Endangered and Threatened Wildlife and Plants; Establishment of a Nonessential Experimental Population of Sonoran Pronghorn in Southwestern Arizona, 25593-25611 [2011-10467]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 76, Number 87 (Thursday, May 5, 2011)]
[Rules and Regulations]
[Pages 25593-25611]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-10467]



[[Page 25593]]

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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[Docket No. FWS-R2-ES-2009-0077; 92220-1113-0000; ABC Code: C3]
RIN 1018-AW63


Endangered and Threatened Wildlife and Plants; Establishment of a 
Nonessential Experimental Population of Sonoran Pronghorn in 
Southwestern Arizona

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Final rule.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), are 
reestablishing the Sonoran pronghorn, a federally listed endangered 
mammal, in its historical habitat in King Valley, Kofa National 
Wildlife Refuge, in Yuma County, and the Barry M. Goldwater Range--
East, Maricopa County, in southwestern Arizona. We are reestablishing 
the Sonoran pronghorn under section 10(j) of the Endangered Species Act 
of 1973, as amended, and classify that reestablished population as a 
nonessential experimental population (NEP). The NEP is located in 
southwestern Arizona in an area north of Interstate 8 and south of 
Interstate 10, bounded by the Colorado River on the west and Interstate 
10 on the east; and an area south of Interstate 8, bounded by Highway 
85 on the west, Interstates 10 and 19 on the east, and the United 
States-Mexico border on the south.
    This action is one of the recovery actions that the Service, 
Federal and State agencies, and other partners are conducting 
throughout the historical range of the species. This final rule 
establishes the NEP and provides for limited allowable legal taking of 
Sonoran pronghorn within the defined NEP area. An Environmental 
Assessment and Finding of No Significant Impact have been prepared for 
this action (see ADDRESSES section below).

DATES: The effective date of this rule is June 6, 2011.

ADDRESSES: This final rule, along with the public comments, 
Environmental Assessment (EA) and Finding of No Significant Impact 
(FONSI), is available on the Internet at https://www.regulations.gov and 
https://www.fws.gov/southwest/es/arizona/. Supporting documentation is 
also available for public inspection, by appointment, during normal 
business hours, at the U.S. Fish and Wildlife Service's Arizona 
Ecological Services Office at 2321 W. Royal Palm Road, Suite 103, 
Phoenix, AZ 85021.

FOR FURTHER INFORMATION CONTACT: Steve Spangle, Field Supervisor, 
Arizona Ecological Services Office, 2321 W. Royal Palm Road, Suite 103, 
Phoenix, AZ 85021 (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

    It is our intent to discuss only those topics directly relevant to 
this final rule establishing a Sonoran pronghorn nonessential 
experimental population (NEP). For more information on the Sonoran 
pronghorn, refer to the February 4, 2010, proposed rule (75 FR 5732) 
and the 1998 Revised Sonoran Pronghorn Recovery Plan (Service 1998: 
https://ecos.fws.gov/docs/recovery_plan/981203.pdf) and its amendments 
(Service 2002: https://ecos.fws.gov/docs/recovery_plan/031126.pdf).

Regulatory Background

    We listed the Sonoran pronghorn subspecies (Antilocapra americana 
sonoriensis) as endangered throughout its range on March 11, 1967 (32 
FR 4001), under the Endangered Species Preservation Act of October 15, 
1966, without critical habitat. This subspecies was included as an 
endangered species when the Endangered Species Act was signed into law 
in 1973 (Act; 16 U.S.C. 1531 et seq.). The Act provides that species 
listed as endangered are afforded protection primarily through the 
prohibitions of section 9 and the requirements of section 7. Section 9 
of the Act, among other things, prohibits the take of endangered 
wildlife. ``Take'' is defined by the Act as to harass, harm, pursue, 
hunt, shoot, wound, kill, trap, capture, or collect, or attempt to 
engage in any such conduct. Service regulations (50 CFR 17.31) 
generally extend the prohibitions of take to threatened wildlife. 
Section 7 of the Act outlines the procedures for Federal interagency 
cooperation to conserve federally listed species and protect designated 
critical habitat. It mandates that all Federal agencies use their 
existing authorities to further the purposes of the Act by carrying out 
programs for the conservation of listed species. It also states that 
Federal agencies will, in consultation with the Service, ensure that 
any action they authorize, fund, or carry out is not likely to 
jeopardize the continued existence of a listed species or result in the 
destruction or adverse modification of designated critical habitat. 
Section 7 of the Act does not affect activities undertaken on private 
or other non-Federal land unless they are authorized, funded, or 
carried out by a Federal agency.
    Under section 10(j) of the Act, the Secretary of the Department of 
the Interior can reestablish populations outside the species' current 
range and designate them as ``experimental.'' With the experimental 
population designation, the relevant population is treated as 
threatened for purposes of section 9 of the Act, regardless of the 
species' designation elsewhere in its range. Threatened designation 
allows us discretion in devising management programs and special 
regulations for such a population. Section 10(j) of the Act allows us 
to adopt whatever regulations are necessary and advisable to provide 
for the conservation of a NEP. In these situations, the general 
regulations that extend most section 9 prohibitions to threatened 
species do not apply to that species, and the 10(j) rule contains the 
prohibitions and exemptions necessary and appropriate to conserve that 
species.
    For the purposes of section 7 of the Act, we treat an NEP as a 
threatened species when the NEP is located within a National Wildlife 
Refuge or unit of the National Park Service, and section 7(a)(1) and 
the consultation requirements of section 7(a)(2) of the Act apply. 
Section 7(a)(1) requires all Federal agencies to use their authorities 
to carry out programs for the conservation of listed species. Section 
7(a)(2) requires that Federal agencies, in consultation with the 
Service, ensure that any action authorized, funded, or carried out is 
not likely to jeopardize the continued existence of a listed species. 
When NEPs are located outside a National Wildlife Refuge or National 
Park Service unit, then for the purposes of section 7, we treat the 
population as proposed for listing, and only two provisions of section 
7 apply--section 7(a)(1) and section 7(a)(4).
    In these instances, NEPs provide additional flexibility because 
Federal agencies are not required to consult with us under section 
7(a)(2). Section 7(a)(4) requires Federal agencies to confer (rather 
than consult) with the Service on actions that are likely to jeopardize 
the continued existence of a species proposed to be listed. The results 
of a conference are in the form of conservation recommendations that 
are optional as the agencies carry out, fund, or authorize activities. 
Because the NEP is, by definition, not essential to the continued 
existence of the species

