Endangered and Threatened Wildlife and Plants; Removing the Bald Eagle in the Lower 48 States From the List of Endangered and Threatened Wildlife, 37346-37372 [07-4302]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 72, Number 130 (Monday, July 9, 2007)]
[Rules and Regulations]
[Pages 37346-37372]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 07-4302]



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Part III





Department of the Interior





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Fish and Wildlife Service



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50 CFR Part 17



Endangered and Threatened Wildlife and Plants; Removing the Bald Eagle 
in the Lower 48 States From the List of Endangered and Threatened 
Wildlife; Final Rule; Endangered and Threatened Wildlife and Plants; 
Draft Post-Delisting and Monitoring Plan for the Bald Eagle (Haliaeetus 
leucocephalus) and Proposed Information Collection; Notice

Federal Register / Vol. 72, No. 130 / Monday, July 9, 2007 / Rules 
and Regulations

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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

RIN 1018-AF21


Endangered and Threatened Wildlife and Plants; Removing the Bald 
Eagle in the Lower 48 States From the List of Endangered and Threatened 
Wildlife

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Final rule.

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SUMMARY: The best available scientific and commercial data indicate 
that the bald eagle has recovered. Therefore, under the authority of 
the Endangered Species Act of 1973, as amended (Act), we, the U.S. Fish 
and Wildlife Service, remove (delist) the bald eagle (Haliaeetus 
leucocephalus) in the lower 48 States of the United States from the 
Federal List of Endangered and Threatened Wildlife. This determination 
is based on a thorough review of all available information, which 
indicates that the threats to this species have been eliminated or 
reduced to the point that the species has recovered and no longer meets 
the definition of threatened or endangered under the Act.
    Fueled by a reduction in the threats to the bald eagle, the 
population in the lower 48 States has increased from approximately 487 
breeding pairs in 1963, to an estimated 9,789 breeding pairs today. The 
recovery of the bald eagle is due in part to the reduction in levels of 
persistent organochlorine pesticides (such as DDT) occurring in the 
environment and habitat protection and management actions. The 
protections provided to the bald eagle under the Bald and Golden Eagle 
Protection Act (BGEPA) and the Migratory Bird Treaty Act (MBTA) will 
continue to remain in place after the species is delisted. To help 
provide more clarity on the management of bald eagles after delisting, 
we recently published a regulatory definition of ``disturb'', the final 
National Bald Eagle Management Guidelines and a proposed rule for a new 
permit that would authorize limited take under BGEPA and grandfather 
existing Act authorizations.

DATES: This rule is effective August 8, 2007.

FOR FURTHER INFORMATION CONTACT: Chief, Branch of Recovery and 
Delisting, telephone (703) 358-2061 or facsimile (703) 358-1735.
    Additional information is also available on our Web site at https://
www.fws.gov/migratorybirds/BaldEagle.htm. Individuals who use a 
telecommunications device for the deaf (TDD) may call the Federal Relay 
Service at 1-800-877-8339 for TTY assistance, 24 hours a day, 7 days a 
week.

SUPPLEMENTARY INFORMATION:

Background

    Information about the bald eagle's life history can be found in our 
February 16, 2006, reopening of the public comment period on the 
proposed delisting rule (71 FR 8238) (U.S. FWS 2006a) and our five 
recovery plans for the bald eagle (U.S. FWS 1982, 1983, 1986, 1989, 
1990), Gerrard and Bortolotti (1988), and Buehler (2000).

Previous Federal Actions

    Bald eagles gained protection under the Bald Eagle Protection Act 
(16 U.S.C. 668-668d) in 1940 and the Migratory Bird Treaty Act (MBTA) 
(16 U.S.C. 703-712) in 1972. A 1962 amendment to the Bald Eagle 
Protection Act added protection for the golden eagle and the amended 
statute became known as the Bald and Golden Eagle Protection Act 
(BGEPA).
    On March 11, 1967 (32 FR 4001), the Secretary of the Interior 
listed bald eagles south of 40 north latitude as endangered under the 
Endangered Species Preservation Act of 1966 (Pub. L. 89-699, 80 Stat. 
926) due to a population decline caused by DDT and other factors. On 
February 14, 1978, the Service listed the bald eagle as endangered 
under the Act (16 U.S.C. 1531 et seq.) in 43 of the contiguous States, 
and threatened in the States of Michigan, Minnesota, Wisconsin, Oregon, 
and Washington (43 FR 6230, February 14, 1978). Sub-specific 
designations for northern and southern eagles were removed.
    On February 7, 1990, we published an advance notice of proposed 
rulemaking (55 FR 4209) to reclassify the bald eagle from endangered to 
threatened in the 43 States where it had been listed as endangered and 
retain the threatened status for the other 5 States. On July 12, 1994, 
we published a proposed rule to accomplish this reclassification (59 FR 
35584), and the final rule was published on July 12, 1995 (60 FR 
36000).
    On July 6, 1999, we published a proposed rule to delist the bald 
eagle throughout the lower 48 States due to recovery (64 FR 36454). Due 
to the availability of new information, on February 16, 2006 (71 FR 
8238), we reopened the public comment period on our July 6, 1999 (64 FR 
36454), proposed rule to delist the bald eagle in the lower 48 States. 
The reopening notice contained updated information on several State 
survey efforts and population numbers. Simultaneously with the 
reopening of the public comment period on the proposed delisting, we 
also published two Federal Register documents soliciting public 
comments on two new items intended to clarify the BGEPA protections for 
the bald eagle after delisting: (1) A proposed rule for a regulatory 
definition of ``disturb'' (71 FR 8265, February 16, 2006), and (2) a 
notice of availability for draft National Bald Eagle Management 
Guidelines (71 FR 8309, February 16, 2006). On May 16, 2006, we 
published three separate notices in the Federal Register that extended 
the public comment period on the proposed delisting (71 FR 28293), the 
proposed regulatory definition of ``disturb'' (71 FR 28294), and the 
draft Guidelines (71 FR 28369). The comment period for all three 
documents was extended to June 19, 2006.
    On December 12, 2006, we published in the Federal Register a notice 
requesting public comment on two BGEPA items. First, we re-opened the 
public comment period on our February 16, 2006, proposed regulatory 
definition of ``disturb.'' Second, we also announced the availability 
the draft environmental assessment on the definition of ``disturb'' (71 
FR 74483).
    On October 6, 2004, we received a petition, dated October 6, 2004, 
from the Center for Biological Diversity, the Maricopa Audubon Society, 
and the Arizona Audubon Council requesting that the bald eagle 
population found in the Sonoran Desert (as defined by Brown 1994) or, 
alternately, in the upper and lower Sonoran Desert (as defined by 
Merriam (Northern Arizona University 2006, p. 2)) be classified as a 
distinct population segment (DPS), that this DPS be reclassified from a 
threatened species to an endangered species, and that we concurrently 
designate critical habitat for the DPS. On August 30, 2006, we made a 
90-day finding (71 FR 51549) that the petition did not present 
substantial scientific or commercial information indicating that the 
petitioned action may be warranted.
    On January 5, 2007, the Center for Biological Diversity and the 
Maricopa Audubon Society brought suit against the Service, Center for 
Biological Diversity v. Kempthorne, CV 07-0038-PHX-MHM (D. Ariz.), 
challenging the Service's 90-day finding that the Sonoran Desert 
population did not qualify as a DPS, and further challenging the 
Service's 90-day finding that the Sonoran Desert population should not 
be up-listed to endangered

