[Federal Register Volume 75, Number 37 (Thursday, February 25, 2010)]
[Proposed Rules]
[Pages 8601-8621]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2010-3794]


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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[Docket No. FWS-R2-ES-2008-0059; MO 92210-0-0008]


Endangered and Threatened Wildlife and Plants; 12-Month Finding 
on a Petition To List the Sonoran Desert Population of the Bald Eagle 
as a Threatened or Endangered Distinct Population Segment

AGENCY: Fish and Wildlife Service, Interior.

ACTION: 12-month petition finding.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), announce a 
12-month finding on a petition to list the Sonoran Desert Area 
population of the bald eagle (Haliaeetus leucocephalus) as a distinct 
population segment (DPS). In the petition, we were asked that the DPS 
be recognized, listed as endangered, and that critical habitat be 
designated under the Endangered Species Act of 1973, as amended (Act). 
After review of all available scientific and commercial information, we 
find that the Sonoran Desert Area population of the bald eagle does not 
meet the definition of a DPS and, therefore, is not a listable entity 
under the Act. As a result, listing is not warranted, and we intend to 
publish a separate notice to remove this population from the List of 
Threatened and Endangered Wildlife once the District Court for the 
District of Arizona has been notified. We ask the public to continue to 
submit to us any new information that becomes available concerning the 
taxonomy, biology, ecology, and status of this population of the bald 
eagle and to support cooperative conservation of the bald eagle within 
the Sonoran Desert Area.

DATES: The finding announced in this document was made on February 25, 
2010.

ADDRESSES: This finding is available on the Internet at http://www.regulations.gov at Docket Number [FWS-R2-ES-2008-0044]. Supporting 
documentation for this finding is available for inspection, by 
appointment, during normal business hours at the Arizona Ecological 
Services Office, 2321 West Royal Palm Road, Suite 103, Phoenix, AZ 
85021-4951. Please submit any new information, materials, comments, or 
questions concerning this species or this finding to the above address, 
Attention: Sonoran Desert Area bald eagle.

FOR FURTHER INFORMATION CONTACT: Steve Spangle, Field Supervisor, 
Arizona Ecological Services Office (see ADDRESSES); telephone, 602-242-
0210; facsimile, 602-242-2513. If you use a telecommunications device 
for the deaf (TDD), call the Federal Information Relay Service (FIRS) 
at 800-877-8339.

SUPPLEMENTARY INFORMATION: 

Background

    Section 4(b)(3)(B) of the Act (16 U.S.C. 1531 et seq.) requires 
that, for any petition to revise the Lists of Endangered and Threatened 
Wildlife and Plants that contains substantial scientific or commercial 
information that listing may be warranted, we make a finding within 12 
months of the date of our receipt of the petition on whether the 
petitioned action is: (a) Not warranted, (b) warranted, or (c) 
warranted, but the immediate proposal of regulation implementing the 
petitioned action is precluded by other pending proposals to determine 
whether species are threatened or endangered, and expeditious progress 
is being made to add or remove qualified species from the List of 
Endangered and Threatened Wildlife and Plants. Section 4(b)(3)(C) of 
the Act requires that we treat a petition for which the requested 
action is found to be warranted but precluded as though resubmitted on 
the date of such finding, that is, requiring that we make a subsequent 
finding within 12 months. Such 12-month findings must be published in 
the Federal Register.
    This notice constitutes our 12-month finding on a petition to list 
the Sonoran Desert Area bald eagle. In this document, the Sonoran 
Desert Area population is the name given to the entity under evaluation 
for designation as a DPS. For the purposes of this assessment, the 
Sonoran Desert Area population includes all bald eagle territories 
within Arizona, the Copper Basin breeding area in California near the 
Colorado River, and the territories of interior Sonora, Mexico, that 
occur within the Sonoran Desert or adjacent, transitional communities. 
For more detail on the boundary of the DPS, see the discussion below 
under Determination of the Area for Analysis.

Previous Federal Action

    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 dichloro-
diphenyltrichloroethane (DDT) and other factors. On February 14, 1978, 
the Service listed the bald eagle as an endangered species under the 
Act (16 U.S.C. 1531 et seq.) in 43 of the contiguous States, and as a 
threatened species in the States of Michigan, Minnesota, Wisconsin, 
Oregon, and Washington (43 FR 6230). Sub-specific designations for 
northern and southern eagles were removed.

[[Page 8602]]

    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 five 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). On 
February 16, 2006, we reopened the public comment period to consider 
new information received on our July 6, 1999 (71 FR 8238), 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), and (2) a notice of availability for draft National Bald Eagle 
Management Guidelines (71 FR 8309). 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.
    Between publication of the July 6, 1999, proposed rule to delist 
the bald eagle and the February 16, 2006, reopening of the comment 
period on the proposed rule to delist the bald eagle, we received a 
petition regarding bald eagles in the southwestern United States. On 
October 6, 2004, we received a petition from the Center for Biological 
Diversity (CBD), the Maricopa Audubon Society, and the Arizona Audubon 
Council requesting that the ``Southwestern desert nesting bald eagle 
population'' be classified as a DPS, that this DPS be reclassified from 
a threatened species to an endangered species, and that we concurrently 
designate critical habitat for the DPS under the Act.
    On March 27, 2006, the CBD and the Maricopa Audubon Society filed a 
lawsuit against the U.S. Department of the Interior and the Service for 
failing to make a timely finding on the petition. The parties reached a 
settlement, and the Service agreed to complete its petition finding by 
August 2006. We announced in our 90-day finding on August 30, 2006 (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 CBD and the Maricopa Audubon Society filed 
a lawsuit challenging the Service's 90-day finding that the ``Sonoran 
Desert population'' of the bald eagle did not qualify as a DPS, and 
further challenging the Service's 90-day finding that the population 
should not be uplisted to endangered status.
    On July 9, 2007 (72 FR 37346), we published the final delisting 
rule for bald eagles in the lower 48 States. This final delisting rule 
also constituted the Service's final determination on the status of the 
Sonoran Desert population of bald eagles. In that final delisting rule, 
we stated that our findings on the status of the Sonoran Desert 
population of bald eagles superseded our 90-day petition finding 
because the final delisting rule constituted a final decision on the 
DPS determination. This determination was based on a thorough review of 
the best available data, which indicated that the threats to the 
species had been eliminated or reduced to the point that the species 
had recovered and no longer met the definition of a threatened or 
endangered species under the Act. It addressed 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 and then 
subsequently conducted the required status review. We determined that 
the final delisting rule therefore rendered moot any issues regarding 
the 90-day petition finding.
    On August 17, 2007, the CBD and the Maricopa Audubon Society filed 
a Motion for Summary Judgment, requesting the court to make a decision 
on their January 5, 2007, lawsuit. In early 2008, several Native 
American Tribes submitted amicus curiae (``friend of the court'') 
briefs in support of the August 17, 2007, Motion for Summary Judgment. 
The San Carlos Apache Tribe, Yavapai-Apache Nation, and Tonto Apache 
Tribe submitted an amicus curiae brief to the court on January 29, 
2008; the Salt River Pima-Maricopa Indian Community submitted an amicus 
curiae brief to the court on February 4, 2008; and the Fort McDowell 
Yavapai Nation submitted an amicus curiae brief to the court on 
February 7, 2008.
    On March 5, 2008, the U.S. District Court for the District of 
Arizona made a final decision in the case and ruled in favor of the CBD 
and the Maricopa Audubon Society. The court order (Center for 
Biological Diversity v. Kempthorne, CV 07-0038-PHX-MHM (D. Ariz)), was 
filed on March 6, 2008.
    The court:
    (1) Ordered the Service to conduct a status review of the Desert 
bald eagle population pursuant to the Act to determine whether listing 
that population as a DPS is warranted, and if so, whether listing that 
DPS as threatened or endangered pursuant to the Act is warranted;
    (2) Ordered the Service to issue a 12-month finding on whether 
listing the Desert bald eagle population as a DPS is warranted, and if 
so, whether listing that DPS as threatened or endangered is warranted;
    (3) Ordered the Service to issue the 12-month finding within 9 
months of the court order pursuant to 16 U.S.C. 1533(b)(3)(B), which 
translates to on or before December 5, 2008;
    (4) Enjoined the Service's application of the July 9, 2007 (72 FR 
37346), final delisting rule to the Sonoran Desert population of bald 
eagles pending the outcome of our status review and 12-month petition 
finding.
    On May 1, 2008, we published a final rule designating bald eagles 
within the Southwest as a DPS for purposes of conforming to the court-
ordered requirement to retain listing status as threatened for those 
bald eagles in the petitioned area (73 FR 23966). A map of the DPS for 
that action was included in the rule.
    On May 20, 2008, we published a Federal Register notice (73 FR 
29096) initiating a status review for the bald eagle in the Sonoran 
Desert Area of central Arizona and Northwestern Mexico. The information 
collection period remained open until July 7, 2008. Additional comments 
were received and considered beyond this date as discussed below.
    On August 27, 2008, the CBD and Maricopa Audubon Society filed an 
unopposed motion (CV07-0038-PHX-MHM) to amend the March 6, 2008, court 
order by extending the completion date of the status review of the 
Desert bald eagle population until October 12, 2009. Supporting 
declarations were filed by the Salt River Pima-Maricopa Indian 
Community, the Inter Tribal Council of Arizona, and Joe P. Sparks. The 
motion was granted on August 29, 2008.
    On September 14, 2009, the Service filed an unopposed motion to 
amend the March 6, 2008, court order by extending the completion date 
of the status review of the Sonoran Desert bald eagle population until 
February 12,

[[Page 8603]]

2010 (CV07-0038-PHX-MHM). The motion was granted on September 25, 2009, 
and a second extension was put in place.
    On February 11, 2010, the Service filed, and was granted, an 
unopposed motion for a one week extension, extending the completion 
date to February 19, 2010.

Public Information

    As noted above, on May 20, 2008, the Service published a notice to 
initiate a 12-month status review for the Sonoran Desert population of 
bald eagle in central Arizona and northwestern Mexico, and a 
solicitation for new information. To allow adequate time to consider 
the information, we requested that information be submitted on or 
before July 7, 2008. On January 15, 2009, a second Federal Register 
notice (74 FR 2465) was published announcing the continuation of 
information collection for the 12-month status review. In order to 
allow us adequate time to consider and incorporate submitted 
information, we requested that we receive information on or before July 
10, 2009. Between May 2008 and the time that we published this 
document, 31 responses were submitted to http://www.regulations.gov and 
5 letters were received by U.S. mail.

Tribal Information

    In accordance with Secretarial Order 3206, the Service acknowledges 
our responsibility to consult with Federally recognized Tribes on a 
government-to-government basis. Over the course of the bald eagle 
status review, we have corresponded and met with various Tribes in 
Arizona, all of whom support protection of the bald eagle under the 
Act. On July 2, 2008, the Service and Tribal representatives from four 
Western Apache Tribes and one Nation (White Mountain Apache, San Carlos 
Apache, Tonto Apache Tribes, and Yavapai-Apache Nation) met to hear 
testimony from cultural authorities on a variety of subjects including 
the history of the eagle in Arizona, and the importance of the eagle to 
the Apache people. At the request of Tribal representatives, this 
meeting was recorded and incorporated into the administrative record 
for the 12-month finding. On July 3, 2008, the Service met with members 
of the Salt River Pima-Maricopa Indian Community, Gila River Indian 
Community, Tohono O'Odham Nation, Ak-Chin Indian Community, Tonto 
Apache Tribe, Fort McDowell Yavapai Nation, the Hopi Tribe, Pascua 
Yaqui Tribe, Zuni Tribe, and the InterTribal Council of Arizona. This 
meeting was held in Phoenix, Arizona, and a court reporter was present 
recording the meeting minutes. Members of the Tribes and nations 
present, however, did not consider this meeting government-to-
government consultation pursuant to Secretarial Order 3206. On July 20, 
2009, an official consultation meeting between the Service and Salt 
River Pima-Maricopa Indian Community occurred. Written comments were 
provided by the Western Apache Tribes and Nation and the Salt River 
Pima-Maricopa Indian Community on July 10, 2009.
    Although comments from the Native American communities were 
provided in writing, much of the knowledge about the bald eagle was 
offered during the above-referenced face-to-face meetings. Native 
American knowledge about the eagle is passed down orally from one 
generation to the next, which is often referred to in the literature as 
traditional ecological knowledge. Traditional ecological knowledge 
refers to the knowledge base acquired by indigenous and local peoples 
over many hundreds of years through direct contact with the 
environment. Traditional knowledge is based in the ways of life, belief 
systems, perceptions, cognitive processes, and other means of 
organizing and transmitting information in a particular culture. 
Traditional ecological knowledge includes an intimate and detailed 
knowledge of plants, animals, and natural phenomena; the development 
and use of appropriate technologies for hunting, fishing, trapping, 
agriculture, and forestry; and a holistic knowledge, or ``world view,'' 
which parallels the scientific discipline of ecology (Inglis 1993, p. 
vi).
    Testimony by the Western Apache Tribes and Nation and Salt River 
Pima-Maricopa Indian Community clearly demonstrates the importance of 
the bald eagle to their culture, its relevance to their well-being, and 
their respect for its power. Their testimony also demonstrates the 
Western Apache and Salt-River Pima Maricopa knowledge base of the bald 
eagle and its habitat. The Native American relationship with the bald 
eagle in the Sonoran Desert Area predates modern Western scientific 
knowledge of the bald eagle by thousands of years (Lupe et al. pers. 
comm. 2008, p. 1). Given the expertise and traditional ecological 
knowledge about the bald eagle in the Southwest by the Western Apache 
Tribes and Nation and Salt-River Pima Maricopa Indian Community, we 
have attempted to incorporate their indigenous knowledge and 
information into our status review and 12-month finding.

Species Information

    The bald eagle (Haliaeetus leucocephalus) is the only species of 
sea eagle regularly occurring in North America (60 FR 35999; July 12, 
1995). Literally translated, H. leucocephalus means white-headed sea 
eagle. Bald eagles are birds of prey of the Order Falconiformes and 
Family Accipitridae. They vary in length from 28 to 38 inches (in) (71 
to 96 centimeters (cm)), weigh between 6.6 and 13.9 pounds (lbs) (3.0 
and 6.3 kilograms (kg)), and have a 66- to 96-in (168- to 244-cm) 
wingspan. Distinguishing features of adult bald eagles include a white 
head, tail, and upper- and lowertail-coverts; a dark brown body and 
wings; and a yellow iris, beak, leg, and foot. Immature bald eagles are 
mostly dark brown and lack a white head and tail until they reach 
approximately 5 years of age (Buehler 2000, p. 2).

