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Eagles and Wind Energy: Identifying Research Priorities

Authors:
  • Renewable Energy Wildlife Institute

Abstract and Figures

The Bald and Golden Eagle Protection Act prohibits the taking (killing, wounding, or disturbing) of bald and golden eagles without a permit. Eagles can be killed by wind turbines, yet, as the most commercially viable and scalable form of renewable energy, wind power is critical to addressing climate change, a major threat to eagles and other wildlife. The U.S. Fish and Wildlife Service (Service) has developed a framework for permitting lawful take and conserving eagles and has recently proposed regulations for the issuance of eagle take permits where the take is associated with an otherwise lawful activity, such as wind energy. Helping to reconcile the goals of wind energy development and eagle conservation is an urgent priority of the American Wind Wildlife Institute (AWWI) and its partners. This white paper and the November 2011 AWWI Eagle Workshop at which an earlier working draft was discussed draw on input from scientific experts on bald and golden eagles to define the technical issues around wind energy development and eagles, and to identify research that would improve implementation of and compliance with the Service’s Eagle Guidance. We summarize information about the population status and trends of bald and golden eagles and discuss “take” threshold in terms of eagle management units. We review anthropogenic sources of eagle mortality along with estimated magnitude of take from wind energy and from leading sources such as electrocution, collision, shooting, and poisoning. Potential mitigation options are identified. Research topics considered include: a) identifying and addressing information gaps on demography and status relevant to calculating take thresholds; b) developing unbiased estimates of eagle mortality; c) creating models for siting and operational strategies that avoid or minimize eagle fatalities at wind energy facilities; d) expanding options for compensatory mitigation; and e) coordinating and enhancing existing collaborative eagle research. Because bald eagle populations appear to be thriving, Eagle Workshop participants recommend that AWWI emphasize research on golden eagles that is directly relevant to wind energy development. The white paper concludes that AWWI should focus over the next 12 months on expanding options for compensatory mitigation while continuing to identify, support, and collaborate with other research initiatives, as appropriate.
Content may be subject to copyright.
Eagles and Wind
Energy:
Identifying
Research Priorities
Dr. Taber D. Allison, Ph.D.
May 2012
www.awwi.org
CITATION:
Allison, T.D. 2012. Eagles and Wind Energy: Identifying Research Priorities. A white paper of the
American Wind Wildlife Institute, Washington, DC.
The American Wind Wildlife Institute (AWWI) brings together wind energy industry, national
conservation organization and wildlife agency leaders in a shared mission: to facilitate the timely and
responsible development of wind energy while protecting wildlife and wildlife habitat. To accomplish
this mission, AWWI advances research that addresses priority wind-wildlife issues, and develops tools
and strategies that have impact on the ground. More information about AWWI is available at
www.awwi.org.
American Wind Wildlife Institute
1110 Vermont Avenue, NW, Suite 950
Washington, DC 20005-3544
202.656.3303 | info@awwi.org
www.awwi.org
ACKNOWLEDGEMENTS
This white paper is the result of a collaborative effort, for which we deeply thank many participants.
This paper builds on their years of work.
We are grateful for the insights and constructive input that academic, scientific, federal and regional
agency, conservation, industry, and other experts provided in the course of the preparation of this paper
and through their participation in the American Wind Wildlife Institute (AWWI) Eagle Workshop held
November 15-17, 2011 in Denver, CO. A list of Workshop participants is provided in Appendix C.
For allowing AWWI to use data referenced in this paper, we thank the U.S. Fish and Wildlife Service, the
American Wind Energy Association, and WEST, Inc.
We thank Jon Bart, Erica Craig, Wally Erickson, Mark Fuller, Terry Grubb, Al Harmata, Doug Johnson,
Todd Katzner, David Mehlman, Brian Millsap, Ryan Nielson, Bob Oakleaf, Jeff Smith, Dale Strickland,
Kenton Taylor, Jim Watson, and Stu Webster for comments on this and earlier versions of the paper.
Our thanks also go to the industry, agency, and conservation Partners who made it possible to hold the
AWWI Eagle Workshop and who support AWWI and its work, including AES Wind Generation, American
Wind Energy Association, Association of Fish & Wildlife Agencies, Audubon, AWS Truepower, BP Wind
Energy, Clean Line Energy Partners, Clipper Windpower, Defenders of Wildlife, Duke Energy, EDP
Renewables, Edison Mission Energy, Environmental Defense Fund, enXco, First Wind, GE Energy,
Iberdrola Renewables, National Wildlife Federation, Natural Resources Defense Council, NextEra Energy
Resources, NRG Systems, PG&E, Pattern Energy Group, RES Americas, Ridgeline Energy, Shell
WindEnergy, Sierra Club, Terra-Gen Power, The Nature Conservancy, Union of Concerned Scientists, and
Vestas Americas. Through their generous support, active engagement, and commitment to a shared
mission, they are blazing a trail forward for wind energy and wildlife.
AWWI is ultimately responsible for the paper’s contents.
TABLE OF CONTENTS
Abstract ................................................................................................................................... 1
Preface .................................................................................................................................... 2
I. Introduction ......................................................................................................................... 4
II. Status and Trends of Bald and Golden Eagle Populations in North America ......................... 6
A. Bald Eagle ......................................................................................................................................... 6
Figure 1. 2006 bald eagle breeding pairs in the contiguous United States ............................... 7
B. Golden Eagle .................................................................................................................................... 8
Table 1. Estimated population totals (all ages) of golden eagles in each Bird Conservation
Region (BCR) .............................................................................................................................. 9
III. Anthropogenic Sources of Eagle Take ................................................................................. 9
A. Wind Energy Vulnerability of Eagles ........................................................................................... 10
Table 2. Golden eagle fatalities compiled from publicly available reports and from the
Altamont Pass Wind Resource Area (Altamont) ..................................................................... 11
Table 3. Eagle fatalities reported at wind energy facilities in the U.S. .................................... 13
Figure 2. Average pre-construction golden eagle use values for facilities with and without
observed golden eagle fatalities ............................................................................................. 14
B. Other Anthropogenic Contributors to Eagle Mortality and Threats to Eagles .............................. 15
Table 4. Anthropogenic sources of eagle mortality 2006-2011 .............................................. 16
IV. Mitigating Eagle Take ....................................................................................................... 18
V. Research and Conservation Priorities ................................................................................ 19
VI. References Cited .............................................................................................................. 23
Appendix A: Potential Sources of Compensatory Mitigation for Offsetting Take of Golden
Eagles at Wind Energy Facilities ..................................................................................... 29
Appendix B: Compendium of Priority Golden Eagle Research Topics ..................................... 31
Appendix C: AWWI Eagle Workshop Participants .................................................................. 33
May 2012 Eagles and Wind Energy: Identifying Research Priorities
1
Abstract
The Bald and Golden Eagle Protection Act prohibits the taking (killing, wounding, or disturbing) of bald and golden
eagles without a permit. Eagles can be killed by wind turbines, yet, as the most commercially viable and scalable
form of renewable energy, wind power is critical to addressing climate change, a major threat to eagles and other
wildlife. The U.S. Fish and Wildlife Service (Service) has developed a framework for permitting lawful take and
conserving eagles and has recently proposed regulations for the issuance of eagle take permits where the take is
associated with an otherwise lawful activity, such as wind energy. Helping to reconcile the goals of wind energy
development and eagle conservation is an urgent priority of the American Wind Wildlife Institute (AWWI) and its
partners. This white paper and the November 2011 AWWI Eagle Workshop at which an earlier working draft was
discussed draw on input from scientific experts on bald and golden eagles to define the technical issues around
wind energy development and eagles, and to identify research that would improve implementation of and
compliance with the Service’s Eagle Guidance.
We summarize information about the population status and trends of bald and golden eagles and discuss “take”
threshold in terms of eagle management units. We review anthropogenic sources of eagle mortality along with
estimated magnitude of take from wind energy and from leading sources such as electrocution, collision,
shooting, and poisoning. Potential mitigation options are identified. Research topics considered include: a)
identifying and addressing information gaps on demography and status relevant to calculating take thresholds; b)
developing unbiased estimates of eagle mortality; c) creating models for siting and operational strategies that
avoid or minimize eagle fatalities at wind energy facilities; d) expanding options for compensatory mitigation; and
e) coordinating and enhancing existing collaborative eagle research.
Because bald eagle populations appear to be thriving, Eagle Workshop participants recommend that AWWI
emphasize research on golden eagles that is directly relevant to wind energy development. The white paper
concludes that AWWI should focus over the next 12 months on expanding options for compensatory mitigation
while continuing to identify, support, and collaborate with other research initiatives, as appropriate.
May 2012 Eagles and Wind Energy: Identifying Research Priorities
2
Preface
The purpose of the AWWI Eagle Workshop held November 15-17, 2011 in Denver, CO was to define the science
needs most directly relevant to AWWI’s mission: promoting wind energy development that minimizes impacts to
wildlife – in this case, to eagles. The Bald and Golden Eagle Protection Act prohibits the taking (killing, wounding,
or disturbing) of bald and golden eagles without a permit. Wind energy facilities have "taken" eagles in the course
their operations. Through its 2009 Eagle Rule and 2011 Eagle Guidance, the U.S. Fish and Wildlife Service (Service)
has developed a framework for permitting lawful takeand conserving eagles, which are protected under the
Bald and Golden Eagle Protection Act. Given the broad potential range of eagles and the gaps in our
understanding of eagle wind energy interactions, which make it difficult to predict possible risk to eagles,
accomplishing the dual objective of permitting lawful take and conserving eagles creates a challenge for
developing and operating wind energy projects where eagles occur.
To address this challenge, support the Service’s implementation of the Eagle Guidance, and assist wind industry
compliance with the Eagle Rule and Eagle Guidance, AWWI convened the November 2011 Eagle Workshop in
collaboration with stakeholders from state and federal agencies, eagle experts, and AWWI Partners from the wind
energy industry and the conservation community. The goals of the workshop were to describe the current state
of knowledge of bald and golden eagles and to identify research that would improve implementation of and
compliance with the Eagle Guidance for wind energy. There is an urgent need to define the research that will
enable us to meet this challenge within the next five to ten years.