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status. That suit is still pending. However, the Service's finding in 
this final delisting rule supersedes the Service's 90-day petition 
finding because it constitutes a final decision on whether the 
Southwestern bald eagles, including those in the Sonoran Desert, 
qualify for listing as a DPS. This decision was made after notice and 
comment, as described above, and was based on all of the relevant 
information that the Service has obtained. Even if the court in the 90-
day finding suit were to find that the plaintiffs' petition warranted 
further review, this finding addresses the same issues that the Service 
would have considered as part of a 12-month finding had the Service 
made a positive 90-day finding on the petition. This document 
constitutes the Service's final determination on these issues, and is 
judicially reviewable with respect to them; therefore, any controversy 
regarding the August 30, 2006, 90-day finding is now moot.
    On June 5, 2007, we published four documents in the Federal 
Register announcing one proposed action and three final actions under 
the BGEPA: (1) A final rule on the regulatory definition of ``disturb'' 
(72 FR 31132); (2) a notice of availability for the final National Bald 
Eagle Management Guidelines (72 FR 31156); (3) a notice of availability 
for the final environmental assessment on the definition of ``disturb'' 
(72 FR 31156); and (4) a proposed rule for a new permit that would 
authorize limited take under BGEPA, and to grandfather existing Act 
authorizations after delisting occurs under the Act (72 FR 31141).

Bald Eagle Recovery

    Section 4(f) of the Act directs us to develop and implement 
recovery plans for listed species. In establishing the recovery program 
for the species in the mid-1970s, the Service divided the bald eagle 
population in the lower 48 States into five recovery regions. These 
recovery regions were administrative boundaries to help the Service 
plan for recovery, given the information we had at the time. During 
this timeframe the bald eagle population was continuing to decline and 
little was known about where the important areas might be. Given the 
lack of information on this issue, the Service generally decided that 
recovery planning should be conducted in all parts of the range. 
However, as discussed below in the Conclusion of the 5-Factors analysis 
section, based on the information present today, the southwest region 
is a not a significant portion of the range.
    In some cases, we appoint experts to recovery teams to assist in 
the preparation of recovery plans. For the bald eagle, separate 
recovery teams composed of experts in each geographic area prepared 
recovery plans for their region. The teams established recovery 
objectives and criteria and identified tasks to achieve those 
objectives. Coordination meetings were held regularly among the five 
teams to exchange data and discuss progress towards recovery.
    We used these five recovery plans to provide guidance to the 
Service, States, and other partners on methods to minimize and reduce 
the threats to the bald eagle and to provide measurable criteria that 
would be used to help determine when the threats to the bald eagle had 
been reduced so that the bald eagle could be removed from the Federal 
List of Endangered and Threatened Wildlife.
    Recovery plans in general are not regulatory documents and are 
instead intended to provide a guide on how to achieve recovery. There 
are many paths to accomplishing recovery of a species in all or a 
significant portion of its range. The main goal is to remove the 
threats to a species, which may occur without meeting all recovery 
criteria contained in a recovery plan. For example, one or more 
criteria may have been exceeded while other criteria may not have been 
accomplished. In that instance, the Service may judge that, overall, 
the threats have been reduced sufficiently, and the species is robust 
enough, to reclassify the species from endangered to threatened or 
perhaps to delist the species. In other cases, recovery opportunities 
may be recognized that were not known at the time the recovery plan was 
finalized. Achievement of these opportunities may be counted as 
progress toward recovery in lieu of methods identified in the recovery 
plan. Likewise, we may learn information about the species that was not 
known at the time the recovery plan was finalized. The new information 
may change the extent that criteria need to be met for recognizing 
recovery of the species. Overall, recovery of species is a dynamic 
process requiring adaptive management, and judging the degree of 
recovery of a species is also an adaptive management process that may, 
or may not, fully follow the guidance provided in a recovery plan.
    Recovery of the bald eagle has been a dynamic process. As new 
information became available, it was used during the recovery 
implementation process to help the Service determine whether recovery 
was on track. For instance, after the bald eagle was downlisted in 
1995, the Southeastern Recovery Plan did not have specific delisting 
goals, and the Service used the recovery team to help determine the 
appropriate goal. This new delisting goal is considered the best 
available data in helping the Service determine whether the threats 
have been removed and to move forward with the delisting.
    All of the bald eagle recovery plans established goals for the 
number of occupied breeding areas and the productivity of the 
populations in the individual recovery regions. By setting a goal to 
monitor population numbers and productivity, the Service could 
determine whether the threats that led to the bald eagle's endangerment 
were being removed. With the reduction in levels of persistent 
organochlorine pesticides (such as DDT) occurring in the environment 
and the habitat protection and management actions that have been put in 
place, the bald eagle population has shown a remarkable increase in 
numbers. Between 1990 and 2000, the bald eagle population had a 
national average productivity of at least one fledgling per nesting 
pair per year. As a result, the bald eagle's nesting population 
increased at a rate of about 8 percent per year during this time 
period. Since 1963, when the Audubon Society estimated that there were 
487 nesting pairs, bald eagle breeding in the lower 48 States has 
expanded to more than 9,789 nesting pairs today (U.S. FWS 1995, p. 
36001; U.S. FWS 1999, p. 36457.)
    Some States have shown increases in their bald eagle pairs over the 
past several years. For example, Illinois had an estimated 36 pairs in 
1999, but the State had an estimated 100 pairs in 2006 (Conlin 2006, p. 
1). Iowa had an estimated 100 pairs in 1999, and their bald eagle 
population has doubled to an estimated 200 pairs in 2006 (Vonk 2006, p. 
1). Minnesota had an estimated 681 pairs in 2001, and an estimated 
1,312 pairs in 2005 (Moore 2006, p. 1). In recent decades, Vermont was 
the only State in the conterminous United States that did not have 
nesting bald eagles. In 2006, a pair of bald eagles nested in Vermont 
for the first time since the 1940s, and now Vermont has one nesting 
pair (Amaral 2006, p. 3). To date, the bald eagle's population growth 
has exceeded all the numeric goals established in the five recovery 
plans. In most of the recovery regions, the numeric goals for breeding 
pairs have been significantly exceeded. For example, the delisting goal 
in the Northern States Recovery Plan calls for 1,200 breeding pairs 
distributed over a minimum of 16 States. Today, there are an estimated 
4,215 breeding pairs covering every State in that recovery region.
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    For more information on recovery of the bald eagle in general and 
specific recovery of the individual recovery areas, see the discussion 
on pages 8240-8243 of the February 16, 2006, reopening of the public 
comment period on the proposed rule to delist the species (71 FR 8238).