Biology and Distribution

    Though once considered endangered, the bald eagle population in the 
lower 48 States has increased considerably in recent years. Regional 
bald eagle populations in the Northwest, Great Lakes, Chesapeake Bay, 
and Florida have increased five-fold in the past 20 years. Bald eagles 
are now repopulating areas throughout much of the species' historical 
range that were unoccupied only a few years ago.
    The bald eagle ranges throughout much of North America, nesting on 
both coasts from Florida to Baja California, Mexico in the south, and 
from Labrador to the western Aleutian Islands, Alaska, in the north. 
Fossil records indicate that bald eagles inhabited North America 
approximately 1 million years ago, but they may have been present 
before that (Stahlmaster 1987, p. 5). An estimated quarter to a half 
million bald eagles lived on the North American continent before the 
first Europeans arrived.
    In many Western Apache groups, the bald eagle is called 
Istlg[aacute][iacute], which translates to ``the white eagle'' and is 
distinguished from the golden eagle, which is called Itsa Cho or ``the 
big eagle.'' The bald eagle was first described in Western culture in 
1766 as Falco leucocephalus by Linnaeus. This South Carolina specimen 
was later renamed as the southern bald eagle, subspecies Haliaeetus 
leucocephalus leucocephalus (Linnaeus) when Townsend identified the 
northern bald eagle as Haliaeetus leucocephalus alascanus in 1897 
(Buehler 2000, p. 4). By the time the bald eagle was listed throughout 
the lower 48 States under the Endangered Species Act in 1978, 
ornithologists no longer recognized the

[[Page 8604]]

subspecies (American Ornithologists Union 1983, p. 106).
    The bald eagle is a bird of aquatic ecosystems. It frequents 
estuaries, large lakes, reservoirs, major rivers, and some seacoast 
habitats. Fish is the major component of its diet, but waterfowl, 
gulls, and carrion are also eaten. The species may also use prairies if 
adequate food is available. Bald eagles usually nest in trees near 
water, but are known to nest on cliffs and (rarely) on the ground. The 
trees must be sturdy and open to support a nest that is often 5 feet 
(ft) (1.52 meters (m)) wide and 3 ft (0.91 m) deep. Adults tend to use 
the same breeding areas year after year, and often the same nest, 
though a breeding area may include one or more alternate nests. Nest 
shape and size vary, but typical nests are approximately 4.9 to 5.9 ft 
(1.5 to 1.8 m) in diameter and 2.3 to 4.3 ft (0.7 to 1.2 m) tall 
(Stahlmaster 1987, p. 53). In winter, bald eagles often congregate at 
specific wintering sites that are generally close to open water and 
offer good perch trees and night roosts.
    Bald eagles are long-lived. One of the longest-living bald eagles 
known in the wild was reported near Haines, Alaska, as 28 years old 
(Schempf 1997, p. 150). In 2009, a female eagle nesting at Alamo Lake 
in Arizona turned 30 years old (J. Driscoll, Arizona Game and Fish 
Department (AGFD), pers. comm. 2009). In captivity, bald eagles may 
live 40 or more years. It is presumed that once they mate, the bond is 
long-term. Variations in pair bonding are known to occur. If one mate 
dies or disappears, the other will accept a new partner.
    Bald eagle pairs begin courtship about a month before egg-laying. 
In the south, courtship occurs as early as September, and in the north, 
as late as May. The nesting season lasts about 6 months. Incubation 
lasts approximately 35 days, and fledging takes place at 11 to 12 weeks 
of age. Parental care may extend 4 to 11 weeks after fledging (Hunt et 
al. 1992, p. C9; Wood et al. 1998, pp. 336-338). The fledgling bald 
eagle is generally dark brown except the underwing linings, which are 
primarily white. Between fledging and adulthood, the bald eagle's 
appearance changes with feather replacement each summer. Young, dark 
bald eagles may be confused with the golden eagle, Aquila chrysaetos. 
The bald eagle's distinctive white head and tail are not apparent until 
the bird fully matures, usually at 4 to 5 years of age.
    The migration strategies for breeding, nonbreeding, and juvenile or 
subadult age classes of bald eagles will vary depending on geographic 
location. Young eagles may wander widely for years before returning to 
nest in natal areas. Northern bald eagles winter in areas such as the 
Upper Mississippi River, Great Lakes shorelines, and river mouths in 
the Great Lakes area. For midcontinent bald eagles, wintering grounds 
may be the southern States, and for southern bald eagles, whose nesting 
may begin in the winter months, the nonbreeding season foraging areas 
may be the Chesapeake Bay or Yellowstone National Park during the 
summer. Eagles seek wintering (nonnesting) areas offering an abundant 
and readily available food supply with suitable night roosts. Night 
roosts typically offer isolation and thermal protection from winds. 
Carrion and easily scavenged prey provide important sources of winter 
food in terrestrial habitats far from open water.
    The first major decline in the bald eagle population probably began 
in the mid to late 1800s. Widespread shooting for feathers and trophies 
led to extirpation of eagles in some areas. Shooting also reduced part 
of the bald eagle's prey base. Big game animals like bison, which were 
seasonally important to eagles as carrion, were decimated. Hunters also 
reduced the numbers of waterfowl, shorebirds, and small mammals. 
Ranchers used carrion treated with strychnine, thallium sulfate, and 
other poisons as bait to kill livestock predators and ultimately killed 
many eagles as well. These were the major factors, in addition to loss 
of nesting habitat from forest clearing and development, which 
contributed to a reduction in bald eagle numbers through the 1940s. In 
1940, Congress passed the Bald Eagle Protection Act (16 U.S.C. 668-
668d). This law prohibits the take, possession, sale, purchase, barter, 
or offer to sell, purchase or barter, transport, export or import, of 
any bald eagle, alive or dead, including any part, nest, or egg, unless 
allowed by permit (16 U.S.C. 668(a)). ``Take'' includes pursue, shoot, 
shoot at, poison, wound, kill, capture, trap, collect, molest or 
disturb (16 U.S.C. 668c; 50 CFR 22.3). The Bald Eagle Protection Act 
and increased public awareness of the bald eagle's status resulted in 
partial recovery or at least a slower rate of decline of the species in 
most areas of the country.
    In the late 1940s, the use of dichloro-diphenyltrichloroethane 
(DDT) and other organochlorine compounds became widespread. Initially, 
DDT was sprayed extensively along coastal and other wetland areas to 
control mosquitoes (Carson 1962, pp. 28-29, 45-55). Later farmers used 
it as a general crop insecticide. As DDT accumulated in individual bald 
eagles from ingesting prey containing DDT and its metabolites, 
reproductive success plummeted. In the late 1960s and early 1970s, it 
was determined that dichlorophenyl-dichloroethylene (DDE), the 
principal breakdown product of DDT, accumulated in the fatty tissues of 
adult female bald eagles. DDE impaired calcium release necessary for 
normal eggshell formation, resulting in thin shells and reproductive 
failure.
    In response to this decline, the Secretary of the Interior, on 
March 11, 1967 (32 FR 4001), listed bald eagles south of the 40th 
parallel as endangered under the Endangered Species Preservation Act of 
1966 (16 U.S.C. 668aa-668cc). Bald eagles north of this line were not 
included in that action primarily because the Alaskan and Canadian 
populations were not considered endangered in 1967. On December 31, 
1972, the Environmental Protection Agency banned the use of DDT in the 
United States. The following year, Congress passed the Endangered 
Species Act of 1973 (16 U.S.C. 1531- 1544).
    Nationwide bald eagle surveys, conducted in 1973 and 1974 by the 
Service, other cooperating agencies, and conservation organizations, 
revealed that the eagle population throughout the lower 48 States was 
declining. We responded in 1978 by listing the bald eagle throughout 
the lower 48 States as endangered except in Michigan, Minnesota, 
Wisconsin, Washington, and Oregon, where it was designated as 
threatened (43 FR 6233, February 14, 1978).
    To facilitate the recovery of the bald eagle and the ecosystems 
upon which it depends, we divided the lower 48 States into five 
recovery regions. Separate recovery teams composed of experts in each 
geographic area prepared recovery plans for their region. The teams 
established goals for recovery and identified tasks to achieve those 
goals. Coordination meetings were held regularly among the five teams 
to exchange data and other information. 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 and Plants.
    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.

[[Page 8605]]

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. During the 
recovery implementation process the Service used new information as it 
became available, to help 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, developed by a team of individuals with bald eagle 
expertise, was the best guidance available to the Service for use in 
determining whether threats had been removed and whether to move 
forward with delisting was appropriate.
    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 eight 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 (Service 1995, p. 36001; Service 1999, p. 
36457). By 2007, the bald eagles bred in each of the lower 48 States, 
with the greatest number of breeding pairs occurring in Minnesota 
(1,313), Florida (1,133), Wisconsin (1,065), and Washington (848) 
(Service 2007, p. 37349).
    Regional bald eagle populations in the Northwest, Great Lakes, 
Chesapeake Bay, and Florida have increased five-fold from the late 
1970s to the late 1990s. Bald eagles are now repopulating areas 
throughout much of the species' historical range that were unoccupied 
only a few years ago (64 FR 36454; July 6, 1999). The nationwide 
recovery of the bald eagle is due in part to the reduction in levels of 
persistent organochlorine pesticides (such as DDT) and habitat 
protection and management actions.

Historical and Current Status of the Sonoran Desert Area Population

    Below we discuss the status of eagles in the Sonoran Desert Area 
population and in the States surrounding the Sonoran Desert Area 
population because it provides a context for our evaluation of whether 
the Sonoran Desert Area is a distinct population segment of bald 
eagles. As described above, the Sonoran Desert Area refers to all 
Sonoran Desert bald eagle territories within Arizona, the Copper Basin 
breeding area along the Colorado River just into California, and the 
territories of interior Sonora, Mexico. Bald eagles in Baja California 
are not included in our definition of the Sonoran Desert Area 
population because (1) they are associated with a marine, rather than 
inland, environment (Figure 1), (2) there is no documentation of Baja 
bald eagles interchanging with those in the Sonoran Desert Area, and 
(3) currently extant nests in Baja are limited to the Magdalena Bay 
region along the coast of the Pacific Ocean (Arnaud et al. 2001, p. 
136; and King 2006, p. 4), in a coastal, rather than inland, climate.
Arizona
    Hunt et al. (1992, pp. A11-A12) summarized the earliest records 
from the literature for bald eagles in Arizona. Coues noted bald eagles 
in the vicinity of Fort Whipple (now Prescott) in 1866, and Henshaw 
reported bald eagles south of Fort Apache in 1875. Bent (1937, pp. 321-
333) reported breeding eagles at Fort Whipple in 1866 and on the Salt 
River Bird Reservation (since inundated by Roosevelt Lake) in 1911. 
Breeding eagle information was also recorded in 1890 near Stoneman Lake 
by S.A. Mearns. Additionally, there are reports of bald eagles along 
rivers in the White Mountains from 1937, and reports of nesting bald 
eagles along the Salt and Verde Rivers as early as 1930. Hunt et al. 
(1992, pp. D41-D46, D291-D326, Figures D4.0-1, D5.0-1, F3, F4, and F5) 
determined from reports and personal communications dating back to 1866 
that historically there were 28 known breeding areas, 22 known and 
probable nest sites, and at least 60 unverified reports of possible 
nests/nest sites and unverified reports of bald eagles located across 
the State of Arizona. Many of the 60 possible nests/nest sites reported 
by Hunt et al. (1992) could be a collection of nests belonging to the 
same breeding territory. These reported locations ranged to the 
boundaries of the State from the Grand Canyon near Lake Powell, to the 
lower Colorado River where it separates Arizona and California, to the 
upper San Pedro River near the international border with Mexico, and 
east near the boundary with New Mexico (Hunt et al. 1992, Figures D4.0-
1, D5.0-1, F3, F4, and F5).
    More recent survey and monitoring efforts have increased our 
knowledge of bald eagle distribution in Arizona. The number of known 
breeding areas in Arizona in 1971 was 3; the number known in 2009 is 
59. The number of bald eagle pairs occupying these sites increased from 
3 in 1971 to 48 in 2009. The number of young hatched increased from a 
low of zero in 1972 to a high of 55 in 2006 (Driscoll et al. 2006, pp. 
48-49; McCarty and Johnson 2009, p. 8, in draft). Productivity has also 
changed at the bald eagle breeding areas since the 1970s. Between 1975 
and 1984, average annual productivity was 0.95 young per occupied 
breeding area. Between 1987 and 2005, average annual productivity was 
0.78 young per occupied breeding area (derived from Table 7, pp. 48-50 
in Driscoll et al. 2006). (These data take into account productivity 
for breeding areas throughout Arizona, and are not restricted to the 
Sonoran Desert population of bald eagles evaluated under the petition.)
    Hunt et al. (1992, p. A155) conclude that it is likely that bald 
eagles nested on rivers throughout the Southwest in more pristine 
times, as reports on the nature of river systems and the assemblage of 
prey fishes both seem conducive to nesting success and suggest ``richer 
and more extensive habitat in the lower desert'' than would have been 
available on the Mogollon Plateau, where bald eagles are known to have 
occurred historically. Recent reoccupation of some of these historical 
breeding areas by bald eagles lends credibility to these reports. We 
evaluated a subset of the Allison et al. (2008, pp. 17-18) data to 
determine the status of 43 breeding areas within the Sonoran Desert 
Area of Arizona and concluded that 16 (37 percent) were pioneer 
breeding areas, or occupied for the first time. An additional 27 (63 
percent) were either reoccupied, meaning they were known to have been 
occupied in the past, then vacated, and