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(see below) then the effects of proposed actions on the NEP will 
generally not rise to the level of jeopardizing the continued existence 
of the species. As a result, a formal conference will likely never be 
required for Sonoran pronghorn established within the NEP area. 
Nonetheless, some agencies (e.g., Bureau of Land Management (BLM)) 
voluntarily confer with the Service on actions that may affect a 
proposed species. Section 10(j)(2)(c)(ii) precludes the designation of 
critical habitat for nonessential populations. Activities that are not 
carried out, funded, or authorized by Federal agencies are not subject 
to provisions or requirements in section 7.
    Based on the best scientific and commercial data available, we must 
determine whether the experimental population is essential or 
nonessential to the continued existence of the species. The regulations 
(50 CFR 17.80(b)) state that an experimental population is considered 
essential if its loss would be likely to appreciably reduce the 
likelihood of survival of that species in the wild. All other 
populations are considered nonessential. We have determined that this 
experimental population is not essential to the continued existence of 
the species in the wild (see Status of Reestablished Populations 
section below). Therefore, the Service is designating a nonessential 
experimental population for the species in this area.
    Sonoran pronghorn used to establish the experimental population 
will come from a captive-rearing pen on Cabeza Prieta National Wildlife 
Refuge (NWR), as long as appropriate permits are issued in accordance 
with our regulations (50 CFR 17.22) prior to the animals' removal. The 
donor population is a captive-bred population derived primarily from 
wild stock at Cabeza Prieta NWR and from a wild Sonoran pronghorn 
population in northwestern Sonora, Mexico. The purpose of the captive 
population is to provide stock for augmenting existing U.S. and Mexican 
populations of Sonoran pronghorn, as well as supplying founder animals 
for establishment of an additional U.S. herd(s), in accordance with 
recovery actions 2.1-2.4 of the Sonoran Pronghorn Recovery Plan 
(Service 2002, pp. 47-48). The proposed population establishment will 
involve two phases: (1) Construction and operation of a captive-
breeding pen at Kofa NWR, with subsequent releases to establish a new 
herd; and (2) relocation of excess Sonoran pronghorn from the existing 
breeding pen at Cabeza Prieta NWR to the eastern portion of the BMGR-E, 
east of Highway 85 and south of Interstate 8, with the intent of 
establishing another herd.

Biological Information

    The Sonoran pronghorn was first described by Goldman (1945, pp. 3-
4) and is small in terms of cranial measurements compared to the 
measurements of other subspecies of pronghorn (Nowak and Paradiso 1971, 
p. 857). Historically, the Sonoran pronghorn ranged in the United 
States from approximately the Santa Cruz River, Arizona, in the east, 
to the Gila Bend and Kofa Mountains, Arizona, to the north, and to 
Imperial Valley, California, to the west (Service 1998, pp. 4-6). In 
northwestern Sonora, Mexico, the subspecies is thought to have occurred 
historically as far south as Bahia Kino and east to Santa Ana and 
Nogales. In Baja California, Mexico, the subspecies occurred in the 
northeast from the United States border south to the vicinity of Punta 
Estrella (Phelps and Webb 1981, pp. 20-21; Service 2002, Fig. 2). 
Currently, three populations of the Sonoran pronghorn are extant: (1) A 
U.S. population in southwestern Arizona, south of Interstate 8, west of 
Highway 85, and east of the Copper and Cabeza Prieta mountains (80-90 
wild pronghorn); (2) a population in the El Pinacate Region of 
northwestern Sonora (101 pronghorn); and (3) a population south and 
east of Mexico Highway 8 and west and north of Caborca, Sonora (381 
pronghorn). The three populations are geographically isolated due to 
barriers such as roads and fences (Service 2002, pp. 4-10, Fig. 1). The 
current range of the Sonoran pronghorn in the United States is defined 
by the boundaries described in number (1) above. Section 10(j)(2)(A) of 
the Act states that, ``The Secretary may authorize the release (and the 
related transportation) of any population (including eggs, propagules, 
or individuals) of an endangered species or a threatened species 
outside the current range of such species * * *'' Consistent with years 
of survey data, we are confident that no Sonoran pronghorn population 
occurs outside of the current range (Phelps 1981, pp. 23-24; Service 
2002, pp. 16 and 47).
    Threats to the Sonoran pronghorn include:
    (1) Highways, fences, railroads, developed areas, and irrigation 
canals that block access to essential forage or water resources;
    (2) a variety of human activities that disturb pronghorn or degrade 
habitat, including livestock grazing in the United States and Mexico; 
military activities; recreation; poaching and hunting; clearing of 
desert scrub and planting of buffelgrass (Pennisetum ciliare), 
particularly in Sonora; gold mining southeast of Sonoyta, Sonora; 
dewatering and development along the Gila River and R[iacute]o Sonoyta; 
and high levels of undocumented immigration and drug trafficking across 
the international border, and associated law enforcement response in 
the United States;
    (3) wildfire, fueled by nonnative perennial and ephemeral plants 
that have increased fine fuels and allowed fire to become a much more 
frequent event in the Sonoran Desert;
    (4) drought and associated limited food and water; and
    (5) small population size and random changes in demographics.
    Populations at low levels may experience random variations in sex 
ratios, age distributions, and birth and death rates among individuals, 
which can cause fluctuations in population size and possibly extinction 
(Service 2002, pp. 14-35; Primack 2002, pp. 196-197). In very sparse 
populations, males may have trouble finding females, causing an unequal 
sex-ratio, which may lead to a reduction in productivity (Primack 2002, 
pp. 310-311). In 2002, a severe drought was the primary cause of a 
major die off of Sonoran pronghorn. The U.S. population declined in 
2002 by 83 percent, to 21 animals (Bright and Hervert 2005, p. 46). The 
Mexican populations declined at the same time, but not to the same 
degree. The population southeast of Highway 8 declined by 18 percent, 
while the El Pinacate population declined by 26 percent. The 
differences between the rates of decline north and south of the border 
may be due to high levels of human disturbance on the U.S. side, due 
primarily to heightened levels of illegal immigration, smuggling, and 
law enforcement response (Service 2008, p. 55).