Summary of Comments and Recommendations

    We requested written comments from the public on February 16, 2006 
(71 FR 8238), when we reopened the public comment period on our July 6, 
1999 (64 FR 36454), proposed rule to delist the bald eagle in the lower 
48 States. In that reopening notice, we responded to comments 
previously received on the July 6, 1999 (64 FR 36454) proposed 
delisting rule. Therefore, the preamble to this final rule addresses 
only the comments we received on the February 16, 2006, notice. The 
comment period was reopened from February 16, 2006, to May 17, 2006. 
During that time, we received two requests to extend the public comment 
period. In response to those requests, on May 16, 2006 (71 FR 28293), 
we extended the public comment period to June 19, 2006. As part of the 
reopening of the public comment period, we also contacted the States 
and Tribes to solicit their comments.
    In conformance with our policy on peer review, published on July 1, 
1994 (59 FR 34270), we solicited opinions from three scientific experts 
who are familiar with this species to peer review the proposed rule. We 
received comments from two of the three peer reviewers, and those two 
peer reviewers convened panels of scientific experts to review the 
information provided. Their comments are included in the summary below. 
One peer reviewer generally supported the proposed delisting, and the 
other peer reviewer did not.
    We reviewed all comments received from the peer reviewers, State 
and Tribal agencies, and the public for substantive issues and new 
information regarding the proposed delisting. We received a total of 
387 new comments.
    Section 4(b)(1)(A) of the Act requires that determinations as to 
whether any species is a threatened or endangered species shall be made 
``solely on the basis of the best scientific and commercial data 
available,'' including all information received during the public 
comment period. Comments merely stating support or opposition to the 
proposed delisting without providing supporting data, although noted, 
were not considered substantial and therefore were not considered in 
our determination. Substantial comments received during the comment 
period have either been addressed below or incorporated directly into 
this final rule.

Peer Review Comments

    Issue: Several commenters, including one of the peer reviewers, 
stated that threat of habitat loss, including foraging, breeding, and 
wintering/roosting habitat (including communal roosting areas), due to 
development will continue because there are no adequate habitat 
protections (existing regulatory mechanisms) for bald eagles after 
delisting. One peer reviewer acknowledged that BGEPA and MBTA provide 
protection to birds, their nests, and eggs, but opined that those 
statutes offer no protection to habitat. In addition, the commenters 
believed that the proposed regulatory definition of ``disturb'' and the 
draft National Bald Eagle Management Guidelines will not be adequate to 
provide habitat protection. One peer reviewer expressed an opposite 
opinion stating that the proposed BGEPA definition and guidelines 
provide an adequate framework for protecting eagles and their habitat 
using BGEPA and MBTA.
    Response: As discussed in detail under Factor A, the bald eagle 
population is continuing to increase in the lower 48 States, showing 
that reduced availability of habitat is not a current threat to the 
species. Nesting habitat is secure on many public and private locations 
throughout the lower 48 States. We acknowledge that some habitat 
threats continue to exist. However, this localized habitat loss will be 
limited by the operation of various Federal laws that will remain in 
effect after delisting (e.g., BGEPA, MBTA, and the Clean Water Act 
(CWA)).
    The commenters are correct in that the BGEPA contains no provisions 
that directly protect habitat, except for nests. However, as further 
discussed under Factor A below, individual bald eagles are protected 
from certain effects that are likely to occur as the result of various 
human activities, including some habitat manipulation. Activities that 
disrupt eagles at nests, foraging areas, and important roosts can 
wound, kill, or disturb eagles, all of which are prohibited by the 
BGEPA. Through promulgation of the regulatory definition of disturb (72 
FR 31132; June 5, 2007) and issuance of the National Bald Eagle 
Management Guidelines (72 FR 31156; June 5, 2007), we have clarified 
that eagle nests, important foraging areas, and communal roost sites 
are afforded protection under the BGEPA to the degree that adjacent 
habitat modification would disturb, injure, or kill eagles.
    Issue: One of the peer reviewers stated that the final delisting 
rule should include a list of updated population data by State with 
references to the survey from which the data were obtained.
    Response: We have included an updated national population estimate 
in this final rule along with a map with the estimated number of 
breeding pairs per State. To ensure that our determination on the 
status of the bald eagle was based ``solely on the basis of the best 
scientific and commercial data available'' as required by the Act, we 
used State population data provided to us directly by a State agency, 
the Pacific Flyway Council, or from a State Web site. Based on this 
information, there are an estimated 9,789 bald eagle pairs in the lower 
48 States. We believe this is a conservative estimate based on the 
results of our pilot studies for the post-delisting monitoring plan 
(USFWS 2007). For example, in the pilot study conducted by Minnesota, 
872 known nest sites were observed as occupied in 2005. Incorporating 
the use of area random plots for our pilot study, Minnesota's estimate 
of nesting bald eagle pairs increased to 1,312. Minnesota estimates 
that their known nest survey, which is similar to those conducted by 
each of the States and used to produce data for the delisting, may only 
count two-thirds of the breeding pairs in the State (Moore 2006, pp. 1-
2).
    Issue: Both peer reviewers expressed concern about using out-dated 
recovery plans and delisting criteria. One peer reviewer recommended 
that the delisting criteria in the recovery plan for Southeastern 
United States bald eagles should be peer reviewed before finalizing the 
delisting. One commenter thought the Service should seek more advice 
from the recovery team members.
    Response: Recovery plans are not regulatory documents and are 
instead intended to provide guidance to the Service, States, and other 
partners on methods of minimizing threats to listed species and on 
criteria that may be used to determine when recovery is achieved. There 
are many paths to accomplishing recovery of a species, and recovery may 
be achieved without fully meeting all criteria in a recovery plan. 
Overall, recovery of species is a dynamic process requiring adaptive 
management, and judging the degree of recovery of a species is also an 
adaptive management process that may, or may not, fully follow the 
guidance provided in a recovery plan.
    Over the years, the Service sought advice from several recovery 
teams. In the Southeast, we used the advice of the recovery team to 
give us a population target that would indicate that the threats had 
been reduced. We believe

