Federal Register: August 30, 2006 (Volume 71, Number 168)
DOCID: FR Doc 06-7180
DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
CFR Citation: 50 CFR Part 17
NOTICE: PROPOSED RULES
ACTION: Endangered and threatened species:
DOCUMENT ACTION: Notice of 90-day petition finding.
Endangered and Threatened Wildlife and Plants; Petition to List the Sonoran Desert Population of the Bald Eagle as a Distinct Population Segment, List that Distinct Population Segment as Endangered, and Designate Critical Habitat
DATES: The finding announced in this document was made on August 29, 2006.
We, the U.S. Fish and Wildlife Service (Service), announce a 90day finding on a petition to reclassify the Sonoran Desert population of the bald eagle (Haliaeetus leucocephalus) in central Arizona and northwestern Mexico as a distinct population segment, list that distinct population segment as endangered, and designate critical habitat for that distinct population segment under the Endangered Species Act of 1973, as amended (Act). On the basis of a review of the information contained within the petition, we find that the petition does not provide substantial scientific or commercial information indicating that the petitioned action may be warranted. Therefore, we will not initiate a further status review in response to this petition. We ask the public to submit to us any new information that becomes available concerning the status of this population of the bald eagle or threats to it.
Critical habitat designations—; Bald eagle; Sonoran Desert population,
Section 4(b)(3)(A) of the Endangered Species Act of 1973, as amended (16 U.S.C. 1531 et seq.) (Act), requires that we make a finding on whether a petition to list, delist, or reclassify a species presents substantial scientific or commercial information to indicate that the petitioned action may be warranted. We are to base this finding on information provided in the petition. To the maximum extent practicable, we are to make this finding within 90 days of our receipt of the petition, and publish our notice of this finding promptly in the Federal Register.
Our standard for substantial information within the Code of Federal Regulations (CFR) with regard to a 90day petition finding is ``that amount of information that would lead a reasonable person to believe that the measure proposed in the petition may be warranted'' (50 CFR 424.14(b)). If we find that substantial information was presented, we are required to promptly commence a review of the status of the species, if one has not already been initiated under our internal candidate assessment process.
In making this finding, we relied on information provided by the petitioners and evaluated that information in accordance with 50 CFR 424.14(b). Our process of coming to a 90day finding under section 4(b)(3)(A) of the Act and Sec. 424.14(b) of our regulations is limited to a determination of whether the information in the petition meets the ``substantial information'' threshold.
On October 6, 2004, we received a formal petition, dated October 6, 2004, from the Center for Biological Diversity (Center), the Maricopa Audubon Society, and the Arizona Audubon Council requesting that the bald eagle population found in the Sonoran Desert (as defined by Brown 1994) or, alternately, in the upper and lower Sonoran Desert (as defined by Merriam) be classified as a distinct population segment (DPS) and this DPS be reclassified as an endangered species, in accordance with the Act. The petition also requested that critical habitat be designated concurrently for the DPS.
Because the Sonoran Desert described by Brown (1994) encompasses a different geographic area than that defined as upper and lower Sonoran Desert by Merriam, the Service requested clarification on the intended geographic boundaries for the Sonoran population on February 11, 2005. The petitioners responded with clarification on March 5, 2005, requesting that we consider in the DPS analysis those bald eagles nesting along riparian areas in the Sonoran Desert in Arizona and northwestern Mexico. At that time, further action on this petition was precluded by higher listing priorities. On January 19, 2006, we received from the Center a 60day Notice of Intent (NOI) to sue the Service for failure to respond to the petition within the statutory timeframe. On March 27, 2006, the Center and the Maricopa Audubon Society filed a lawsuit against the U.S. Department of the Interior (DOI) and the Service for failure to make a finding on the petition within 90 days.
The bald eagle (Haliaeetus leucocephalus) is the only species of sea eagle native to North America. Literally translated, H. leucocephalus means whiteheaded sea eagle (USFWS 1995, p. 36000). Bald eagles are birds of prey of the Order Falconiformes and Family Accipitridae. Bald eagles vary in length from 28 to 38 inches (71 to 97 centimeters), weigh between 6.5 to 14 pounds (2.9 to 6.4 kilograms), and have a 66 to 96 inch (1.8 to 2.6 meter) wingspan (Arizona Game and Fish Department (AGFD) 1999, p. 3). Distinguishing features include a yellow hooked bill and yellow unfeathered legs and feet. Adults of the species have a dark brownishblack body color, black talons, and a white head, neck, and tail. Immature bald eagles are mostly dark brown and lack a white head and tail until they reach approximately 5 years of age (AGFD 2006, pg. 3).
Gerrard and Bartolotti (1988, p. 2) note that bald eagles are believed to have nested on both coasts, along all major rivers and large lakes in the interior from Florida to Baja California in the south, and north to Labrador and Alaska. The species is known to have bred in every State and province in the United States and Canada except Hawaii (Hunt et al. 1992, p. A9).
Hunt et al. (1992, pp. A11 and A12) summarized the earliest records from the literature for bald eagles in Arizona. Coues noted bald eagles in the vicinity of Fort Whipple in 1866 (now Prescott), and Henshaw reported bald eagles south of Fort Apache in 1875. Bent 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.
The bald eagle population of the Southwest Recovery Region, as
identified in the final recovery plan for the species, reaches
throughout Oklahoma and Texas west of the 100th meridian, all of New
Mexico and Arizona, and the area of California bordering the Lower Colorado River (USFWS 1982, p. 1). The vast majority
of these breeding bald eagles are found within the State of Arizona. The occurrence of breeding bald eagles in the State of New Mexico is very limited (USFS 2004, p. 153). In 2001, the New Mexico Department of Game and Fish (NMDGF) reported the occurrence of four bald eagle nest sites, all on private lands, in New Mexico.
Nationwide, bald eagles are known to nest primarily along seacoasts and lakeshores, as well as along banks of rivers and streams (Stalmaster 1987, p. 120). In the Southwest, bald eagle breeding areas (BA) (eagle nesting sites and the area where eagles forage) are located in close proximity to a variety of aquatic sites, including reservoirs, regulated river systems, and freeflowing rivers and creeks. The term ``BA'' is used to define eagle nesting sites and the area where they forage. In the Southwest, nests are placed mostly on cliff edges, rock pinnacles, and in cottonwood trees. However, artificial structures, junipers, pinyon pines, sycamores, willows, ponderosa pines, and snags of these trees also have supported eagle nests (AGFD 2006, p. 4).
In Arizona, the majority of nests are located in the Upper and Lower Sonoran Life Zones (zones of plant and animal life associated with a given elevation), including the riparian habitats and transition areas of both zones (Hunt et al. 1992, p. A17). Representative vegetation of these life zones includes Arizona sycamore (Platanus wrightii), blue paloverde (Parkinsonia florida), cholla (Opuntia spp.), Fremont cottonwood (Populus fremontii), Gooding willow (Salix gooddingii), mesquite (Prosopis spp.), saguaro (Carnegiea gigantea), and tamarisk or salt cedar (Tamarix pentandra; an exotic species) (Brown 1994, p. 200).