[[Page 8606]]

subsequently reoccupied, or are considered to have been existing before 
their discovery (Allison et al. 2008, pp. 15-16).
    The Salt River Pima-Maricopa Indian Community states that the 
O'odham have inhabited the Sonoran Desert and have known eagles since 
``time immemorial'' (Anton and Garcia-Lewis 2009, p. 1). Although 
anthropologists debate what this means, at least one noted 
archaeologist has documented detailed evidence of cultural remains in 
the nearby Pinacate area that date back more than 40,000 years (Hayden 
and Dykinga 1988, p. XIV). A local, informal consensus of 10,000 years 
is less controversial (Toupal 2003, p. 11). Bald eagles have been 
documented historically within the culture of the Four Southern Tribes 
of Arizona, which includes the Salt River Pima-Maricopa Indian 
Community, Ak-Chin Indian Community, Gila River Indian Community, and 
Tohono O'odham Nation (Anton and Garcia-Lewis 2009, p. 2). Because 
eagles are considered to have equal or greater standing to humans, 
eagle burials were carried out identical to human burial practices 
(Anton and Garcia-Lewis 2009, p. 2), and bald eagle burials have been 
recovered from archaeological sites ancestral to the O'odham culture. 
In addition, eagles are extremely prominent in the O'odham song culture 
(Anton and Garcia-Lewis 2009, p. 2). A paired set of songs recorded by 
Underhill (1938, p. 109) for a Tohono O'odham eagle purification 
ceremony recognized the bald eagle as the ``white-headed eagle.''
    More recent evidence exists to demonstrate the importance and use 
of bald eagles in Apache culture. Herrington et al. (1939, pp. 13-15) 
noted the use of eagle feathers in religious practices and ceremonial 
dances. The Apache Tribes have documented numerous artifacts that were 
collected from the Tribes at Cibecue and East Fork/Whiteriver on the 
White Mountain Apache Reservation and on the San Carlos Reservation 
between 1901 and 1945. These Tribes note that these artifacts were 
made, in part, with eagle feathers, and include hats or caps; shields; 
medicine rings, shirts, and strings; amulets; war bonnets; armbands; 
hair ornaments; and wooden figurines and crosses. The Tribes note that 
these ceremonial items are of deep historical and ongoing importance, 
such that they are actively pursuing their return from the museums to 
the Tribes. The existence of these items demonstrates the use of eagle 
feathers by the Tribes for at least the last 100 years (Apache Tribes 
2009, Tabs 6-10).
    Traditional ecological knowledge from the Apache Tribes report more 
breeding bald eagles 150 years ago than are present today. 
Specifically, Tribal representatives note that many areas that were 
considered nesting sites on the San Carlos Apache Reservation such as 
Warm Springs Canyon, Black River Canyon, and Salt Creek Canyon no 
longer contain active bald eagle nests. Bald eagles are no longer found 
at four out of seven areas that have Apache place-names that reference 
bald eagles (Lupe et al. pers. comm. 2008, p. 4). The traditional 
ecological knowledge shared by the Tribes at a July 2, 2008, meeting 
indicate that more bald eagles were observed below Coolidge Dam and at 
Talkalai Lake than currently exist.
Nevada
    There are few historical or current breeding records for the State 
of Nevada. The lone historical record describes bald eagles that nested 
in a cave on an island at Pyramid Lake in northwestern Washoe County in 
northwestern Nevada in 1866 (Service 1986, p. 7; Detrich 1986, p. 11; 
S. Abele, Service, pers. comm. 2008a; 2008b). Over 100 years later, the 
next verified nesting record occurred in 1985 along Salmon Falls Creek 
in Elko County in northeastern Nevada near the Idaho border. More 
modern nesting records are limited to approximately five breeding sites 
associated with human-made water impoundments. Reproductive performance 
and persistence of bald eagle pairs in Nevada has been varied. No 
breeding has been observed at the Salmon Falls site since 1985.
Colorado
    According to the Northern Bald Eagle Recovery Plan, bald eagles in 
Colorado historically nested in the mountainous regions up to 10,000 ft 
(3,048 m). Successful nesting records exist for nests found in 
southwestern and west-central Colorado. Bald eagles were considered 
common residents in the 1940s and 1950s in and around Rocky Mountain 
National Park (Service 1983, p. 12). For southwestern Colorado, there 
were no verified records of nesting bald eagles in the 1960s (Bailey 
and Niedrach 1965 in Stahlecker and Brady 2004, p. 2). The first 
confirmed record for southwestern Colorado occurred in 1974 at Electra 
Lake (Winternitz 1998 in Stahlecker and Brady 2004, p. 2). In 1974, the 
Colorado Division of Wildlife reported that only a single nesting pair 
was known (Colorado Division of Wildlife 2008, p. 1). However, by 1981, 
there were five known occupied bald eagle territories in the State of 
Colorado (Service 1983, p. 23), and from the early 1980s to 2008, the 
known bald eagle population increased to nearly 80 territories, of 
which 60 are currently known to be active. Concentrations of breeding 
eagles are found east of the Continental Divide within the South Platte 
River watershed, on the Yampa River, on the White River, and on the 
Colorado River. Greater than 40 territories are monitored annually, 
with near 70 percent nest success, 1.19 young fledged per occupied 
site, and 1.72 young fledged per successful site (Colorado Division of 
Wildlife 2008, p. 1).
New Mexico
    Available information indicates there was no specific, first-hand 
information on bald eagles nesting in New Mexico prior to 1979. 
Unverified reports (Bailey 1928, p. 180; Ligon 1961, p. 75) suggest one 
or two pairs may have nested in southwestern New Mexico, on the upper 
Gila River and possibly the San Francisco River, prior to 1928. These 
second-hand reports lacked specifics and may have referred to other 
species (Williams 2000, p. 1).
    Since completion of the 1982 Recovery Plan, seven bald eagle 
territories have been discovered, five in northern New Mexico in Colfax 
and Rio Arriba Counties and two in southwest New Mexico in Sierra and 
Catron Counties. Four have been recently occupied and productivity has 
been fair with young produced in at least 6 to 15 years, depending on 
the territory (H. Walker, New Mexico Department of Game and Fish, pers. 
comm. 2008).
Southern California
    In southern California, historical bald eagle records are known 
from the Channel Islands and mainland counties along the Pacific Ocean 
(Detrich 1986, pp. 9-27). Prior to 1900, three bald eagle territory 
records were known (Detrich 1986, pp. 10-13). From 1900 to 1940, 
reports of 24 to 60 nest sites existed on islands off the coast of 
California, and are believed to have been extirpated from the islands 
soon after 1958 (Detrich 1986, pp. 18, 24). In inland areas in southern 
California, at least eight bald eagle pairs were known from Santa 
Barbara, Ventura, Los Angeles, Orange, and San Diego counties between 
1900 and 1940, with indications of presence prior to this timeframe 
(Detrich 1986, pp. 13-19). By 1981, largely due to adverse changes to 
bald eagle habitat and the effects of the pesticide DDT on 
reproduction, no breeding eagles were detected on the southern 
California mainland (Detrich

[[Page 8607]]

1986, pp. 32, 33, 36, 39; California Department of Fish and Game 2008, 
p. 2).
    Beginning in 1980, bald eagles were translocated to Santa Catalina 
Island as chicks or eggs from wild nests on the mainland, or from 
captive breeding. Pairs of bald eagles have been breeding on the island 
since 1987. In a subsequent relocation effort between 1987 and 1995 in 
the central coast mountains of Monterey Bay, 66 eaglets were 
translocated and released. A nesting pair first formed from those 
releases in 1993, and there are currently three nesting pairs 
(California Department of Fish and Game 2008, pp. 2-3). Releases of 
birds occurred through 2000, with no releases conducted between 2002 
and 2008 (Ventana Wildlife Society 2009, p. 1). Currently, there are 
approximately six pairs of bald eagles on Catalina Island, with an 
additional three pairs at Santa Cruz Island, and one pair at Santa Rosa 
Island. There are approximately 35 to 40 bald eagles around the 
Northern Channel Islands, and another 20 birds around Catalina, for a 
total of approximately 60 birds among the Channel Islands (A. Little, 
pers. comm. 2008).
    Presently, mainland southern California nesting bald eagles occur 
at inland isolated manmade reservoirs. Bald eagle breeding sites can be 
found in northwestern San Luis Obispo County (San Antonio and 
Nacimiento Lakes), central Santa Barbara County (Lake Cachuma), 
southwestern San Bernardino County (Silverwood Lake), extreme eastern 
San Bernardino County near the Colorado River (Copper Basin Lake), 
southwestern Riverside County (Hemet and Skinner lakes), and central 
San Diego County (Lake Henshaw) (AGFD 2008, California Department of 
Fish and Game 2008, pp. 2-3; Driscoll and Mesta in prep. 2005, p. 110; 
Ventana Wildlife Society 2008, p. 1).
    Nesting attempts at Silverwood and Hemet Lakes are considered 
sporadic (Service 2005, p. 110). At Skinner Lake, reproduction efforts 
in the mid-1990s were affected by DDT, and the nest area subsequently 
burned down (Driscoll and Mesta in prep. 2005; AGFD 2008). Nest sites 
in northwestern San Luis Obispo County appear to be very productive, 
producing eaglets in all but one year from 1993 to 2006 (Ventana 
Wildlife Society 2008, p. 7). For 2001 to 2008, two or three young have 
fledged annually from the Copper Basin breeding area, with the 
exception of 2004 when the nest was blown down (M. Melanson, 
Metropolitan Water District of Southern California, pers. comm. 2006a, 
2007, 2008). The blue aluminum leg bands of one of the adult bald 
eagles at the Copper Basin site indicate that the bird likely 
originated in Arizona (M. Melanson, Metropolitan Water District of 
Southern California, pers. comm. 2006b).
Utah
    Bald eagles were recorded as ``more or less frequent'' by Allen in 
1871 (p. 164) in the vicinity of Ogden in northern Utah. There are 
seven historical records for Utah between 1875 and 1928, with five 
records of nesting bald eagles, and two other records of nonbreeding 
bald eagle observations, all located between Great Salt Lake and Utah 
Lake in northern Utah. In 1967, a nest was found to the south in Wayne 
County at Bicknell, and in 1972, an additional nest was located at Joes 
Valley Reservoir in San Pete County in central Utah, but it has since 
fallen. Additional records from the 1970s were of nests along the 
Colorado River at Westwater Canyon in 1975, and at the head of 
Westwater Canyon between 1973 and 1977. Beginning in 1983, nesting 
attempts occurred at three nesting territories in southeast Utah. Two 
of the territories were along the Colorado River near the eastern 
border of Utah, with the third near Castle Dale in the center of the 
State (Boschen 1995, pp. 7-8). Three known nest sites (Cisco, Bitter 
Creek, and Castle Dale) were reported following survey work completed 
in 1994. These three nest sites produced an average of approximately 
1.4 nestlings, with 1.05 successfully fledged between 1983 and 1994 
(Boschen 1995, p. 103). Approximately 11 breeding areas were known, 
considered active, and monitored between 1983 and 2005 (Darnell, 
Service, pers. comm. 2008).
West Texas
    Historically, there were five nesting records for bald eagles west 
of the 100th Meridian in Texas. Lloyd (1887, p. 189) reported nesting 
in Tom Green and Concho counties in 1886. Oberholser (1974, p. 246) and 
Boal (2006, p. 46) reported eggs collected in Potter County near 
Amarillo by E.W. Gates in 1916. Oberholser (1974, in Service 1982, p. 
8) additionally reported eggs collected by Smissen in 1890 in Scurry 
County south of Lubbock. Oberholser also reported an undated sight 
record of breeding eagles in Armstrong County near Amarillo. Kirby 
(pers. comm., in Service 1982) reported an active nest in nearby 
Wheeler County in 1938, and indicated it had been active for 
approximately 20 years. Throughout the 1980s and early 1990s there were 
no known breeding bald eagles in western Texas (Mabie et al. 1994, p. 
215; Service 1982, p. 9). In 2004 and 2005, two adult bald eagles and a 
nestling were observed at a nest in the southern Great Plains of the 
Texas Panhandle. One young was produced in 2004, and two in 2005. No 
leg bands were readily observable on the adult eagles (Boal et al. 
2006, pp. 246-247).
Sonora, Mexico
    Bald eagle territories were first recorded in Sonora along the Rio 
Yaqui drainage in 1986 (Brown et al. 1986, pp. 7-14). Since that time, 
a total of seven bald eagle breeding areas were verified (Brown et al. 
1986, pp. 7-14; Brown et al. 1987b, pp. 1-2, 1987b, p. 279; Brown 1988, 
p. 30; Brown and Olivera 1988, pp. 13-16; Brown et al. 1989, pp. 13-15; 
Brown et al. 1990, pp. 7, 9; Mesta et al. 1993, pp. 8-12; Russell and 
Monson 1998, pp. 62-63; Driscoll and Mesta 2005 in prep., pp. 78-90). 
Four of these bald eagle breeding areas have remained occupied 
(Driscoll and Mesta, in prep., pp. 78-90). However, reproductive 
performance of these nests has been relatively poor. Only a single 
nestling was recorded fledging in 2000 and 2001, and no successful 
nests were observed in 1999, 2002, and 2005 (Driscoll and Mesta in 
prep., p. 43). In 2008, no occupancy was detected at bald eagle 
territories (R. Mesta, Service, pers. comm. 2008). A bald eagle pair 
was observed in 2009; however, the previously used cliff nest is gone, 
and a new nest was not confirmed. Illegal drug activity in the area has 
increased human presence, making survey work difficult to accomplish. 
The area is also affected by extensive water withdrawals, and drought 
and dam operations, leaving the future of this site uncertain (R. 
Mesta, Service, pers. comm. 2009).

Defining a Species Under the Act

    Section 3(16) of the Act defines ``species'' to include ``any 
species or subspecies of fish and wildlife or plants, and any distinct 
population segment of any species of vertebrate fish or wildlife which 
interbreeds when mature'' (16 U.S.C. 1532(16)). To interpret and 
implement the distinct vertebrate population segment provisions of the 
Act and congressional guidance, the Service and the National Marine 
Fisheries Service (now the National Oceanic and Atmospheric 
Administration--Fisheries Service), published the Policy Regarding the 
Recognition of Distinct Vertebrate Population Segments (DPS Policy) in 
the Federal Register on February 7, 1996 (61 FR 4722). The DPS Policy 
sets forth a three-step process: First, the Policy requires the Service 
to determine that a vertebrate population is discrete

[[Page 8608]]

and, if the population is discrete, then a determination is made as to 
whether the population is significant. Lastly, if the population is 
determined to be both discrete and significant then the Policy requires 
a conservation-status determination to determine if the DPS is an 
endangered or threatened species.