Recovery Efforts

    Restoring an endangered or threatened species to the point where it 
is recovered is a primary goal of the endangered species program. Thus, 
in 1982 we published the Sonoran Pronghorn Recovery Plan (Plan) 
(Service 1982), which was produced by a Recovery Team comprised of 
representatives from the Arizona Game and Fish Department (AGFD), 
Cabeza Prieta NWR, BLM, and Organ Pipe Cactus National Monument 
(OPCNM). The Plan was subsequently revised in 1994, 1998, and 2002. 
Major recovery actions include:
    (1) Enhance present populations of Sonoran pronghorn by providing 
supplemental forage and/or water;

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    (2) Determine habitat needs and protect present range;
    (3) Investigate and address potential barriers to expansion of 
presently used range, and investigate, evaluate, and prioritize present 
and potential future reintroduction sites within the historical range;
    (4) Establish and monitor a new, separate herd(s) to guard against 
catastrophes decimating the core population;
    (5) Continue monitoring populations and maintain a protocol for a 
repeatable and comparable survey techniques; and
    (6) Examine additional specimen evidence to assist in verification 
of taxonomic status (Service 1998, pp. iii-iv).
    The 2002 Supplement did not include delisting criteria; however, 
eight short-term recovery actions were identified as necessary to 
downlist the species to threatened. The supplement goes on to say that 
accomplishing these actions would provide the information necessary to 
determine delisting criteria. One of the short-term recovery actions 
was ``evaluating potential transplant locations, establishing 
methodology and protocols, developing interagency agreements (including 
with Mexico as required), acquiring funding, and initiating 
reestablishment projects'' (Service 2002, p. 38).
    After the catastrophic die off of Sonoran pronghorn in 2002, the 
Service and its partners embarked on a number of aggressive recovery 
actions to ensure the species' continued existence and to begin to 
rebuild populations. The cornerstone of these actions was a semi 
captive breeding facility, constructed in Childs Valley of Cabeza 
Prieta NWR in 2003, and stocked with wild Sonoran pronghorn in 2004. In 
2009, as of May, 69 Sonoran pronghorn resided in the pen. To date, 44 
Sonoran pronghorn have been released into the wild population. The goal 
of the facility is to produce at least 20 fawns each year for release 
to the current U.S. population, to newly established population(s) in 
the United States, and to augment Mexican populations.
    A number of other projects are under way to increase availability 
of green forage and water during dry periods and seasons, offsetting to 
some extent the effects of drought and barriers that prevent Sonoran 
pronghorn from accessing greenbelts and water, such as the Gila River 
and R[iacute]o Sonoyta. Nine emergency water sources (six on Cabeza 
Prieta NWR, one on OPCNM, and two on BMGR-West) have been constructed 
in recent years throughout the range of the U.S. population. Four 
forage enhancement plots, each consisting of a well, pump, pipelines, 
and irrigation lines, have been developed to irrigate the desert and 
produce forage for pronghorn. Another plot is nearing completion, and 
two additional plots will be installed over the next 5 years. These 
crucial projects, intended to pull the U.S. population back from the 
brink of extinction, have been cooperative efforts among the Service, 
AGFD, Marine Corps Air Station--Yuma, Luke Air Force Base, BLM, and 
OPCNM, with volunteer efforts from the Arizona Desert Bighorn Sheep 
Society, Arizona Antelope Foundation, and the Yuma Rod and Gun Club.
    The U.S. wild population of Sonoran pronghorn has rebounded from 21 
in 2002 to 80-90 in 2010; this increase has been facilitated by the 
collaborative recovery efforts for this species. However, at 80-90 
animals currently, the U.S. population is far from being secure. We 
have begun to work with our Mexican partners on recovery of the Sonoran 
pronghorn in Sonora. Although the number of pronghorn in Sonora (482 
animals) is significantly greater than in the United States, the safety 
net of water sources and forage plots is not in place there, and a 
severe drought could decimate those populations.