AWWI Partners came together in recognition that climate change is a looming threat of potentially enormous
magnitude to all wildlife, including eagles. Many climate experts state that emissions reductions in the next five
to ten years will have major consequences for the amount of climate change that will occur over this century. To
meet a broad range of pollution as well as climate change emissions reduction goals, many states and regions
have established targets for renewable and emission-free electricity production, and wind energy is the most
commercially viable form of renewable electricity.
In planning the Eagle Workshop, AWWI recognized that understanding the status of eagles and the threats to
eagles, especially golden eagles, from the development and operation of wind energy facilities and other
anthropogenic activities has been a major focus of research scientists at government agencies, wildlife consulting
firms, and at academic institutions and non-governmental conservation organizations. Among recent efforts to
define research priorities for golden eagles, the 2010 Colloquium and Science meetings and the 2011 Research
Roundtable (GOEA Colloquium 2010; GOEA Science Meeting 2010) have resulted in the initiation of several
collaborative research efforts between the Service and scientists at the U.S. Geological Survey (USGS). These
efforts inform AWWI’s investment in wind energy and eagle research, which is intended to complement and
support the research of the Service and the USGS.
AWWI staff prepared a version of this white paper prior to the workshop to help AWWI better understand the
technical issues around wind energy development and eagles. Although much of the recent concern has focused
on golden eagles and wind energy, the workshop and white paper included a review of bald eagles because
interactions between wind energy production and bald eagles are likely to increase as wind energy development
continues to expand, especially at coastal and nearshore locations. The white paper also was intended to help
May 2012 Eagles and Wind Energy: Identifying Research Priorities
3
identify areas of remaining uncertainty and to create a framework for defining a research agenda to reduce these
uncertainties. The principal outcome of the workshop was a set of priorities which AWWI would implement to fill
the knowledge gaps identified and to support the permitting of lawful take while conserving eagles.
The first draft of this white paper was provided on October 17, 2011 to the more than 20 technical experts invited
to participate in the mid-November Eagle Workshop. Invited technical experts were asked to provide comments
to AWWI by October 31. A second draft of the white paper was prepared by AWWI staff on the basis of
comments received, and on November 4, this draft was distributed to all workshop participants and discussed
during a webcast open to all AWWI Sustaining Partners and Friends. The final pre-workshop draft of the white
paper, incorporating comments from the webcast discussion, was distributed to invited participants and AWWI
Sustaining Partners and Friends on November 9.1
The workshop took place in Denver, CO, November 15-17,
2011. Results from the workshop were incorporated into a post-workshop draft, which was shared with invited
technical participants for further comment. This white paper reflects this additional input.
1 AWWI gratefully acknowledges the input of workshop participants that improved the style and substance of the white
paper. AWWI assumes all responsibility for the white paper’s content.
May 2012 Eagles and Wind Energy: Identifying Research Priorities
4
I. Introduction
Eagles are protected under the Bald and Golden
Eagle Protection Act (BGEPA), the Migratory Bird
Treaty Act (MBTA), and various state laws. BGEPA
states that it is unlawful for anyone to “take,
possess, sell, purchase, barter, offer to sell, purchase
or barter, transport, export or import, at any time or
in any manner, any bald eagle . . . or any golden
eagle, alive or dead, or any part, nest, or egg thereof
. . . .”2 BGEPA further defines “takeas "[to]
pursue, shoot, shoot at, poison, wound, kill, capture,
trap, collect, molest or disturb individuals, their
nests and eggs."3 In delisting the Bald Eagle from
the Endangered Species Act (ESA) in 2007, the
Service issued a rule to further define disturb as “to
agitate or bother a bald or golden eagle to a degree
that causes, or is likely to cause, based on the best
scientific information available, 1) injury to an eagle,
2) a decrease in its productivity, by substantially
interfering with normal breeding, feeding, or
sheltering behavior, or 3) nest abandonment, by
substantially interfering with normal breeding,
feeding, or sheltering behavior."4
Generating electricity from wind can wound or kill
eagles when they collide with turbine blades, and
can also disturb eagles during construction and
operation of the wind energy facility resulting in nest
abandonment or displacement from breeding
territories. In February 2011, the Service released
“Proposed Guidance for Eagle Conservation Plans
Module 1: Wind Energy Development” (Eagle
In September
2009, the Service published a Final Rule (50 CFR
22.26) under BGEPA authorizing limited issuance of
permits to take” bald and golden eagles during
otherwise lawful activity.
2 U.S.Code § 668a
3 Ibid.
4 See http://cfr.regstoday.com/50cfr22.aspx; section 22.3
Definitions
Guidance; USFWS 2011b) to provide
recommendations for the development of Eagle
Conservation Plans (ECPs) for the issuing of
programmatic take permits for wind energy facilities.
The Eagle Guidance proposed procedures for
applicants and biologists to assess potential risk to
eagles and to implement conservation practices and
adaptive management. Public comment on the
Eagle Guidance was received by the Service until
May 2011, and a revised version of the Eagle
Guidance has been completed and is undergoing
internal review; publication is anticipated in summer
2012 (Brian Millsap, U.S. Fish and Wildlife Service,
personal communication).
Wind energy is projected to contribute significantly
to a national strategy for meeting growing electricity
demand while reducing production of greenhouse
gases and other forms of air and water pollution,
decreasing water consumption for power production
(Averyt et al. 2011), diversifying national energy
supplies, and reducing dependence on foreign
energy supplies. The U.S. Department of Energy
(DOE) has developed a scenario for obtaining 20% of
U.S. electricity from wind energy by 2030 (DOE
2008). Generation of electricity from wind in 2010
was 2.3% of the total U.S. electricity generation in
the U.S.5
Bald and golden eagles are widespread in the
contiguous United States, and most wind energy
projects will have some overlap with breeding,
wintering, or migrating individuals of one or both
species. There are large areas of the U.S. where
encounters with eagles will be rare or infrequent
(e.g., see Good et al. 2007); thus the risk to eagle
populations from wind energy development will vary
Thus, to achieve the DOE scenario, a
substantial increase in installed wind capacity will
need to occur in the next 18 years.
5 http://www.eia.gov/cneaf/solar.renewables/page/wind/
wind.html
May 2012 Eagles and Wind Energy: Identifying Research Priorities
5
ESTABLISHING TAKE THRESHOLDS FOR
BALD AND GOLDEN EAGLES
As defined by BGEPA, take involves effects
leading to injury, mortality, or reduced
productivity. The Final Environmental
Assessment for the 2009 Eagle Rule (USFWS FEA
2009) described the modeling methodology used
by the Service to define allowable take for bald
and golden eagles. The model included
parameters estimated from available data on the
status and trends in populations, annual
productivity and age-specific survival, and
existing mortality sources for both species.
Model simulations resulted in estimates of
sustainable “harvest” or take for each
management unit as a small percentage of
annual productivity. Detailed information was
available on bald eagle nest distribution as a
result of this species’ delisting review, and this
information was used in defining management
units for this species. Similar information was
not available for golden eagles, and
management units for this species corresponded
to Fish and Wildlife Service Bird Conservation
Regions. Take thresholds are to be reviewed and
updated every five years.
geographically. Nevertheless, the requirements of
the Eagle Rule and Eagle Guidance and the
widespread range of eagles in the U.S. represent a
significant challenge to meeting the country’s energy
production goals.
To support the Service’s implementation of the Eagle
Guidance and to assist wind industry compliance
with the Eagle Rule and Eagle Guidance, AWWI in
collaboration with stakeholders from the wind
industry, state and federal agencies, eagle experts,
and the conservation community convened an Eagle
Workshop in Denver, CO on November 15-17, 2011.
The goals of the workshop were to describe the
current state of our knowledge of bald and golden
eagles and to identify research that would improve
implementation of and compliance with the Eagle
Guidance for wind energy development.
Specifically in the context of the Eagle Guidance,
research needs were to be articulated under the
following premises:
Operating wind energy facilities may “take”
eagles by collision with turbines and possibly
by disturbance of eagles that results in nest
abandonment or displacement (as further
defined in BGEPA) and reduced productivity.
Allowable eagle take reflects our
understanding of the status and trends in
eagle populations (or sub-populations),
which includes the ability of populations to
sustain increased mortality (see sidebar:
Establishing Take Thresholds for Bald and
Golden Eagles).
Evaluation of the need for take permits will
be determined by our ability to predict take,
i.e., our ability to predict risk of a specific
project to eagles and our ability to avoid and
minimize this risk through the
implementation of “advanced conservation
practices” to the extent practicable (as
defined in 50 CFR 22.26).
When avoidance and minimization are
insufficient to eliminate all predicted take,
then compensatory mitigation may be
required.6
In those situations where compensatory
mitigation is required, proposed mitigation
must demonstrate a direct numerical offset
of predicted take.
6 Measures to offset eagle take will be required only when
take thresholds for a particular eagle management unit
are being exceeded.
May 2012 Eagles and Wind Energy: Identifying Research Priorities
6
Prior to the workshop, AWWI staff, with input from
invited participants, prepared a synopsis of: 1) the
known population status of bald and golden eagles
in the contiguous U.S.; 2) sources of eagle mortality
from wind energy development and other
anthropogenic activities; and 3) potential measures
for mitigating potential negative impacts of wind
energy development on eagles, focusing primarily on
information relevant to reducing take of eagles
solely at wind energy facilities. This white paper
does not explore the applications of this research
and mitigation effort for addressing other related
issues, though they may set the stage for such a
discussion.
In preparing this synopsis it was readily
acknowledged that there has been a longstanding
and intensive focus on the conservation of both
eagle species. Comprehensive species accounts
were prepared and published for the Birds of North
America series on bald eagles (Buehler 2000) and
golden eagles (Kochert et al. 2002), and an update
on the status of both species was prepared as part of
the Final Environmental Assessment in support of
the development of the Eagle Rule (USFWS FEA
2009a). In 2010 two workshops involving federal
research scientists and wildlife managers reviewed
the state of knowledge about golden eagles,
including population status and threats, and defined
research priorities (GOEA Colloquium 2010; GOEA
Science Meeting 2010). This white paper relies
heavily on the substantial body of knowledge for
both species reflected in these efforts.
II. Status and Trends of Bald
and Golden Eagle Populations
in North America
The population status and trends of bald and golden
eagles are key elements in the application of the
Eagle Rule and Eagle Guidance, as applied to eagle
management units (see sidebar: Establishing Take
Thresholds for Bald and Golden Eagles for the
definition). The Service has stated (50 CFR 22.26)
that programmatic permits will be issued when take
is compatible with the preservation of eagles defined
as consistent with the goal of stable or increasing
populations. If the estimated take from a proposed
project exceeds the established take thresholds for
the relevant eagle management unit, the proposed
activity must completely offset predicted take
resulting in no net mortality increase.