Distinct Vertebrate Population Segment Analysis

    In accordance with our DPS Policy, this section details our 
analysis of whether the vertebrate population segment under 
consideration for listing may qualify as a DPS. Specifically, we 
determine (1) the population segment's discreteness from the remainder 
of the species to which it belongs and (2) the significance of the 
population segment to the species to which it belongs. Discreteness 
refers to the ability to delineate a population segment from other 
members of a taxon based on either (1) physical, physiological, 
ecological, or behavioral factors, or (2) international boundaries that 
result in significant differences in control of exploitation, 
management, or habitat conservation status, or regulatory mechanisms 
that are significant in light of section 4(a)(1)(B) of the Act.
    Under our DPS Policy, if we have determined that a population 
segment is discrete under one or more of the discreteness conditions, 
we consider its significance to the larger taxon to which it belongs in 
light of congressional guidance (see Senate Report 151, 96th Congress, 
1st Session) that the authority to list DPSs be used ``sparingly'' 
while encouraging the conservation of genetic diversity. In carrying 
out this examination, we consider available scientific evidence of the 
population's importance to the taxon to which it belongs. This 
consideration may include, but is not limited to the following: (1) The 
persistence of the population segment in an ecological setting that is 
unique or unusual 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.
    The first step in our DPS analysis was to identify populations of 
the Sonoran Desert Area population to evaluate. The petition from CBD, 
the Maricopa Audubon Society, and the Arizona Audubon Council requested 
that the ``Southwestern desert nesting bald eagle population'' be 
classified as a DPS, that this DPS be reclassified from a threatened 
species to an endangered species, and that we concurrently designate 
critical habitat for the DPS under the Act.

Determination of the Area for Analysis

    The March 6, 2008, court order directed the Service to conduct a 
status review of the ``Desert bald eagle population.'' The population 
referenced in the court order consists of those bald eagles in the 
Sonoran Desert of the southwest that reside in central Arizona and 
northwestern Mexico. While we had specific clarification from the 
petitioners with respect to elevational boundaries, bald eagle breeding 
areas, the Upper and Lower Sonoran Life Zones, and the State of 
Arizona, they provided ambiguous clarification with respect to the 
boundaries of ``central Arizona'' and which transition areas outside of 
the Upper and Lower Sonoran Life Zones to include. Because of these 
ambiguities and lack of a specific map in the petition, we were left to 
interpret them, primarily at the perimeters of the boundary.
    In responding to the court order, we published a rule on May 1, 
2008, reinstating threatened status under the Act to the bald eagle in 
the Sonoran Desert Area of Central Arizona in eight Arizona counties: 
(1) Yavapai, Gila, Graham, Pinal, and Maricopa Counties in their 
entirety; and (2) southern Mohave County (that portion south and east 
of the centerline of Interstate Highway 40 and east of Arizona Highway 
95), eastern LaPaz County (that portion east of the centerline of U.S. 
and Arizona Highways 95), and northern Yuma County (that portion east 
of the centerline of U.S. Highway 95 and north of the centerline of 
Interstate Highway 8). We limited the reinstatement of threatened 
status to these areas because Sonoran Desert bald eagles were only 
listed under the Act in Arizona (and not in Mexico) at the time of the 
petition. Therefore, the court's order enjoining our final delisting 
decision applied only to those eagles that reside in the Sonoran Desert 
of central Arizona.
    For this status review, we revisited the issue of defining the 
potential DPS based on a more in-depth review of information received 
from the public, Tribes, and information in our files. We determined 
that an appropriate delineation for this analysis includes all Sonoran 
Desert bald eagle territories within Arizona, the Copper Basin breeding 
area along the Colorado River just into California, and the territories 
of Sonora, Mexico. This expanded boundary was developed using 
vegetation community boundaries, elevation, and breeding bald eagle 
movement. This interpretation combines geographic proximity and 
recognized Sonoran Desert vegetation and transition life zones. We 
determined the transition areas based on our knowledge of their 
proximity to the Sonoran Desert itself, excluding territories more 
properly classified as montane or grassland habitat. Bald eagles in 
Baja California, Mexico, occur in an area where the Sonoran Desert 
vegetation community abuts a coastal environment. We excluded bald 
eagles in this area because they depend on marine resources rather than 
inland fisheries. We based delineation of the potential DPS on the best 
available scientific information, including the parameters provided by 
CBD (i.e., bald eagle territories, elevation, life zones, and 
transition areas), and the resulting expanded boundary includes known 
bald eagle breeding areas within the Sonoran Desert vegetation 
community and transition areas, as defined by Brown (1994, pp. 181-
221), except Baja California.
    As noted above, we included Sonora, Mexico, in the potential DPS 
because both areas have the same vegetation and climate. Bald eagles in 
Sonora use Sonoran Desert and transition vegetation communities as do 
bald eagles in the Sonoran Desert areas of Arizona and southern 
California. In addition, breeding season chronology in both areas 
appears to be similar (Driscoll et al. 2005 in prep., pp. 31-32), 
occurring between December and June. Bald eagles in Sonora also nest in 
riparian trees and cliffs, as they do in Arizona (Driscoll et al. 2005 
in prep., p. 31).
    When based strictly on vegetation or elevation lines, the expanded 
boundary is irregular and complex, and would be difficult to interpret. 
For this reason, we delineated the boundary with more easily 
identifiable road, county, and State lines.

Discreteness

    Under the DPS Policy, a population segment of a vertebrate taxon 
may be considered discrete if it satisfies either one of the following 
conditions:
    (1) It is markedly separated from other populations of the same 
taxon as a consequence of physical, physiological, ecological, or 
behavioral factors. Quantitative measures of genetic or morphological 
discontinuity may provide evidence of this separation.
    (2) It is delimited by international governmental boundaries within 
which differences in control of exploitation,

[[Page 8609]]

management of habitat, conservation status, or regulatory mechanisms 
exist that are significant in light of section 4(a)(1)(D) of the Act.

Boundaries of the Potential DPS

    Many terms have been used in describing the bald eagles that occupy 
the desert southwest, and we identify here the geographic area covered 
by the various terms. At the broadest geographic scale, bald eagles 
were managed under the Southwest Bald Eagle Recovery Region, which 
encompassed Oklahoma, Texas west of the 100th meridian, all of New 
Mexico and Arizona, and those portions of southeastern California that 
border the lower Colorado River. Bald eagles within this area were 
called ``southwestern bald eagles'' (Service 1982, p. 1). Much of the 
data used in the development of the potential DPS boundary for this 
discreteness analysis came from those eagles within the boundaries of 
the State of Arizona. The petition that initiated this 12-month status 
review referred to the Southwestern Desert Nesting Bald Eagle 
Population, which included those eagles that breed predominantly in the 
upper and lower Sonoran life zone habitat. In our August 30, 2006, 
analysis at the 90-day petition finding stage (71 FR 51549), we 
evaluated ``Sonoran Desert bald eagles,'' which included those bald 
eagles in the Sonoran Desert of central Arizona and northwest Mexico.
    In analyzing the potential DPS under this 12-month status review, 
we considered habitat use by bald eagles breeding in the Southwest, 
vegetation communities in which breeding areas occur, and elevation 
levels at which breeding areas occur, as we did at the 90-day petition 
finding stage. However, we have reevaluated all potential areas 
including those considered in the 90-day finding to include any areas 
that meet the criteria described below. As a result, in this review, we 
did not restrict the boundary to the State of Arizona and have expanded 
the area covered by our previous analysis to include portions of 
southeastern California along the Colorado River, Arizona, and Sonora, 
Mexico. We now refer to this expanded potential DPS area as the Sonoran 
Desert Area population, which replaces the term ``Sonoran Desert Area 
of central Arizona,'' as described in our May 1, 2008, Federal Register 
rule (73 FR 23966) to list the Sonoran Desert bald eagle as threatened.
    To determine which areas should be included within the expanded 
boundary for the Sonoran Desert Area, we considered three factors: (1) 
The Sonoran Desert vegetation community (Brown 1994, pp. 180-221; Brown 
and Lowe 1994, map), (2) an elevational range for known breeding areas 
within the Sonoran Desert (excluding Baja California), and (3) movement 
patterns of breeding bald eagles both into and out of the Sonoran 
Desert Area. We included within the boundary portions of the Sonoran 
Desert, including its subdivisions and ``transition areas.'' 
Subdivisions of the Sonoran Desert include the Lower Colorado River 
Valley, Arizona Upland, Vizcaino, Central Gulf Coast, Plains of Sonora, 
and Magdalena (Brown 1994, pp. 190-221). Transition areas are those 
vegetation communities adjacent to the Sonoran Desert community. Brown 
(1994, p. 181) includes as transition areas semidesert grasslands, 
Sinaloan thornscrub, and chaparral. The majority of the breeding areas 
within the boundary occur in the Arizona Upland Subdivision of the 
Sonoran Desert. Exceptions include those breeding areas in the 
transition communities (where 14 of 61 breeding areas are located) of 
Interior Chaparral, Plains & Great Basin Grassland, Semidesert 
Grassland, and Sinaloan Thornscrub (Brown 1994). These communities are 
most often adjacent to the Arizona Upland Subdivision of the Sonoran 
Desert, where bald eagles in these areas forage at least partially 
within the desertscrub.
    We also based the boundary on those portions of the Southwest 
within the elevational range of 984 to 5,643 ft (300 to 1,720 m). This 
elevational range encompasses all known bald eagle breeding areas 
within the Sonoran Desert in the United States and Sonora, Mexico. 
Using Geographic Information Systems, the appropriate elevational 
ranges were overlapped with the Sonoran Desert vegetation community to 
determine where both criteria were met.
    We also considered information on movement of bald eagles into and 
out of the Sonoran Desert, as determined through banding and monitoring 
information. Specifically, we included within the boundary those bald 
eagles known to originate in or breed in the Sonoran Desert and 
transition areas, excluding Baja California. The banding and monitoring 
information used to determine eagles originating or breeding in the 
Sonoran Desert Area is described in detail below.
    Figure 1 below illustrates the boundary developed based on 
vegetation community, elevation, and breeding bald eagle movement. The 
boundary was modified from following strictly elevational or vegetation 
lines to follow more easily identifiable road, county, and State lines.
BILLING CODE 4310-55-P

[[Page 8610]]

[GRAPHIC] [TIFF OMITTED] TP25FE10.000

BILLING CODE 4310-55-C
    The northern perimeter of the expanded potential DPS boundary in 
Arizona is the same as the potential DPS boundary that we used in our 
May 1, 2008, Federal Register notice (73 FR 23966) to list the Sonoran 
Desert bald eagle DPS as threatened. This boundary follows the southern 
edges of Coconino, Navajo, and portions of Apache Counties. It follows 
the Graham County line south on the east side until it reaches the 
Cochise County boundary.
    On the west, the boundary drops south along the Mohave-Yavapai 
boundary until it reaches Interstate 40. The discreteness boundary then 
follows Interstate 40 west until its intersection with the State 
boundary. It continues west 5 miles (mi) (8 kilometers (km)) and then 
south along a line drawn 5 mi (8 km) west of and parallel to the 
Colorado River until it reaches Highway 2 in Sonora, Mexico.
    The southern boundary of the expanded potential DPS follows Highway 
2 in Mexico east until its intersection with Highway 15. It follows 
Highway 15 until its intersection with Highway 16. The southern 
boundary continues along Highway 16 until it reaches the State boundary 
between Sonora and Chihuahua. The eastern boundary of the expanded 
potential DPS follows the State line between Sonora and Chihuahua north 
until it reaches the international boundary between the United States 
and Mexico at New Mexico, and continues west to the State boundary 
between Arizona and New Mexico. The eastern boundary then continues 
north along Cochise County, turning slightly west along the northern 
edge of Cochise County before rejoining the northern perimeter.

[[Page 8611]]

    Bald eagles within the boundary that constitute the expanded 
potential DPS include those that occur within the appropriate 
vegetation communities and elevational range. The breeding area located 
in southeastern California is within the Lower Colorado River 
subdivision of the Sonoran Desert. In addition, the bald eagles at that 
breeding area originated at the Horseshoe Breeding Area in Arizona. We 
have included Sonora, Mexico, within the potential DPS because bald 
eagles occur in Sonoran Desert and transitional communities there, as 
do those in Arizona and California. As discussed above, we have 
excluded from the expanded potential DPS bald eagles occurring in Baja 
California, Mexico.
    There are additional bald eagle breeding areas within Arizona but 
outside of the expanded potential DPS boundary. These breeding areas 
include Canyon de Chelly, Luna, Becker, Crescent, Greer, Woods Canyon, 
and Lower Lake Mary. These breeding areas were excluded because they 
are not located within the Sonoran Desert.

Banding and Monitoring Information

    Bird banding and resighting are important tools used to answer 
questions regarding the biology and movement of individual birds (U.S. 
Geological Survey 2008, p. 1). The techniques used on bald eagles in 
the Southwest are consistent with marking technique standards (Varland 
et al. 2007, pp. 222-228). Within this analysis, we use banding and 
resighting data for bald eagles to determine if bald eagles in the 
Sonoran Desert Area are markedly separate from other breeding 
populations of bald eagles. Specifically, we use banding and resighting 
data to determine if bald eagles originating in areas outside the 
Sonoran Desert Area have moved into the Sonoran Desert Area to breed 
(immigration), or if bald eagles originating in the Sonoran Desert Area 
have moved out of the Sonoran Desert Area to breed (emigration).
    We used bald eagle banding and resighting information collected 
between 1987 and 2007 as this is the time period during which banding 
and resighting efforts were most thorough in the Southwest. Banding of 
bald eagle nestlings began prior to this time in Arizona, starting in 
approximately 1977, and multiple researchers contributed to early 
banding efforts (Hildebrandt and Ohmart 1978; Haywood and Ohmart 1980, 
1981, 1982, 1983; Grubb 1986), as summarized in Hunt et al. 1992 (pp. 
C181-C202). However, early banding efforts were opportunistic, and the 
bands used at that time were difficult to read without capturing birds 
or recovering dead birds. As a result, little resight information was 
gained. Beginning in 1987, biologists increased efforts to band all 
nestlings and improved the effectiveness of banding and resighting by 
using color visual identification bands, which are more easily 
identified (Hunt et al. 1992, pp. C181-C202; Driscoll et al. 2006, p. 
26). In total, the banding and resighting effort for bald eagles in 
Arizona has continued for 30 years with the last 20 years using the 
more informative color bands.
    To determine the movement of breeding bald eagles in our target 
time period of 1987 to 2007, we relied on data from two datasets. The 
first dataset, called the Bird Banding Lab (BBL) dataset, is derived 
from data collected and collated by the U.S. Geological Survey Bird 
Banding Laboratory (U.S. Geological Survey 2008). The BBL dataset 
consists of over 19,000 records for bald eagles throughout the species' 
range, including those banded in the Southwest. The second dataset, 
called the AGFD dataset, is derived from data compiled and used by 
Allison et al. (2008) in a demographic analysis for bald eagles in 
Arizona.
    Because our analysis focused on determining whether or not there is 
immigration or emigration of bald eagles to and from the Sonoran Desert 
Area, we analyzed bald eagles banded as nestlings and resighted as 
adults. Using only those birds banded as nestlings ensures that the 
origin of the banded birds is known, and that young birds originating 
in other areas are not included in the analysis. Using only resight 
information for breeding bald eagles eliminates data associated with 
juvenile migrants, which would not be contributing to the breeding 
population. Generally, age five is accepted as the age at which adult 
bald eagles breed throughout most of the species' range. For this 
reason, when evaluating the nationwide BBL dataset, we considered bald 
eagles 5 years of age or older as breeding adults. However, for the 
AGFD dataset, where there are numerous instances of bald eagles 
breeding at 4 years of age in Arizona (Allison et al. 2008), we 
considered bald eagles 4 years of age or older as breeding adults.