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this is the best available information at this time.
    Issue: One peer reviewer and several commenters noted concern over 
the viability of the Southwest population of bald eagles based on low 
numbers of breeding pairs, relatively low productivity, relatively high 
adult mortality, and threats of habitat alteration and human 
disturbance. Based on this information, the peer reviewer recommended 
designating the population as a DPS and deferring the delisting.
    Response: As further discussed in the Summary of Factors Affecting 
the Species section, the Service does not believe the bald eagle 
population in the Southwest meets the criteria stated in our DPS policy 
(61 FR 4722; February 7, 1996), nor is this population a significant 
portion of the range of the lower 48 States population of bald eagles. 
Therefore, consideration of the viability of, or threats to, the 
Southwestern population, standing alone, is not relevant to the 
delisting determination for the lower 48 States bald eagle population.
    Issue: Several commenters, including peer reviewers, commented that 
a post-delisting monitoring (PDM) plan should be in place when 
delisting occurs and should remain in effect longer than 5 years. In 
addition, the plan should be comprehensive and scientifically based to 
monitor changes in population, productivity, wintering populations, 
habitat, and contaminants.
    Response: Based on comments from the 1999 proposed delisting rule, 
we have been working steadily on the development of a revised national 
post-delisting monitoring plan, including conducting several pilot 
studies in cooperation with the States, to produce a monitoring plan 
that will be more scientifically robust than previously proposed in the 
1999 proposed delisting rule. We have modified the draft post-delisting 
monitoring plan to take into account the life cycle of the bald eagle.
    We are making the revised draft of the monitoring plan is available 
for public comment simultaneously with this rule elsewhere in today's 
Federal Register. We agree that a plan should ideally be in place at 
the time of delisting; however, given the proposed 20-year monitoring 
effort, we believe the plan will be finalized in a sufficient amount of 
time to adequately monitor the status of the species after delisting. 
Given the continued increase in the population, we do not expect a 
precipitous decline over the short term, prior to our completion of the 
final monitoring plan.

Other Comments

Factor A. The Present or Threatened Destruction, Modification, or 
Curtailment of Its Habitat or Range

    Issue: One commenter stated that the delisting criteria have not 
been met for habitat protection in the Chesapeake Bay region. Another 
commenter stated that while lands have been protected in the Chesapeake 
Bay Recovery Region to sustain the targeted levels of breeding pairs, 
the proposed delisting does not address protection of summer and winter 
concentration areas. The commenter noted that neither the Service's 
National Wildlife Refuges nor State management areas provide enough 
land to provide the necessary concentration areas. Another commenter 
stated that habitat loss and development are not limiting factors in 
Maryland, and are not likely to cause endangerment in the future. The 
commenter believes that the Chesapeake Bay Critical Area Program will 
continue to conserve forested shoreline habitat, and that it is not 
necessary for us to fully meet the habitat preservation goals in the 
Chesapeake Bay Recovery Plan.
    Response: The Chesapeake Bay bald eagle population has experienced 
significant growth over the past 30 years. Within the Chesapeake Bay 
Bald Eagle Recovery Region, approximately 280 nests occur on Federal or 
State lands (48 nests from Koppie 2007b and 230 nests from Otto 2007). 
In addition to the long term habitat protection afforded on these 
lands, nearly 200 other nests occur within areas regulated by the 
Maryland Critical Areas Act (Koppie 2007b), which is discussed below. 
Together, these areas will continue to play active roles in providing 
additional protection of nests, nest buffers, forest blocks, and 
roosting habitat for bald eagles in the foreseeable future.
    Habitat loss is still likely to occur in this region in the 
foreseeable future through incremental land clearing. It is projected 
that between 1978 and 2020, the developed area of the Chesapeake Bay 
watershed will increase by 74 percent in Maryland and 80 percent in 
Virginia (Gray et al. 1988). The Service acknowledges ongoing shoreline 
development will continue for the foreseeable future, which will likely 
set limits on the rate of future expansion and overall population 
growth of the bald eagle in the Chesapeake Bay region. Bald eagle 
nesting pairs currently continue to increase despite the increased 
construction of new homes, business parks, boat marinas, and other 
infrastructure within habitats sustaining bald eagles. Therefore, it 
appears that unoccupied forested habitat currently still remains 
available, leading to the conclusion that the species has not yet 
reached the carrying capacity limits for nesting eagle pairs in the 
Chesapeake Bay region. The Service anticipates a continued upward 
population growth at least through the next decade based on the 
availability of habitat and behavioral adaptation. In addition, bald 
eagles have been able to adapt to higher densities of birds by 
decreasing the size of nesting territories in certain areas of the 
region where birds are starting to saturate the habitat. At some point, 
the Service expects the growth rate to decrease and level off, 
establishing a population that is stable over the long term.
    A study published in 1996 used modeling to predict that the 
population of bald eagles in the Chesapeake Bay region would increase 
until reaching carrying capacity, after which there would be a rapid 
decline of the population (Fraser et al. 1996, p. 185). However, we 
find that model to be unpersuasive for a number of reasons. First, it 
predicts that a decline might have begun by about 2005, but bald eagle 
numbers continue to increase in the Chesapeake Bay area. In Maryland, 
the population has increased from 338 breeding pairs to 400 between 
2003 and 2004, and in Virginia bald eagle pairs increased from 371 to 
485 between 2003 and 2006.
    Second, the predictive model showing a decline in the Chesapeake 
Bay bald eagle population does not take into account nest protection 
measures or refugia such as State and Federal wildlife refuges (Fraser 
et al. 1996, p. 185). In Virginia, the Eastern Virginia Rivers National 
Wildlife Refuge Complex was established to protect bald eagle nesting 
sites and communal roost sites that are part of concentration areas 
along the Rappahannock and James rivers. These refuges are within the 
Rappahannock River Watershed and the James River Watershed, which hold 
approximately half of Virginia's nesting population of bald eagles. In 
addition, the first ``eagle refuge,'' Mason Neck National Wildlife 
Refuge, was established to protect bald eagles along the Potomac River 
in 1967. In Maryland, communal roost sites and nesting areas are 
protected at the U.S. Army Aberdeen Proving Ground, Blackwater National 
Wildlife Refuge, Naval Surface Warfare Center at Indian Head, and an 
area below the Conowingo Dam along the Susquehanna River. All these 
areas (excluding the Conowingo Dam) are located within forested 
habitats on federal lands and therefore have long term protection, as 
explained under Factor A (Koppie 2007a).