Reestablishment Areas

    O'Brien et al. (2005) used landscape-level classification and 
modeling to assess potential Sonoran pronghorn habitat in southwestern 
Arizona, including current and historical range, as a means of 
beginning the process of identifying potential locations for 
establishing a second U.S. Sonoran pronghorn herd. Both models 
identified greater than 4,632 square miles (sq. mi) (greater than 
12,000 square kilometers (sq. km)) of potential habitat (O'Brien et al. 
2005, pp. 28-30). The largest blocks of potential habitat outside of 
the current range were the Ranegras and Harquahala plains, King Valley 
at Kofa NWR north of Interstate 8; Sentinel Plain and other areas to 
the west between Interstate 8 and the Gila River; and areas not 
currently occupied south of Interstate 8 and immediately west of 
Highway 85. The models also identified a large land area east of 
Highway 85 and south of Interstate 8 as potential habitat. The authors 
did not evaluate potential habitats in the far eastern portions of the 
historical range of the Sonoran pronghorn in Arizona (O'Brien et al. 
2005, Figs. 3 and 4). O'Brien et al. (2005, p. 32) further explained 
that their models were an initial step toward identifying and 
evaluating potential translocation sites. They recommended soliciting 
public input, and reviewing predator presence and density, fencing, and 
the presence of preferred forage and water as additional steps in the 
evaluation process (O'Brien et al. 2005, p. 32).
    An Interdisciplinary Team (IDT), comprising members of the Sonoran 
Pronghorn Recovery Team, the Tohono O'odham Nation, and representatives 
from land management agencies located in southwestern Arizona, was 
convened in 2008 to address these and other issues and considerations, 
and to recommend specific areas for establishing an additional U.S. 
herd or herds. Development of alternatives for population establishment 
entailed consideration of three key variables: (1) Geographical areas 
for establishing populations outside of the current range; (2) 
potential establishment techniques; and (3) legal status of established 
populations under the Act. Each of these three key variables had a 
range of options. The IDT evaluated the three key variables to arrive 
at the most effective combinations of geographical areas, establishment 
techniques, and legal status options.
    The IDT conducted a mapping exercise to identify areas within the 
historical range of Sonoran pronghorn in the United States that were 
under Federal or State ownership and that contained suitable habitat 
for the species. The result of this exercise was identification of 
seven potential reestablishment areas, designated Areas A through G. 
The seven areas were then ranked by the IDT, using seven selection 
criteria, to determine the best areas for translocation. Area A (King 
Valley at Kofa NWR, and adjacent portions of primarily Yuma Proving 
Grounds and BLM lands) and Area D (primarily portions of the BMGR-E, 
BLM lands, and a portion of the Tohono O'odham Nation, all east of 
Highway 85) were ranked 1 and 2, respectively.
    Public scoping for the Sonoran pronghorn population establishment 
project included three open houses held in November 2008 on successive 
evenings at Yuma, Tucson, and Phoenix, Arizona. After consideration of 
public input, two alternatives were carried forward in the National 
Environmental Policy Act (NEPA) (42 U.S.C. 4321 et seq.) process, 
including establishment of Sonoran pronghorn in Areas A and D, which we 
will implement as per this final rule. Specific population 
establishment techniques are described for both areas (see Release 
Procedures, below), and we are establishing Sonoran pronghorn as a NEP 
in these areas under section 10(j) of the Act.
    The NEP encompasses Areas A and D in Arizona, as well as all areas 
into

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which Sonoran pronghorn are likely to disperse. The NEP is defined as 
follows: An area north of Interstate 8 and south of Interstate 10, 
bounded by the Colorado River on the west and Interstate 10 on the 
east; and an area south of Interstate 8, bounded by Highway 85 on the 
west, Interstates 10 and 19 on the east, and the United States-Mexico 
border on the south.
    Section 10(j) of the Act requires that an experimental population 
be wholly separate geographically from other wild populations of the 
same species. The Colorado River; Interstates 8, 10, and 19; and 
Highway 85, which form the boundaries of the NEP, are barriers to 
movement. Interstate 8 separates Area A from the current U.S. 
population, and Highway 85 forms a boundary between Area D and the 
current U.S. population. We do not expect Sonoran pronghorn to cross 
these barriers. Brown and Ockenfels (2007, p. 29) found that high-speed 
highways with right-of-way fences, such as these, were virtually 
Sonoran pronghorn-proof due to comprehensive fencing and high-volume 
traffic, and that interstate highways are effectively impassable for 
the species. Only once, in 1973, has a Sonoran pronghorn been known to 
cross Interstate 8 (Phelps 1981, p. 27). In 2008, a Sonoran pronghorn 
crossed Highway 85 and its associated right-of-way fences into BMGR-E 
(Howard 2008, pers. comm.); this is the only confirmed case of a 
Sonoran pronghorn crossing Highway 85 and its right-of-way fences. 
However, in July 2010, an unconfirmed sighting of a pronghorn doe was 
reported well east of Highway 85 in BMGR-E. This animal was not 
collared or ear-tagged, so its origins are uncertain, but it presumably 
crossed Highway 85 into BMGR-E from the wild population. No other 
documented cases of Sonoran pronghorn crossing Highway 85 and its 
right-of-way fences are known.
    Nonetheless, in the unlikely event that a Sonoran pronghorn moves 
outside the NEP, the individual or individuals would not constitute a 
population. Our regulations define ``population'' as a ``group of fish 
or wildlife * * * in common spatial arrangement that interbreed when 
mature'' (50 CFR 17.3) and thus determine that a ``geographic 
separation'' is any area outside the area in which a particular 
population sustains itself. See Wyo. Farm Bureau Fed'n v. Babbitt, 199 
F. 3d 1224, 1234 (10th Cir. 2000). These definitions preclude the 
possibility of population overlap as a result of the presence of 
individual dispersing Sonoran pronghorn--by definition lone dispersers 
do not constitute a population or even part of a population, since they 
are not in ``common spatial arrangement'' sufficient to interbreed with 
other members of a population. The evidence suggests that the 
likelihood of a lone pronghorn crossing the NEP boundary is very low, 
so it follows that the probability of that lone disperser encountering 
another Sonoran pronghorn of the opposite sex and reproducing is even 
more remote.
    The status, as endangered or as a member of the NEP, of any 
dispersing Sonoran pronghorn that manages to cross Highway 85, 
Interstate 8, or other barriers between the NEP and the current range 
is defined geographically. Any Sonoran pronghorn within the NEP area is 
considered a member of the nonessential experimental population 
(including any dispersing animals from within the current range that 
cross into the NEP area), whereas any Sonoran pronghorn outside of the 
NEP is fully protected under the Act as an endangered species.
    The geographical extent of the NEP designation includes areas 
unlikely to be used by Sonoran pronghorn, as only portions of this 
proposed NEP area contain suitable habitat. In the NEP area, Sonoran 
pronghorn habitat is limited to undeveloped areas within valleys. 
Mountainous areas, such as the Kofa, Castle Dome, Palomas, and Gila 
Bend mountains, do not provide habitat for this species; nor do 
developed areas within the valleys, such as agricultural areas and 
towns and cities. However, the NEP area represents what we believe to 
be the maximum geographical extent to which Sonoran pronghorn could 
move if released in Areas A and D. Once released into these areas, we 
expect the Sonoran pronghorn population(s) to grow and expand into 
adjacent suitable habitats, potentially moving to the boundaries of the 
NEP. In the unlikely event that any of the released Sonoran pronghorn, 
or their offspring, move across interstate highways or other barriers 
(e.g., rivers or mountainous areas, developed agriculture areas, or 
urban areas) to outside the designated NEP area (but not into the area 
occupied by the wild population), then the Service will evaluate the 
need, in the context of the 10(j) requirements, to amend the 10(j) rule 
to enlarge the boundaries of the NEP area to include the area of the 
expanded population. As discussed above, the likelihood of Sonoran 
pronghorn moving from the NEP area into the current range is very low.

