupied Good
SU050CORA – – Occupied Good
Unidentified Raptor SU001XRAP Unoccupied Unoccupied Occupied Fair
SU004XRAP Unoccupied Unoccupied Occupied Remnant
SU020XRAP Unoccupied Unoccupied Occupied Remnant
1. Nest was occupied by an incubating Peregrine Falcon.
2. These three nest ledges are likely within 1 territory and have evidence they previously hatched young, but a pair did not appear to
nest in 2012 or 2013.
3. These two nests were within the same territory.
4. These two nests were within the same territory.
5. These two nests were within the same territory.
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Table 5.1-5. Other Raptor Nest Success and Territory Occupancy for Gyrfalcon, Merlin, Peregrine Falcon and Common
Raven (in the Golden Eagle Survey Area) and Northern Goshawk (in the Raptor Survey Area), 2014. Numbers in
parentheses indicate additional possible territories or nests as a result of nests with an unknown occupancy status.
Species Survey Area
No.
Occupied
Nests
No.
Occupied
Territories1
No.
Breeding
Pairs
No.
Successful
Pairs2
No. of
Young2
Northern
Goshawk
Dam and Camp Facility Area 0 0 0 0 0
Denali East 0 0 0 0 0
Denali West 0 0 0 0 0
Expanded Golden Eagle 0 0 0 0 0
Gold Creek 0 0 0 0 0
Reservoir 1 1 0 0 0
Total Northern Goshawk 1 1 0 0 0
Merlin4 Dam and Camp Facility Area 0 0 0
Denali East 0 0 0
Denali West 1 1 1
Expanded Golden Eagle 0 0 0
Gold Creek 1 1 1
Reservoir 0 0 0
Total Merlin 2 2 2
Gyrfalcon Dam and Camp Facility Area 0 0 0 0 0
Denali East 1 1 0 0 0
Denali West 2 2 1 1 2 3
Expanded Golden Eagle 2 2 2 0 0
Gold Creek 0 0 0 0 0
Reservoir 0 0 0 0 0
Total Gyrfalcon 5 5 3 1 2 3
Peregrine Falcon4 Dam and Camp Facility Area 0 0 0 0 0
Denali East 0 0 0 0 0
Denali West 2 1 1 0 0
Expanded Golden Eagle 0 0 0 0 0
Gold Creek 4 (1) 4 (1) 3 0 0
Reservoir 8 (1) 6 3 0 0
Total Peregrine Falcon 14 (2) 11 (1) 7 0 0
Common Raven Dam and Camp Facility Area 0 0 0 0 0
Denali East 1 1 1 1 Unk 5
Denali West 0 0 0 0 0
Expanded Golden Eagle 1 1 1 1 Unk 5
Gold Creek 4 4 4 2 Unk 5
Reservoir 6 6 4 2 Unk 5
Total Common Raven 12 12 10 6 Unk 5
Unidentified
Raptor
Dam and Camp Facility Area 0 0 0 0 0
Denali East 0 0 0 0 0
Denali West (2) (2) 0 0 0
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Species Survey Area
No.
Occupied
Nests
No.
Occupied
Territories1
No.
Breeding
Pairs
No.
Successful
Pairs2
No. of
Young2
Expanded Golden Eagle (1) (1) 0 0 0
Gold Creek 0 0 0 0 0
Reservoir 0 0 0 0 0
Total Unidentified 0 (3) 0 (3) 0 0 0
1. Some occupied territories contain more than one occupied nest.
2. Young ≥75% of fledging age (estimated by comparing with known-age photos).
3. Gyrfalcons often fledged before our final productivity survey, but a minimum count of young was possible.
4. Ledges and nests were only recorded if currently occupied by a Merlin or Peregrine Falcon.
5. Common Ravens fledged too early to count young, but successful nests could be determined by copious feces at the nest.
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Table 5.1-6. Other Raptor Nest Numbers and Condition for Gyrfalcon, and Common Raven (in the Golden Eagle Survey
Area) and Northern Goshawk (in the Raptor Survey Area), 2014.