Immigration Into the Sonoran Desert Area

    For purposes of this analysis, immigration is defined as the 
movement of individuals banded as nestlings outside of the Sonoran 
Desert Area that are subsequently resighted as breeding birds inside 
the Sonoran Desert Area. In our analysis of the likelihood of bald 
eagle immigration into the Sonoran Desert Area from areas in closest 
proximity to the Sonoran Desert Area, we used data from the AGFD and 
the broader BBL dataset and considered bald eagle banding and 
resighting information from the States in proximity to the Sonoran 
Desert Area, including California, Colorado, Nevada, New Mexico, Texas, 
and Utah, as well as birds in Arizona but outside of the Sonoran Desert 
Area (see Table 1).

 Table 1--Records for Bald Eagles Banded as Nestlings in Areas Outside the Sonoran Desert Area and Resighted as
 Breeding Birds From 1987 to 2007 (U.S. Geological Survey 2008; K. McCarty, AGFD, pers. comm. 2009; Driscoll et
                                                al. 2006, p. 49)
[Please note that the table summarizes data from 1987 to 2007. Available data from 2008 are not as thorough, but
   they are consistent with the findings from the data reported. Further, the Texas bird resighted in Arizona
 occurs at a high-elevation nest outside of the Sonoran Desert area. Note we know of no banding information for
                             birds banded in Mexico outside the Sonoran Desert area]
----------------------------------------------------------------------------------------------------------------
                                         Number of
                                     nestlings banded      Number of
                                        in areas in    banded nestlings                             Number of
                                      close proximity     resighted as    States where banded    resightings in
         State where banded           to the Sonoran    breeding birds   eagles were resighted     the Sonoran
                                        Desert area    between 1987 and                            Desert area
                                     between 1987 and        2007
                                           2002
----------------------------------------------------------------------------------------------------------------
Arizona outside the Sonoran Desert                 12                 0  .....................                 0
 Area.
California.........................               103        13 (12.6%)  British Columbia, CA,                 0
                                                                          WA.
Colorado...........................               152          7 (4.6%)  CO, WY...............                 0
Nevada.............................                 0            0 (0%)  .....................                 0

[[Page 8612]]

 
New Mexico.........................                 0            0 (0%)  .....................                 0
Texas..............................                64          5 (7.8%)  AZ, CA, NE, NM, TX...                 0
Utah...............................                 6            0 (0%)  UT...................                 0
                                    ----------------------------------------------------------------------------
    Total..........................               337         25 (7.4%)  .....................                 0
----------------------------------------------------------------------------------------------------------------

    Using the AGFD dataset, Allison et al. (2008, p. 25) indicate that 
anticipated survival rates for fledglings to age four is 28 percent. It 
should be noted that the mortality rates derived by Allison et al. 
(2008, p. 4) are based on modeling; however, the model was based on 
data collected over a 10-year period from 1993 to 2003.
    The information summarized in Table 1 indicates that 337 bald 
eagles were banded as nestlings between 1987 and 2002 (the latest year 
for which a banded cohort could reach 5 years of age by 2007) in the 
areas outside of but in proximity to the Sonoran Desert Area. Applying 
the survival rate of 28 percent to the 337 bald eagles reported banded 
as nestlings in Table 1, we would anticipate that approximately 94 
nestlings would have survived to age four. Only 25 of the banded 
nestlings were resighted as adults, and the fate of the remaining 69 
nestlings is unknown. However, none of the 25 banded nestlings were 
resighted as breeding birds within the Sonoran Desert Area (see Table 
1).
    While the number of banded and resighted birds in Table 1 is small, 
given the intensive effort in Arizona to identify the origins of banded 
breeding birds, we believe some inference is possible suggesting that 
the probability of nestlings originating outside of the Sonoran Desert 
Area and immigrating into the Sonoran Desert Area to breed is low.
    There is no known immigration from the Canyon de Chelly, Lower Lake 
Mary, Becker, Woods Canyon, Crescent, Greer, and Luna Lake breeding 
areas located at higher elevations within Arizona outside of the 
Sonoran Desert Area. To date, 29 nestlings produced at these breeding 
areas have been banded. Twenty-five of these were banded at the Luna 
breeding area from 1994-2000, 2002-2005, and in 2007, with 22 of them 
fledging successfully (K. McCarty, AGFD, pers. comm. 2009). As of 2008, 
none of these banded offspring are known to have entered the breeding 
population of bald eagles in the Sonoran Desert Area (AGFD 2008a, pp. 
1-2). The male bird at the Crescent breeding area is from the Luna 
breeding area (the female is unbanded) (Jacobson et al. 2004, p. 16). 
Similarly, the male bird at the Greer breeding area is from the Luna 
breeding area, and the female is unbanded (McCarty and Jacobson 2008, 
p. 9). Lower Lake Mary fledged four young in 2005 and 2006, and the 
young were banded. The Woods Canyon and Greer breeding areas were first 
detected in 2008, and no young fledged that year from either breeding 
area. Six young have successfully fledged from Canyon de Chelly as of 
this date, none of which were banded (AGFD 2006, pp. 1-2; AGFD 2007, 
pp. 1-2; Jacobson et al. 2007, pp. 16-19; AGFD 2008a, pp. 48-49; AGFD 
2008, unpubl. data; AGFD 2009, pp. 1-2).
    Biologists, primarily R. Mesta, estimate that, due to difficulty in 
accessing territories in Sonora, Mexico, they are able to monitor 
approximately 40 to 60 percent of the known nest sites each year, and 
20 to 30 percent of the known birds are observed while visiting these 
territories. Approximately 80 percent of the birds detected have been 
examined for auxiliary markers, such as colored bands, and biologists 
believe that if marked bald eagles were occupying known territories 
after 1990, they would likely have been detected. However, they note 
that, in years in which surveys are conducted, breeding areas are 
visited only once and for a short period of time, which would make it 
easy to miss an individual eagle. They note that, in 1992, an adult at 
the Fig Tree breeding area had a yellow wing tag (potentially 
indicating it had originated in Texas or Florida) that could not be 
read, but no one has observed the bird since ((Driscoll and Mesta 2005, 
in prep., p. 62; R. Mesta, Service, pers. comm. 2008, Ortego et al. 
2009, p. 10).

Emigration From the Sonoran Desert Area

    Emigration is defined here as the movement of individuals 
originating in the Sonoran Desert Area to areas outside the Sonoran 
Desert Area where they are resighted as birds of breeding age. Our 
analysis of data from the BBL dataset found that 41 of the 42 nestlings 
(97.6 percent) banded within the Arizona portion of the Sonoran Desert 
Area were subsequently resighted within the Sonoran Desert Area. Only 
one eagle (2.4 percent) of breeding age was resighted outside of the 
Sonoran Desert Area, near Temecula, California (see Table 2). The BBL 
dataset shows that there were 371 bald eagles banded in Arizona between 
1987 and 2007. With anticipated survival rates from fledgling to 4 
years of age at 28 percent, we estimate that approximately 104 
nestlings should have survived to age four. While we know that 42 were 
resighted, the fate of the remaining 62 birds is unknown.

[[Page 8613]]



  Table 2--Bald Eagles Banded in Arizona Between 1987 and 2002 and Recaptured or Resighted as Birds of Breeding
                                                       Age
                                         [U.S. Geological Survey 2008)]
----------------------------------------------------------------------------------------------------------------
                                           Number of birds
                  State                     (% recovered)                           Notes
----------------------------------------------------------------------------------------------------------------
                                         Within the Sonoran Desert Area
----------------------------------------------------------------------------------------------------------------
Arizona.................................         40 (95.2%)
Sonora, Mexico..........................           1 (2.4%)  Records indicate this bird was an adult entangled
                                                              in fishing line at El Novillo Reservoir in Sonora.
                                                              There was no breeding area at the reservoir, and
                                                              the bird was not subsequently detected at a
                                                              breeding area.
                                         -----------------------------------------------------------------------
    Subtotal............................         41 (97.6%)
                                         --------------------
                                       Outside of the Sonoran Desert Area
----------------------------------------------------------------------------------------------------------------
California..............................           1 (2.4%)  This bird established a breeding area in California
                                                              near Temecula. Birds in this breeding area were
                                                              not successful in reproducing, and the nest site
                                                              subsequently burned down (AGFD 2008a, p. 6).
Colorado................................             0 (0%)
Nevada..................................             0 (0%)
New Mexico..............................             0 (0%)
Oklahoma................................             0 (0%)
Texas...................................             0 (0%)
Utah....................................             0 (0%)
                                         --------------------
    Subtotal............................           1 (2.4%)
                                         --------------------
        Total...........................          42 (100%)
----------------------------------------------------------------------------------------------------------------

    With respect to emigration, data in the AGFD dataset, a separate 
dataset than the BBL discussed above, illustrate the fate of 89 of 314 
nestlings banded within the Sonoran Desert Area. Only 1 of the 89 birds 
was documented breeding outside the Sonoran Desert Area. Fifty returned 
to breed in the Sonoran Desert Area, 1 bred (unsuccessfully) in 
California, and 38 were known to have died before breeding (see Table 
3) (Allison et al. 2008, p. 19). Allison et al. (2008, p. 7) note that, 
from 1987 through 2003, 83 percent of known fledglings in the Sonoran 
Desert Area were banded. Traditional ecological knowledge about bald 
eagles supports these data on emigration. Western Apache informants 
having expert knowledge of bald eagles in the Sonoran Desert Area 
testified that adult eagles do not leave Arizona.

  Table 3--Disposition of Arizona Bald Eagles Banded as Nestlings From
                              1987 to 2003
                      [Allison et al. 2008, p. 19]
------------------------------------------------------------------------
                                                              Number of
                     Fate of nestlings                          eagles
------------------------------------------------------------------------
Dead before fledging.......................................          123
Unbanded Nestlings.........................................           62
Banded Nestlings--Fate Unknown.............................          225
Banded Nestlings--Fate Known
  Dead before Breeding.....................................           38
  Bred in Arizona..........................................           50
  Bred in California.......................................            1
                                                            ------------
    Total..................................................          499
------------------------------------------------------------------------

    Banding and resighting efforts have not been as intensive in the 
areas in close proximity to the Sonoran Desert Area as they have been 
in Arizona, including the Sonoran Desert Area. We sent a questionnaire 
to bald eagle biologists in surrounding States in 2008 in an attempt to 
determine the level of banding and monitoring efforts in some of these 
regions. In response to the questionnaire, we determined that surveys 
for breeding birds occur annually at Santa Cruz and Santa Rosa Islands 
off the coast of California, as well as in southern California at Lake 
Hemet. In survey efforts for these areas, all known territories and 100 
percent of the known birds are visited, and no birds have bands or 
markers from Arizona (Hoggan 2008, pp. 1-2; P. Sharpe, pers. comm. 
2008). Additionally, less-formal monitoring occurs in other areas in 
California through a variety of agencies and interested groups, 
including the U.S. Forest Service, the California Department of Fish 
and Game, the Ventana Wildlife Society, and the Channel Islands Live! 
Web site with similar results (i.e., no birds with bands from Arizona 
have been reported). In addition, sites known to support breeding 
pairs, such as the Copper Basin site, are monitored regularly.
    Six New Mexico territories have been monitored closely since their 
discovery in 1979, with no bands or markers from Arizona observed (S. 
Williams, pers. comm. 2008). Beginning in 1974, the Colorado Division 
of Wildlife began monitoring nesting activity, and currently monitors 
approximately 40 of their 80 nests each year, and bands eaglets at 
approximately one-third of those (Colorado Division of Wildlife 2008, 
p. 1). No bands or markers from Arizona were observed.
    We have received no data for Utah or Nevada. Information on bald 
eagles banded within Arizona but outside the Sonoran Desert Area is 
summarized above under the ``Immigration into the Sonoran Desert Area'' 
discussion above.
    The data from areas in close proximity to the Sonoran Desert Area 
are not as thorough as those collected in Arizona, including in the 
Sonoran Desert Area. However, the banding and monitoring effort for 
breeding bald eagles in Arizona over a 30-year period has revealed only 
one breeding bird to date that immigrated into Arizona (Luna Lake, 
outside the Sonoran Desert Area).

[[Page 8614]]

We anticipate that, if immigration is occurring at such a low level, 
the same could be true of emigration as there are no known barriers 
that would favor emigration over immigration.

Conclusion on Banding Data

    We find that the data on banding and resighting, while not 
extensive for areas in proximity to the Sonoran Desert Area, are 
collectively sufficient to document that bald eagles in the Sonoran 
Desert Area experience limited or rare reproductive interchange with 
bald eagles outside the Sonoran Desert Area. Bald eagle banding and 
resighting studies have been ongoing for greater than 30 years in 
Arizona, with the last 20 years using the more informative color bands. 
As reported in the BBL dataset, of the 79 nestlings banded in Arizona 
and later resighted, 1 emigrated to California, outside of the Sonoran 
Desert Area, and never successfully reproduced. This finding indicates 
that 97.6 percent of the bald eagles banded and resighted as breeding 
birds originated and returned to breed in the Sonoran Desert Area, with 
only 2.4 percent (one bird) of breeding birds resighted in other areas 
(Table 2). Similarly, the AGFD dataset indicates that, for the 
nestlings banded between 1987 and 2003 in areas outside of but in close 
proximity to the Sonoran Desert Area and resighted as breeding birds, 
none have immigrated to breed in the Sonoran Desert Area.
    While it is not possible to band and resight all bald eagles as 
breeding birds, the information provided suggests that the majority of 
breeding bald eagles within the Sonoran Desert Area population 
originated in the Sonoran Desert Area population, and have not been 
known to emigrate elsewhere to become part of a breeding population. 
There is one documented case of emigration for a bald eagle that 
originated in Arizona and established a breeding area outside of the 
Sonoran Desert Area in Temecula, California. No successful reproduction 
occurred, and that nest subsequently burned down (AGFD 2008a, p. 6).
    Data have been collected over a substantial time period under this 
effort, during which only one instance of a possible immigration and 
only one instance of emigration have been observed within the Sonoran 
Desert Area. We believe it is reasonable to conclude that in rare 
instances, immigration or emigration of an occasional bald eagle may 
occur; however, we consider the results from this 20-year period 
sufficient to document a marked separation of breeding populations. Our 
DPS Policy does not require complete isolation, and allows for some 
limited interchange among population segments considered to be discrete 
(61 FR 4722; February 7, 1996). Based on the results of these banding 
and resighting data in Arizona and in neighboring States, we conclude 
that the Sonoran Desert Area bald eagles are not interbreeding with 
other populations, although some intermixing may occur at a very small 
rate. We conclude that the best scientific data available indicates a 
marked separation of Sonoran Desert Area bald eagles from bald eagles 
outside of the Sonoran Desert Area.