Historical evidence to document bald eagles nesting in New Mexico is lacking, although unverified reports suggest one or two pairs may have nested in southwestern New Mexico prior to 1928. In the mid1980s, a pair established a territory in Colfax County in an area where bald eagles concentrated in winter, and in 1987, an active nest was discovered nearby which produced two fledglings that year. In 1988, an active nest was discovered in Sierra County, also in an area of wintering eagle concentration; the nest fledged one young that year. Through 1999, those two nests together fledged a minimum of 31 young, with Colfax County being one of the more productive nests in North America. Additional nesting activity was recorded elsewhere after the mid1980s, always in areas of wintering concentrations, including in San Juan, Rio Arriba, Quay, and Sierra counties. However, in each instance, eagles built nests only to abandon the effort prior to egg laying; such ``practice'' nests are not uncommon among inexperienced adults. In 1998, two additional nests were discovered in Colfax County, and each fledged young in both 1998 and 1999 (five young total) (Williams 2000, abstract).
Bald eagles are longlived bird species. Southwestern bald eagles are known to exceed 12 years of age (USFWS 1999, p. 36454; Hunt et al. 1992, p. Av). Bald eagles primarily eat fish, but they will also eat amphibians, reptiles, birds, small mammals, carrion (dead animals), and carcasses of large mammals (cows, elk, deer, etc.). Their food habits can change daily or seasonally, but when a choice is available, bald eagles invariably select fish over other prey. Bald eagles will scavenge, steal, or actively hunt to acquire food. Carrion constitutes a higher proportion of the diet for juveniles and subadults than it does for adult eagles. Bald eagles are primarily sitandwait hunters, perching in trees in order to detect available prey (Stalmaster 1987, p. 104).
Eagles in the Southwest frequently construct nests on cliffs. By 1992, of the 111 nest sites known, 46 were in trees, 36 on cliffs, 17 on pinnacles, 11 in snags, and 1 on an artificial platform (Hunt et al. 1992, p. A17). However, for breeding areas where both cliff and tree nests were available, one study found that cliff nests were selected 73 percent of the time, while tree nests were selected 27 percent of the time (Hunt et al. 1992, p. A17). Additionally, eagles nesting on cliffs were found to be slightly more successful in raising young to fledgling, though the difference was not statistically significant. Nests may be used year after year. Hunt et al. (1992, p. A20) determined the mean diameter of nests was 5 feet (156 centimeters).
Food strongly influences bald eagle productivity (Newton 1979, pp. 9596, 101106; Hansen 1987, p. 1389). A female's health in the months preceding egg laying can affect egg production, and the prey availability during the breeding cycle affects the survivorship of nestlings and postfledging juveniles. Thus, any factor affecting the adults' ability to acquire food can influence productivity and adult survivorship (Newton 1979, pp. 9596, 101106). The most common fish eaten in the Southwest are Sonora and desert suckers; channel and flathead catfish; common carp largemouth, smallmouth, yellow, and white bass; and black crappie. Less common are roundtail chub, green sunfish, bluegill, tilapia, and rainbow trout (USFWS 1982, p. 11; AGFD 1999, p. 6). Prey availability has decreased on the upper Salt River in Arizona. The introduction of predatory flathead catfish in the late 1970s nearly extirpated native fish populations. Flathead catfish, while available as bald eagle prey when smaller, grow to large sizes (up to 50 pounds, or 22.6 kilograms) making them too large for a prey item. Flathead catfish populations have increased while other fish species have decreased (AGFD 2006, p. 19). Productivity for the four bald eagle BAs on the upper Salt River decreased from 1.12 young per year per occupied BA in the 1980s to 0.29 young per occupied BA in the 1990s.
Bald eagles in the Southwest establish their breeding territories in December or January and lay eggs in January or February, which is early compared to bald eagles in more northerly areas (Stalmaster 1987, p. 63). Hunt et al. (1992, p. C16) indicate that this may be a behavioral adaptation so that chicks can avoid the extreme desert heat of midsummer and adults can take advantage of food resources for the rearing of eaglets. Young fledgling eagles can remain in their nest area though June, learning how to fly and land, while still being primarily fed by adult eagles (Hunt et al. 1992, pp. C6 and C7).
About 45 days after leaving the nest, young southwestern bald eagles migrate to Canada, northern California, Idaho, Montana, North and South Dakota, Oregon, Washington, and Wyoming (Hunt et al. 1992, pp. A104 through A114), returning to Arizona in the fall of the same year. They are known to repeat this behavior for a minimum of 2 years (Hunt et al. 1992a112; p. A122A123). Resident adult bald eagles often stay in their BAs yearround, although local, shortterm migrations are common (AGFD 1999, p. 6).
The first major decline in bald eagle populations began in the mid
to late1800s, when widespread shooting for feathers and trophies led
to extirpation of eagles in some areas. Carrion treated with
strychnine, thallium sulfate, and other poisons were used as bait to
kill livestock predators and ultimately killed many eagles as well.
These and other factors contributed to a reduction in bald eagle
numbers through the 1940s (USFWS 1999, p. 36455). In the late 1940s,
the use of dichlorodiphenyltrichloroethane (DDT) and other
organochlorine compounds became widespread. While DDT was initially sprayed along coastal and other wetland
areas for mosquito control, it later was used as a general crop insecticide. DDT accumulated in individual bald eagles that had ingested contaminated prey, and reproductive success plummeted (USFWS 1999, p. 36455). In the late 1960s and early 1970s, it was determined that dichlorophenyldichloroethylene (DDE), a breakdown product of DDT, accumulated in fatty tissues of adult female eagles and impaired the calcium release needed for normal egg shell formation.
On March 11, 1967 (32 FR 4001), the Secretary of the Interior listed bald eagles south of the 40th parallel (latitudinal line running roughly from northern California to New Jersey) as endangered under the Endangered Species Preservation Act of 1966 (16 U.S.C. 668aa668cc). On December 31, 1972, DDT was banned from use in the United States by the Environmental Protection Agency.
Nationwide bald eagle surveys conducted in 1973 and 1974 revealed the declining trend of bald eagle population numbers throughout the lower 48 States. We responded by listing the bald eagle throughout the lower 48 States as endangered except in Michigan, Minnesota, Wisconsin, Washington, and Oregon, where the bald eagle was designated as threatened (43 FR 6233, February 14, 1978). Nesting populations of bald eagles have more recently been increasing throughout the United States. Data from surveys conducted between 1963 and 1998 show that known active nest sites in the lower 48 States have grown from 417 to over 5,748 occupied BAs (USFWS 1995, p. 36001; USFWS 1999, p. 36457). Today, the Service estimates the population in the lower 48 states to be at approximately 7,066 breeding pairs (USFWS 2006, p. 8239).