A. Bald Eagle
Bald eagles were listed under the Endangered
Species Act (ESA) in 1978. Prior to listing, population
estimates in the contiguous U.S. comprised
approximately 400 breeding pairs in the early 1960s
(Figure 1), and the species had been extirpated from
much of the eastern and southern U.S. (Buehler
2000). Low bald eagle numbers reflected centuries
of persecution and, in the 1950s and 1960s, a
decline in breeding success due to the widespread
use of organochlorine-based pesticides. Some
protection was afforded bald eagles with passage of
the Bald Eagle Protection Act in 1940,7
7 Amended to include Golden Eagle in 1962, aka ‘BGEPA’
but bald
eagle numbers began to increase substantially only
after DDT was banned in the U.S. in 1972. Since that
time the number of breeding pairs has increased
rapidly and substantially to the point that recovery
targets (e.g., 1,200 breeding pairs in the northern
U.S.; USFWS 1983) were significantly exceeded in the
late 1990s. The species was proposed for delisting in
1999, and, with the exception of the Sonoran Desert
sub-population, the bald eagle was removed from
the endangered species list in June 2007. The
Sonoran Desert sub-population was delisted in
September 2011. The bald eagle currently is
considered a species of “Least Concern” by the
May 2012 Eagles and Wind Energy: Identifying Research Priorities
7
Figure 1. 2006 bald eagle breeding pairs in the contiguous United States
Based on annual state surveys, which largely ceased after 2000.
From http://www.fws.gov/midwest/Eagle/population/chtofprs.html
International Union for Conservation of Nature
(BirdLife International 2009).
Buehler (2000) provided an estimate of 100,000
individual bald eagles as of 1999 with the largest
numbers in Alaska and British Columbia, and
numbers may be substantially higher (USFWS
2009a). The last reliable estimate of the number of
breeding pairsmore than 9,000 in the contiguous
U.S. – comes from the national survey of 2006
(Figure 1). A national monitoring protocol for
assessing future trends in bald eagles was developed
as part of the delisting plan (USFWS 2009b) and was
intended to work with state-based nest surveys.
Annual surveys of bald eagles remain a fixture in
many states as the rapid increase in bald eagles from
the lows of the 1950s and 1960s continues to be a
newsworthy item especially in states where the
species had been extirpated.8
Paradoxically,
expanding and thriving bald eagle populations as
well as tight budgets are causing many states to stop
survey efforts, which will complicate the ability to
monitor future status and trends in this species.
8 e.g., Ohio
(http://newsdemocrat.com/main.asp?SectionID=2&SubSe
ctionID=2&ArticleID=119620), Virginia
(http://www.vagazette.com/articles/2011/09/09/news/d
oc4e68ac589a3a8109626317.txt), New Jersey
(http://www.njherald.com/story/16351531/recovery-of-
bald-eagle-in-nj-a-success-story), and Michigan
(http://www.mlive.com/news/muskegon/index.ssf/2011/
07/bald_eagle_population_continue.html), Arizona
(http://www.azcentral.com/arizonarepublic/news/articles
/2010/09/28/20100928arizona-bald-eagle-population-
gain.html)
May 2012 Eagles and Wind Energy: Identifying Research Priorities
8
B. Golden Eagle
Several long-term studies of golden eagles in
different regions of the U.S. have raised concerns
that this species is declining (Kochert and Steenhof
2002)a tentative conclusion reached by the
Service in its 2009 Final Environmental Assessment
(USFWS 2009a) and shared by others (e.g., Katzner
et al. 2012). Habitat changes that negatively affect
the eagle prey base have been suggested as
explanations for these declines. Eagle abundance
may track fluctuations in preferred prey species, e.g.,
black-tailed jackrabbit, making it a challenge to
separate cyclical declines from declines resulting
from long-term habitat shifts or human disturbance
(Kochert and Steenhof 2002; USFWS 2009a).
Stable or increasing trends of migrating golden
eagles were reported in counts from the early 1970s
to 2004 in eastern Canada and the eastern U.S.
following a decline recorded between the 1930s and
early 1970s (Kochert and Steenhof 2002; Farmer et
al. 2008). In western North America, both longer-
term (since the 1980s) and recent declines were
indicated at most sites analyzed through 2005 (Smith
et al. 2008). In the Great Basin, increases in adult
detection rates but decreases in migratory immature
golden eagles may indicate reduced reproduction
(Hoffman and Smith 2003; Smith et al. 2008). In a
recent review of current research and monitoring at
the 2010 North American Golden Eagle Science
Meeting (GOEA Science Meeting 2010), nine of the
28 regional reports estimated population status, and
of these, six estimated declines in numbers based on
territory occupancy or migration counts.
In 2003, the Service contracted with WEST, Inc. to
design and conduct aerial surveys to provide
statistically rigorous estimates of golden eagle
abundance in four Bird Conservation Regions (BCRs)
comprising an estimated 80% of the golden eagle
population in the contiguous U.S. Good et al. (2007)
described the methods and results for the initial
pilot survey conducted in 2003. Surveys were not
conducted in 2004 and 2005. Surveys were resumed
in 2006 with a somewhat modified protocol and
have been repeated annually from 2006 through
2011 using this same protocol and survey transects
(Nielson et al. 2012). The estimated average number
of golden eagles in the regions surveyed from 2006-
2010 was approximately 23,000 (Table 1) with no
statistically significant change in numbers detected
over that period. Because the Great Plains BCR was
not surveyed in 2011, no total was provided for that
year (see Nielson et al. 2012 for further discussion).
The total number of golden eagles classified as
juveniles has declined significantly in two of the four
BCRs. No significant trends in the numbers of golden
eagles classified as juveniles have been observed in
the Great Basin or Northern Rockies, or when
analyzed across the entire study area during the
same period (Nielson et al. 2012).
The surveys were designed to detect an average 3%
change in eagle numbers per year over a 20-year
period with a statistical power of 80% (alpha = 0.1)
assuming surveys would be conducted annually. An
inability to detect small changes is to be expected at
this stage of the project, but larger changes could be
detected. Kochert and Steenhof (2002)
recommended that any survey of golden eagle
populations should continue for a minimum of ten
years because of possible fluctuations in numbers of
eagles in response to prey cycles referenced earlier
in this section.
The USGS, the Service, and WEST have developed a
log-linear hierarchical model that integrates the
WEST survey data and Breeding Bird Survey (BBS)
data, and enables scaling of the BBS data to
population density estimates. BBS data have been
assumed to be of limited value for estimating golden
eagle population levels (e.g., Kochert et al. 2002),
but tests of the model indicate that BBS and WEST
survey data provide consistent estimates of
May 2012 Eagles and Wind Energy: Identifying Research Priorities
9
population trends within the overlapping BCRs.
Extension of this modeling approach to all BCRs
encompassing golden eagle range and to the
expanded time period provided by BBS surveys
(1968-2010) could provide a more robust analysis of
golden eagle population trends. Preliminary results
based on this extension suggest that golden eagle
populations appear to be stable over the time period
and BCRs analyzed (Brian Millsap, U.S. Fish and
Wildlife Service, personal communication). A paper
is in preparation and will be submitted for peer-
review and publication. Until the results are
published, the approach and results should be
considered preliminary.
III. Anthropogenic Sources of
Eagle Take
Accurate estimation of the causes and magnitude of
anthropogenic sources of mortality (take) for bald
and golden eagles including wind energy
development – is important for several reasons.
First, modeling that sets current take thresholds
incorporates assumptions of age-specific survival.
Second, reduction in mortality attributable to wind
energy development requires a better
understanding of the magnitude and risk factors
associated with that mortality and development of
Table 1. Estimated population totals (all ages) of golden eagles in each Bird
Conservation Region (BCR)
Excludes military lands, elevations > 10,000 ft, large water bodies, and large urban areas. Data from 2003 and 2006
2010 as estimated from WEST, Inc. aerial surveys (Nielson et al. 2012). Estimates for 2006-2010 were obtained by
pooling observations across years to improve estimates of detection probabilities. Thus, estimates for 2006-2009 have
been updated and are slightly different than those presented in previous reports. BCR 17 was not surveyed in 2011 and
the total was not calculated. Ninety-percent confidence intervals are in parentheses.
Year Great Basin
(BCR 9)
Northern
Rockies
(BCR10)
Southern
Rockies/
Colorado Plateau
(BCR16)
Badlands and
Prairies
(BCR17)
Total
2003 10,939
(7,522; 15,754)
4,831
(2,262; 8,580)
4,998
(3,199; 7,275)
6,624
(4,611; 9,207)
27,392
(21,556; 35,369)
2006 4,301
(2,687; 6,093)
6,074
(3,594; 9,116)
4,196
(2,728; 5,889)
9,358
(6,448; 12,544)
23,930
(19,545; 28,957)
2007 6,043
(4,238; 7,955)
7,150
(4,102; 11,209)
2,714
(1,568; 4,022)
9,025
(6,350; 11,995)
24,933
(20,296; 30,664)
2008 4,217
(2,830; 5,771)
7,433
(5,039; 10,387)
1,526
(804; 2,359)
6,109
(4,076; 8,305)
19,286
(15,802; 23,349)
2009 4,812
(3,389; 6,397)
7,185
(4,455; 10,873)
2,588
(1,229; 4,153)
6,011
(3,572; 8,777)
20,597
(16,314; 25,666)
2010 5,680
(3,542; 8,117)
7,554
(4,831; 10,961)
2,503
(1,361; 3,830)
8,095
(5,158; 11,736)
23,833
(18,948; 29,541)
2011 6,199
(4,732; 8,555)
6,862
(4,853; 9,994)
2,917
(2,053; 4,228)
May 2012 Eagles and Wind Energy: Identifying Research Priorities
10
practices that avoid and minimize fatalities. Third, if
mitigation offsetting unavoidable take is required,
mitigation opportunities and evaluation will be
enhanced by an understanding of the importance of
adult survival and productivity, defined as fledgling
production/nesting, in affecting trends in eagle
populations.