Species Survey Area Nest Condition Total1 Collapsed
in 2014 Good Fair Poor Remnant
Northern
Goshawk
Dam and Camp Facility Area 0 0 0 0 0 0
Denali East 0 0 0 0 0 0
Denali West 0 0 0 0 0 0
Expanded Golden Eagle 0 0 0 0 0 0
Gold Creek 0 0 0 0 0 0
Reservoir 4 0 0 0 4 0
Total Northern Goshawks 4 0 0 0 4 0
Gyrfalcon Dam and Camp Facility Area 0 0 0 0 0 0
Denali East 0 0 0 0 0 0
Denali West 2 0 0 0 2 0
Expanded Golden Eagle 2 0 0 0 2 0
Gold Creek 1 0 0 0 1 0
Reservoir 1 0 0 0 1 0
Total Gyrfalcons 6 0 0 0 6 0
Common
Raven
Dam and Camp Facility Area 0 0 0 0 0 0
Denali East 2 0 0 0 2 0
Denali West 2 0 0 1 3 0
Expanded Golden Eagle 0 1 1 0 2 0
Gold Creek 9 0 0 3 12 1
Reservoir 19 1 2 3 25 1
Total Common Ravens 32 2 3 7 44 2
Unidentified
Raptor
Dam and Camp Facility Area 0 0 0 0 0 0
Denali East 0 0 0 0 0 0
Denali West 2 1 1 5 9 0
Expanded Golden Eagle 3 0 0 2 5 0
Gold Creek 2 0 2 4 8 2
Reservoir 3 1 0 2 6 0
Total Unidentified 10 2 3 13 28 2
1. Total nests located does not include collapsed nests.
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10. FIGURES
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Figure 3-1. Raptor Study Area for the Susitna-Watana Hydroelectric Project, 2014.
This needs to be updated. White border.
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Figure 5.1-1. Distribution and Occupancy of Bald Eagle and Golden Eagle Nests, 2014.
STUDY IMPLEMENTATION REPORT SURVEYS OF EAGLES AND OTHER RAPTORS (STUDY 10.14)
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Figure 5.1-2. Eagle Nest Occupancy and Nesting Habitat in the Reservoir and Expanded Golden Eagle Survey Areas, 2014.
STUDY IMPLEMENTATION REPORT SURVEYS OF EAGLES AND OTHER RAPTORS (STUDY 10.14)
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Figure 5.1-3. Eagle Nest Occupancy and Nesting Habitat in the Gold Creek Survey Area, 2014.
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Figure 5.1-4. Eagle Nest Occupancy and Nesting Habitat in the Denali Survey Area, 2014.
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Figure 5.1-5. Distribution and Occupancy of Other Raptor Nests, 2014.
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Figure 5.1-6. Distribution and Occupancy of Other Raptor Nests in the Reservoir Survey Area, 2014.
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Figure 5.1-7. Distribution and Occupancy of Other Raptor Nests in the Gold Creek Survey Area, 2014.
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Figure 5.1-8. Distribution and Occupancy of Other Raptor Nests in the Denali Survey Area, 2014.
STUDY IMPLEMENTATION REPORT SURVEYS OF EAGLES AND OTHER RAPTORS (STUDY 10.14)
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APPENDIX A: 2012 AND 2013 GOLDEN EAGLE AND RAPTOR STUDY
AREAS FOR THE SUSITNA-WATANA HYDROELECTRIC PROJECT.
STUDY IMPLEMENTATION REPORT SURVEYS OF EAGLES AND OTHER RAPTORS (STUDY 10.14)
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APPENDIX B: NEST SUCCESS AND TERRITORY OCCUPANCY OF
RAPTOR NESTS FOUND OUTSIDE OF THE STUDY AREA
BOUNDARIES, 2012–2014.
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Nest Success and Territory Occupancy of Raptor Nests Found Outside of the Study Area Boundaries, 2012–