The 1982 recovery plan for the Southwestern Recovery Region states that when the total reproduction for the eagle population within the Southwestern Recovery Region as a whole has effectively doubled to 10 12 young per year over a 5year period, and the population range has expanded to include one or more river drainages in addition to the Salt and Verde River Systems, the southwestern bald eagle should be reclassified to threatened. The 1982 recovery plan indicated that Arizona was the only State in the recovery region containing nesting bald eagles, with 42 unverified historical nesting territories in the Salt and Verde River systems, and one occupied territory along the Colorado River. As discussed in the February 16, 2006, Federal Register notice reopening the comment period on the proposed rule to delist the bald eagle through its range (71 FR 8238), the downlisting goal established in the recovery plan for the southwestern bald eagle has been exceeded. Further, on July 12, 1995, we reclassified the bald eagle from endangered to threatened in the lower 48 States (60 FR 36000).
The number of known BAs has increased from a low of 3 in 1971, to a high of 50 in 2006, while the number of occupied BAs increased from a low of 3 in 1971, to a high of 43 in 2006. The number of young hatched increased from a low of 0 in 1972, to a high of 55 in 2006 (AGFD 2006, pp. 4849; AGFD unpubl. data 2006). Productivity has also changed. Between 1975 and 1984, average productivity was 0.95 young per occupied BA. Between 1987 and 2005, average productivity was 0.78 young per occupied BA. These data take into account productivity for BAs throughout the Southwest, and they are not restricted to the Sonoran Desert population of bald eagles evaluated under the petition.
While the number of BAs has increased, there was no expectation that these BAs would demonstrate a corresponding increase in reproductive performance. In part, this is because early monitoring detected BAs with the highest quality habitat that were easily discovered. Following an intensive survey effort, we now know of more BAs, but habitat conditions within them ranges from poor to excellent. As a result, we are now tracking productivity in BAs with a variety of habitat conditions, rather than tracking productivity in only those BAs that were easily detected and were in prime habitat. The result of having more thorough, representative data from more BAs in a variety of habitat types is that we show fewer ``boom and bust'' years. Productivity data between 1987 and 2005 indicates a more stabilized performance. For example, in 1971, with only three known BAs, productivity was 1.33. In 1972, with the same number of known BAs, productivity was 0.0. In 1973, productivity was at 1.5. By comparison, with more BAs known, productivity fluctations now typically vary by only 0.20 to 0.30 (AGFD 2006, pp. 4849; AGFD unpubl. data 2006).
AGFD (2006c, p. 5) additionally notes that the change in productivity could be due to a difference in monitoring protocols. More importantly, they note that an average productivity rate of 0.78 young/ occupied breeding area is consistent with the range of many other areas in the species range with larger bald eagle populations, including Minnesota, British Columbia, Interior Alaska, and Washington.
For the Sonoran Desert population of bald eagles (i.e., excluding those BAs not considered within the area of analysis under this action), the number of occupied BAs increased from a low of 3 in 1971 to a high of 36 in 2004. Productivity for only those BAs within the Sonoran Desert population is that same as that for the southwestern population up until 1994, when BAs outside of the Sonoran Desert population were discovered. From 1994 forward, productivity within the Sonoran Desert population has ranged between 0.62 and 1.06, reaching a high in 2004. Productivity remained high at 1.01 young per occupied BA for 2005 (AGFD 2004a, p. 15; AGFD 2004, p. 6; AGFD 2005, p. 7; AGFD 2006, Table 7, pp. 4850). The average annual productivity for this time period is at 0.78, which corresponds to that for the overall southwestern population.
Previous Federal Actions
On March 11, 1967 (32 FR 4001), bald eagles south of 40 degrees north latitude were federally listed as an endangered species. Bald eagles north of this line were not listed at that time because those populations had not experienced the same threats and population declines as of 1967. On February 14, 1978, we listed the bald eagle as endangered in 43 States, and threatened in 5 others (43 FR 6233). Bald eagles were not listed in Alaska, and are not found in Hawaii. On July 12, 1995, we reclassified the bald eagle from endangered to threatened in the lower 48 States (60 FR 36000). The bald eagle remained classified as threatened in Michigan, Minnesota, Wisconsin, Oregon, and Washington, as originally listed.
On July 6, 1999, we proposed to remove the bald eagle from the List of Endangered and Threatened Wildlife in the lower 48 States, including the Southwest Recovery Region (64 FR 36454). The original comment period was open for 90 days, until October 5, 1999. We reopened the comment period on that proposal on February 16, 2006 (71 FR 8238), for an additional 90 days, until May 17, 2006, and we extended the comment period on May 16, 2006 (71 FR 28369), for another 30 days, until June 19, 2006.
Distinct Vertebrate Population Segment
We consider a species for listing under the Act if available
information indicates such an action might be warranted. ``Species'' is
defined by the Act as including any species or subspecies of fish and wildlife or plants,
and any distinct vertebrate population segment of fish or wildlife that interbreeds when mature (16 U.S.C. 1532(16)). We, along with the National Marine Fisheries Service (now the National Oceanic and Atmospheric AdministrationFisheries), developed the Policy Regarding the Recognition of Distinct Vertebrate Population Segments (DPS policy) (61 FR 4722, February 7, 1996), to help us in determining what constitutes a DPS. The policy identifies three elements that are to be considered in a decision regarding the status of a possible distinct population segment (DPS). These elements include (1) the discreteness of the population in relation to the remainder of the species to which it belongs; (2) the significance of the population segment to the species to which it belongs; and (3) the population segment's conservation status in relation to the Act's standards for listing. Our policy further recognizes it may be appropriate to assign different classifications (i.e., threatened or endangered) to different DPSs of the same vertebrate taxon (61 FR 4721; February 7, 1996).
In the Service's final rule reclassifying the bald eagle from endangered to threatened (July 12, 1995, 60 FR 36000), we determined that eagles in the Southwestern Recovery Region were part of the same bald eagle population as that of the remaining lower 48 States, and we determined it was appropriate to include it in the reclassification. However, the petition requests action with respect to an area (i.e., Sonoran Desert) that differs from the area that was analyzed in the reclassification rule (i.e., Southwestern Recovery Region),and provides new information not considered in 1995.
The DPS policy states that a population segment of a vertebrate
species may be considered discrete if it satisfies either one of the
following two conditions: It must be markedly separated from other
populations of the same taxon as a consequence of physical,
physiological, ecological, or behavioral factors, or it must be
delimited by international boundaries within which significant
differences in control of exploitation, management or habitat
conservation status or regulatory mechanisms exist that are significant
in light of section 4(a)(1)(D) of the Act. Our evaluation of
discreteness under the DPS policy, based on information provided in the petition and available in our files, is presented below.