A. Wind Energy – Vulnerability of
Eagles
Eagles may collide with wind turbines, and an
important part of the take permit application
process is an accurate estimation of whether and
how many collision strikes will occur at individual
projects. Impact estimates are based on models that
utilize a variety of assumed risk factors, such as
activity levels in the project area and estimated
relationships between exposure, avoidance, and
collision risk (USFWS 2011). Estimates of eagle
avoidance come from analysis of eagle activity and
eagle fatalities at existing projects (e.g., Whitfield
2009, but see Ferrer et al. 2012). Fatality estimates
come from comprehensive and systematic searches
for all bird and bat carcasses, usually at a subset of
turbines at a project. Fatality reports also come
from “incidental finds,” defined as carcasses not
found as part of the standardize search process, but
during maintenance or other visits to individual
turbines at the project site. Fatalities are adjusted
for various detection biases, which have been
discussed thoroughly elsewhere (e.g., Huso 2011;
Strickland et al. 2011). Any error in the estimation
or application of these adjustment terms could lead
to over- or under-estimated eagle fatality rates and,
therefore, compromised risk predictions.
How many golden eagles are killed at wind facilities?
The longest and most detailed record comes from
the Altamont Pass Wind Resource Area (Altamont) in
California, a 37,000-acre area containing
approximately 4,500 mostly old-generation turbines
in dense aggregations or turbine strings.9
Detailed studies of golden eagle behavior at
Altamont suggest that most of the eagle fatalities
have been sub-adults and non-breeding adults
(floaters) because current home ranges of breeding
eagles have kept them out of the project area (Hunt
2002). Population-level consequences of the high
fatality rate are not certain. For example, all
territories in the vicinity of the Altamont remained
occupied after multiple years of tracking (Hunt and
Hunt 2006), and there was no evidence for a lack of
Large
numbers of golden eagle fatalities (and raptor
fatalities, in general) have been reported from
Altamont (Table 2), but developing a consistent
methodology for estimating golden eagle fatality
rates at Altamont and comparing those estimates
with other projects has been a challenge for a
variety of reasons, including lack of consistent
sampling of all turbine strings (due to access
constraints); lack of site-specific scavenger
adjustment factors; long search intervals and varying
search protocols; and varying operation of turbine
strings, in part related to attempts to mitigate avian
fatalities. As a result, estimates of average annual
Altamont-wide adjusted fatality rates vary
considerably from 30 to 70 golden eagles per year
(e.g., see Smallwood and Thelander 2008,
Smallwood and Karas 2009, and ICF 2011 for
details), and recent estimates of annual eagle
fatalities between 1998 and 2008 have ranged from
15 to 50 golden eagles (ICF 2011).
9 Construction of wind turbines at Altamont began in the
1960s and continued into the 1980s. Capacity of turbines
installed during this period ranged from 40 to 400 kW;
most turbines were 100 kW and 150 kW. Repowering at
Altamont began in 2005, and large numbers of shorter,
lower-capacity wind turbines are being replaced by fewer
taller, higher-rated wind turbines.
May 2012 Eagles and Wind Energy: Identifying Research Priorities
11
Table 2. Golden eagle fatalities compiled from publicly available reports and
from the Altamont Pass Wind Resource Area (Altamont)
Eagle carcasses were located systematically (“carcass search”) or incidentally, and these are reported separately for each
project with the exception of Altamont where sources are combined. Fatality reports are not adjusted for searcher efficiency or
scavenger removal. Time period corresponds to the the period of data collection. MW Capacity is total project capacity
calculated as the nameplate capacity of individual turbines multiplied by the number of turbines installed. For Altamont, MW
capacity and the number of turbines has declined since 1998, so a range or an approximation are presented. Full citations for
reports are provided in the Literature Cited section.
Project
Name State Time
Period
MW
Capacity
#
Turbines
#
Fatalities Method Reference
Buena Vista CA 2008 38.00 38 1 incidental Insignia (2009)
Buena Vista CA 2008 38.00 38 2 carcass search Insignia (2009)
Diablo CA 2005-
2007
20.46 31 1 incidental WEST (2006);
WEST (2008)
Diablo CA 2005-
2007
20.46 31 1 carcass search WEST (2006);
WEST (2008)
Elkhorn OR 2010 101.00 61 1 carcass search Enk et al. (2011)
Elkhorn OR 2010 101.00 61 3 incidental Enk et al. (2011)
Foote Creek
Rim (Phase I)
WY 2001-
2002
41.40 69 1 incidental Young et al.
(2003d)
Goodnoe WA 2009 94.0 47 1 carcass search URS (2010)
High Winds
2005
162.00
90
1
incidental
Kerlinger et al.
(2006)
High Winds CA 2005 162.00 90 1 carcass search Kerlinger et al.
(2006)
Pine Tree CA 2009-
2010
135.00 90 1 unknown; not
in the report
BioResource
Consultants (2010)
Shiloh 1 CA 2009 150.00 100 1 carcass search Kerlinger et al.
(2010)
Altamont-
wide
CA 1998-
2007
480-556 ~5,000 495 carcass search
and incidental
Smallwood and
Karas (2009)
available non-breeding adults to replace annual
losses among breeders. Nest productivity in the
Altamont vicinity, however, is not sufficient to
replace estimated collision fatalities (Hunt and Hunt
2006). Altamont eagle studies were begun after
installation and operation of wind turbines. Suitable
nesting sites can be found in the Altamont. It is
possible that eagles nested in the area prior to
development of the wind energy facilities, although
no golden eagles currently nest within the Altamont
boundaries (Grainger Hunt, Peregrine Fund, personal
communication).
For a variety of reasons Altamont fatality numbers
may be an outlier with regard to golden eagle
fatalities at wind energy facilities. In addition to the
May 2012 Eagles and Wind Energy: Identifying Research Priorities
12
characteristics mentioned earlier (i.e., the dense
configuration of older-generation turbines), high
prey densities and lack of breeding eagles possibly
attract sub-adults and floaters to the Altamont,
contributing to the high activity and high fatality
rates. In addition, the limited amount of repowering
that has occurred at Altamont suggests that eagle
(and raptor) fatality rates will decline as the older
turbines are replaced by fewer, taller, and higher
power-rated turbines. Initial results of the
repowering suggest that golden eagle fatality rates
could decline by more than 80% with complete
turbine replacement and comparable power output
(Insignia 2009; Smallwood and Karas 2009; ICF
2011).
A search of publicly available reports for 72 wind
energy projects representing more than 7,000 MW
of installed capacity also suggests that Altamont
fatality rates are unusually high. A total of 15 golden
eagle fatalities between 2001 and 2010 were
recorded at eight of the 72 projects conducting
systematic carcass searches satisfying specific
selection criteria;10 at the remaining 64 projects, of
which all but one overlapped with some portion of
golden eagle breeding and non-breeding range,
there were no reports of eagle fatalities (Table 2).11
10 Included reports satisfied the following criteria: 1) bias
trials were used to adjust fatality estimates; 2) surveys
took place during all seasons of occupancy; and 3) used
accepted protocols in search and data summaries.
The public reports noting eagle fatalities included a
combination of systematic carcass surveys and
incidental finds. Total project capacity and number
of turbines are also provided for projects with eagle
fatality reports to facilitate comparison amongst the
projects and Altamont.
11 For references on additional sites consult Strickland et
al. 2011.
Additional data are available in a separate
compilation of eagle fatalities covering a multiple
year period, prepared by the Service. Service
regional offices reported five bald eagle and 54
golden eagle fatalities at wind energy facilities other
than Altamont, with most fatality reports originating
between 2006 and 2011 (Table 3; Pagel et al. 2011;
Brian Millsap, U.S. Fish and Wildlife Service,
unpublished data).12 Fatality reports are mostly
incidental and not the result of systematic searches,
and project location details are not available. The 29
golden eagle fatalities from Wyoming involved eight
wind energy projects that occur within close
geographic proximity (Brian Millsap, U.S. Fish and
Wildlife Service, personal communication). The
compilation also includes 14 golden eagle fatalities
from California, but it is uncertain as of this writing
whether that total includes the 2010 and
2011reports of golden eagle fatalities at the Pine
Tree Wind Energy Facility near Tehachapi, CA.13
We are not able to determine the degree of overlap
between these different summaries, although there
likely is some overlap. The public reports cover a
slightly longer period than that covered in the
Service reports, and do not include “incidental”
fatalities reported elsewhere (e.g., Anderson et al.
2004) that do not meet the criteria for inclusion in
the summary of public reports described above.
These different sets of data do suggest that the
situation at Altamont is unusual, and that collision
risk to eagles varies among wind energy projects.
Preliminary analysis of data from 13 wind projects in
the western U.S. sorted by “fatalities” or “no
fatalities” showed a large separation in these two
12 Data are currently under Service review and may
change.
13 http://articles.latimes.com/2011/aug/03/local/la-me-
wind-eagles-20110803 and
http://articles.latimes.com/2012/feb/16/local/la-me-
eagles-20120216 for a recent report of two eagle fatalities
May 2012 Eagles and Wind Energy: Identifying Research Priorities
13
Table 3. Eagle fatalities reported at wind energy facilities in the U.S.
Data in this report were compiled from reports provided by each of the U.S. Fish and Wildlife Service
Regional Offices. The data reflect the results of systematic surveys as well as incidental observations
provided to the Service by wind energy developers and their consultants. Data were reported by Service
regional offices and compilation by state was done by AWWI staff. Data summary does not include
summaries from Altamont Pass Wind Resource Area or reports from regional offices where no take reports
were received. It was presumed that the absence of a report from a region indicated an absence of known
fatalities (Brian Millsap, USFWS, personal communication).
State/Province Bald Eagle Golden Eagle
Date # Date #
California _ _ 2006-2011 14
Iowa
2011
1
_ _
New Mexico
_ _ no date
5
Ontario
2010-2011
2
_ _
Oregon
_
_
2009-2011
5
Washington
_
_
2009
1
Wyoming
2010-2011
2
2009-2011
29
categories based on pre-construction estimates of
activity (Figure 2). Specific behaviors may also
increase golden eagle vulnerability to collision. Hunt
(2002) suggested that prey availability and
topographic conditions interact to create a high-risk
area for golden eagles at Altamont. High abundance
of ground squirrels is promoted by habitat
management for the federally endangered San
Joaquin kit fox, and the data suggest that eagles are
most vulnerable to blade strikes while hunting (e. g.,
Hunt 2002).