Release Procedures

    The IDT developed the methods of release of Sonoran pronghorn into 
Areas A and D with the objective of maximizing the likelihood of 
success in establishing herds, while minimizing the impact to the 
source population (the animals in the captive breeding pen at Cabeza 
Prieta NWR) and limiting mortality or injury to translocated Sonoran 
pronghorn to the maximum extent possible. In King Valley, Kofa NWR 
(Area A), a rectangular-shaped, 0.5-square-mile (sq.-mi) (1.29-square-
kilometer (sq.-km)) captive-breeding pen will be constructed. The pen 
will include water sources and irrigated areas to enhance forage 
production, as well as two observation towers from which the animals 
will be monitored. In December 2011/January 2012, we anticipate moving 
11 Sonoran pronghorn (10 females and 1 male) to the pen from the 
captive-rearing pen at Cabeza Prieta NWR. These animals will be 
captured, either by use of a boma (a circular trap used inside the pen) 
or tranquilizer dart gun and moved one or two at a time by helicopter.
    Prior to movement to Kofa NWR, Sonoran pronghorn will be screened 
for epizootic hemorrhagic disease (EHD) and bluetongue (BTV). Both 
diseases can infect bighorn sheep and mule deer, as well as Sonoran 
pronghorn. To ensure these diseases are not inadvertently moved to Kofa 
NWR, only Sonoran pronghorn not exhibiting clinical signs (active 
lesions) of EHD and BTV will be transported to the new captive breeding 
pen at Kofa NWR. Biennial rotation of the breeding male and death of 
any Sonoran pronghorn in the breeding pen at Kofa NWR would require 
additional flights to bring new animals from Cabeza Prieta NWR. Methods 
perfected at Cabeza Prieta NWR will be employed in these activities, 
which have been used successfully with minimal mortality of pronghorn.
    Assuming successful captive-breeding at the Kofa NWR pen, up to 20 
Sonoran pronghorn will be released annually into suitable habitats 
outside of but adjacent to the pen site at Kofa NWR, beginning as early 
as the winter of 2012 or 2013 and recurring each winter until 2020. 
Sonoran pronghorn in the pen, as well as animals released, will be 
closely monitored to determine success or need for adaptive management. 
Success criteria will be developed by the recovery team prior to the 
release of any animals, but the objective will be to continue releases 
until the population can sustain itself without augmentation. 
Concurrently, but only if excess animals are available from the 
captive-breeding pen at Cabeza Prieta NWR (not needed to augment 
existing herds or for the pen at Kofa NWR), these animals will be

[[Page 25597]]

captured from the pen, transported to a holding pen in Area D, held 
temporarily, and then released as a group. The holding pen in Area D is 
located in the Midway Well area near Hat Mountain (an area locally 
known as BMGR-E ``Area B'') in Maricopa County, Arizona. Ideally, the 
Sonoran pronghorn will be captured together and moved quickly to a 
holding pen, allowed to recover for a brief period, and released 
together.
    Released animals in Area D will be monitored via aircraft and on-
the-ground personnel to determine survival, reproduction, and other 
measures of success. Details of the monitoring plan will be developed 
prior to release and will include collection of enough data to 
quantitatively determine if we are meeting success criteria and, if 
not, what needs to be corrected to ensure success. Through adaptive 
management, release techniques and other management will be revised as 
needed to ensure success. Additional description of the release 
procedures and monitoring protocols can be found in the final EA (for 
copies of this document, see ADDRESSES above).