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    Third, the model does not take into account the increase in bald 
eagle tolerance to human disturbance. The Service has documented 
several cases in which bald eagles around the Chesapeake Bay have 
continued to nest and successfully produce young within distances that 
were previously considered too close to human activity (Koppie 2007a). 
In addition, in both Virginia and Maryland, compression of nesting 
territories (i.e., eagles nesting in closer proximity to each other 
than in recent decades) has been observed, suggesting that the density 
of nesting pairs can be higher than once documented (Koppie 2007a).
    In addition, certain State authorities and programs may afford 
additional, unquantifiable habitat protection. For example, in Maryland 
the Critical Area Act covering the Chesapeake Bay and Atlantic Coastal 
Bays enables the State and local governments to jointly address the 
impacts of land development on habitat and aquatic resources. This 
program can indirectly protect bald eagle habitat by, among other 
things, categorizing predominant land uses, focusing new development 
towards existing developed areas, and designating natural resource 
areas, habitat protection areas and buffers. These measures may reduce 
the rate of bald eagle habitat alteration depending on how they are 
employed across the landscape. To the extent that the Critical Areas 
program is maintained, it has the potential to contribute to forested 
shoreline preservation within 1,000 feet of the Chesapeake and Atlantic 
Coastal Bays where upwards of 70 percent of Maryland's eagles nest 
(Koppie 2007b).
    There are currently an estimated 1,093 breeding pairs in the 
Chesapeake Bay Recovery Region. Habitat loss is still likely to occur 
in the Chesapeake Bay region in the foreseeable future. However, based 
on the number of nests and associated habitat found on protected lands, 
the existence of refuges and other lands specifically to conserve 
concentration and foraging areas, the availability of additional 
unoccupied habitat, behavioral adaptation, potentially increased 
compression of nesting territories, and the continuation of protection 
under BGEPA (as discussed under Factor A), we do not expect the bald 
eagle population in the Chesapeake Bay area to decline below the 
recovery target of 300-400 nesting pairs in the foreseeable future. 
Similarly, we do not anticipate that habitat loss will have a 
significant negative impact on important concentration areas.
    Issue: Eagles have not recovered in the Southwestern United States. 
They are threatened with oil and gas development. The Bureau of Land 
Management is allowing gas wells and pipelines to be constructed in 
prime eagle habitat, and it will only get worse after delisting. For 
example, the Bureau of Land Management is allowing gas wells and 
pipelines to be constructed in prime bald eagle habitat around Navajo 
Reservoir.
    Response: We do not have any data to indicate that oil and gas 
development is currently threatening the future security of the bald 
eagle or its habitat in the Southwest. The Bureau of Reclamation 
manages the land around the Navajo Reservoir, and the Resource 
Management Plan includes areas specifically designated to protect bald 
eagles (U.S. BR 2005, p. 2-2, map 2-1). We believe the measures 
described in the Resource Management Plan will provide adequate 
protections for bald eagles and their habitat around the Navajo 
Reservoir after delisting.
    Issue: One commenter stated that the final rule needs to include a 
discussion on the declines in some fisheries as a past and present 
concern. For example, the demise of a kokanee salmon run in Glacier 
National Park ended a large autumn aggregation of bald eagles in that 
area. Declines in alewives and herring in Maine have also restricted 
eagle aggregations.
    Response: Bald eagle populations have increased despite isolated 
declines in local fish populations. As opportunistic feeders, bald 
eagles will move to alternative food sources, particularly during the 
non-nesting season. Therefore, we do not believe this is a threat that 
would limit the population of bald eagles in the lower 48 States, or a 
significant portion of its range in the foreseeable future such that 
continued protection under the Act would be warranted.
    Issue: One commenter felt that a State-level management plan for 
bald eagles in the Southwest Recovery Region was needed because the 
Arizona Bald Eagle Nestwatch Program will likely disappear after 
delisting.
    Response: The Conservation Assessment and Strategy for the Bald 
Eagle in Arizona has been developed by the Arizona Game and Fish 
Department, cooperating agencies, and Tribes to continue management 
practices for the bald eagle after delisting, including the Bald Eagle 
Nestwatch Program (Driscoll et al. 2006, pp. 1, 33). As we stated in 
our August 30, 2006, petition finding, the Arizona Bald Eagle Nestwatch 
Program will likely remain in place because the funding comes from a 
variety of sources, including State wildlife grants, donations, Arizona 
Game and Fish Department's Heritage Funds (State lottery), and matching 
funds for Federal grants. In any case, there is no specific requirement 
under the Act for a State management plan.
    Issue: BGEPA does not require landowners or developers to provide 
notification of their projects that may affect eagle nests. BGEPA and 
MBTA only come into effect after discovery of an infringement. There 
currently is no mechanism under BGEPA to allow for lawful activities 
(such as transportation construction and maintenance) to proceed. Left 
without options, landowners will be very tempted to cut down nest trees 
rather than lose the use of their property.
    Response: Actions that result in take as defined under BGEPA or 
MBTA are prohibited unless permitted by the Service. Thus, such 
notification is not required under either statute, but an action 
resulting in take is prohibited nonetheless. As currently occurs under 
the Act, providing such notification may be in the interest of a 
project proponent as it can help them avoid potential legal liabilities 
from enforcement of BGEPA or MBTA. We believe that working 
cooperatively with landowners to avoid or minimize adverse impacts to 
bald eagles is likely to achieve more positive conservation than 
reliance on regulatory enforcement. In addition, we have proposed a 
program that would allow us to authorize limited take associated with 
otherwise lawful activities under BGEPA (72 FR 31141; June 5, 2007), 
similar to the incidental take authorizations that we have made under 
sections 7 and 10 of the Act.

Factor B. Overutilization for Commercial, Recreational, Scientific, or 
Educational Purposes

    Issue: Poaching and illegal trade of bald eagle parts is still a 
threat that will increase if the bald eagle is delisted.
    Response: There is no legal commercial or recreational use of bald 
eagles, and such uses of bald eagles will remain illegal under various 
statutes, as described under Factor B below. We consider current laws 
and enforcement measures apart from the Act sufficient to protect the 
bald eagle from illegal activities, including poaching and illegal 
trade.
    Issue: Eagle parts and feathers should continue to be available for 
Native American religious and cultural needs. If the bald eagle is 
delisted, Native Americans should be given priority for eagle parts and 
feathers.
    Response: To respond to the religious needs of Native Americans, in 
the early 1970s, we established the National Eagle Repository in 
Commerce City, Colorado,

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which serves as a collection point for dead raptors, including bald 
eagles. As a matter of policy, all Service units transfer salvaged bald 
eagle parts and carcasses to this repository. Federal and State 
conservation agencies, zoological parks, rehabilitators, and others who 
may legally possess and transport dead bald and golden eagles are 
encouraged to send the dead birds, and their parts, to the repository 
so they can be utilized by federally recognized Native American Tribes 
(16 U.S.C. 668a and 50 CFR 22.22).
    Native Americans are given priority for eagle parts and feathers, 
and only members of Federally recognized tribes can obtain a permit 
from us authorizing them to receive and possess whole eagles, parts, or 
feathers from the repository for religious purposes. This policy is 
authorized by the provisions of BGEPA and will continue after 
delisting.
    Issue: One commenter did not want the bald eagle delisted due to 
the importance of the bald eagle to Native American religious and 
spiritual practices and ceremonies. Another commenter recommended 
continuing the Act's protections until recovery had been achieved such 
that Native Americans no longer need a permit for Indian religious 
activities. Several commenters stated that Native Americans should not 
be allowed to sacrifice eagles, even if doing so is for religious 
ceremonies.
    Response: As required by the Act, we are delisting the bald eagle 
because it no longer meets the definition of a threatened species; the 
bald eagle will continue to be protected under the BGEPA and MBTA once 
it is delisted. These statutes prohibit unauthorized take and require 
permits for limited designated uses of eagles, their parts, and related 
items. The BGEPA expressly authorizes issuance of permits to take bald 
eagles for the religious purposes of Indian tribes. We will continue to 
issue only permits that we determine are consistent with the 
preservation of the bald eagle.