Discreteness Criteria 1. The Population Segment 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
The petition notes the geographic region occupied by Sonoran Desert bald eagles is much drier and hotter than that of any other bald eagle population, and represents a significant departure from the habitat selected by bald eagles in the rest of North America. The petition concludes that, in order to adapt to high summer temperatures and to time breeding cycles to the accessibility and spawn of native fish (primarily suckers), Sonoran Desert bald eagles breed earlier, nest earlier, and fledge their young sooner than bald eagles elsewhere (AGFD 1999a, 2000; Gerrard and Bortolotti 1988; Hunt et al. 1992; Stalmaster 1987; USFWS 2003b). In addition, the petition notes that, unlike bald eagles elsewhere in North America, Sonoran Desert bald eagles use cliff nest sites and that 53 of 111 known nests, or 48 percent, are on cliffs or pinnacles. They further note the only other place this occurs is in the Aleutian Islands (Hunt et al. 1992).
Response to the Petition
The information provided in the petition on behavioral adaptations to the Sonoran Desert is, in part, accurate. While it is true that Sonoran Desert bald eagles initiate nesting earlier than eagles in some parts of the country, Stalmaster (1987, p. 63) notes bald eagles in Florida initiate breeding activities in October, even earlier than Arizona bald eagles. Florida bald eagles also lay eggs earlier (Stalmaster 1987, p. 63; Gerrard and Bortolotti 1988 p. 76). Accordingly, Florida bald eagles hatch and fledge earlier than those in Arizona. Stalmaster (1987, p.63) concludes timing of various breeding events is tied to latitude of the nesting area, with eagles at more northern latitudes breeding at later dates.
With respect to cliff nesting, the information presented on the use of cliff nests is accurate. However, this is not necessarily a unique trait of Sonoran Desert bald eagles. Gerrard and Bortolotti (1988, p. 41) note bald eagles in other areas may nest on cliffs if suitable trees are not available. Stalmaster (1987) noted exceptions to tree nests as well, but indicated that, while eagles in other areas may rarely use cliffs or other surfaces, this is an exception, whereas in Arizona, cliff nesting is common. In addition, bald eagles are known to nest on cliffs on the Channel Islands off California (Montrose Settlements Restoration Program 2005).
The petition provides information alleging that the Sonoran Desert
bald eagles are reproductively isolated. Specifically, the petition
contends that 352 out of 353 individuals (99.997 percent) objectively
identified while participating in breeding activity in this population
came from within the Sonoran Desert bald eagle population.
Additionally, the petition notes that, since 1977, biologists in
Arizona have banded 256 nestlings with only one individual identified
as having emigrated. According to the petition, this indicates that
99.6 percent of individuals born into the Sonoran Desert remain in the
desert (AGFD 1999a, 2000). The petition states that, to date, evidence
from the banding and identification of breeding adults supports the
hypothesis that the Sonoran Desert bald eagle breeding population is
not supported or maintained by immigration from other states or regions. They quote AGFD (1999a, 2000):
``[B]ecause adults return to the vicinity of their natal area to breed, the large distance between small breeding populations in the Southwest decreases the chance for movement between neighboring populations. Probably most convincing are the results from banding 256 nestlings over 20 years and identifying 372 breeding adults over 8 years. Only one individual from outofstate entered the breeding population and only one left. Additionally, the proportion of breeding adults with color bands had steadily increased, while the presence of unmarked Bald Eagles has decreased. Thus, continued attention to the survivorship of all Arizona Bald Eagles is vital to the maintenance of our breeding population. We can not depend on immigration to Arizona from nearby states to make up for poor management in Arizona * * *''
The petition claims the AGFD (1994b) warned that repopulation of the Sonoran Desert bald eagle population following a population crash would be highly unlikely, and quote the AGFD (1994b) as follows: ``Because Arizona continues to possess nearly the entire breeding population within the Southwestern Region, concerns remain over retaining the genetic integrity of this population * * * Should a population crash occur in Arizona, the pool of eagles to repopulate the Southwest could be left to the few pairs in the neighboring states or Mexico. However, at this time, there is no documentation of eagles from these neighboring Southwestern states breeding in Arizona or vice versa.''
The petition further states that natal site fidelity is common for bald eagles, noting that, in a study of nine bald eagle populations including thousands of banded birds, only two nestlings were found to have bred in other areas. One of these birds moved 331 kilometers (205 miles) north from its natal site in the Greater Yellowstone Ecosystem (Harmata in litt.) while the other traveled 418 kilometers (260 miles) south from its natal site near Charleston, South Carolina (T. Murphy, pers. comm., Wood in litt.). They conclude that the tendency for banded nestlings to breed within their natal populations is well known (Hunt et al. 1992).
Response to the Petition
The information in the petition appears to be accurate and reliable; however, it should be noted the only individual cited as entering the breeding population from outofstate refers to a bald eagle from Texas (AGFD 2006, p. 27) that currently occupies the Luna BA, which is not part of the Sonoran Desert bald eagle population. As a result, the appropriate conclusion is all birds objectively identified while participating in breeding activity in the Sonoran Desert bald eagle population came from within the population. It should also be noted that subadult bald eagles do migrate and return annually. As noted above, about 45 days after leaving the nest, young southwestern bald eagles migrate to Canada, northern California, Idaho, Montana, North and South Dakota, Oregon, Washington, and Wyoming (Hunt et al. 1992, p. A104A114), returning to Arizona in the fall of the same year. They are known to repeat this behavior for a minimum of 2 years (Hunt et al. 1992a112; p. A122A123). Resident adult bald eagles often stay in their BAs yearround, although local shortterm migrations are common (AGFD 1999, p. 6).
We agree with the petitioners that, should the Sonoran Desert bald eagle population experience a rapid decline, there are few eagles in neighboring southwestern states or Mexico which could serve as a source population for the Sonoran Desert bald eagle population. Finally, we find the information from Harmata et al. (1999, p. 788) and Hunt et al. (1992, p. A144) supports the discussion on the natal origins of breeding adults, and the probability that adult bald eagle will not immigrate to the Sonoran Desert bald eagle population from surrounding southwestern states or farther.