Natal Dispersal and Fidelity

    Bald eagles are known to return close to their place of birth to 
breed (Stahlmaster 1987, p. 41). To illustrate the potential for 
breeding bird exchange between populations, the Service examined the 
records of bald eagles that were banded as nestlings and recovered 5 or 
more years later at breeding age. We analyzed data associated with the 
eagles in the lower 48 States to derive a median dispersal distance of 
43 mi (69 km) from their natal site to their breeding area. Known 
nesting sites were then buffered by 43 mi (69 km) to determine the 
amount of breeding bird exchange that typically occurs (Service 2008, 
pp. 17-18). Based on this analysis, Sonoran Desert Area bald eagles in 
the United States are separated from other southwestern populations by 
distances exceeding the median dispersal distance of 43 mi (69 km) for 
the species. The higher elevation breeding areas in Arizona are an 
exception to this separation, as they are less than 43 mi (69 km) from 
Sonoran Desert Area bald eagles; however, we believe these birds to be 
reproductively isolated from Sonoran Desert Area bald eagles, as 
described in the discussions on immigration above.
    Observations of actual dispersal behavior support the same 
conclusion as that derived from the modeling exercise discussed above. 
Hunt et al. (1992, p. A144) surveyed biologists studying nine bald 
eagle populations throughout North America consisting of more than 
2,000 breeding pairs of bald eagles. Of those breeding pairs, only two 
adults were observed to breed outside of their natal area. Mabie et al. 
(1994, p. 218) similarly concluded through their study in Texas and the 
Greater Yellowstone ecosystem that bald eagles tend to breed near their 
natal area. Gerrard et al. (1992, pp. 159, 164) observed four marked 
adults in Saskatchewan, Canada, and determined that they bred within 
15.5 mi (25 km) of their natal territory.
    Natal dispersal patterns for Sonoran Desert Area bald eagles are 
similar to those in the studies discussed above. Data from 21 female 
and 35 male bald eagles in Arizona indicate that adult females 
dispersed an average of 68.1 mi (109.7 km) from their natal areas, 
while males dispersed an average of 28.0 mi (45.1 km) from their natal 
areas to breed (Allison et al. 2008, p. 30), but remained within the 
Sonoran Desert Area.

Morphological Differences

    Emigration and immigration may also be influenced by the morphology 
of birds in different populations. Breeding bald eagles in the Sonoran 
Desert Area are smaller than those in northern States, which is typical 
of species in different latitudes (AGFD 2008a, p. 1). This is 
consistent with Bergmann's Rule, which states that in the northern 
hemisphere, animals in warmer, southern environments are generally 
smaller than their counterparts in cooler northern climates (Futuyma 
1986, pp. 104-105). Stahlmaster (1987, pp. 16-17) found that northern 
eagles are larger and heavier than their southern counterparts. Hunt et 
al. (1992, pp. A158-A161) compared the means of nine standard 
morphological measurements (e.g., tail length, weight, beak depth) from 
adult eagles in Arizona to those from Alaska, northern California, and 
the Greater Yellowstone ecosystem. Measurements from adult Arizona 
eagles were smaller than mean measurements of other populations for all 
morphological characteristics except two: Depth of the bird's leg bone 
and arc of its wing. Using a statistical analysis (t-Test), 26 
different comparisons were made between the nine morphological 
characteristics. Test results indicated that male Arizona eagles were 
significantly smaller than males of the other three populations in 21 
of those 26 comparisons (Hunt et al. 1992, p. A160; Driscoll and Mesta 
2005, in prep. p. 60). Adult females from Arizona were significantly 
smaller than females of the other populations in 14 of 26 comparisons. 
Gerrard and Bortolotti (1988, p. 14) note that bald eagles in Florida 
that are farther south than Arizona are the smallest. Hunt et al. 
(1992, p. A165) indicate the size difference was significant enough 
that they believed a decision to release birds into Arizona from 
elsewhere should be considered only as a last resort, because the size 
difference could potentially be an adaptation to desert conditions 
which could be disrupted by the introduction of foreign genes. As 
discussed below, given that all bald eagles in southern latitudes are 
smaller than those at northern latitudes, the best

[[Page 8615]]

available information suggests that that the Sonoran Desert Area bald 
eagles do not provide any unique adaptations important to the 
conservation of the species as a whole.
    Another possible adaptation mentioned by bald eagle experts is the 
possible differences in egg shell characteristics of Arizona bald 
eagles from bald eagles in other parts of the range of the species. 
Hunt et al. (1992) discuss pores in eggshells of bald eagles in Arizona 
and some of the public comments (including some eagle experts) 
questioned whether or not these pores may have an effect on water loss 
from bald eagle eggs in the arid environment. Hunt et al. (1992) note 
that the pores are actually one to two orders of magnitude smaller than 
those in California bald eagle eggs; however, they did not reach any 
conclusions as to the significance that this may have to Arizona 
eagles. We also do not draw any conclusions from this information given 
the small sample size (four eggs).
    Morphological differences, whether due to local adaptations due to 
natural selection and a small amount of gene flow (Hunt et al. 1992, p. 
A163) or simply to Bergmann's Rule, may reduce the success of 
immigration and emigration efforts. Bergmann's Rule holds that the 
surface area to body weight ratio decreases as body weight increases, 
meaning that a large body loses proportionately less heat than a small 
one, which is advantageous in a cool climate, but disadvantageous in a 
warm one (Allaby 1991, p. 52). Thus if birds from further north 
immigrated into Arizona they could be at a competitive disadvantage 
coping with the hot climate during the breeding season. Similarly, if 
Arizona birds emigrated to far northern areas they would likely be at a 
competitive disadvantage for resources due to an inability to compete 
with birds in those areas, which are larger in size (AGFD 2008a, p. 5). 
In addition, Driscoll et al. 1999 (p. 223) note that if gene flow into 
Arizona from the north or west, where eagles are larger, had occurred, 
it should at least be reflected in the overall variance of measurable 
characteristics (i.e. standard morphological measurements for raptors 
such as tarsus width, length of feathers, arch of wing, etc.), and that 
they found no suggestion of that variance within the Arizona sample.
    For these reasons, it is unlikely that bald eagles interchange in a 
north-to-south direction, or vice versa. The adult eagle that 
immigrated from Texas to establish a high-elevation nesting in Arizona, 
and the eagle that left Arizona to establish a breeding area (still 
within the Sonoran Desert Area) in extreme southeastern California near 
the Colorado River both dispersed laterally, with no north or south 
immigration or known emigration of breeding birds.

Lack of Population Sources

    The immigration of adult bald eagles into the Sonoran Desert Area 
population from populations in relatively close proximity to the 
Sonoran Desert Area is likely limited by small population sizes in 
surrounding States, and their separation from the Sonoran Desert Area 
by long distances, over unoccupied habitats. There are currently eight 
known breeding areas in southern California in addition to populations 
on Santa Cruz and Santa Rosa Islands off the coast of California 
(California Department of Fish and Game 2008, pp. 2-3; Ventana Wildlife 
Society 2008, p. 1). Colorado has a somewhat larger population, with 
approximately 80 active breeding areas (Colorado Division of Wildlife 
2008, p. 1). Nevada has approximately one inactive and five active 
breeding territories. Two territories, Carson River and Lahontan 
Reservoir, last had eagles detected in 2002 and 2006, respectively. The 
occupancy of two others is not yet confirmed. The remaining breeding 
area produced only two young from 1996 to 2007 (K. Kritz, Service, 
pers. comm. 2008). Utah has approximately 10 active territories and one 
inactive breeding territory (N. Darnall, Service, pers. comm. 2008). 
For New Mexico, the population of bald eagles consists of four 
currently occupied territories (H. Walker, NMDGF, pers. comm. 2009). 
West Texas currently has one active breeding territory west of the 
100th Meridian. This territory has been active since 1994 (C. Boal, 
pers. comm. 2009).

Marked Separation as a Consequence of Ecological Factors

    A final factor isolating Sonoran Desert Area bald eagles is the 
unsuitability of habitat in areas surrounding the Sonoran Desert Area 
for occupancy by breeding birds. The majority of the bald eagle 
population in the Sonoran Desert Area occurs in central Arizona within 
the riparian areas of the Sonoran Desert as described in Brown (1994, 
pp. 180-221) and adjacent vegetation communities. Across the western 
United States, there are large geographic areas where breeding bald 
eagles are rarely found. These areas are associated with the Great 
Basin and Mohave Deserts, indicating that conditions in these desert 
biotic communities are not suitable for occupancy. In contrast, the 
Sonoran Desert and its subdivisions, where nesting bald eagles within 
the Sonoran Desert Area are located, are suitable for breeding areas 
because of the availability of water, prey, and trees suitable for 
nesting and perching. The Sonoran Desert scrub vegetation community is 
unique from other desert scrub formations in North America in its 
tropical and subtropical influences. Within the community, the riparian 
or riverine habitat occupied by breeding bald eagles is limited to 
areas where there is sufficient winter precipitation to support 
vegetation along streams (Brown 1994, p. 269).
    Western Apache traditional ecological knowledge corroborates these 
data regarding bald eagles within the Sonoran Desert Area being 
ecologically separated from other populations. Three Apache place names 
use the term Itsa Bigow (``bald eagle's home''). Apaches use the term 
gowa (meaning ``home'') referring to the eagle's entire habitat, as 
opposed to the term bit'oh (``its nest''). According to Basso (1996), 
the Western Apaches' perception of the land works in specific ways to 
influence Apaches' awareness of themselves. The process of ``place 
naming'' documents where and how Apaches learned about the environment 
and how they incorporated these names into social and environmental 
ethics (Basso 1996). This concept is further exemplified by the Apache 
word ``ni'', this expression translates to mean both ``mind'' and 
``land,'' and thus, the two words cannot be separated (Chairman Ronnie 
Lupe, pers. comm., 2008). The Apache bald eagle place names evoke an 
entire area or ecosystem of which the bald eagle is an intrinsic part. 
The place names include entire mountainsides composed of chaparral, 
pinyon-juniper woodland, and ponderosa pine forests, always in 
proximity to water (i.e., riparian areas) (Lupe et al. pers. comm. 
2008).
    Bald eagles, including those in the Sonoran Desert Area, typically 
nest within 1 mi (1.6 km) of water. Bald eagles require cliff ledges, 
rock pinnacles or large trees or snags in which to construct nests 
(Driscoll et al. 2006, pp. 19-20). Those areas most immediately 
surrounding the Sonoran Desert Area, which contain no known breeding 
eagles or suitable habitat, fall within the Great Basin and Mohave 
Deserts. Areas in the Great Basin and Mohave Deserts surrounding the 
Sonoran Desert Area lack the appropriate bald eagle habitat parameters 
of water, fish, and nesting areas. Nonbreeding bald eagles from other 
populations migrate through these areas to reach the Sonoran Desert 
Area. Therefore, we believe these desert areas result in a 
discontinuity of distribution of breeding birds, rather than as a 
barrier to dispersal, and serve to further

[[Page 8616]]

isolate Sonoran Desert Area bald eagles from those in other 
populations.
    Bald eagles nesting at high elevation in Arizona in areas in 
proximity to the Sonoran Desert Area occupy Petran Montane Conifer 
Forest and Plains, and Great Basin Grassland above the Mogollon Rim 
(Brown and Lowe 1994, map). These eagles are not believed to have 
originated from within the Sonoran Desert Area, as described above. 
Similarly, bald eagles occupying these areas are not known to have 
occupied Sonoran Desert habitat within the Sonoran Desert Area. These 
high-elevation areas appear to be unsuitable to Sonoran Desert Area 
bald eagles, as indicated by the lack of emigration to these areas by 
eagles originating in the Sonoran Desert Area.

Conclusion on Discreteness

    Based on the available information in the petition, scientific 
literature, traditional ecological knowledge, and information in our 
files regarding bald eagles in the Sonoran Desert Area, we have 
determined that the Sonoran Desert Area population of bald eagles is 
markedly separate from other populations of the species due to a lack 
of immigration to and emigration from surrounding bald eagle 
populations, and the fact that the areas immediately surrounding the 
Sonoran Desert Area lack the appropriate bald eagle habitat parameters 
of water, fish, and nesting areas and contain no known breeding bald 
eagles. Therefore, we have determined that the Sonoran Desert Area 
population meets the requirements of our DPS Policy for discreteness. 
Banding studies and resighting efforts demonstrate that breeding bald 
eagles in the Sonoran Desert Area are largely geographically separate 
from those in surrounding areas. Limited source populations and 
unsuitable habitat in surrounding areas further separate bald eagles in 
the Sonoran Desert Area from those in other areas. Although not 
absolute, we believe this separation to be marked, and to meet the 
intent of the DPS Policy for discreteness. We made a similar argument 
and drew the same conclusion for similar reasons in our final delisting 
rule for the species in the lower 48 States (72 FR 37246, July 9, 
2007).

Significance

    If we determine that a population segment is discrete under one or 
more of the discreteness conditions described in the DPS Policy, we 
then evaluate its biological and ecological 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). Since 
precise circumstances are likely to vary considerably from case to 
case, the DPS Policy does not describe all the classes of information 
that might be used in determining the biological and ecological 
importance of a discrete population. However, the DPS Policy describes 
four possible classes of information that provide evidence of a 
population segment's biological and ecological importance to the taxon 
to which it belongs. As specified in the DPS Policy (61 FR 4722), 
consideration of the population segment's significance may include, but 
is not limited to the following: (1) 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.
    Evidence with respect to any one of the classes of information 
listed in the DPS Policy may allow the Service to conclude that a 
population segment is significant to the taxon to which it belongs. 
Furthermore, the Service may consider other information relevant to the 
question of significance, as appropriate.