Factor C. Disease or Predation

    Issue: One commenter stated that avian influenza is a threat to the 
bald eagle and that it should be thoroughly discussed in the delisting 
rule. Another commenter was concerned about the threats to bald eagles 
from other diseases such as avian vacuolar myelinopathy, West Nile 
virus, and raptor beak overgrowth syndrome.
    Response: The Department of the Interior is currently testing 
migratory birds for the presence of H5N1 high path avian influenza. At 
this time, there are no confirmed cases of migratory birds, including 
bald eagles, testing positive for avian influenza in the United States 
(USGS 2007a). At least 80 bald eagles and possibly thousands of 
American coots have died from avian vacuolar myelinopathy since it was 
discovered in 1994 at DeGray Lake in Arkansas. Studies on avian 
vacuolar myelinopathy are continuing, but the cause is still unknown 
(USGS 2007b). These and other diseases may affect individual bald 
eagles at the local level, but as discussed below under Factor C, are 
not considered to be a significant threat to the overall bald eagle 
population.

Factor D. The Inadequacy of Existing Regulatory Mechanisms

    Issue: Several commenters were concerned that many States and local 
jurisdictions will remove the protections for the bald eagle after 
delisting. One commenter stated that Memoranda of Agreement should be 
in place between the Service and the States to provide protection for 
the bald eagle after delisting. One commenter wanted to make sure that 
States with small bald eagle populations will still provide protection 
after delisting. One State government commented that State laws provide 
little habitat protection. Several States indicated that they will play 
a large role in bald eagle conservation after delisting.
    Response: Some States will likely maintain the sensitive status of 
the bald eagle under individual State laws; however, such protection is 
not needed to assure that the bald eagle population in the lower 48 
States will continue to be a viable population after delisting. As 
described in the discussions of Factors A and B below, the Service 
believes that BGEPA and other Federal laws that will remain in place 
after delisting provide the necessary protections in the future for a 
recovered bald eagle population. Many States have developed State-
specific management plans, regulations, and/or guidance for landowners 
and land managers to protect and enhance bald eagle habitat, and we 
encourage the continued development and use of these planning tools to 
benefit bald eagles. Such measures can only offer more protection for 
bald eagles than is already offered by BGEPA and MBTA. The States will 
play a key role in continuing to monitor bald eagles in the lower 48 
States to make sure that the species continues to maintain its 
recovered status.
    Issue: One commenter asserts that BGEPA and MBTA will continue to 
protect bald eagles after delisting, and, because of these protections, 
bald eagles will likely become overpopulated in some areas of the 
country.
    Response: The bald eagle has not yet reached carrying capacity in 
many parts of its range, and we anticipate that the population will 
continue to increase in these areas following delisting. In prime 
congregation areas, numbers of nesting pairs will level off as the 
nesting habitat reaches carrying capacity. Many of the bald eagles 
displaced from saturated habitats will be able to relocate to other 
suitable habitats. However, territorial competition between eagles will 
likely maintain a naturally fluctuating population once carrying 
capacity has been reached.
    Issue: Several commenters were concerned that the Service will not 
maintain adequate funding for staff to provide technical assistance or 
enforce BGEPA after delisting.
    Response: The Service is committed to maintaining adequate staff to 
respond to requests for technical assistance. The ultimate mechanisms 
for delivering that assistance will be determined prior to making a 
decision on the proposed BGEPA permit program (72 FR 31141; June 5, 
2007).
    Issue: Several commenters expressed concern that the proposed 
delisting did not include grandfathering of existing take 
authorizations/permits under sections 7 and 10 of the Act.
    Response: After delisting of the bald eagle, the Service will honor 
existing Act authorizations until the Service completes a final 
rulemaking for permits under the BGEPA. We do not intend to refer for 
prosecution the incidental take of any bald eagle under the MBTA, as 
amended (16 U.S.C. 703-712), or the BGEPA, as amended (16 U.S.C. 668-
668d), if such take is in full compliance with the terms and conditions 
of an incidental take statement issued to the action agency or 
applicant under the authority of section 7(b)(4) of the Act or the 
terms and conditions of a permit issued under the authority of section 
10(a)(1)(B) of the Act. The Service has proposed a rulemaking to 
establish criteria for issuance of a permit to authorize activities 
that would ``take'' bald eagles under the BGEPA. The Service has 
addressed the existing Act authorizations in that rulemaking, which if 
finalized, might extend comparable authorizations under the BGEPA (72 
FR 31141; June 5, 2007).

Factor E. Other Natural or Manmade Factors Affecting Its Continued 
Existence

    Issue: Several commenters were concerned about ongoing impacts of 
contaminants. One commenter noted that mercury is still a threat to 
bald