A more salient question is the proportion of the
“truenumber of eagle fatalities collectively or at
individual projects. Accurately estimating this
proportion will depend on accurate estimation of
the different biases including: 1) searcher efficiency
if an eagle is present in a search plot what is the
probability of it being found; 2) scavenging rate
what is the rate at which scavengers remove eagle
carcasses from search areas; 3) areal bias what
proportion of the area where eagle carcasses occur
is searched; and 4) background mortality what
proportion of eagle carcasses located were the result
of collision strike versus other causes? The size of
the adjustments for the first two factors is
influenced by vegetation cover and topography.
Searcher efficiency for large raptors has been
variously estimated between 80 to 100% (e.g.,
Anderson, et al. 2004; Whitfield 2009; Strickland et
al. 2011). Scavenging losses are estimated to be low,
but there are challenges in using appropriate
surrogate carcasses for estimating scavenging on
eagles (e.g., Whitfield 2009). Background mortality,
or mortality from other sources, is rarely estimated.
Where it has been estimated for all bird species,
background mortality has been substantial (Johnson
et al. 2000; Olson 2001), but comparable data do not
exist for eagles.
The Service data reported above (Pagel et al. 2011)
are noteworthy in that they represent some of the
first confirmed fatalities of bald eagles at wind
energy projects. The lack of bald eagle fatality data
May 2012 Eagles and Wind Energy: Identifying Research Priorities
14
Figure 2. Average pre-construction golden eagle use values for facilities with
and without observed golden eagle fatalities
Erickson 2011; compiled by WEST, Inc.
Data from the following sources:
Wind Energy Facility Use Estimate Fatality Estimate
Campbell Hill, WY Taylor et al. 2008 WEST 2012
In preparation
Combine Hills, WA Young et al. 2003c Young et al. 2006
Diablo Winds, CA WEST 2006 WEST 2006, 2008
Elkhorn, OR WEST 2005 Enk et al. 2011
Foot Creek Rim, WY Johnson et al. 2000 Young et al. 2003b
Grand Ridge, IL Derby et al. 2009 Derby et al. 2010
Hopkins Ridge, WA Young et al. 2003a Young et al. 2007
Klondike, OR Johnson et al. 2002 Johnson et al. 2003
Leaning Juniper, OR Kronner et al. 2005 Kronner et al. 2007; Gritski et al. 2008
Nine Canyon, WA Erickson et al. 2001 Erickson et al. 2003
Stateline, OR/WA Erickson et al. 2002 Erickson et al. 2004b
Vansycle, OR Erickson et al. 2002 Erickson et al. 2000
Wild Horse, WA Erickson et al. 2003b Erickson et al. 2008
May 2012 Eagles and Wind Energy: Identifying Research Priorities
15
makes it impossible to evaluate relative vulnerability
of bald eagles to collision fatality. A recent
observational study conducted at a small wind
energy facility on Pillar Mountain, Kodiak Island, AK
in 2006-2007, 2010, and 2011, indicated that bald
eagles actively avoided operating wind turbines at
this facility (Sharp et al. 2011). No bald eagle
fatalities have been recorded at the Pillar Mountain
wind project, although no systematic surveys have
been conducted (Lynn Sharp, Tetra Tech, personal
communication). Substantial numbers of fatalities
have been reported for white-tailed eagles, a
congener of the bald eagle, in Smøla, Sweden where
41 fatalities have been reported at this coastal wind
energy facility during the last five years (Nygård
2011).
Although assessment of the impact of wind energy
development on eagles has focused on collision
fatalities, the definition of take also includes
reductions in productivity due to direct disturbance
effects causing lower nest productivity, or indirect
effects that include abandonment of nesting
territories or foraging areas. The models the Service
uses to estimate eagle take thresholds weigh the
consequences of these types of take differently
(USFWS 2009a). It is important therefore, to
understand the relative importance of collision
fatalities versus avoidance behavior leading to
displacement and productivity declines to best
inform risk assessment and mitigation practices (see
USFWS 2009a). There are, however, too few studies
examining the effects of wind energy development
on nesting raptors, in general (e.g., Madders and
Whitfield 2006), and golden eagles, in particular
(e.g., Gregory 2010, Johnson et al. 2000; Young et al
2010), to estimate the scope and importance of such
effects. (See more detailed discussion below.)
B. Other Anthropogenic Contributors to
Eagle Mortality and Threats to
Eagles
Sources of anthropogenic eagle mortality include
electrocution, shooting, collision, poisoning, and in
the eastern U.S., incidental trapping (Katzner et al.
2012). Systematic, unbiased estimates of the
relative frequency and magnitude of these sources
of eagle take generally are not available. Under-
reporting may be common and variation in detection
is likely; carcasses from electrocution or collision are
more likely to be found, while other sources of
mortality that are latent in effect, such as poisoning,
may go relatively undetected. Multiple compilations
have been conducted based on searches of available
sources, but lack of consistent and systematic
reporting and detection bias limits our ability to
extrapolate these compilations accurately to a
population context.
Wood et al. (1990, cited in Buehler 2000) reported a
summary of 1,428 individual bald eagles necropsied
by the National Wildlife Health Center (NWHC) from
1963 to 1984. Of these individuals, 329 (23%) died
from trauma, primarily impact with wires and
vehicles; 309 (22%) died from gunshot; 158 (11%)
died from poisoning; 130 (9%) died from
electrocution; 68 (5%) died from trapping; 110 (8%)
from emaciation; and 31 (2%) from disease; cause of
death was undetermined in 293 (20%) of the cases.
Kochert et al. (2002) reported that humans caused
over 70% of recorded golden eagle deaths, directly
or indirectly. Accidental trauma (collisions with
vehicles, power lines, or other structures) was noted
as the leading cause of death (27%), followed by
electrocution (25%), gunshot (15%), and poisoning
(6%) (Franson et al. 1995, cited in Kochert et al.
2002). Ingesting poisoned carcasses intended for
mammalian predator control and ingestion of lead
shot (30-50% of eagles tested with elevated blood
levels) was also an important source of mortality.
May 2012 Eagles and Wind Energy: Identifying Research Priorities
16
Table 4. Anthropogenic sources of eagle mortality 2006-2011
Fatality numbers and percentages are derived from TetraTech (2011). The factors listed below do
not include all factors potentially affecting eagle numbers such as loss and deterioration of foraging
and nesting habitat, which are thought to be important but have yet to be systematically quantified.
Mortality Source
Bald Eagle Fatalities Golden Eagle Fatalities
#
%
#
%
vehicle strike 199 5.8% 119 4.5%
aircraft strike 85 2.5% 36 1.4%
train strike 28 0.8% 1 0.0%
wire collision 22 0.6% 27 1.0%
collision/electrocution 33 1.0% 0 0.0%
electrocution 357 10.4% 1,316 50.0%
turbine blade collision (Altamont) N/A 0.0% 565 21.5%
turbine blade collision (other) 1 0.0% 12 0.5%
unknown collision 36 1.1% 10 0.4%
gun shot 737 21.5% 138 5.2%
trap 195 5.7% 42 1.6%
poisoning 1,257 36.8% 349 13.3%
illegally taken 18 0.5% 4 0.2%
unknown trauma 452 13.2% 11 0.4%
Total
3,420 100.0% 2,630 100.0%
Eighty to 100 golden eagles were reported killed on
highways near Rock Springs, WY, in winter 1984
1985 (Phillips 1986). More than 200 golden eagles
were electrocuted in Wyoming during an 18-month
period between 2007 and 2009.14
A more recent review of the literature and databases
concerning eagle fatalities found documentation of
6,956 bald eagle and 3,715 golden eagle fatalities
recorded in the contiguous United States since 1960
(Tetra Tech 2011), of which 3,420 bald eagle and
2,630 golden eagle fatalities recorded since 2006
(Table 4). Fifty percent of all (natural and human-
14 e.g., www.ens-newswire.com/ens/jul2009/2009-07-14-
092.html
caused) bald eagle fatalities and 35% of golden eagle
fatalities were from undetermined causes (Tetra
Tech 2011). Of the known human causes of fatality,
poisoning (37%), shooting (22%), electrocution
(10%), and accidental trauma (as defined above,
11%) were the most commonly reported fatality
sources for bald eagles; the remaining 20% included
illegal take, trapping, and unknown trauma (Tetra
Tech 2011). Golden eagle fatalities with known
causes were dominated by electrocution (50%),
collisions with wind turbines at Altamont (21%), and
poisonings (13%); the remaining 16% included
several sources such as accidental trauma, trapping,
and shooting. This study reported only 12 eagle
fatalities at wind energy facilities other than
Altamont (Tetra Tech 2011)fewer than the
May 2012 Eagles and Wind Energy: Identifying Research Priorities
17
numbers reported in the survey of 72 publicly
available reports described earlier, but that study
contained a few additional reports that did not meet
the criteria of the previously described survey.
Hunt (2002) recorded the deaths of 100 radio-tagged
eagles during his seven-year study. Wind turbine
blades killed at least 42 eagles, although he
concluded that the actual number may have been
higher because the blades occasionally destroyed
the transmitter. Twelve eagles were electrocuted,
all outside Altamont. Altogether, human-related
fatalities, including wire strikes, vehicle strikes, and
poisoning, accounted for at least 68% of the total
(Hunt 2002); the remaining 32% died either through
natural or otherwise unknown causes. Use of
transmitters that provide the ability to locate
carcasses is a promising technique for systematically
obtaining eagle mortality data, although potential
biases remain if significant numbers of instrumented
eagles are not recovered (Hunt 2002).
Elevated blood lead levels are prevalent and
quantifiable in both eagle species, and may have
significant impacts on eagle populations. For
example, elevated lead levels may contribute
indirectly to eagle mortality by weakening eagles
and reducing their ability to hunt or by making them
more susceptible to the sources of mortality
mentioned above, e.g., collision and electrocution
(Redig 1979). Lead poisoning was reported in 338
bald and golden eagles turned in from 34 states to
the NWHC from 1963 to the early 1990s (Franson et
al. 1995 cited in Buehler 2000). Kramer and Redig
(1997) noted a high incidence of lead poisoning: 138
out of 634 bald eagles admitted to the Raptor Center
at the University of Minnesota (Raptor Center) from
1980 to 1995 had elevated blood lead levels.