Evidence of Genetic Discontinuity
With respect to genetic isolation, the petition found that the
current understanding of genetics does not refute the discrete and
isolated nature of the desert nesting bald eagle. The petition notes a
review of all information regarding genetic analysis of the
southwestern desert nesting bald eagle reveals consistent uncertainty,
and concludes current genetic data support no definitive conclusions
concerning isolation or lack of isolation (CBD 2004e; Hunt et al. 1992;
SWCBD 1999). The petition states that, while no definitive conclusions
are supported by the limited genetic data, this is not required under
the current DPS policy. Specifically, the petition quotes from the policy:
``Thus, evidence of genetic distinctness or of the presence of genetically determined traits may be important in recognizing some DPS's, but the draft policy was not intended to always specifically require this kind of evidence in order for a DPS to be recognized * * *''
Similarly, the petition notes absolute reproductive isolation is not required under the policy, which states:
``The Services do not consider it appropriate to require absolute reproductive isolation as a prerequisite to recognizing a distinct population segment. This would be an impracticably stringent standard, and one that would not be satisfied even by some recognized species that are known to sustain a low frequency of interbreeding with related species * * *''
Response to the Petition
The information presented within the petition on completed genetic studies for bald eagles appears accurate and reliable. Hunt et al. (1992, pp. E96 to E110) contains the genetic work completed to date on the southwestern bald eagle population. Vyse (1992, p. E100, E101) notes the data are inconclusive, as evidenced by such statements as ``These findings must be assumed to be preliminary (and treated with due caution), because of a lack of information concerning sampling procedures. The results we have obtained could easily be explained by sampling procedures''; and ``At present these data (HinfI/M13) are too incomplete to be considered further.'' In addition, Zegers et al. (1992, p. E106 to E109) notes that ``Question 4 * * * is difficult to answer with precision because of the different sample sizes between 1985 and 1990. * * * [T]his difference is possibly an artifact of the many fewer samples in 1985''; ``six loci may not be enough to give a reliable estimate of the true genetic distance'; and ``We feel caution should be exercised when interpreting these results due to the low numbers of individuals sampled from most states but especially because of the few loci examined.''
Evidence of Morphological Discontinuity
The term ``morphological discontinuity'' refers to some difference in physical characteristics that may exist between two groups. The petition contends that quantitative measures of the physical differences between Sonoran Desert bald eagles and bald eagles elsewhere offers evidence of morphological discontinuity. The petition cites quantitative measures of physical difference, stating that average weights of male bald eagles are 3.3 kilograms (kg) (7.3 pounds (lbs.)) in Arizona, 4.1 kg (9.0 lbs.) in California, and 4.7 kg (10.4 lbs.) in Alaska. Similarly, average weight for females is 4.5 kg (9.9 lbs.) in Arizona, 5.1 kg (11.2 lbs.) in California, and 5.8 kg (12.8 lbs.) in Alaska (Hunt et al. 1992).
Response to the Petition
The information provided on size differences appears to be accurate
and reliable, as found in Hunt et al. (1992, p. A159). Stalmaster
(1987, pp. 1617) notes southern eagles are much smaller and lighter
than their northern counterparts. This is consistent with Bergmann's
Rule, which holds that animal size increases with increasing latitude.
Gerrard and Bortolotti (1988, p. 14) note Florida birds are the
smallest, with a gradation of small to large from south to north. The
importance of this morphological difference and its potential isolating
effects are discussed by Hunt et al. (1992, p. A165), who notes
morphological differences such as small size may be an adaptation
related to desert conditions, noting a decision to release birds into
Arizona from elsewhere should be considered only as a last resort, as
the introduction of foreign genes into the Sonoran Desert population
might disrupt coadapted gene complexes specific to the desert population.
Discreteness Criteria 2. It is Delimited by International Government Boundaries Within Which Differences in Control of Exploitation, Management of Habitat, Conservation Status, or Regulatory Mechanisms Exist That are Significant in Light of Section 4(a)(1)(D) of the Act
No specific information was identified in the petition for this category. Therefore we will not address this category in our analysis of discreteness.
We have reviewed the information presented in the petition, and have
evaluated the information in accordance with 50 CFR 424.14(b). On the basis of our review, we find available genetic studies on bald eagles are dated, the sample size was small, and researchers conducting the studies found the results to be inconclusive. We therefore believe that the best available genetic information is inconclusive with regard to the discreteness of the Sonoran Desert bald eagle population. However, we believe the petition presents substantial information on the Sonoran Desert bald eagles with respect to size. However, size in birds is known to be a clinal function of latitude and does not necessarily indicate discreteness. We believe the petition provides substantial information on natal site fidelity in breeding birds and the limited number of other eagles in neighboring southwestern states or Mexico. Finally, we believe the data indicating that 20 years of monitoring have resulted in the determination that no eagles have immigrated to and only one eagle has emigrated from the Sonoran Desert bald eagle population is substantial. We, therefore, conclude that the petition contains substantial information with respect to the discreteness requirements of the DPS policy to warrant considering the Sonoran Desert bald eagle population as discrete from other bald eagle populations.
If we determine that a population segment is discrete under one of
the above conditions, we must then consider its biological and
ecological significance to the taxon to which it belongs, within the
context that the Service's authority to list DPSs be used ``sparingly''
while encouraging the conservation of genetic diversity (61 FR 4722;
February 7, 1996). This consideration may include, but is not limited
to the following: (1) Evidence of the persistence of the population
segment in an ecological setting that is 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.
Significance Criteria 1. Persistence of the Population Segment in an Ecological Setting That Is Unusual or Unique for the Taxon
Information Provided in the Petition
The petition contends that the Sonoran Desert bald eagle persists in the unique ecological setting of the Sonoran life zones of the desert Southwest (AGFD 1999a, 2000; Hunt et al. 1992; USFWS 2002a, 2003b). With the exception of a single 8,000 foot (2,438 meter) elevation nest (Luna BA), the petition states that all known Arizona BAs are located in the Sonoran Desert in the central part of the State in Upper and Lower Sonoran Desert habitats from elevations of 1,080 feet (330 meters) to 5,640 feet (1,720 meters), and are closely associated with the Salt, Verde, and Gila river drainage waters (Beatty and Driscoll 1994, 1996a; Beatty et al. 1995a, 1995b, 1998; Driscoll and Beatty 1994; Driscoll et al. 1992; Hunt et al. 1992). The petition further identifies several Arizona tree species native to the desert Southwest as representative vegetation for these areas (Brown 1994). Response to the Petition
The breeding range of the bald eagle is associated with aquatic
habitats (coastal areas, river, lakes, and reservoirs) with forested
shorelines or cliffs in North America (Buehler 2000). The ecological
setting in which the bald eagle persists in the Sonoran Desert may at
first seem unusual for the species. However, despite the desert
setting, bald eagles of the Sonoran Desert are consistently associated
with preferred bald eagle habitat, the riparian ecosystem. The petition
clearly states that the Sonoran Desert nests are closely associated
with the Salt, Verde, and Gila river drainage waters and cites Brown
(1994) when describing the riparian vegetation of these areas. As with
all populations of bald eagles throughout the lower 48 States, suitable
riparian habitat, or other comparable aquatic habitat, is an essential
prerequisite to successful eagle reproduction in the desert Southwest
(USFWS 1982). Riparian ecosystems occupied by nesting bald eagles in
the Sonoran life zones of the desert Southwest, therefore, do not
constitute a unique setting for the species. The persistence of the
bald eagle in this setting likely represents an example of a species
occupying the edge of its range of suitable habitats. Therefore, we
conclude that the petition does not present substantial evidence that
the population is persisting in an ecological setting that is unique for the taxon.