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eagles in the Northeast United States. Another commenter noted that 
PCBs and DDE were still an ongoing threat to the Great Lakes population 
of bald eagles. Another commenter noted that the upper Midwest 
population of bald eagles is experiencing a heavy metal contaminant 
problem that affects the ratio of immature eagles to adults. Another 
commenter stated that too many nests in northern Illinois have zero 
productivity due to contaminants.
    Response: As we discuss further in Factor E below, we acknowledge 
that certain contaminants may pose a threat to individual bald eagles. 
We believe many of these instances are localized and that contaminants 
will not be a large enough threat to limit the population of bald 
eagles in the lower 48 States or any significant portions of its range 
in the foreseeable future such that the protection of the Act would be 
warranted. This is evidenced by the population increases that have 
occurred despite the presence of certain levels of contaminants, 
including mercury and PCBs, in the environment.
    Issue: One commenter was concerned that climate change may be an 
issue, and we should, therefore, keep the bald eagle listed until we 
can guarantee that habitats are safe.
    Response: Section 4(b)(1)(A) of the Act directs that determinations 
as to whether any species is a threatened or endangered species shall 
be made ``solely on the basis of the best scientific and commercial 
data available.'' We did not receive any data during the public comment 
period to indicate that climate change is currently threatening the 
future security of the bald eagle or its habitat. Since the bald eagle 
is currently successful in a wide range of climate conditions 
throughout North America, climate change will not likely be a factor 
threatening the species in the foreseeable future.
General Comments
    Issue: The Service may take too long to re-list the bald eagle if 
it is warranted.
    Response: If data from the post-delisting monitoring plan show that 
the bald eagle population is decreasing below a trigger threshold 
specified in the plan, we will investigate the cause of the decline and 
take the necessary measures to address the decline. If the population 
decline is severe, then we will promptly evaluate whether re-listing 
under the Act is warranted, including the Act's provision for emergency 
listing, as appropriate.
    Issue: The Service used an out-of-date, non-scientific population 
productivity value of 0.7 young/pair.
    Response: Our information indicates that a productivity value of 
0.7 young/pair for a stable population is still the best available data 
(see Sprunt et al. 1973, p. 104; Buehler 2000, p. 20).
    Issue: The delisting is too reliant on current eagle numbers. 
Research on survivorship, sex ratios, and population recruitment are 
all important parameters of recovery, not just productivity. Delisting 
criteria should be based on numbers of active nests, not breeding 
pairs.
    Response: The recovery criteria and goals were established by 
recovery teams composed of experts in each geographic region. The 
purpose of the criteria was to allow the Service to monitor the status 
of the recovery efforts. By setting a goal to monitor population 
numbers and productivity, the Service, in conjunction with the recovery 
teams, could determine whether the threats that led to the bald eagle's 
endangerment had been removed. Monitoring the additional parameters 
would have been more costly and would not provide any more data that 
would enable the Service to monitor recovery. Given the increase in the 
population parameters, the threats have been shown to have decreased to 
the point where the bald eagle no longer meets the definition of 
threatened or endangered under the Act.
    Issue: The population data presented are estimates and not 
supported by field work. Data provided by the commenter indicate that 
the percentage of immature eagles to adults is dropping, which may 
influence reproduction or survival in the bald eagle population.
    Response: The data discussed by the commenter are midwinter counts 
collected on one day in a 2-hour period from northern Minnesota to 
Reelfoot, Tennessee. These data, on their face, did show a fluctuation 
in the number of immature bald eagles throughout the time period from 
1961 to 2006, with some years having a higher number than others. 
However, these data also indicated a trend of increasing adults from 
470 in 1961 to 1,299 in 2006. Throughout this time period, the number 
of adults also fluctuated. Because surveys of wintering bald eagles, 
such as the midwinter counts described above, are weather dependent 
(mild winters cause fewer birds to move south) and can include birds 
migrating down from Canada, the Service has relied on nesting data as 
the stronger indicator of bald eagle population trends in the lower 48 
States. We plan to continue monitoring population trends with 
implementation of our post-delisting monitoring plan. However, we 
support the public involvement related to midwinter counts, and such 
data have highlighted the importance of wintering habitats used by 
these eagles.

Distinct Vertebrate Population Segment

    Section 4 of the Act and its implementing regulations (50 CFR part 
424) set forth the procedures for listing species, reclassifying 
species, or removing species from listed status. ``Species'' is defined 
by the Act as including any species or subspecies of fish or wildlife 
or plants, and any distinct vertebrate population segment of fish or 
wildlife that interbreeds when mature (16 U.S.C. 1532(16)). We, along 
with the National Marine Fisheries Service (now the National Oceanic 
and Atmospheric Administration--Fisheries), developed the Policy 
Regarding the Recognition of Distinct Vertebrate Population Segments 
(DPS policy) (61 FR 4722; February 7, 1996), to help us in determining 
what constitutes a Distinct Population Segment (DPS). The policy 
identifies three elements that are to be considered in a decision 
regarding the status of a possible DPS. These elements are: (1) The 
discreteness of the population in relation to the remainder of the 
species to which it belongs; (2) the significance of the population 
segment to the species to which it belongs; and (3) the population 
segment's conservation status in relation to the Act's standards for 
listing. Our policy further recognizes it may be appropriate to assign 
different classifications (i.e., threatened or endangered) to different 
DPSs of the same vertebrate taxon (61 FR 4725; February 7, 1996).

Sonoran Desert Distinct Population Segment

    As discussed above, the Service made a negative 90-day finding on a 
petition to list the Sonoran Desert bald eagle population as an 
endangered DPS (71 FR 51549; August 30, 2006). In this final 
determination on the proposed delisting of the entire bald eagle 
population in the lower 48 states, we also consider, as a final 
determination, whether the Sonoran Desert population of the bald eagle 
constitutes a DPS, and should remain listed as either an endangered or 
threatened species. The main bald eagle population center of the 
Sonoran Desert currently consists of 42 breeding pairs (AZ Game and 
Fish Dept. 2006, p. 6) that are found in the southern half of Arizona, 
west of the New Mexico state boundary. One breeding pair in Arizona is 
found outside the Sonoran Desert.

Discreteness

    The DPS policy states that a population segment of a vertebrate

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species may be considered discrete if it satisfies either one of the 
following two conditions: It must be markedly separated from other 
populations of the same taxon as a consequence of physical, 
physiological, ecological, or behavioral factors; or it must be 
delimited by international boundaries within which significant 
differences in control of exploitation, management of habitat, 
conservation status, or regulatory mechanisms exist that are 
significant in light of section 4(a)(1)(D) of the Act. The second 
criterion, international boundaries, is easily addressed because the 
Sonoran Desert population of bald eagles is not delimited by 
international boundaries that could be the basis of a review of 
management of habitat, conservation status or regulatory mechanisms. 
Therefore, the Sonoran Desert population of bald eagles is not discrete 
based on this criterion. As discussed below, under the first criterion, 
we find that the Sonoran Desert population is markedly separated from 
other populations as a consequence of behavioral factors. Therefore, we 
do not address separation by physical, physiological, or ecological 
factors.
    In looking at whether Sonoran Desert bald eagle are markedly 
separated from other populations it is helpful to evaluate whether 
there is a level of interchange between this population and adjacent 
populations. Biologists in Arizona made a concerted effort to band all 
nestlings in Arizona since 1987. Of those birds that were sighted with 
bands between 1987 and 2005, 41.8 percent hatched in Arizona, 18.8 
percent likely hatched in Arizona before 1987 (due to a different band 
type), less than one percent were from another State, and 38.8 percent 
were from unknown origin (unbanded) (Driscoll et al. 2006, p. 26). One 
adult breeding in Arizona is known to have originated from another 
State (banded as a nestling in 1988 in southeast Texas). Only one 
nestling with a band was identified as subsequently nesting outside the 
recovery region (Temecula, California) (Driscoll et al. 2006, p. 27). 
Roughly 20 percent of the population does not receive a band for a 
variety of reasons (e.g., logistics of reaching the nestlings), and 
therefore 38 percent of the population without bands would not be 
unusual.
    In addition, because of the clinal variation in these birds, bald 
eagle populations from around the same latitude would likely be the 
supplier of birds that would immigrate into the population. Currently, 
we do not have any populations surrounding the Sonoran Desert that are 
large enough that juveniles would likely start to disperse into the 
Sonoran Desert. Within the last 30 years, these adjacent populations 
have not increased in size to the same degree as we have seen with the 
populations in other parts of the bald eagle's range. Given that we do 
not have large bald eagle population centers surrounding the Sonoran 
Desert, and given the limited habitat found between currently known 
populations, it is likely that interchange between the Sonoran Desert 
and other populations will be minimal in the foreseeable future.
    These data indicate that immigration to and emigration from the 
Sonoran Desert population is very limited. Reproductive isolation of 
the bald eagles nesting in the Sonoran Desert region of Arizona, 
although probably not absolute, appears to be substantial. Our DPS 
Policy does not require that populations experience total reproductive 
isolation in order to meet the discreteness criterion; rather, they 
need only to be ``markedly separated.'' We believe the documented low 
levels of immigration and emigration indicate that this population is 
currently markedly separated from other bald eagles in the United 
States.
    On the basis of the immigration by the southeast Texas eagle, in 
1995, the Service determined as part of the Service's final rule 
reclassifying the bald eagle from endangered to threatened (60 FR 
36000; July 12, 1995) that eagles in the Southwestern Recovery Region 
were not reproductively isolated. The banded bald eagle from Texas, 
although located within the Southwestern Recovery Region, occupies an 
area outside the Sonoran Desert. Furthermore, no additional banded bald 
eagles from outside the Sonoran Desert have been discovered immigrating 
into the Sonoran Desert since 1995. In addition, the analysis during 
the 1995 rule was conducted prior to implementation of the DPS policy 
in 1996. Therefore, now reviewing the same question in the context of 
the DPS policy, combined with more data on immigration and emigration, 
leads us to a conclusion that this population is discrete.