2014. Only nests that were visited in 2014 are included.
Species Nearest Survey Area
No. of
Occupied
Nests
No. of
Occupied
Territories
No. of
Breeding
Pairs
No. of
Successful
Pairs1
No. of
Young1
Golden Eagle 2013 Chulitna 0 0 0 0 0
Dam and Camp Facility Area 0 0 0 0 0
Denali West 0 0 0 0 0
Denali East 1 1 1 1 1
Expanded Golden Eagle 0 0 0 0 0
Gold Creek 1 2 0 2 0 2 0 2 0 2
Reservoir 0 0 0 0 0
Total Golden Eagle 2 1 1 1 1
Bald Eagle 2013 Chulitna 0 0 0 0 0
Dam and Camp Facility Area 0 0 0 0 0
Denali West 1 1 1 0 0
Denali East 0 0 0 0 0
Expanded Golden Eagle 7 6 6 1 1
Gold Creek 3 2 3 2 3 1 1
Reservoir 0 0 0 0 0
Total Bald Eagle 11 9 3 9 3 2 2
Peregrine
Falcon
2013 Chulitna 0 0 0 0 0
Dam and Camp Facility Area 0 0 0 0 0
Denali West 0 0 0 0 0
Denali East 0 0 0 0 0
Expanded Golden Eagle 0 0 0 0 0
Gold Creek 1 1 0 0 0
Reservoir 0 0 0 0 0
Total Peregrine Falcon 1 1 0 0 0
Common
Raven
2013 Chulitna 0 0 0 0 0
Dam and Camp Facility Area 0 0 0 0 0
Denali West 0 0 0 0 0
Expanded Golden Eagle 0 0 0 0 0
Gold Creek 1 1 1 1 –
Reservoir 0 0 0 0 0
Total Common Raven 1 1 1 1 –
1. Young ≥75% of fledging age (estimated by comparing with known-age photos).
2. One nest (172GOEA) with an incubating adult was located 440 m outside of the study area. Due to this nest’s proximity to the study
area, this territory was included in calculations for within the study area.
3. One nest located 185 m outside of the study area was occupied by a breeding pair of Bald Eagles. Due to this nest’s proximity to the
study area, this territory was included in calculations for within the study area.
STUDY IMPLEMENTATION REPORT SURVEYS OF EAGLES AND OTHER RAPTORS (STUDY 10.14)
Susitna–Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 November 2015
APPENDIX C: NUMBER AND LAST KNOWN CONDITION OF NESTS
BUILT BY RAPTORS FOUND OUTSIDE OF THE STUDY AREA
BOUNDARIES, 2012–2014.
STUDY IMPLEMENTATION REPORT SURVEYS OF EAGLES AND OTHER RAPTORS (STUDY 10.14)
Susitna–Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Appendix C - Page 1 November 2015
Species Nearest Survey Area Last Known Nest Condition Total Collapsed Good Fair Poor Remnant Unknown
Golden
Eagle
2013 Chulitna 22 5 7 5 1 40 0
Dam and Camp Facility Area 0 0 0 0 0 0 0
Denali East 1 0 0 0 0 1 0
Denali West 1 0 1 0 0 2 0
Expanded Golden Eagle 0 0 1 0 0 1 0
Gold Creek 2 0 1 0 0 3 0
Reservoir 0 0 0 0 0 0 0
Total Golden Eagle 26 5 10 5 1 47 0
Bald Eagle 2013 Chulitna 7 3 0 0 0 10 0
Dam and Camp Facility Area 0 0 0 0 0 0 0
Denali East 0 0 0 0 0 0 0
Denali West 0 1 0 0 0 1 0
Expanded Golden Eagle 8 1 2 0 0 11 2
Gold Creek 14 1 1 0 0 16 1
Reservoir 0 0 0 0 0 0 0
Total Bald Eagle 29 6 3 0 0 38 3
Peregrine
Falcon
2013 Chulitna 0 0 0 0 0 0 0
Dam and Camp Facility Area 0 0 0 0 0 0 0
Denali East 0 0 0 0 0 0 0
Denali West 0 0 0 0 0 0 0
Expanded Golden Eagle 0 0 0 0 0 0 0
Gold Creek 1 0 0 0 0 1 0
Reservoir 0 0 0 0 0 0 0
Total Peregrine Falcon 1 0 0 0 0 1 0
Common
Raven
2013 Chulitna 0 1 0 0 0 1 0
Dam and Camp Facility Area 0 0 0 0 0 0 0
Denali East 0 0 0 0 0 0 0
Denali West 0 0 0 0 0 0 0
Expanded Golden Eagle 0 0 0 0 0 0 0
Gold Creek 5 0 0 0 0 5 0
Reservoir 0 0 0 0 0 0 0
Total Common Raven 5 1 0 0 0 6 0
Unidentified
Raptor
2013 Chulitna 0 0 1 0 0 1 0
Dam and Camp Facility Area 0 0 0 0 0 0 0
Denali East 0 0 0 0 0 0 0
Denali West 0 0 0 0 0 0 0
Expanded Golden Eagle 0 0 0 0 0 0 0
Gold Creek 0 0 0 0 0 0 0
Reservoir 0 0 0 0 0 0 0
Total Unidentified Raptor 0 0 1 0 0 1 0
STUDY IMPLEMENTATION REPORT SURVEYS OF EAGLES AND OTHER RAPTORS (STUDY 10.14)
Susitna–Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 November 2015
APPENDIX D: SUMMARY OF BREEDING PARAMETERS OF EAGLES
AND OTHER RAPTORS, 2012–2014.