Status of Reestablished Populations

    We have determined that these reestablished populations are 
nonessential, based on the following:
    (a) Wild populations of the Sonoran pronghorn, totaling about 562 
to 572 animals, currently exist at: (1) Cabeza Prieta NWR, OPCNM, BMGR, 
and adjacent BLM lands; (2) in the El Pinacate region of Sonora; and 
(3) south and east of Highway 8 in Sonora.
    (b) A captive-breeding pen at Cabeza Prieta NWR maintains a captive 
population and provides stock to augment the wild populations in 
Arizona and Sonora. The pen has been highly successful. It was first 
stocked with Sonoran pronghorn in 2004; the original group of 11 
animals has grown to 69 (May 2010), and another 44 Sonoran pronghorn 
have been released from the pen into the wild.
    (c) The first priority for use of animals in the captive-breeding 
pen at Cabeza Prieta NWR is to augment herds within the boundaries of 
the current range of the species. Relocation of Sonoran pronghorn from 
the captive breeding pen to Kofa NWR will not appreciably inhibit the 
augmentation efforts for the herds within the boundaries of the current 
range of the species. Sonoran pronghorn produced at the Cabeza Prieta 
NWR pen that are not needed to augment herds within the current range 
or to populate the Kofa NWR pen will be used to establish a population 
in Area D.
    (d) The possible failure of this action will not appreciably reduce 
the likelihood of survival of the species in the wild, because (1) the 
first priority for use of Sonoran pronghorn from the captive-breeding 
pen at Cabeza Prieta NWR is to augment the wild herd, and (2) recovery 
actions have been, and continue to be, implemented in the United States 
to reduce the effects of drought on the species (Service 2009, pp. 9, 
18-19).
    (e) Through programs of work endorsed by the Canada/Mexico/U.S. 
Trilateral Committee for Wildlife and Ecosystem Conservation and 
Management, the Service and AGFD coordinate with our Mexican partners 
on recovery actions for Sonoran pronghorn in Mexico, enhancing the 
likelihood of their survival and recovery.
    We will ensure, through our section 10 permitting authority and the 
section 7 consultation process, that the use of Sonoran pronghorn from 
the donor population at Cabeza Prieta NWR for releases in Areas A or D 
is not likely to jeopardize the continued existence of the species in 
the wild. Establishment of additional Sonoran pronghorn populations 
within the species' historical range is a necessary step in recovery 
(Service 2002, p. 38).
    The special rule that accompanies this 10(j) rule is designed to 
broadly exempt take of Sonoran pronghorn from the section 9 
prohibitions outside of National Wildlife Refuge and National Park 
Service lands, as long as the take is incidental to otherwise lawful 
activities. We provide this exemption because we believe that 
incidental take of members of the NEP associated with otherwise lawful 
activities will not pose a substantial threat to the recovery of 
Sonoran pronghorn, as activities that currently occur or are 
anticipated in the NEP area are generally compatible with Sonoran 
pronghorn recovery. For example, in Area A, there are vast expanses of 
open valleys without major barriers to Sonoran pronghorn movement that 
provide suitable habitat. These valleys include King Valley at Kofa 
NWR, Palomas Plain, the southern end of the Ranegras Plain, and 
portions of the Yuma Proving Grounds. The La Posa Plain and Castle Dome 
Plain also provide habitat. Highway 95 runs north-south through those 
plains, and although it may somewhat inhibit movement to the west side 
of those plains, it is not a substantial barrier because it lacks 
right-of-way fences. In Area D, there is considerable habitat in the 
valleys among the Sauceda, Sand Tank, Batamote, and other mountains in 
that region.
    There are existing military activities at Yuma Proving Grounds in 
Area A and BMGR-E in Area D, but pronghorn have coexisted with military 
activities for many years at the BMGR (deVos 1990, pp. 49-50; Krausman 
et al. 2004, pp. 29-33; Krausman et al. 2005, pp. 20-22); as a result, 
we believe they will persist with the similar activities conducted at 
Yuma Proving Grounds and in Area D. Although some forms of military 
activities could potentially result in incidental death or injury of 
individual pronghorn, no incidental take has ever been documented due 
to military activities, even before precautions were set in place as a 
result of section 7 consultations to minimize the likelihood of such 
take at the BMGR.
    There is some likelihood of Sonoran pronghorn drowning in canals in 
Area A. Canals are present in agricultural areas on the southern, 
eastern, and northeastern portions of Area A; Sonoran pronghorn are 
known to drown in such canals (Rautenstrauch and Krausman 1986, p. 9). 
The major canal in Area A most likely to be accessed by Sonoran 
pronghorn is the Wellton Canal, located north of the Gila River and on 
the northern edge of the agricultural lands in the Gila Valley. It is 
equipped with ramps and steps designed to prevent ungulate drownings. 
In addition, a series of wildlife water sources exists to the north of 
the canal as alternative water sources. Most of the canals elsewhere in 
Area A are too small to result in Sonoran pronghorn entrapment, or are 
surrounded by agriculture or other developments and are unlikely to be 
accessed by Sonoran pronghorn. Other activities such as recreational 
hunting and camping, vehicle use, livestock grazing, and small-scale 
rural or agricultural development, are anticipated to either have 
minimal effects on Sonoran pronghorn or will be limited in extent 
(e.g., rural and agricultural development).
    Under section 7(a)(1) of the Act, all Federal agencies are mandated 
to use their authorities to conserve listed species. In addition, the 
BLM has a policy of conferring with the Service, under section 7(a)(4), 
on their actions that may affect proposed species (BLM 6840 Manual). 
Some activities do have greater potential to compromise the success of 
the Sonoran pronghorn reestablishment than those described above. For 
instance, construction of new highways, particularly those with rights-
of-way fencing, or new canals in the NEP could create barriers to 
movement and bisect important pronghorn habitats. There is also the 
potential for BLM to permit large-scale solar power

[[Page 25598]]

plants, which would be constructed in the valleys and could eliminate 
up to tens of thousands of acres of habitat. Other BLM-authorized 
projects, such as agricultural leases, could also potentially remove 
large blocks of habitat and perhaps compromise the success of this 
project. The potential for these projects to impact the reestablishment 
is probably greatest on BLM lands in the valleys to the east of Kofa 
NWR. The Service will have the opportunity through the section 7(a)(4) 
conference process to work with the BLM to minimize the potential 
adverse effects of solar plants, agricultural leases, highways, or 
other projects that may compromise Sonoran pronghorn recovery.