Persistence in a Unique Ecological Setting

    As stated in the DPS Policy, the Service believes that occurrence 
in an unusual ecological setting may be 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 includes unique features not used by the taxon 
elsewhere and whether the habitat shares many features common to the 
habitats of other populations. The bald eagle: (1) Is continent wide in 
its distribution (stretching from the Aleutian Islands to Baja 
California, Mexico, and from northeastern Canada to Florida), (2) 
breeds from sea level to mountains as high as 10,000 feet, (3) lives in 
some of the driest areas in the United States and in some of the 
wettest, and (4) is capable of nesting in trees, on cliff faces, on the 
ground, and even in caves. In other words, the species is able to 
occupy a broad range of vegetation communities and ecosystems 
throughout North America. Because the bald eagle occurs in so many 
diverse environments, it is difficult to determine what the ``usual'' 
ecological setting is for the species, and, therefore, difficult to 
conclude that the bird's presence in any particular ecological setting 
is ``unusual,'' possibly indicating significance under our DPS policy.
    Bald eagles in the Sonoran Desert Area inhabit a desert ecosystem 
characterized by hot and dry summers. On its face, this seems to 
represent an ecological setting that is highly unusual or unique for 
the species. For instance, according to Hunt et al. (1992, p. A163) and 
Glinski (1998, p. 52) bald eagle nesting habitats in Arizona are among 
the most unusual nesting habitats occupied by the species, with many of 
the nests located in open desert under conditions of high heat and low 
humidity. As a highly adaptable species, however, bald eagles are 
flexible with respect to habitat selection. They inhabit many diverse 
environments. They inhabit hot climates elsewhere, such as in Florida. 
They even inhabit other desert ecosystems in Baja California Sur 
(Henney et al. 1978, 1993). Bald eagle breeding in Baja is limited, but 
nest sites are known from both the Pacific Ocean and Gulf of California 
sides of the peninsula, in arid and semi-arid ecosystems of the Sonoran 
Desert (Henney et al. 1978, 1993). Bald eagles in desert habitats, 
including the potential Sonoran Desert Area DPS, essentially use the 
same ecological niche as those in other parts of their range. Bald 
eagles in the Sonoran Desert Area feed primarily on fish, consistent 
with bald eagles in other parts of the range. With respect to nesting 
requirements, according to Grier and Guinn (2003, p. 44), habitat 
structure and proximity to a sufficient food source are usually the 
primary factors that determine suitability of an area for nesting. 
Throughout their range, bald eagles are known to nest primarily along 
seacoasts and lakeshores, as well as along banks of rivers and streams 
(Stahlmaster 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 Area are located in close 
proximity to a variety of aquatic sites, including reservoirs, 
regulated river

[[Page 8617]]

systems, and free-flowing rivers and creeks.
    Although the Sonoran Desert differs in some ways from other 
habitats that the bald eagle inhabits, every area differs somewhat from 
other occupied areas. Under the DPS Policy, for a population segment to 
qualify as a DPS it must be significant to the species to which it 
belongs. The Policy further lists four issues that the Service may 
consider in making this determination. Those considerations include 
whether the population segment persists in a unique or unusual 
ecological setting. However, the question of ecological setting is not 
considered in the abstract, or itself determinative as to whether a 
population segment is significant. As with the other considerations 
under the significance prong of the DPS Policy, it must be considered 
in the context of the population segment's importance to the taxon to 
which it belongs. Thus, to the extent that a population segment 
arguably persists in an unusual ecological setting, the Service must 
consider how persistence in this setting may in fact be important to 
the taxon. Failure to consider this context would lead to the 
conclusion that an unreasonable and potentially infinite number of 
population segments are significant. However, our DPS Policy states 
that the requirement that a DPS be significant is intended to carry out 
the expressed congressional intent that this authority be exercised 
sparingly as well as to concentrate conservation efforts undertaken 
under the Act on avoiding important losses of genetic diversity. We 
conclude that the best information available does not indicate that 
persistence in the ecosystem of the Sonoran Desert Area is important to 
the species as a whole.
    We considered whether cliff nesting is an adaptation to the 
conditions in the Sonoran Desert Area that indicates that the southwest 
is an unusual or unique ecological setting for bald eagles. While 
Stahlmaster (1987, p. 121) noted that cliff nesting is common in 
Arizona, he also noted that exceptions to tree nests occur in other 
areas. Gerrard and Bortolotti (1988, p. 41) note that bald eagles in 
other areas may nest on cliffs if suitable trees are not available. 
This is supported by Buehler (2000) who states that bald eagles use 
ground nests (a category in which he includes nests built on cliff 
sides) in treeless regions such as Alaska, north Canada, islands off 
the coast of California, and Arizona. 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 pers. comm. 2007). Ground 
nesting has been documented in northwestern Minnesota and Florida but 
is the exception rather than the rule (Hines and Lipke 1991, pp. 155-
157; Shea et al. 1979, pp. 3-5). Eagles also nest in a variety of 
unconventional situations, such as utility poles, abandoned heavy 
equipment, mangroves, cacti (in Baja), and root wads washed up on 
sandbars.
    Cliff nesting in Sonoran Desert Area 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 aquatic areas they inhabit; in the Sonoran Desert Area these sites 
often happen to be cliffs. In fact, although bald eagles use cliffs, 
ledges, and pinnacles for nesting in the Sonoran Desert Area, they have 
also nested there in cottonwood, willow, sycamore, pinyon pine, and 
ponderosa pine trees. Many Sonoran Desert Area 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 Area are smaller in size than 
many other bald eagles. However, as previously discussed, examination 
by latitude reveals differences between birds in the northern regions 
and birds in the southern regions in general. For instance, Stahlmaster 
(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, pp. A158-A161) report 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. 
Although this information might be interpreted as suggesting that all 
southern birds are significant to the taxon as a whole (since southern 
birds are smaller), it does not suggest that small size of the Sonoran 
Desert Area bald eagle in particular is important to the taxon as a 
whole. This is especially true given that Florida has one of the 
largest breeding populations of bald eagles in the lower 48 States, and 
bald eagles in Florida are reported to be even smaller than those in 
the Sonoran Desert Area. This information suggests that there are many 
bald eagles outside the Sonoran Desert Area that are smaller than those 
within it, diminishing any potential importance of small size in the 
Sonoran Desert Area to the taxon as a whole.
    We considered the belief of Hunt et al. (1992, p. A165) that the 
smaller size of Arizona bald eagles was significant enough that the 
introduction of foreign genes into the population might disrupt 
coadapted gene complexes (a group of genetic traits which have high 
fitness when they occur together, but which without each other have low 
fitness) specific to the population. Given there are smaller birds 
elsewhere in the bald eagle's range, it is unlikely small size would be 
considered an indicator of coadapted gene complexes specific to bald 
eagles within the Sonoran Desert Area. We conclude that the best 
available information does not suggest the Sonoran Desert Area bald 
eagle population possesses coadapted gene complexes specific to the 
population. Thus, we conclude that the best available information does 
not suggest the Sonoran Desert Area bald eagles are important to the 
taxon as a whole due to coadapted gene complexes.
    Bald eagles in the Sonoran Desert Area breed earlier than many 
other bald eagles, which could indicate adaptation to the Sonoran 
Desert Area setting. However, as with bald eagle size variation, 
examination by latitude reveals differences between bald eagles in 
northern and bald eagles in southern regions, in general. Timing of 
various breeding events in bald eagles is tied to latitude of the 
nesting area, with eagles at more northern latitudes breeding at later 
dates (Stalmaster 1987, p. 63). Citing unpublished data, Watts et al. 
(2007) even note differences in breeding chronology with slight 
variation of latitude within the Chesapeake Bay region; pairs on the 
James River lay eggs four to six days earlier than pairs on the Potomac 
River. The breeding chronology of Florida birds is even earlier than 
those in the Sonoran Desert Area. Gerrard and Bortolotti (1988, p. 76) 
note that bald eagles in Florida lay eggs from early November to mid-
December. Henry et al. (1993 p.208) report that Baja California bald 
eagles are already incubating by mid January, which indicates a mid-
December to early-January egg laying period. In Louisiana, bald eagles 
lay eggs between October and mid-March, but most clutches are complete 
by late December (Service 1989). Even bald eagles within the Chesapeake 
Bay region of Virginia

[[Page 8618]]

and Maryland, which experience a more mild (i.e. coastal) climate than 
their inland counterparts at similar latitude, are similar in their 
breeding chronology to those of the Sonoran Desert Area; bald eagles in 
the Chesapeake Bay region typically lay eggs between mid-January and 
late February. Further evidence of variation in breeding chronology in 
bald eagles is given by Buehler (2000):

    Timing of laying varies with latitude. Bent (1937) reported 
range of egg dates (dates eggs were collected from nests) but 
because incubation is long (35 d), and eggs persist in abandoned 
nests, these data do not accurately document laying and incubation 
phenology. In Florida, breeding season is prolonged, with incubation 
beginning as early as Oct and as late as Apr; Apr breeding may be 
second attempt; most incubation initiated Dec-Jan (Broley 1947). On 
Chesapeake Bay, begin incubation last week in Jan to end of Feb 
(DAB). In Saskatchewan, laying is fairly synchronous, with 90% of 
pairs laying within a 10-d period in mid-Apr (Gerrard and Bortolotti 
1988). In greater Yellowstone ecosystem, WY, clutch laid from early 
Mar-mid-Apr; later dates at greater elevations (Swenson et al. 
1986). Eggs typically laid in Arizona late Jan-mid-Feb (Grubb 1983). 
Nests observed in Mexico had incubating adults in Jan; therefore, 
laying may have occurred from late Dec to early Jan (Henny et al. 
1993). In Alaska and Yukon Territory, laying extends from late Apr 
to end of May, peaking in second week of May (Hensel and Troyer 
1964, Blood and Anweiler 1990).

    Given that early breeding by bald eagles in the Sonoran Desert Area 
is not unique among eagles, and in fact occurs in some of the largest 
breeding areas in the lower 48 States, it is unlikely that early 
breeding by bald eagles in the Sonoran Desert Area is important to the 
species as a whole.
    Although the best available information indicates that the Sonoran 
Desert Area is in some ways a unique ecological setting, we know of no 
information suggesting bald eagle persistence in the Sonoran Desert 
Area is important to the species as a whole. In fact, the best 
information available indicates otherwise. Bald eagles are behaviorally 
flexible--they can and do persist in a broad range of ecological 
settings, and are known to nest on a variety of substrates when 
suitable trees are not available. As with many other vertebrates, bald 
eagles follow Bergmann's rule; their size decreases with decreasing 
latitude. In addition, Sonoran Desert Area bald eagle breeding 
chronology is consistent with bald eagles in general; bald eagle 
breeding chronology occurs earlier with decreasing latitude and 
increasing temperature. Rather than possessing characteristics unique 
to the Sonoran Desert Area ecological setting that may be important to 
the species as a whole, bald eagles in the Sonoran Desert Area display 
the behavioral variability and follow the morphological and annual 
cycle (such as breeding chronology) trends of bald eagles throughout 
North America. In other words, the variability in bald eagle nest-site 
selection, timing of breeding, and size differences are noted elsewhere 
in the range where the species confronts similar limitations, such as 
the absence of nesting trees or high temperatures. Even though bald 
eagles persist in the Southwest desert setting, they remain 
consistently associated with aquatic sites, including reservoirs, 
regulated river systems, and free-flowing rivers and creeks. Bald 
eagles use whatever high nest sites are available near aquatic areas 
they inhabit in the Sonoran Desert Area; these sites often happen to be 
cliffs. These aquatic areas are common to eagle habitats throughout the 
species' range, and the best available data indicate that the nesting 
preferences of the Sonoran Desert Area eagles are not unique to the 
taxon as a whole.
    We also considered whether the juvenile migration characteristics 
of Arizona bald eagles may suggest genetic adaptation. Hunt et al. 
(2009, p. 125) indicates that juvenile bald eagles from Arizona exhibit 
similar migrating characteristics, and that the similarity of these 
characteristics, which were exhibited while migrating solitarily, is 
evidence of genetic control of migration. Bald eagles as a species 
exhibit a ``complex pattern of migration dependent on age of the 
individual (immature or adult), location of breeding site (north vs. 
south, interior vs. coastal), severity of climate at breeding site 
(especially during winter but also possibly during summer), and year-
round food availability (Buehler 2000).'' For example, bald eagles in 
northeastern North America migrate south in the fall and return north 
in the spring, whereas bald eagles in Florida move north in late spring 
and early summer and return south in the fall (Kerlinger 1989, p. 12). 
Kerlinger (1989, p. 57) discusses that natural selection has likely 
shaped the migratory strategy of birds. Natural selection likely exerts 
pressure over time to emphasize the survival of successful migration 
strategies, and therefore, successful genes. In other words, birds that 
make errors in migration are eliminated from the population and do not 
go on to reproduce and pass their genes to the next generation. Thus, 
the birds that do survive migration and reproduce successfully may 
become more genetically similar. Thus, the migration characteristics of 
bald eagles in the Sonoran Desert Area could be interpreted as 
providing anecdotal evidence that there may be some genetic adaptation 
in this population with respect to juvenile migratory behaviors; 
however, we know of no information suggesting that these potential 
adaptations are significant to the species as a whole, especially in 
light of the fact that a wide variety of migration strategies are 
utilized throughout the range of the species.
    Some members of the public questioned the future of the bald eagle 
given the possibilities associated with climate change. All but one 
model evaluating changing climatic patterns for the southwestern United 
States and northern Mexico predict a drying trend for the region 
(Seagar et al. 2007, pp. 1181-1184). We acknowledge that drought and 
the loss of surface water in riparian and aquatic communities are 
related to changing climatic conditions (Seagar et al. 2007, pp. 1181--
1184). The extent to which changing climate patterns will affect bald 
eagles in the Sonoran Desert Area is not known. However, because bald 
eagles are highly adaptable, the best available information indicates 
it is unlikely the Sonoran Desert Area population adds resiliency to 
the taxon as a whole. For this reason, it is also unlikely that the 
Sonoran Desert Area bald eagles will be significant to the species as a 
whole if the southwest becomes more arid in the future as predicted.
    Many biological opinions prepared by the Service in connection with 
section 7 consultations in the Sonoran Desert and other Service 
documents issued over the last 30 years stated that Arizona bald eagles 
live in a unique ecological setting and demonstrate unique behavioral 
characteristics, including the use of cliffs instead of trees as nest 
sites, breeding at earlier times of the year, and development of 
smaller body sizes. Several comment letters, including those from bald 
eagle experts, referred to the Service's previous management practice 
of recognizing the bald eagles in a Southwest Recovery Region separate 
unit. As stated above and in the final delisting rule (72 FR 37355), 
that was prior to the DPS policy of 1996, and we conclude that the DPS 
evaluation of significance should be evaluated per the policy, as 
described in this document. Some of these documents also stated that 
the Arizona bald eagles had been considered a distinct population for 
the purposes of section 7 consultation and recovery efforts under the 
Act. Many of these biological opinions and other documents were issued 
prior to the