STUDY IMPLEMENTATION REPORT SURVEYS OF EAGLES AND OTHER RAPTORS (STUDY 10.14)
Susitna–Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Appendix D - Page 1 November 2015
Summary of Breeding Parameters of Eagles and Other Raptors, 2012–2014.
Species Year
Area
Surveyed
(km²)
Nest Structures Occupied
Territories Breeding Pairs Successful
Pairs1 Productivity
No. Density
(km²)
No.
Occupied
Nests
No. Density
(km²) No. Density
(km²)
Breeding
Rate (%) No. Success
Rate (%)
No.
Young
Density
(km²)
Young/
Occupied
Territory
Golden
Eagle
2012 3,017 99 0.0328 32 25 0.0083 13 0.0043 52 6 46 8 0.0027 0.32
2013 5,091 235 0.0462 43 37 0.0073 5 0.0010 14 2 40 2 0.0004 0.05
2014 4,535 217 0.0478 37 37 0.0082 22 0.0049 59 4 18 4 0.0009 0.11
Average 4,214 184 0.0423 37 33.0 0.0079 13.3 0.0034 42 4.0 35 4.7 0.0013 0.16
Bald Eagle 2012 3,017 41 0.0136 19 17 0.0056 12 0.0040 71 8 67 10 0.0033 0.59
2013 3,293 40 0.0121 23 23 0.0070 13 0.0039 57 5 38 5 0.0015 0.22
2014 2,614 30 0.0115 14 15 0.0057 11 0.0042 73 7 64 10 0.0038 0.67
Average 2,975 37 0.0124 19 18.3 0.0061 12.0 0.0040 67 6.7 56 8.3 0.0029 0.49
Gyrfalcon2 2012 3,017 5 0.0017 4 4 0.0013 4 0.0013 100 0 0 0 0.0000 0.00
2013 5,091 6 0.0012 3 3 0.0006 3 0.0006 100 2–3 67–100 3–4 0.0006–
0.0008 1.00–1.33
2014 4,535 6 0.0013 5 5 0.0011 3 0.0007 60 1 33 2 0.0004 0.40
Average 4,214 6 0.0014 4 4.0 0.0010 3.3 0.0009 87 0.5 17 1.0 0.0002 0.20
Peregrine
Falcon3
2012 3,017 – 11 7 0.0023 4 0.0013 57 1 25 3 0.0010 0.43
2013 5,091 – 7 7 0.0014 7 0.0014 100 4–6 57–186 9–13 0.0018–
0.0026 1.29–1.86
2014 4,535 – 14 11 0.0024 7 0.0015 64 0 0 0 0.0000 0.00
Average 4,214 11 8.3 0.0020 6.0 0.0014 74 0.5 13 1.5 0.0005 0.21
Common
Raven4
2012 3,017 24 0.0080 6 6 0.0020 6 0.0020 100 unk 0 unk
2013 5,091 35 0.0069 6 6 0.0012 5 0.0010 83 unk 0 unk
2014 4,535 44 0.0097 12 12 0.0026 8 0.0018 67 >=6 0 unk
Average 4,214 34 0.0082 8 8.0 0.0019 6.3 0.0016 83
1. Young ≥75% of fledging age (estimated by comparing with known-age photos).
2. Gyrfalcons often fledged before our final productivity survey, but a minimum count of young was often possible.
3. Ledges and nests were only recorded if currently occupied by a Peregrine Falcon.
4. Common Ravens fledged too early to count young, but successful nests could be determined by copious feces at the nest.