Significance Criteria 2. Loss of the Population Segment Would Result in a Significant Gap in the Range of the Taxon
Information Provided in the Petition
The petition contends that for more than twenty years, the Service has recognized the fact that the Southwest represents a ``significant portion of the bald eagle range'' and further states that it follows logically then that the loss of the [Sonoran] Desert nesting population would result in a significant gap in the range of the bald eagle (Hunt et al. 1992; USFWS 1982, 1994a, 1995, 2001a). The petition claims that bald eagles in the Southwestern United States have been considered as a distinct population for the purposes of consultation and recovery efforts under the Act (USFWS 2003b).
The petition further contends that several authors have speculated about the consequences of this population's loss (AGFD 1994b; Hunt et al. 1992), and the petitioners can find no credible evidence that bald eagles elsewhere possess the ability to adapt to the unique and hostile environmental habitat in which the [Sonoran] Desert nesting population has evolved. Specifically the petition quotes Hunt et al. (1992): ``[W]ere the [Southwestern Desert Nesting Bald Eagle] population extirpated, there is no firm reason to believe that bald eagles released into Arizona from elsewhere would posses [sic] the adaptations required to increase their numbers.''
The petition further quotes correspondence from the Arizona Game and Fish Department to the Service (1994b):
``Because Arizona continues to possess nearly the entire breeding population within the Southwestern Region, concerns remain over retaining the genetic integrity of this population. * * * Should a population crash occur in Arizona, the pool of eagles to repopulate the Southwest could be left to the few pairs in the neighboring states or Mexico. However, at this time, there is no documentation of eagles from these neighboring Southwestern States breeding in Arizona or vice versa.''
Response to the Petition
The petition cites several Service publications (1982, 1994a, 1995,
2001a) in addition to a report prepared by Hunt et al. (1992) when
making this claim, but does not make specific reference to instances in
which the Service has ``recognized the fact that the Southwest
represents a significant portion of the Bald Eagle range.'' Therefore,
for this analysis we will assume that the petition is referring to the fact that the
Service has continued to identify the Southwest population of the bald eagle as one of five recovery populations in the lower 48 States for more than twenty years (Hunt et al. 1992; USFWS 1982, 1994a, 1995, 2001a).
In establishing a recovery program for the species in the mid 1970's, the Service divided the bald eagles of the lower 48 States into five recovery populations, based on geographic location, termed Recovery Regions. This was as a result of the wide distribution of the bald eagle in the lower 48 States. Recovery plans were prepared for the five Recovery Regions, including the Southwest Recovery Region (USFWS 1982), by separate recovery teams composed of species experts in each geographic area. The Service views the establishment of recovery regions as a management tool allowing for effective regional coordination and planning among State and Federal conservation agencies and species experts. The existence of a recovery region does not, in itself, imply significance under the DPS policy (USFWS and NMFS 1996), as the petitioner claims, and therefore the Southwestern Recovery Region is not a DPS for the purposes of recovery.
In the 1994 proposed rule to reclassify the bald eagle from endangered to threatened (59 FR 35584; July 12, 1994), the Service determined that current information indicates the Southwestern population is at risk and remains in danger of extinction due to excessively low survival rates and the need for intensive management, particularly at nest sites. This decision was based on the understanding that the population was isolated and thus subject to the genetic, demographic, and environmental threats known to be associated with small populations. Data provided in the Hunt et al. (1992) publication indicated there had been no immigration to the Southwestern population of bald eagles. At that time the Service recognized the Southwestern Recovery Region as a DPS based on evidence that it appeared to be reproductively isolated (59 FR 35584; July 12, 1994). However, in the 1995 final rule to reclassify bald eagles from endangered to threatened, the Service affirmed that the Southwestern Recovery Region of the bald eagle is not a DPS but instead part of the same bald eagle population as that of the remaining lower 48 States (USFWS 1995). This determination was based on evidence of immigration into the population (USFWS 1995), interpopulation movements (Mabie et al. 1994), and the then existing genetic data, which did not support the Service's previous assertion that the bald eagles of the Southwestern Recovery Region are reproductively isolated (Hunt et al. 1992).
On July 6, 1996, the Service and the National Marine Fisheries Service jointly published a policy that clarifies the Agencies' interpretation of the phrase ``distinct population segment of any species of vertebrate fish or wildlife'' for the purposes of listing, delisting, and reclassifying species under the Act (USFWS and NMFS 1996). The policy identifies three elements that are to be considered in a decision regarding the status of a possible distinct population segment (DPS). These elements include (1) the discreteness of the population segment in relation to the remainder of the species to which it belongs; (2) the significance of the population segment to the species to which it belongs; and (3) the population segment's conservation status in relation to the Act's standards for listing (USFWS and NMFS 1996).
Subsequent to publication of the DPS policy, the Service published a proposed rule to remove the bald eagle in the lower 48 States from the list of endangered and threatened wildlife (USFWS 1999). On February 16, 2006 the Service reopened the comment period for the proposed rule (USFWS 2006). In both of these publications the Service recognized a single listed population of bald eagles throughout the lower 48 States as had been done in the earlier 1995 final rule (USFWS 1995), although a formal analysis consistent with the 1996 DPS policy had not been completed for the Southwestern Recovery Region (USFWS 1999, 2006).
The petition is correct in that early biological opinions, as part of consultations with Federal action agencies under section 7 of the Act, finalized by the Arizona Ecological Services Office referred to the Southwestern population as a DPS. However, in the 1995 final rule to reclassify bald eagles from endangered to threatened (USFWS 1995), the Service affirmed that the Southwestern population of the bald eagle is not a DPS. Some biological opinions dated after the final rule note that the Southwestern population of the bald eagle was previously considered a DPS, but no longer is considered as such. In the February 16, 2006 reopening of the comment period for the proposed rule to delist the bald eagle, the Service further explains that when preparing biological opinions under section 7 of the Act the potential effects to the Southwestern or any of the other four recovery regions of the bald eagle are considered in terms of whether they appreciably reduce the likelihood of both survival and recovery of the bald eagle throughout the lower 48 States, not solely for the geographic area in which the impacts may occur (USFWS 2006). Therefore, the bald eagles in the Southwestern United States are not considered as a distinct population for the purposes of consultation under the Act. Further, the petition under consideration in this finding requests action with respect to a geographic area (i.e., Sonoran Desert) that differs from the area that was analyzed in the Service's reclassification rule (i.e., Southwestern Recovery Region) (USFWS 1995). In this context, claims regarding how the Service has referred to the Southwest Recovery Region are not relevant to the petitioned action.