Significance

    If we determine that a population segment is discrete under one or 
more of the discreteness conditions, then we evaluate its significance 
based on ``the available scientific evidence of the discrete population 
segment's importance to the taxon to which it belongs'' (61 FR 4725). 
We make this evaluation in light of congressional guidance that the 
Service's authority to list DPSs be used ``sparingly'' while 
encouraging the conservation of genetic diversity (61 FR 4722; February 
7, 1996). This consideration may include, but is not limited to the 
following elements: (1) Evidence of the persistence of the population 
segment in an ecological setting that is unusual or unique for the 
taxon; (2) evidence that loss of the population segment would result in 
a significant gap in the range of the taxon; (3) evidence that the 
population segment represents the only surviving natural occurrence of 
a taxon that may be more abundant elsewhere as an introduced population 
outside of its historic range; and (4) evidence that the discrete 
population segment differs markedly from other populations of the 
species in its genetic characteristics.
    (1) Evidence of the persistence of the population segment in an 
ecological setting that is unusual or unique for the taxon.
    As stated in the DPS policy, the Service believes that occurrence 
in an unusual ecological setting is potentially an indication that a 
population segment represents a significant resource warranting 
conservation under the Act (61 FR 4724). In considering whether the 
population occupies an ecological setting that is unusual or unique for 
the taxon, we evaluate whether the habitat shares many features common 
to the habitats of other populations. The Sonoran Desert bald eagle 
population inhabits a desert ecosystem characterized by hot and dry 
summers that, on its face, seems to represent an ecological setting 
that is highly unusual or unique for the species. However, bald eagles 
in the Sonoran Desert population essentially use the same ecological 
niche as those in other parts of the lower 48 States population. Bald 
eagles in the Sonoran Desert feed primarily on fish, consistent with 
bald eagles in other parts of the range. Habitat structure and 
proximity to a sufficient food source are usually the primary factors 
that determine suitability of an area for nesting (Grier and Guinn 
2003, p. 44). Nationwide, bald eagles are known to nest primarily along 
seacoasts and lakeshores, as well as along banks of rivers and streams 
(Stalmaster 1987, p. 120). Similar to the remainder of the population, 
bald eagle breeding areas (eagle nesting sites and the area where 
eagles forage) in the Sonoran Desert are located in close proximity to 
a variety of aquatic sites, including reservoirs, regulated river 
systems, and free-flowing rivers and creeks.
    We considered whether cliff nesting is an adaptation to the 
conditions in the Sonoran Desert that indicates the Southwest is a 
unusual or unique ecological setting for bald eagles. While Stalmaster 
(1987) noted that cliff nesting

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is common in Arizona, he also noted that exceptions to tree nests in 
other areas do occur. Gerrard and Bortolotti (1988, p. 41) note that 
bald eagles in other areas may nest on cliffs if suitable trees are not 
available. For instance, bald eagles are known to nest on cliffs on the 
Channel Islands off California (NOAA 2006). Bald eagles in Alaska also 
are known to nest on cliffs, sea stacks, hillsides, and rock 
promontories where there are no suitable nest trees (Sherrod et al. 
1976, p. 153). It is likely that up to 10 percent of the bald eagles in 
Alaska nest on the ground (Schempf 2007). Ground nesting has been 
documented in northwestern Minnesota and Florida but is the exception 
rather than the rule (Hines, P. and H. Lipke 1991; Shea, R.E. and 
Robertson W.B. Jr. 1979). Eagles also nest in a variety of odd 
situations, such as utility poles, abandoned heavy equipment, 
mangroves, and root wads washed up on sandbars. Cliff nesting in the 
Sonoran Desert bald eagles does not seem to be an indication of a 
behavioral adaptation unique to the Sonoran Desert. Bald eagles will 
use whatever high nest sites are available near riparian areas they 
inhabit: in the Sonoran Desert these sites often happen to be cliffs. 
In fact, although bald eagles utilize cliffs, ledges, and pinnacles for 
nesting in the Sonoran Desert, they have also nested in cottonwood, 
willow, sycamore, pinyon pine, and ponderosa pine trees. Many Sonoran 
Desert eagle pairs have built and used both tree and cliff nests within 
their territories. This behavior demonstrates the flexibility in nest 
site selection that bald eagles have throughout the eagles' entire 
geographic range.
    Bald eagles in the Sonoran Desert are smaller in size and breed 
earlier in the season than most other bald eagles, which could indicate 
behavioral adaptations to a unique setting. However, examination by 
latitude reveals differences between birds in the northern regions and 
birds in the southern regions. For instance, Stalmaster (1987, pp. 16-
17) notes northern eagles are much larger and heavier than their 
southern counterparts. This is consistent with Bergmann's Rule, which 
holds that animal size increases with increasing latitude due to 
changes in environmental temperature. Consistent with this rule, Hunt 
et al. (1992) reports that bald eagles in Arizona are smaller than 
those in Alaska, California, and the Greater Yellowstone Region. 
Gerrard and Bortolotti (1988, p. 14) note that bald eagles in Florida, 
which is farther south than Arizona, are the smallest, with a gradation 
of small to large from south to north. Timing of various breeding 
events in bald eagles is also tied to latitude of the nesting area, 
with eagles at more northern latitudes breeding at later dates 
(Stalmaster 1987, p. 63). Stalmaster (1987, p. 63) notes that bald 
eagles in Florida initiate breeding activities in October, even earlier 
than Sonoran Desert bald eagles. Bald eagles in Florida also lay eggs 
earlier (Stalmaster 1987, p. 63; Gerrard and Bortolotti 1988, p. 76). 
Accordingly, Florida bald eagles hatch and fledge earlier than those in 
the Sonoran Desert.
    In summary, Stalmaster's (1987) and Gerrard an