Management

    The lands within the NEP area are managed and listed in descending 
order of acreage within areas A and D as follows: Area A--the Service 
(Kofa NWR), Department of the Army (Yuma Proving Grounds), BLM, Arizona 
State Lands Department, private landowners, and Colorado River Indian 
Tribes; Area D: Tohono O'odham Nation, BLM, Department of the Air Force 
(BMGR-E), private owners, and Arizona State Land Department. Outside of 
Areas A and D, but within the NEP, land ownership is similar, but also 
includes lands within the Gila River Indian Reservation, Ak-Chin Indian 
Reservation, Pascua Yaqui Indian Reservation, San Xavier Reservation, 
Buenos Aires NWR, Saguaro National Park, OPCNM, Tucson Mountain Park, 
and Coronado National Forest. Due to the management flexibility 
provided by the NEP designation and the special rule, we do not 
anticipate that establishment of Sonoran pronghorn in Areas A or D and 
subsequent dispersal of Sonoran pronghorn from the release sites will 
affect management on Tribal, BLM, National Forest, Department of 
Defense, State, or private lands.
    Through section 7 consultations on NWR lands and National Park 
Service lands, some changes in management may occur to reduce adverse 
effects to Sonoran pronghorn, including minimizing the likelihood of 
incidental take. However, we believe few changes will be needed, 
because management of these lands already is broadly compatible with 
Sonoran pronghorn recovery. Other Federal agencies that propose actions 
on Kofa NWR or National Park Service lands will also be required to 
consult with us under section 7 of the Act, if such activities may 
affect Sonoran pronghorn. For instance, some activities conducted by 
Yuma Proving Grounds (e.g., overflights of Kofa NWR) will be subject to 
the consultation requirements. Some Federal agencies, such as BLM, that 
propose actions outside of Kofa NWR or National Park Service lands may 
elect to work with the Service voluntarily through the section 7(a)(4) 
conferring process to ensure that adverse effects of their actions on 
Sonoran pronghorn in the NEP area are minimized.
    The Service (Cabeza Prieta NWR, Kofa NWR, and the Ecological 
Services office in AZ), AGFD, OPCNM, Luke Air Force Base, BLM, and 
other partners, in close coordination with the Sonoran Pronghorn 
Recovery Team, will plan and manage the establishment of new 
populations of Sonoran pronghorn. This group will closely coordinate on 
releases, monitoring, and coordination with landowners and land 
managers, among other tasks necessary to ensure successful population 
establishment. Management issues related to the Sonoran pronghorn NEP 
that have been considered include:
    (a) Mortality: ``Incidental take,'' as defined by regulation at 50 
CFR 17.3, is take that is incidental to, and not the purpose of, the 
carrying out of an otherwise lawful activity, such as agricultural 
activities and other rural development, ranching, military training and 
testing, camping, hiking, hunting, vehicle use of roads and highways, 
and other activities that are in accordance with Federal, Tribal, 
State, and local laws and regulations. With the finalization of this 
10(j) rule, incidental take of Sonoran pronghorn within the NEP area 
outside of National Wildlife Refuge and National Park Service lands 
will not be prohibited, provided that the take is unintentional, not 
due to negligent conduct, and is in accordance with the special rule 
that is a part of this 10(j) rule. However, if there is evidence of 
intentional take, not authorized by the special rule or by a section 10 
permit, of a Sonoran pronghorn within the NEP we will refer the matter 
to the appropriate law enforcement entities for investigation. We 
expect levels of incidental take to be low, because, as discussed in 
paragraph (d) under Status of Reestablished Populations, above, the 
establishment of new populations is compatible with most existing human 
use activities and practices for the area. In the current range of the 
Sonoran pronghorn in the United States, no incidental take has been 
documented from military activities, recreation, use of highways, and 
most other activities that occur both in the current range and in the 
NEP, the exception being canals, in which Sonoran pronghorn have 
drowned on several occasions. More specific information regarding take 
can be found in the Regulation Promulgation section of this final rule.
    (b) Special handling: In accordance with 50 CFR 17.21(c)(3), ``any 
employee or agent of the Service, any other Federal land management 
agency, the National Marine Fisheries Service, or a State conservation 
agency, who is designated by his agency for such purposes, may, when 
acting in the course of his official duties'', handle Sonoran pronghorn 
to aid sick or injured Sonoran pronghorn, or to salvage dead Sonoran 
pronghorn. However, other personnel and their agents, not specifically 
named in these regulations, will need to acquire permits from the 
Service for these activities.
    (c) Coordination with landowners and land managers: During the NEPA 
scoping process, the Service and cooperators identified issues and 
concerns associated with the proposed Sonoran pronghorn population 
establishment. The population establishment was also discussed with 
potentially affected State agencies, tribes, and private landowners. 
All land owners and managers also had an opportunity to review and 
comment on the draft EA and proposed rule. State and Federal land 
management agencies either supported or did not oppose the 
reestablishment of a Sonoran pronghorn herd and designation as a NEP; 
however, at least two private landowners in the NEP expressed 
opposition to the proposal. U.S. Customs and Border Protection strongly 
encouraged limiting reestablishment to Area A. See the section Summary 
of Public and Peer Review Comments and Recommendations below for 
summaries of those comments and how we addressed any concerns.
    (d) Monitoring and Adaptive Management: A monitoring and adaptive 
management plan for the population establishment program will be 
implemented by the Service, AGFD, and other partners to determine if 
the program is successful, and to adjust management as needed to ensure 
success. Success criteria have not yet been finalized, but they will 
include the concept that the objective of the program is to establish 
Sonoran pronghorn herds that are self-sustaining without augmentation 
via releases from captive pens or holding facilities, thereby 
contributing to recovery goals. The monitoring will assess all aspects 
of the population establishment program, from capture and movement of 
the animals to the captive breeding pen (Area A) or holding area (Area 
D), monitoring of the animals in these captive facilities, and 
monitoring and

[[Page 25599]]

tracking released Sonoran pronghorn in the release areas, including 
Sonoran pronghorn water sources and any forage enhancement vegetation 
plots developed to support the established herds. Monitoring of 
released Sonoran pronghorn will be conducted to determine the 
following:
    (1) Mortality and recruitment rates,
    (2) causes of mortality among adult and juvenile Sonoran pronghorn,
    (3) reliance on freestanding water sources,
    (4) movement corridors and barriers to movements, and
    (5) habitat preferences.
    Each released animal will be fitted with an ear tag and radio 
collar. A limited number of Sonoran pronghorn will be fitted with 
Geographic Positioning System (GPS) platform telemetry collars. It is 
expected the GPS transmitters will function for up to 3 years. 
Telemetry flights with a fixed-wing aircraft will be conducted twice a 
month. Each Sonoran pronghorn will be observed from an altitude of 
1,000 feet (ft.) above ground level with the aid of binoculars. Group 
size and composition (sex and age), habitat type, and terrain will be 
recorded. Additional monitoring of individual Sonoran pronghorn and 
herd movements will be done from the ground, particularly from high 
points where valley habitats of the Sonoran pronghorn can be viewed. 
All monitoring flights and on-the-ground surveillance will be closely 
coordinated with and approved by the tribal, military, and other land 
managers and owners where such monitoring will occur. As Sonoran 
pronghorn become established and breed in the establishment areas, the 
percentage of animals tagged or radio-collared will decline over time, 
and additional animals may need to be captured and radio collared to 
adequately monitor the herds. We will attempt to maintain radio collars 
on at least 10 percent of a population.
    Monitoring data will be assessed regularly by the Recovery Team, 
and methods will be revised as needed to increase the likelihood of 
successful population establishment and to increase efficiency. A 
comprehensive review, assessment, and report of the reestablishment 
program by the Recovery Team will occur at a frequency of no less than 
once every 5 years. If at any point the program is not meeting its 
stated objective, or is falling short of meeting the success criteria, 
techniques and methods will be reviewed and revised as needed to 
correct problems and increase the likelihood of success. If revisions 
fall outside the scope of the action evaluated in the EA and FONSI, all 
necessary environmental compliance will be completed before those 
revised techniques or methods are implemented. Additional details of 
the monitoring and adaptive management plan, including quantifiable and 
measurable success criteria, will be finalized and posted on our Web 
site at https://www.fws.gov/southwest/es/arizona/ prior to release of 
Sonoran pronghorn into Areas A or D.
    (e) Public awareness and cooperation: Public scoping for the 
Sonoran pronghorn population establishment project was conducted in the 
fall of 2008. Actions included an October 30, 2008, scoping letter sent 
to approximately 6,000 recipients, a news release to local media 
sources, and a series of 3 open houses held in the Arizona cities of 
Yuma, Tucson, and Phoenix, during November 18-20, 2008. We accepted 
written public scoping comments until December 12, 2008. We received 44 
written responses about the project. In our EA, we discussed issues 
identified in the responses. The IDT and the Service used these issues 
to refine the proposed action and alternatives in the EA, and to 
identify mitigation measures to avoid or reduce potential project 
effects. The IDT and the Service also used the public concerns to 
determine which resources would be the greatest focus of the EA 
analysis. The comments received during the scoping process are listed 
in the EA, and were considered in the formulation of alternatives 
considered in the NEPA process. The following section describes the 
public outreach we conducted and the responses received during the 
public and peer review comment periods on the proposed rule and draft 
EA.