Finally, the bald eagle ranges throughout much of North America, nesting on both coasts from Florida to Baja California in the south, and from Labrador to the western Aleutian Islands, Alaska in the north (Gerrard and Bartolotti 1988). While the statements of two authors who have ``speculated'' about the consequences of the Sonoran Desert population's loss are accurately quoted, these statements do not specifically address how the loss of the Sonoran Desert bald eagle population would constitute a significant gap in the range of the species. Furthermore, the petitioner provides no supporting evidence to substantiate the authors' speculations.
We conclude that the bald eagles in the Southwestern United States
are not considered as a distinct population for the purposes of
consultation or recovery. Furthermore, the petition does no provide
substantial information to support the claim that loss of the Sonoran
Desert bald eagle population would result in a significant gap in the range of the species.
Significance Criteria 3. The Population Segment Represents the Only Surviving Natural Occurrence of a Taxon That May Be More Abundant Elsewhere as an Introduced Population Outside Its Historical Range
The petition does not address this factor. The bald eagle occurs
naturally throughout the contiguous 48 States, Alaska, Canada and
Mexico (Buehler 2000). As such, the Sonoran Desert population does not
represent the only surviving natural occurrence of the taxon. [[Page 51556]]
Significance Criteria 4. The Discrete Population Segment Differs Markedly From Other Populations of the Species in its Genetic Characteristics
Information Provided in the Petition
The petition contends that review of all information regarding genetic analysis of the Southwestern desert nesting bald eagle reveals consistent uncertainty and the current understanding of genetics does not refute the discrete and isolated nature of the desert nesting bald eagle (CBD 2004e; Hunt et al. 1992; SWCBD 1999). The petition specifically quotes excerpts from Hunt et al. (1992), which discuss genetics study methods, results, and conclusions.
Response to the Petition
We have addressed the genetic evidence provided by the petitioner in the analysis of discreteness above. Consistent with that analysis we have determined that the best available genetic information is inconclusive with regard to significance. We conclude that the petition does not present substantial information that the population differs markedly from other populations of the species in its genetic characteristics. Further, the petition does not present nor are we aware of any other factors that would lead us to believe that the Sonoran Desert population of the bald eagle differs markedly from the taxon as a whole.
We have reviewed the information presented in the petition, and have evaluated the information in accordance with 50 CFR 424.14(b). On the basis of our review, we find that the petition does not present substantial scientific or commercial information to indicate that the Sonoran Desert bald eagle constitutes a valid DPS. Although the population is discrete, the petition does not present substantial scientific information that the Sonoran Desert bald eagle may be significant in relation to the remainder of the taxon. Therefore, we conclude that the Sonoran Desert population is not a listable entity pursuant to section 3(15) of the Act. However, recognizing the volume of information provided in the petition, and the national importance of the bald eagle, we have also conducted a threats analysis.
Pursuant to section 4 of the Act, we may list a species,
subspecies, or DPS of vertebrate taxa on the basis of any of the
following five factors: (A) Present or threatened destruction,
modification, or curtailment of habitat or range; (B) overutilization
for commercial, recreational, scientific, or educational purposes; (C)
disease or predation; (D) inadequacy of existing regulatory mechanisms;
or (E) other natural or manmade factors affecting its continued
existence. The Act identifies the five factors to be considered, either
singly or in combination, to determine whether a species may be
threatened or endangered. Our evaluation of these threats in terms of
the petitioned action to reclassify the Sonoran Desert bald eagle from
threatened to endangered, based on information provided in the petition
and available in our files, is presented below. Throughout this finding
we refer to the Sonoran Desert population of the bald eagle, because
that is the petitioned entity; however, as noted above, this reference
does not imply that we have determined, under to our DPS policy, that
this population is a listable entity. Furthermore, although we have
proposed the bald eagle in the lower 48 States for delisting (71 FR
8238, February 16, 2006), our petition finding does not address the
proposed delisting or conditions that may occur if the delisting is finalized.
A. Present or Threatened Destruction, Modification, or Curtailment of the Species' Habitat or Range
Development, Recreation, and Water Use
The petition notes that the Southwest has already lost more than 90 percent of its historical riparian communities (AGFD 1993; Krueper 1993; Lofgren et al. 1990), and that the loss of riparian communities is continuing due to increasing development, dewatering via groundwater pumping and diversions, destructive cattle grazing, and lack of vegetationrejuvenating floods. The petition contends that the Sonoran Desert bald eagle population faces imminent and accelerating loss of increasing amounts of habitat vital to its longterm survival. Specifically, the petition notes that most of the BAs are located along the Salt and Verde rivers near the Phoenix metropolitan area and the towns of Cottonwood and Camp Verde in Yavapai County, where habitat loss is occurring due to the increasing human population in central Arizona. The petition notes that the human population in Maricopa County is expected to double to more than six million people over the next 30 years (Arizona Republic 1998). Growth in Cottonwood, on the Verde River, is projected to increase by 148 percent and in Camp Verde by 158 percent between 1994 and 2040 (Arizona Department of Economic Security 1994). The petition notes that increases in human populations of this magnitude will result in increased housing development, water demands, and recreational use.
The petitioners contend that development will affect the suitability of many BAs due to their proximity to areas with large human populations and projected population growth rates. The petition notes that increased recreational use, development, and water use will follow increasing population sizes, and cites examples of past consultations, conducted by the Service under section 7 of the Act, addressing these issues.
The petition cites recent examples of recreational impacts to Sonoran Desert bald eagle BAs, including river tubing on the Salt River, which increases the human presence near the Blue Point BA, as well as campground development at Roosevelt Lake, which could affect the Sheep and Tonto BAs. The petition cites, as development examples, a 360home development and golf course within 1.0 mile (1.6 kilometers (km)) of the Box Bar BA; the development of lakeside resorts at Lake Pleasant near the Pleasant BA; and continued housing, road, and business developments along lower Tonto Creek near the Sheep and Tonto BAs (AGFD 1999a, 2000).
The petition notes that dewatering of the middle portion of the Verde River is accelerating so that flows have at times been reduced to 12 cubic feet per second (0.3 cubic meters per second) in summer months near the Camp Verde White Bridge gauge (Verde Natural Resources Conservation District 1999). The petition contends that this dewatering is resulting in a reduction in base flows, and increased populations in Cottonwood and Camp Verde are leading to increased groundwater pumping. The petition indicates that groundwater pumping in Arizona has repeatedly been demonstrated to result in a depletion of surface flows, degradation and loss of riparian communities, and adverse impacts and local extirpation of aquatic flora and fauna (ADWR 1994; Ewing et al. 1994; Glennon 1995; Glennon and Maddock 1994; Hendrickson and Minckley 1984; McGavock 1996, Miller 1961; OwenJoyce and bell 1983, Stromberg 1993; Tellman et al. 1997).