The primary source of lead was thought to be lead
shot used in waterfowl hunting. In 1991, lead shot
was banned from hunting in federal areas, and this
ban was implemented statewide in Minnesota and
Wisconsin. Lead shot was banned from the range of
the California condor in California in 2008. Both
situations showed that decline in blood lead levels
can be rapid following a ban. Between 1991 and
1995, although there was no significant change in
the incidence of lead poisoning in eagles admitted to
the Raptor Center, there were declines in the
percentage of eagles with blood levels considered
either fatal or clinicalfrom 50% pre-ban (N = 72) to
36% post-ban (N = 66) (Kramer and Redig 1997).
Eagles admitted to the Raptor Center for
miscellaneous trauma had sub-clinical blood lead
levels consistent with the view that chronic lead
exposure decreases an eagle’s ability to hunt or
increases risk of injury (Redig 1979). In California,
Kelly et al. (2011) reported declines of golden eagles
with elevated blood lead levels (> 10 µg/dL) from
77% of those sampled (N = 17) to 32% (N = 38) one
year after the 2008 ban. The persistence of a
substantial incidence of lead poisoning in eagles
suggests ingestion of lead from other sources, such
as disintegrated bullets in ungulate carcasses (e.g.,
Hunt et al. 2006).
Other contaminants and toxins also kill eagles or
result in reduced productivity and recruitment and
the extensive source list includes carbofuran, DDT
and dieldrin, famphur, heptachlor, mercury (bald
eagles), pentobarbitol, phorate, secondary anti-
coagulant, strychnine, and thallium to cite several
[see Buehler et al. (2000) and Kochert et al. (2002)
for more detail].
Most discussions of threats to eagle species focus on
mortality, but indirect factors, such as loss of
foraging and nesting habitat resulting in reduced
productivity, also are assumed to be important
threats (e.g., Buehler 2000 and references cited
therein). As part of the bald eagle recovery efforts,
for example, buffer zones around nests have been
implemented routinely to protect nesting eagles
from disturbance and habitat alterations (e.g.,
May 2012 Eagles and Wind Energy: Identifying Research Priorities
18
Mathisen et al. 1977). More recently, oil and gas
development has been associated with reduced
nesting of raptors, including golden eagles in
Wyoming and Utah (Smith et al. 2010).
The predicted effects of climate change are thought
to be the greatest threat to all wildlife,15
IV. Mitigating Eagle Take
but the
ecological implications of a warming climate on
eagles are just beginning to be addressed. Both
eagle species range across multiple climate regions
and have broad prey bases. Bald eagles in Michigan
nest nearly a month earlier at present than in the
1960s when monitoring began; the mean egg-laying
date is 12.4 days earlier in 2006 versus 1988. In
Arizona, wintering bald eagles are concentrating
approximately 30 miles farther north and 2,000 feet
higher in elevation since the 1970s (Terry Grubb,
U.S. Forest Service, personal communication).
Effects of climate change may include changes in
distribution and abundance of prey animals due to
vegetation changes in response to warming or
changes in environmental conditions at the onset of
nesting. In the Great Basin, climate change is
predicted to exacerbate the negative impacts of
altered fire regimes and invasive annual grasses on
the quality of golden eagle habitat (Wagner 1998).
Given the presumed importance of prey availability
as a factor limiting golden eagle productivity,
modeling the effects of climate projections on eagles
should be a high priority.
Under the current draft Eagle Guidance, procedures
(aka “Advanced Conservation Practices) are
described for avoiding and minimizing take of eagles
in the development of wind energy facilities. After
such procedures are followed and there remains
unavoidable take, wind energy developers are asked
to obtain programmatic take permits to legally
15 e.g., www.fws.gov/home/climatechange/impacts.html
enable incidental take of eagles. For bald eagles, at
present, these permits can be issued assuming that
the take threshold for a management unit is not
exceeded (USFWS 2009a). For golden eagles,
modeling has predicted that additional mortality
would lead to population declines. Therefore, to
receive a programmatic take permit, the developer
would be required to implement compensatory
mitigation that numerically offsets predicted
fatalities to result in a net take of zero (aka “no net
loss”). This offset could be accomplished by
reducing take from another source (reducing
mortality) or, in theory, by increasing eagle carrying
capacity either through increases in productivity
(number of fledged young) or post-fledging survival.
The challenge is developing a menu of scientifically
justifiable options for numerically offsetting take at
wind energy facilities. For example, electrocution at
power poles is assumed to be a significant source of
eagle mortality, and there are models that can
predict the number of eagle fatalities avoided with
retrofitting of problem poles. The Service has
proposed power-pole retrofitting as one mechanism
for offsetting eagle take, but additional options are
needed.
The AWWI Eagle Workshop developed a list of
potential mitigation options (Appendix A) that
included reductions in eagle mortality from natural
and anthropogenic sources and improving eagle
productivity. Options included mitigating vehicle
and train collisions, poisoning, shooting, and
incidental trapping; reducing human activity that
disturbs eagles causing reductions in nest occupancy
or nestling survival; and management that enhances
eagle carrying capacity by improving habitat in the
breeding or wintering range.
As described previously, lead contamination from
ingesting lead shot or bullet fragments in scavenged
carcasses is widespread in eagles and a significant
conservation concern (Kramer and Redig 1997; Hunt
May 2012 Eagles and Wind Energy: Identifying Research Priorities
19
et al. 2006). Implementing mechanisms to reduce
eagle blood lead levels may present insurmountable
challenges to wind energy developers and operators
who might propose that as mitigation. We are also
not aware of models that link elevated blood lead
levels to eagle mortality or productivity. Despite
these challenges, reducing lead contamination of
eagles should be a major conservation priority even
if this effort may not be useable for mitigating
impacts on eagles at the project level.
Eagles are sometimes struck by vehicles or trains
while feeding on carcasses of other wildlife on
highways or train tracks. In some areas such
collisions occur each year, and in substantial
numbers (e.g., Phillips 1986). Where scientifically
credible estimates of vehicle fatalities are available,
a possible compensatory mitigation strategy would
be to relocate carcasses away from roadways or
tracks frequently enough to eliminate this cause of
eagle mortality. Estimates of mortality from
collisions from prior years could serve as a measure
of the effectiveness of the mitigation action. Again,
translating number of carcasses removed to a
reduction in eagle fatalities needs to be modeled.
Reducing eagle take at existing wind energy facilities
also has been suggested as mitigation for take at
future projects. As described earlier the number of
golden eagle fatalities at Altamont is large in
comparison to all other projects. Repowering and
other activities have been proposed at Altamont to
achieve a 50% reduction in avian fatalities, and
results to date suggest that repowering could
accomplish even higher reductions.
Protecting golden eagle nest sites from sources of
anthropogenic disturbance, such as recreational
camping, climbing, off-highway vehicles (OHVs), and
persecution from sheepherders, is another
potentially effective mitigation alternative. Another
approach to mitigation would involve habitat
management that enhances eagle productivity
and/or adult survival. Managing prey habitat in
parts of the range where productivity is thought to
lag could, in theory, effectively offset increased
mortality by improving eagle productivity. Such
increases would need to reflect a sustained increase
in carrying capacity.
The menu of potential mitigation options is large,
but we lack credible models estimating the impacts
of these various mitigation options in offsetting
eagle take. Developing these models is a major
research priority discussed more fully below.
V. Research and Conservation
Priorities
Research on bald and golden eagles has taken on a
renewed sense of urgency with the publication of
the 2009 Eagle Rule, which identifies concerns about
possibly declining golden eagle populations and risks
to eagles of expanding wind energy development. In
addition to the recent AWWI Eagle Workshop there
have been numerous initiatives to define research
priorities, particularly for golden eagles. The results
of these efforts and resulting research initiatives
were integrated into an evaluation of research
priorities for the AWWI Research Program; these
priority setting exercises are summarized in
Appendix B.
Participants at the Workshop helped identify the
following wind energy-eagle research areas (not
listed in order of priority):
Identifying and addressing information gaps
on demography and status, particularly for
golden eagles, relevant to calculating take
thresholds.
Developing unbiased estimates of eagle
mortality.
Creating models for avoidance and
minimization siting and operational
May 2012 Eagles and Wind Energy: Identifying Research Priorities
20
strategies that reduce eagle fatalities at wind
energy facilities.
Expanding options for compensatory
mitigation that offsets take at wind energy
facilities.
Coordinating and enhancing existing
collaborative eagle research.
As part of the evaluation of AWWI’s role and
contribution to the above research priorities, we
used the following criteria modified from the
Research Plan that was approved by the AWWI
Board on July 21, 2011:
Supports or complements but does not
duplicate, existing activities, e.g., Service-
USGS Integrative Research when
scientifically appropriate.
Emphasizes near-term results to inform
decision-making and regulation.
Applies across a broad geographic range OR
addresses a critical issue.
Takes advantage of the AWWI Research
Information System.
Lays the groundwork to address long-term
research questions.
Is conducted with the highest standards and
scientific rigor, and is subject to independent
peer review.
Offers a distinctive AWWI role.
Attracts funding from public and private
sectors.
Workshop participants also agreed that for the near
term, AWWI should emphasize research on golden
eagles that is directly relevant to wind energy
development. Bald eagle populations appear to be
thriving, although continued monitoring will be
necessary to determine whether this trend
continues. Expanding (and expanded) bald eagle
populations will be confronted with increasing
human development, and the sensitivity of bald
eagles to this development is not completely
understood (see Millsap et al. 2004). Wind energy
development in coastal areas and near shore also is
anticipated to increase, and the experience of white-
tailed eagles in Sweden with wind energy
development raises concerns that wind energy
development could pose a greater risk to bald eagles
in the future. Thus, it is important to understand
bald eagle behavior as it relates to collision risk, and
to determine the sensitivity of bald eagle nesting
success to the proximity of operating wind energy
facilities. Projects currently proposed in areas
important for bald eagle nesting and foraging offer
opportunities to study bald eagle interactions with
wind facilities.
After thorough consideration of the research topics
listed above, AWWI has chosen to focus over the
next 12 months on expanding options for
compensatory mitigation while continuing to
identify, support, and collaborate with other
research initiatives, as appropriate. A more detailed
discussion of the research priorities, and AWWI’s
possible role and participation follows.