[[Page 8619]]

Stahlmaster (1987) and Gerrard and Bortolotti (1988) publications, the 
issuance of the DPS Policy in 1996, or were abstracted from such 
earlier biological opinions without a reanalysis of their relevance. 
The term ``unique ecological setting'' was not used in these documents 
in the context of its meaning within the DPS Policy, which requires 
that the unique or unusual ecological setting be important to the 
conservation of the taxon as a whole. As discussed above, while the 
climate conditions differ in the Southwest compared to other parts of 
the range of the taxon where bald eagles are found, this attribute 
alone is not dispositive as to whether a population segment is 
significant under the DPS Policy. A unique or unusual ecological 
setting must also provide some element that makes the members of the 
population important to the taxon as a whole (61 FR 4724-4725).
    In summary, Stahlmaster's (1987, p. 121) and Gerrard and 
Bortolotti's (1988, p. 41) studies indicate that bald eagles in other 
parts of their range are known to nest on cliffs if suitable trees are 
not available. Hunt et al. (1992) note that Florida bald eagles are the 
smallest bald eagles, and that eagle size increases as the nest sites 
are located farther north. Stalmaster (1987) notes that bald eagles in 
Florida initiate breeding activities in October, even earlier than 
Sonoran Desert Area bald eagles. The best available scientific 
information indicates that the Sonoran Desert Area bald eagles are not 
unusual in these behavioral aspects. Instead, bald eagle behavior and 
morphology gradually changes at different latitudes from north to 
south. In fact, even though bald eagles do persist in the Southwest 
desert setting, they remain consistently associated with aquatic 
ecosystems as they do elsewhere. Bald eagles use whatever high nest 
sites are available near riparian areas they inhabit in the Sonoran 
Desert Area; these sites often happen to be cliffs. These riparian 
areas are common to eagle habitats throughout the species' range. The 
question under the DPS Policy is whether persistence of a species in an 
unusual or unique ecological setting supports a conclusion that the 
discrete population segment is significant to the taxon to which it 
belongs. See National Association of Home Builders v. Norton, 340 F.3d 
835, 849 (9th Cir. 2003) (emphasizing that under the DPS Policy 
significance must be considered in relation to the taxon as a whole). 
The mere fact that a species persists in an ecological setting that 
differs to some degree from other ecological settings in which it is 
found does not mandate a finding that a population is significant to 
the taxon to which it belongs. Here, we find that the species' 
persistence in the Sonoran Desert Area is not significant to the taxon 
as a whole because these particular eagles exhibit similar behavior and 
nesting adaptations to their setting as do bald eagles in other 
settings.
    Therefore, we conclude that the discrete population of bald eagles 
in the Sonoran Desert Area is not ``significant'' within the meaning of 
the DPS Policy as a result of persistence in a unique or unusual 
ecological setting.

Significant Gap in the Taxon's Range

    As stated in the DPS Policy, the Service believes that evidence 
that loss of the discrete population segment would result in a 
significant gap in the range of a taxon, is potentially an indication 
that a population segment represents a significant resource warranting 
conservation under the Act (61 FR 4724). As the Ninth Circuit has 
stated, ``[t]he plain language of the second significance factor does 
not limit how a gap could be important,'' National Ass'n of Home 
Builders v. Norton, 340 F.3d 835, 846 (9th Cir. 2003). Thus, we 
considered a variety of ways in which the loss of the Sonoran Desert 
Area population might result in a significant gap in the range of the 
bald eagle in the lower 48 States (although this range is itself only a 
portion of the broader taxon. There has been much speculation about the 
loss of eagles in the Sonoran Desert Area given that repopulation of 
this area would have to occur from northern Mexico or adjacent States 
in the United States and available evidence indicates that little 
immigration has occurred in this population. We agree that the low 
number of eagles in neighboring States of the United States would 
likely require a large amount of time to repopulate the Sonoran Desert 
Area, if they ever did. The small number of bald eagles and large 
distances between neighboring populations currently limit immigration 
and emigration between them, and bald eagles in the neighboring 
populations would have to increase their population size and expand 
their distribution to occupy the gaps.
    Given that repopulation of the Sonoran Desert Area, if extirpated, 
through immigration is unlikely in the foreseeable future due to 
unsuitable habitat and limited population sources, we must evaluate 
whether loss of this population would create a significant gap in the 
range of the taxon. Bald eagles in the Sonoran Desert Area are neither 
numerous nor constitute a significant percentage of the bald eagles 
throughout the range of the taxon. In 2009, 48 pairs were documented in 
the Arizona portion of the Sonoran Desert Area (McCarty and Jacobson 
2009, p. 8), which is where most of the birds in the Sonoran Desert 
Area population occur. This represents less than one half of 1 percent 
of the current estimated number of breeding pairs of bald eagles in the 
lower 48 States. Because the taxon as a whole also includes bald eagles 
in Canada and Alaska, the number of breeding pairs in the Sonoran 
Desert Area represents much less than one half of a percent of the 
number of breeding pairs throughout the range of the species. In 
addition, the Arizona portion of the Sonoran Desert Area did not 
support a large proportion of the bald eagle population historically. A 
small number, estimated at 15-20 breeding pairs, historically bred in 
this area (Tilt 1976, p. 15). Only one pair was documented in the 
Mexico portion of the Sonoran Desert Area population, but surveys were 
very limited.
    Given the historical and current population number of bald eagles 
throughout the range of the taxon, the Sonoran Desert Area population 
of bald eagles represents a relatively small number of breeding pairs 
in comparison. On balance, having reviewed all the relevant 
information, we conclude that loss of eagles in the Sonoran Desert Area 
would not represent a significant gap in the range of the species due 
to a loss of biologically distinctive traits or adaptations, or genetic 
variability of the taxon. The actual amount of suitable bald eagle 
habitat in the Sonoran Desert Area is in general limited and represents 
a minute fraction of the total suitable habitat available for bald 
eagles throughout their range. The limited size of the current and 
historical bald eagle population in the Sonoran Desert Area directly 
reflects that fact. Thus, we conclude that loss of the Sonoran Desert 
Area would not result in a significant gap in the range of the taxon.
    As discussed previously in this document, we divided the lower 48 
States into five recovery regions to facilitate the recovery of the 
bald eagle. In the southwestern United States bald eagles were managed 
under the Southwest Bald Eagle Recovery Region, which encompassed 
Oklahoma, Texas west of the 100th meridian, all of New Mexico and 
Arizona, and those portions of southeastern California that border the 
lower Colorado River. Several comment letters, including those from 
bald eagle experts, referred to our previous management practice of 
recognizing the bald eagles in a

[[Page 8620]]

Southwest Recovery Region separate unit. As has been stated here and in 
the final delisting rule (72 FR 37355), we delineated bald eagle 
Recovery Regions prior to the DPS Policy of 1996. Thus, the boundaries 
of these units were not delineated based on the significance criteria 
of our DPS policy. These boundaries, therefore, may have little baring 
on an analysis of whether the loss of the Sonoran Desert Area 
population would result in a significant gap in the range of bald 
eagles in North America. We conclude that the DPS evaluation of 
significance should be evaluated per the policy, rather than evaluated 
per pre-DPS-Policy documents.

Natural Occurrence of a Taxon Abundant Elsewhere as an Introduced 
Population

    As stated in the DPS Policy, the Service believes that 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 may be an 
indication that a population segment represents a significant resource 
warranting conservation under the Act (61 FR 4724). However, the 
Sonoran Desert Area population does not represent the only surviving 
natural occurrence of the bald eagle throughout the range of the taxon 
in North America.

Genetic Characteristics

    As stated in the DPS Policy, the Service believes that evidence 
that the discrete population segment differs markedly from other 
populations of the species in its genetic characteristics may be an 
indication that a population segment represents a significant resource 
warranting conservation under the Act (61 FR 4724). Hunt et al. (1992, 
pp. E-96 to E-110) contains the genetic work completed to date on the 
Arizona bald eagle population. Hunt et al. (1992, pp. A150-A165) 
suggested that the desert Arizona population, which includes the 
majority of bald eagles in the Sonoran Desert Area, may be 
reproductively isolated. Vyse (1992, p. E-100, E-101) notes that the 
results obtained could easily be explained by sampling procedures, and 
Zegers et al. (1992, pp. E-106 to E-109) question the reliability of 
the results because of the low numbers of individuals sampled from most 
States and because of the few loci examined. In conclusion, neither 
enzyme electrophoresis nor DNA fingerprinting resolved any specific 
genetic markers with which Arizona eagles could be differentiated from 
other populations.
    The available genetic studies on bald eagles are dated; the sample 
size was small; and researchers conducting the studies found the 
results to be inconclusive. As discussed above, eagles in the Sonoran 
Desert Area do not display any biologically distinctive traits that 
likely signal any unique genetic characteristics. Therefore, given the 
assumptions and cautions in using the data, we have determined that the 
best available data do not support a conclusion that bald eagles in the 
Sonoran Desert Area have genetic characteristics that are markedly 
different from other bald eagles.

DPS Conclusion

    On the basis of the best available information, we conclude that 
the Sonoran Desert Area population of the bald eagle is discrete, but 
it is not significant in relation to the remainder of the taxon (i.e., 
bald eagles in North America). We believe the best scientific 
information provides substantial information on natal site fidelity in 
breeding birds and the limited number of other eagles in neighboring 
southwestern States. Further, we believe the results of the 30 years of 
monitoring data provide substantial information indicating that few, if 
any, eagles immigrate to or emigrate from the Sonoran Desert Area bald 
eagle population. These three factors lead us to conclude that the best 
available scientific information with respect to the discreteness 
requirements of the DPS Policy warrant considering the Sonoran Desert 
Area bald eagle population as discrete from other bald eagle 
populations in North America.
    Although they do persist in a arid region with high heat, as 
discussed above, Sonoran Desert Area bald eagles do not appear to 
express any adaptations that are not found in bald eagles elsewhere or 
that a population persisting in the Sonoran Desert Area will 
significantly increase the resiliency of the taxon as a whole. The 
adaptability of the bald eagle allows its distribution to be widespread 
throughout the North American continent in a variety of habitat types. 
We considered the four classes of information listed in the DPS Policy 
as possible considerations in making a determination as to 
significance; we also considered all other information that might be 
relevant to making this determination for the Sonoran Desert Area 
population. We conclude that the discrete Sonoran Desert Area 
population of bald eagle does not meet the significance criteria of the 
DPS Policy, as detailed above, and, therefore, is not a DPS pursuant to 
our DPS Policy. As a result, the Sonoran Desert Area population of bald 
eagles is not a listable entity under section 3(16) of the Act.
    Since we found that the population segment did not meet the 
significance element and, therefore, does not qualify as a DPS under 
the Service's DPS Policy, we will not proceed with an evaluation of the 
status of the population segment under the Act.
    We note that, although we have determined that this portion of the 
range is not significant for the purposes of section 4 of the Act, we 
recognize that the bald eagles in the Sonoran Desert Area have great 
importance to people in this region, particularly Native Americans, and 
will continue to be protected under the BGEPA. We will continue to work 
with the States, Tribes, and conservation organizations in this region 
to conserve the bald eagle in the Sonoran Desert Area.

Finding

    In making this finding, we considered information provided by the 
petitioners, as well as other information in our files, and otherwise 
available. We reviewed the petition, information submitted by the 
public and the Tribes, and available published and unpublished 
scientific and commercial information. We also consulted with Federal, 
State, and Tribal land managers, along with recognized experts in 
conservation and bald eagle biology. This 12-month finding reflects and 
incorporates information that we received from the public and through 
consultation, literature research, and field visits. Based on the 
rationale detailed above, we find that bald eagles in the Sonoran 
Desert Area constitute a discrete population segment.
    However, on the basis of our review, we find that the best 
scientific and commercial information does not indicate that the 
Sonoran Desert Area bald eagle constitutes a valid DPS, pursuant to the 
DPS Policy (61 FR 4722). As described above, we believe the population 
to be discrete, but have determined that the Sonoran Desert Area bald 
eagle is not significant in relation to the remainder of the taxon 
(i.e. bald eagles in North America). Therefore, we conclude that the 
Sonoran Desert Area population is not a listable entity pursuant to 
section 3(15) of the Act. Finally, we find that the Sonoran Desert Area 
portion of the range of the bald eagle in North America does not 
constitute a significant portion of the species' range as this portion 
does not contribute meaningfully to the representation, resiliency, or 
redundancy of the entire taxon.

[[Page 8621]]

    We encourage interested parties to continue to gather data that 
will assist with the conservation of the species. If you wish to 
provide information regarding the bald eagle, you may submit your 
information or materials to the Field Supervisor, Arizona Ecological 
Services Office (see ADDRESSES section above). The Service continues to 
strongly support the cooperative conservation of the Sonoran Desert 
Area bald eagle.
    On March 6, 2008, the U.S. District Court for the District of 
Arizona enjoined our application of the July 9, 2007 (72 FR 37346), 
final delisting rule for bald eagles to the Sonoran Desert population 
pending the outcome of our status review and 12-month petition finding. 
As a result, we put this population back on the List of Threatened and 
Endangered Species on May 1, 2008. In light of our 12-month finding 
presented above, we intend to publish a separate notice to remove this 
population from the List of Threatened and Endangered Wildlife. 
However, we will only do so once the U.S. District Court for the 
District of Arizona has confirmed that its injunction, which required 
us to add this population to the List of Threatened and Endangered 
Wildlife, has been dissolved. Until that time, the Sonoran Desert Area 
population will remain protected by the Act.

References Cited

    A complete list of all references cited herein is available, upon 
request, from the Arizona Ecological Services Office of the U.S. Fish 
and Wildlife Service (see ADDRESSES section above).

Author

    The primary authors of this notice are the staff of the Arizona 
Ecological Services Office (see ADDRESSES).

Authority

    The authority for this action is the Endangered Species Act of 
1973, as amended (16 U.S.C. 1531 et seq.).

    Dated: February 17, 2010.
Hannibal Bolton,
Acting Director, Fish and Wildlife Service.
[FR Doc. 2010-3794 Filed 2-24-10; 8:45 am]
BILLING CODE 4310-55-P