The petition notes that increased water demand is expected to have
adverse effects on flows within rivers and resulting impacts on
riparian communities. The petition further notes that 59.5 percent of all known desert bald eagle nests in Arizona have been in
riparian trees and snags (Driscoll 1999; E. Gardner, AGFD, pers. comm. 2006). The petition notes that bald eagles at 11 BAs, including the Box Bar, Coolidge, Doka, Fort McDowell, Perkinsville, Pinto, 76, Sheep, Sycamore, Tonto, and Winkelman BAs, nest solely in riparian trees, and that the cottonwood trees used for nesting in these BAs have become overmature, are dying, and are not being replaced (AGFD 1991a, 2000). The petition contends that the loss of habitat in these BAs is particularly damaging to the future stability of the Sonoran Desert bald eagle population, as they have collectively contributed 22 percent of all recorded fledglings since 1971. The petition notes that the Fort McDowell BA has fledged 34 young, second only to the Blue Point BA, which has fledged 35 young (AGFD 1999a, 2000).
Substantial detail is provided in the petition regarding specific development activities and resulting effects to Sonoran Desert bald eagle BAs. The petition notes that pressures associated with human population growth are increasing and will continue to do so as the human population increases.
Response to the Petition
The information provided by the petitioner indicating that human population growth is expected to continue in areas in close proximity to or used by the Sonoran Desert bald eagle population appears accurate and reliable. Human population growth is an ongoing concern, and many of the bald eagle BAs in the Sonoran Desert population are within close proximity to this anticipated growth, including the Granite Reef, Orme, Rodeo, Sycamore, Doka, Fort McDowell, Box Bar, Needle Rock, and Bartlett BAs on the Verde River, and the Bull Dog, Blue Point, and Horse Mesa BAs on the Salt River, as well as the Pleasant BA at Lake Pleasant. As noted in the petition, recreation, development, and water use activities are ongoing and have increased since the bald eagle was listed. We have consulted on many of these actions through section 7 of the Act (including USFWS 1990b, 1996b, 1997b, 1998, 2001a and 2003b on water developments and USFWS 1993a for recreation, as cited in the petition). In addition, the AGFD's Projects Evaluation Program is available for Federal agencies or companies with a Federal nexus. This program can be used to evaluate the impacts of planned or future projects in areas where there may be a species of concern. The AGFD believes the program will help to ensure bald eagles and their habitat are considered and evaluated for possible effects from development projects (AGFD 2006, p. 14).
Under section 7 of the Act, we have concluded to date that these actions would not jeopardize the continued existence of the bald eagle. The AGFD (2006c, p. 13) acknowledges that the need to accommodate human populations in proximity to a major metropolitan area like Phoenix will require ongoing management. However, they conclude that the species can be managed even under this scenario through the ``awareness, collaboration, flexibility, planning, and willingness of all wildlife, land, and recreation managers (AGFD 2006, p. 13).''
We work cooperatively with the AGFD and Federal land managers to minimize the potential threats to bald eagle BAs in close proximity to the major human population growth areas in Arizona by establishing BA closures and monitoring the sites. In 2006, the Bartlett, Box Bar, Granite Reef, Orme, and Tonto BAs were monitored through the Arizona Bald Eagle Nestwatch Program. The program not only interacts with members of the public to provide education, but can intervene if individuals approach the nests too closely. Similarly, the Southwest Bald Eagle Management Committee, composed of State, Tribal, Federal, private, and military agencies, meets twice each year to address ongoing and new threats, funding for needed efforts, and general issues affecting the bald eagle.
With the exception of the Pleasant and Bull Dog BAs, all of the BAs in close proximity to Phoenix successfully fledged young in 2006. One bird from the Bull Dog BA was successfully fledged following fostering in the Granite Reef BA. Orme, Rodeo, Doka, Fort McDowell, Box Bar, Blue Point, and Horse Mesa fledged one young each, while Sycamore, Needle Rock, and Bartlett produced two young each. Additionally, many of these BAs have successfully produced young for many years and, while nest failures do occur, their overall productivity remains high. For example, the Bartlett BA has fledged 28 young in 20 separate years between 1971 and 2002; the Blue Point BA has fledged 38 young in 18 separate years between 1971 and 2002; and the Fort McDowell BA has fledged 41 young in 23 years between 1971 and 2002 (AGFD 2006, Table 7, pp. 4850).
The petitioners presented reliable and accurate data on the use of riparian areas for bald eagles, and on the potential loss of nest trees. In the 11 BAs referenced by the petitioners, existing trees have become overmature, are dying, and are not being replaced (AGFD 2006, p. 12). The eagles in the Doka, Fort McDowell, Granite Reef, Rodeo, 76, and Sheep BAs currently nest in overmature live trees or snags with few available replacements. Trees may be lost to floodwaters, as at Fort McDowell in 1995 and 2005, or inundated due to reservoir level increases, as at the Pinto and Tonto BAs at Roosevelt Lake. In some cases, alternate trees are not available, as is the case at the Pinto BA. Housing communities and watertable reductions limit the available trees at the Tonto BA (AGFD 2006, p. 13).
The AGFD (2006, p. 13) notes that the Fort McDowell Yavapai Nation (FMYN) and Salt River Pima Maricopa Indian Community (SRPMIC) have submitted proposals to the Arizona Water Protection Fund and Wetlands Protection Fund to plant riparian trees. The U.S. Bureau of Reclamation is analyzing groundwater levels in the Pinto BA for possible cottonwood pole plantings, and has helped to implement riparian restoration strategies within the Tonto Creek Riparian Unit. Salt River Project has purchased property for riparian enhancements on Roosevelt Lake. The exact impacts of increased human population growth and riparian losses, as well as the success of planting efforts in riparian areas, are speculative at this point. Through these management efforts, however, managing agencies can begin to minimize the factors impairing riparian regeneration.
We agree with the petitioner that human population growth,
particularly in Maricopa and Yavapai counties, will continue. While we
can anticipate the types of impacts that might occur, the exact results
of those impacts on occupancy and productivity are speculative at this
point. We remain concerned for BAs such as Bartlett, Blue Point, and
Fort McDowell, which have contributed much to the productivity of bald
eagles in the Southwest. However, we find that productivity remains
high despite the ongoing nature of this threat. While this is an
ongoing threat, bald eagles have continued to survive and reproduce, as
evidenced by the increased number of BAs throughout Arizona, and as
evidenced by the productivity of the BAs outlined above. We therefore
find that the petitioners did not provide substantial information to
lead us to conclude that this threat has increased the likelihood of extinction for the Sonoran Desert bald eagle population.
B. Overutilization for Commercial, Recreational, Scientific, or Educational Purposes
No specific threats were identified in the petition for this category.
C. Disease or Predation
No specific threats were identified in the petition for this category.
D. Inadequacy of Existing Regulatory Mechanisms
FOR FURTHER INFORMATION CONTACT
Steve Spangle (see ADDRESSES); telephone, 6022420210; facsimile, 6022422513.