Expanding options for compensatory
mitigation that offsets golden eagle take at
wind energy facilities
In the next 12 months, AWWI’s top priority for
addressing the challenge of wind energy
development and eagle conservation will be to
expand options for compensatory mitigation. AWWI
in collaboration with technical experts and
government agency staff will lead an expert
elicitation process (e.g., Kuhnert et al. 2010) to
develop alternative management scenarios that will
increase either golden eagle productivity or adult
survival and thereby offset golden eagle take at wind
energy facilities.
Utilization of mitigation options would not be limited
solely to wind energy facilities, but would have
broad applications for offsetting eagle take from
May 2012 Eagles and Wind Energy: Identifying Research Priorities
21
other anthropogenic sources as well as enhancing
general golden eagle management. Mitigation
options would focus on management that would
increase eagle carrying capacity through habitat
management, thus increasing productivity and adult
survival, or by reducing anthropogenic sources of
eagle mortality.
A possible extension of this project would entail
working with wind energy companies to evaluate
models developed through expert elicitation at
proposed or existing wind energy facilities where a
programmatic take permit is desired. Results of this
evaluation would be used to adjust the models with
subsequent application at new or other existing
projects.
This project will expand and improve mitigation
strategies for eagles, as discussed at the AWWI Eagle
workshop. Expert elicitation is recognized and
accepted as a valid scientific technique, and one that
is appropriate when insufficient data are available,
but there is a pressing need to make management
decisions. AWWI has begun a scoping process for
the project with the goal of providing new mitigation
options by the end of the 2012 calendar year.
Identifying and addressing information gaps on
demography and status, particularly for golden
eagles relevant to calculating take thresholds
Workshop participants emphasized the importance
of this topic. Specific recommendations included
linking population size, productivity, and age and sex
ratios to effects on demographic rates. The possible
impact of fluctuations in the prey base (e.g.,
jackrabbits, prairie dogs) or other covariates on
eagle demography and adult survival is well
recognized, but needs much greater research
emphasis. The Service and USGS Integrative
Research Collaboration (see Appendix B) along with
other research efforts (e.g., BLM California desert,
Todd Katzner, West Virginia University, personal
communication) are addressing these questions, but
more work is needed. AWWI will support these
activities as appropriate.
Developing unbiased estimates of eagle
mortality
Estimates of eagle mortality from different sources
are an important component of take threshold
models. To more systematically develop these
estimates, the Service and USGS have plans to attach
satellite transmitters to more than 100 golden eagles
across multiple eagle management units.
Transmitters will enable Service staff to locate dead
eagles and perform a detailed necropsy to
determine the cause of death (McIntyre et al. 2006).
Application of this technology may ultimately
provide our best and most unbiased estimate of the
various anthropogenic and natural sources of eagle
mortality, although sample sizes will be limited by
cost. More systematic mortality data will also
support the evaluation and modification of the prior
models described earlier. To reduce bias, eagles
selected for instrumentation should come from a
broad geographic area independent of any particular
source of eagle fatalities. AWWI will coordinate with
the Service to develop accurate estimates of eagle
fatalities at wind energy facilities and help publicize
and distribute the results of the telemetry project.
Creating models for avoidance and
minimization siting and operational strategies
that reduce eagle fatalities at wind energy
facilities
In order to receive a programmatic take permit, the
applicant must demonstrate that all applicable and
scientifically supportable measures have been taken
to avoid take through relevant siting and
management practices. Workshop participants
suggested that AWWI: 1) review existing data to
develop models on the types of factors that have
influenced take of golden eagles; 2) review the
May 2012 Eagles and Wind Energy: Identifying Research Priorities
22
Service’s risk model by applying data and assessing
the modelsstrengths and weaknesses, comparing
and contrasting with other models that are available;
and 3) further develop or revise the Service’s explicit
model for predicting mortality risk. These activities
would help determine what questions currently are
unanswerable and what new data or changes to
existing data collection are needed. Workshop
participants suggested an initial focus on steps 1)
and 2). Step 3) would be a longer-term initiative to
be accomplished through a collaborative RFP-driven
process that would ask investigators to propose
additional research topics. AWWI will support the
Service-USGS efforts in this area.
Coordinating and enhancing existing
collaborative eagle research
Although this priority is last on the list, it is an area
where AWWI is well-positioned to contribute.
AWWI is developing a wind-wildlife research
database (Research Information System RIS) to
enable rigorous analysis of wind-wildlife data in a
secure environment. The database also will provide
a web-based platform for searching publicly
available reports and current research activities
including research and reports on golden eagles
relevant to the goal of reducing the impacts of wind
energy development on this species. Several
research activities are underway including the
Service-USGS Integrative Research Project (see
Appendix B), activities lead by the Services Region 8,
and numerous ongoing projects, which include
telemetry and contaminants analysis (described in
GOEA Science Meeting 2010). Leveraging existing
data and coordinating research efforts are
important, especially in a time of declining public
and private budgets devoted to wildlife research.
May 2012 Eagles and Wind Energy: Identifying Research Priorities
23
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Young, D.P. Jr., W.P. Erickson, J. Jeffrey, K. Bay, R.E. Good, and E.G. Lack. 2003c. Avian and Sensitive Species
Baseline Study Plan and Final Report. Eurus Combine Hills Turbine Ranch, Umatilla County, Oregon. Technical
report prepared by Western EcoSystems Technology, Inc. for Eurus Energy America Corporation, San Diego,
CA and Aeropower Services, Inc., Portland, OR.
May 2012 Eagles and Wind Energy: Identifying Research Priorities
28
Young, D. P., Jr., W. P. Erickson, M. D. Strickland, R. E. Good, and K. M. Semka. 2003d. Comparison of avian
responses to UV-light-reflective paint on wind turbines. NREL/SR-500-32840. National Renewable Energy
Laboratory, Golden, CO.
Young, D.P., Jr., C. LeBeau, W. Erickson, S. Nomani, J.R. Boehrs, and B. Oakleaf. 2010. Status of Breeding
Populations of Ferruginous Hawks, Golden Eagles and Bald Eagles in Albany and Carbon County, Wyoming.
Prepared for the Wyoming Game and Fish Department.
May 2012 Eagles and Wind Energy: Identifying Research Priorities
29
Appendix A: Potential Sources of Compensatory Mitigation for
Offsetting Take of Golden Eagles at Wind Energy Facilities
As discussed by participants at the AWWI Eagle Workshop
Denver, CO, November 15-17, 2011
A. Habitat management: How can we enhance productivity and survival?
1. Define terms clearly:
a. Productivity is measured as the number of fledged young per nest.
b. Survival is defined from post-fledging.
2. Identify the limiting factors for golden eagle productivity and survival.
a. Research results might help us predict strategies for avoiding impacts.
3. Focus on research needed to define habitat management or restoration that will achieve no net loss.
a. A literature review would be useful.
b. Management needs to result in increased eagle carrying capacity.
c. Study areas where eagles are thriving to identify the key components of high-quality habitat.
i. Short-term research how best to increase or selectively reduce abundance of eagle prey
(e.g., prairie dogs)
ii. Identification of prey species, prey ecology, and survival
iii. Understanding of factors that help augment abundance of ground squirrels, jack rabbits
and other key prey species
iv. Role of non-native invasive species, such as cheat grass and investigate mechanisms for
restoring native vegetation
4. Look at supplemental feeding in the winter to increase of survival of sub-adults and adults.
B. Land protection: How best protect the quantity and quality of habitat?
1. Define how many acres of habitat protection are necessary to offset predicted take.
2. Address decline of quantity and quality of habitats.
a. Potentially focus on intermediate-quality areas.
3. Preserve existing high-quality habitat.
a. Purchase conservation easements.
C. Artificial nesting structures: What is the feasibility of encouraging or discouraging nesting in a territory?
1. Evaluate proximity to (or recommended distance from) development.
2. Locate artificial nests closer to better prey concentrations.
3. Measure net benefit to species.
May 2012 Eagles and Wind Energy: Identifying Research Priorities
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D. Direct mortality offsets: Which are the most important options to investigate in the short term?
1. Identify the metrics to evaluate effectiveness, including cost.
2. Develop options at a geographic scale appropriate for the eagle management unit, e.g., by BCR or some
other relevant management scale.
3. Evaluate feasibility of reducing eagle fatalities from other sources.
a. Reduce mortality from vehicle collisions by removing road kill carcasses from roads. (Can we identify
the roads where there are kills?)
b. Shift to non-toxic ammunition (hunter education/voluntary lead abatement).
c. Reduce stock tank drowning.
d. Reduce unintentional poisoning.
e. Implement reward system to reduce poaching.
f. Mark fences to reduce collisions.
g. Reduce impacts of secondary trapping (e.g., by covering bait).
4. Evaluate cost-effectiveness of funding programs.
a. Fund eagle rehabilitation centers.
b. Fund livestock depredation compensation programs and compensate landowners that protect eagles.
c. Decommission or repower old wind projects.
5. Improve management of public recreational activities (e.g., off-road vehicle management, climbing) that
reduce eagle productivity.
May 2012 Eagles and Wind Energy: Identifying Research Priorities
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Appendix B: Compendium of Priority Golden Eagle Research Topics
Several recent initiatives and publications have defined research priorities for golden eagles and these helped
frame the discussion at the AWWI Eagle Workshop on November 15-17, 2011 in Denver, CO. These priorities are
summarized below.
A. Kochert, M. N., K. Steenhof, C. L. Mcintyre, and E. H. Craig. 2002. Golden Eagle (Aquila chrysaetos), The
Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology
1. Develop population monitoring strategy for the western United States, where population declines are
suspected.
2. Improve understanding of factors that influence population trends.
3. Determine effects of environmental contaminants (for example, heavy metals) and habitat alteration for
both breeding and wintering grounds.
4. Assess whether survival rates vary across geographic areas and whether human-caused mortality is
additive or compensatory.
5. Estimate the size of the floating segment of populations and determine how floaters interact with
territorial breeders.
6. Establish whether the rate of interchange among golden eagle sub-populations creates genetically sub-
structured populations.
B. North American Golden Eagle Science Meeting, Minutes and Notes, September 21, 2010, Ft. Collins, CO
In addition to the specific questions listed below, meeting participants recommended that research should be
region-specific with a consistent approach and methodology across the species’ range, and with meta-analysis of
existing data as a top priority. These questions provided a jumping-off point for the USGS-USFWS Integrated
Science Partnership research priorities described below.
1. What geographic areas and habitat attributes are most critical to the golden eagle and its chief prey
resources across breeding and non-breeding seasons?
2. What are minimally biased, age-specific survival rates (especially for adults) and causes of mortality?
3. What are population sizes and trends on regional to continental scales?
4. What are basic attributes of reproductive success and population demography, including age structure,
natality, and mortality, on regional to continental scales?
5. What are spatial use patterns of golden eagles, including seasonal home range configurations and
connectivity among populations within and among regions?
C. USGS Research Roundtable, Portland, OR, June 2011
A list of priorities was developed at the Roundtable with a follow-up online survey to determine rankings of
suggested topics. Four subject areas relevant to wind energy development were defined and subdivided; the
results are summarized below.
May 2012 Eagles and Wind Energy: Identifying Research Priorities
32
Survey Results Overall Priorities % High priority % Medium priority
A. Understanding Mortality (7 respondents)
a. Effect of local scale environment ........................................ 57.1% ............................ 42.9%
b. Effect of turbine height, size, and type ............................... 57.1% ............................ 28.6%
c. Prey density ......................................................................... 28.6% ............................ 71.4%
d. Habituation ............................................................................ 0.0% ............................ 57.1%
e. Habitat fragmentation ........................................................... 0.0% ............................ 28.6%
B. Improved Risk Assessment (8 respondents)
a. Age class habits ................................................................... 33.0% ............................ 50.0%
b. Landscape/human-footprint predictors of risk ................... 16.7% ............................ 66.7%
c. Core areas identification ....................................................... 0.0% ............................ 83.3%
d. Prediction of microscale movements .................................. 16.7% ............................ 83.3%
C. Mitigation Measures (7 respondents)
a. Evaluation of compensatory mitigation .............................. 28.6% ............................ 28.6%
b. Prey removal/management ................................................ 28.6% ............................ 57.1%
c. Deterrence ........................................................................... 42.9% ............................ 42.9%
d. Quantifying mitigation credits ............................................. 42.9% ............................ 42.9%
D. Monitoring (6 respondents)
a. Monitoring protocols for eagle occurrence ......................... 40.0% ............................ 40.0%
b. Criteria for pre-construction evaluation .............................. 100%
D. USGS-USFWS Integrated Science Partnership
The Service and the USGS have initiated multiple golden eagle studies based on Service research questions
derived from the research priorities identified at the September 2010 North American Golden Science Meeting.
The five components are described below.
1. Develop a comprehensive survey and monitoring plan to enable estimation of the status of golden eagles
at different spatial scales (national, regional, and project-level).
2. Model predictions of the occurrence of golden eagles in the western U.S. to identify important geographic
areas and habitats for golden eagles during the breeding and non-breeding seasons.
3. Estimate golden eagle mortality at wind energy projects utilizing a super-population approach to estimate
cumulative mortality from carcass surveys, accounting for carcass removal and non-detection.
4. Develop golden eagle habitat occupancy models and maps necessary for the mitigation of energy
development, assessment of habitat connectivity, and examination of future change scenarios.
5. Develop an adaptive management framework for wind energy permitting with regard to take of bald and
golden eagles at the project-level and at the regional level.
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Appendix C: AWWI Eagle Workshop Participants
The AWWI Eagle Workshop was held November 15-17, 2011 in Denver, CO to describe the current state of
knowledge of bald and golden eagles and to identify research that would improve implementation of and
compliance with the Eagle Guidance for wind energy.
Technical Experts
Mike Azeka AES Wind Generation
Jon Bart U.S. Geological Survey
Clint Boal U.S. Geological Survey Texas Cooperative Research Unit
Erica Craig* Aquila Environmental
Michael Collopy* University of Nevada, Reno
Wally Erickson Western EcoSystems Technology, Inc.
Joe Grennan RES Americas
Terry Grubb* U.S. Forest Service, Rocky Mountain Research Station
Al Harmata Montana State University
Grainger Hunt* The Peregrine Fund
Doug Johnson U.S. Geological Survey, Northern Prairie Wildlife Research Center
Todd Katzner West Virginia University
Philip
Kline
U.S. Department of the Interior, Office of the Solicitor
Karl
Kosciuch
Tetra Tech
Kevin
Kritz
U.S. Fish and Wildlife Service, Migratory Bird Management Program
Dave Mehlman The Nature Conservancy
Brian Millsap U.S. Fish and Wildlife Service, Southwest Region
Robert Murphy U.S. Fish and Wildlife Service, Division of Migratory Birds
Laura Nagy** Tetra Tech
Bob Oakleaf Wyoming Game and Fish Department
Jeff Smith H.T. Harvey & Associates
Dale Strickland Western EcoSystems Technology, Inc.
Jim Watson Washington Department of Fish & Wildlife
* Attended by webinar
**Invited but unable to attend
Observers
Greg Aldrich Duke Energy
Justin Allegro National Wildlife Federation
John Anderson American Wind Energy Association
Mike Best* Pacific Gas & Electric Company
Erica Brand* Pacific Gas & Electric Company
Rene Braud American Wind Wildlife Institute Board of Directors
May 2012 Eagles and Wind Energy: Identifying Research Priorities
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Tim Breen U.S. Fish and Wildlife Service
Amedee Brickey U.S. Fish and Wildlife Service, Pacific Southwest Region
Travis Brown PacifiCorp; Avian Power Line Interaction Committee
Christina Calabrese EDP Renewables
Lew Carpenter National Wildlife Federation
Eliza Cava Defenders of Wildlife
David Cottingham U.S. Fish and Wildlife Service
Mike
Daulton
Audubon
Corey
Duberstein*
Pacific Northwest National Laboratory
Brandy
Gibson
BP Wind Energy
Rick Greiner Pattern Energy
Blayne Gunderman BP Wind Energy
Kevin Harper Ridgeline Energy
Ryan Henning RES Americas
Matt Hogan U.S. Fish and Wildlife Service, Mountain Prairie Region
Michael Horn GE Energy
Peggy Jelen Avian Power Line Interaction Committee
Silka Kempema South Dakota Game, Fish and Parks
Ginny Kreitler* National Audubon
John Kuba* Clean Line Energy Partners
Diana Leiker
Tri-State Generation & Transmission, Inc.; Avian Power Line Interaction
Committee
Brent Leonard PacifiCorp
Sherry Liguori PacifiCorp; Avian Power Line Interaction Committee
Jim Lindsay NextEra Energy Resources
Mike Lockhart National Wildlife Federation
Rick Loughery* Edison Electric Institute; Avian Power Line Interaction Committee
Heather MacLeod Edison Mission Energy
Natalie McCue Pattern Energy Group
Tom Owens U.S. Geological Survey
Mike Pappalardo NextEra Energy Resources
Steve Pelletier Stantec
Jay
Pruett
The Nature Conservancy, Oklahoma Chapter
David
Reinke
Shell WindEnergy
Roby Roberts EDP Renewables
Diane Ross-Leech Pacific Gas & Electric Company
Bob Roy First Wind
David Savage Pioneer Green Energy
Adam Shor* Electric Power Research Institute
Karin Sinclair National Renewable Energy Laboratory
May 2012 Eagles and Wind Energy: Identifying Research Priorities
35
Steve Slater HawkWatch International
Heidi Souder National Renewable Energy Laboratory
Trish Sweanor U.S. Fish and Wildlife Service
Jason Thomas* Clean Line Energy Partners
Genevieve Thompson Audubon
Robert Thresher National Renewable Energy Laboratory
Katie Umekubo Natural Resources Defense Council
John
VanDerZee
EDP Renewables
Allison
Vogt
Association of Fish & Wildlife Agencies
Sarah
Webster
Wind Capital Group
Stu Webster Iberdrola Renewables
Kimberly Wells* BP Wind Energy
David Wolfe Environmental Defense Fund
* Attended by webinar
Staff
Abby Arnold American Wind Wildlife Institute
Taber Allison American Wind Wildlife Institute
Matt Kireker American Wind Wildlife Institute
... To date the only method that has been used as compensation for eagle mortality is retrofitting of power poles to prevent electrocution of eagles by covering exposed power lines (USFWS 2013(USFWS , 2014(USFWS , 2015. The urgent need for additional offsetting tools, such as reducing eagle mortality due to vehicle collisions (Allison 2012), led to our study. ...
... Indeed, given the availability of these data, it should be relatively straightforward to apply the model in other areas of the country where conditions are similar to Wyoming in the winter. Predicted unavoidable take of eagles at proposed wind energy facilities is often <1 bird/year (from Eagle Act permit applications; Allison 2012;USFWS 2014USFWS , 2015. Thus, conducting collision mitigation may be economical where power pole retrofitting is not an offsetting option or in addition to this option. ...
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... Research by Krone et al. (2013) observed the presence of common buzzards and red kites together with adult white-tailed eagles hunting above a wind facility after farming dunghills were piled, suggesting to avoid activities that increase attraction. Another recommendation given from Allison (2012), is for the golden eagle (Aquila chrysaetos) as a form of offsetting any mortality through increasing prey in parts of the range where eagle productivity or adult survival is lagging. However, this is only in theory and not yet tested. ...
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... However, this assumes the possibility for off-site prey base improvements relative to the on-site foraging quality [160]. Specifically protecting existing or creating artificial breeding sites has been proposed for raptors [19,153]. Another option is to erect perching towers outside a wind-power plant, which was suggested to have potential for offshore birds [88,126]. ...
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A 16-yr (1980-95) retrospective study was conducted to assess differences in the prevalence of lead poisoning in Bald (Haliaeetus leucocephalus) and Golden (Aquila chrysaetos) Eagles admitted to The Raptor Center at the University of Minnesota. These years encompass the period before and after federal legislation was enacted restricting the use of lead shot for hunting waterfowl on federal lands (1991). Of 654 eagle admissions reviewed, 138 cases of lead-poisoned eagles were evaluated for the following: recovery location, blood lead concentration, month of admission, radiographic evidence of lead in the ventriculus and primary cause of admission. The prevalence of lead poisoning in eagles did not change after 1991, but mean blood concentrations of lead in the same population decreased. These findings call into question current theories regarding the sources of lead for eagles and the actual mechanisms by which eagles are poisoned. Lead poisoning is a continuing problem both regionally and internationally, and many variables related to this toxicity have yet to be conclusively defined.