Section 7 Consultation

    A special rule under section 4(d) of the Act is included in this 
establishment of an experimental population under section 10(j) of the 
Act. A population designated as experimental is treated for the 
purposes of section 9 of the Act as threatened, regardless of the 
species' designation elsewhere in its range. The development of 
protective regulations for a threatened species is an inherent part of 
the section 4 listing process. The Service must make this determination 
considering only the ``best scientific and commercial data available.'' 
A necessary part of this listing decision is also determining what 
protective regulations are ``necessary and advisable to provide for the 
conservation of [the] species.'' Determining what prohibitions and 
authorizations are necessary to conserve the species, like a listing 
determination of whether the species meets the definition of threatened 
or endangered, is not a decision that Congress intended to undergo 
section 7 consultation.
    Actions associated with the establishment of the experimental 
population, such as construction of pens or the movement of wild 
animals, will undergo section 7(a)(2) consultation, as appropriate.

Summary of Public and Peer-Review Comments and Recommendations

    On February 4, 2010, we published our proposed rule to establish a 
NEP of Sonoran pronghorn in southwestern Arizona (75 FR 5732), and 
requested written comments from the public on the proposed rule and 
draft EA. We also contacted the appropriate Federal, State, and local 
agencies; tribes; scientific organizations; and other interested 
parties and invited them to comment on the proposed rule and draft EA. 
The initial comment period was open from February 4, 2010, to April 5, 
2010. A second comment period was open from June 9, 2010, to July 9, 
2010 (75 FR 32727). A public hearing was held in Gila Bend, Arizona, on 
February 23, 2010; however, no verbal or written comments were 
submitted at that hearing.
    In accordance with our policy on peer review, published on July 1, 
1994 (59 FR 34270), we solicited opinions from three expert biologists 
who are familiar with this species regarding pertinent scientific or 
commercial data and assumptions relating to supportive biological and 
ecological information for the proposed rule. Reviewers were asked to 
review the proposed rule for accuracy and validity of its biological 
information and assumptions. Two out of three peer reviewers provided 
comments. They were both supportive of the proposal to reestablish the 
Sonoran pronghorn in areas of southwestern Arizona, but suggested 
revisions or had some questions about the proposal. The remaining peer 
reviewer asked for additional information, but did not submit a final 
peer review. Their letter requesting additional information is counted 
as a response, with no position taken.
    We reviewed all comments received from the peer reviewers, 
agencies, and the public for substantive issues and new information 
regarding the proposed NEP. Substantive comments received during the 
comment period have been addressed below and, where appropriate, 
incorporated directly into this final rule. The comments are grouped 
below as peer review and agency or public comments.
    We received responses from 29 parties, comprising private 
individuals

[[Page 25600]]

(15), nongovernmental organizations (4), peer reviewers (3), state 
agencies (2), Federal agencies (3), university (1), and anonymous (1). 
Some commenters clearly supported (10), opposed (4), or took no 
position (7) on the proposal. In addition, two supported the 
reestablishment, but opposed the NEP. One supported population 
reestablishment, but conditioned their support of the NEP on continued 
strong commitment by the Department of Defense to Sonoran pronghorn 
conservation. One conditioned their support on implementation of 
predator control, acknowledgement of the importance of water sources, 
and no impacts to hunting. Two others opposed the proposal unless 
predator control was conducted. One supported the Kofa NWR 
reestablishment but not the BMGR-E reestablishment, and one supported 
the BMGR-E reestablishment, but opposed the NEP and establishment of a 
population at Kofa NWR.
    The two peer reviewers who submitted comments agreed with the 
following determinations: (1) The proposed establishment of 
experimental, nonessential populations of Sonoran pronghorn is well 
considered and has great potential to enhance the status of Sonoran 
pronghorn in the United States, and (2) proposed survey, monitoring, 
and capture techniques, and operation of the captive breeding pen, are 
within accepted practices in wildlife management. However, one 
commenter asked that the details of the monitoring program and success 
criteria be more clearly stated.

Peer-Review Comments

    (1) Comment: Continual improvement in capture methods should be 
pursued on non-endangered subspecies across the range of the pronghorn 
to increase efficiency in capturing and maintaining captive 
populations.
    Our Response: Consistent with Adaptive Management in the EA and the 
recovery plan, we will continue to evaluate new information, including 
publications, reports, and personal communications with others working 
on Sonoran pronghorn throughout its range. We will also learn from our 
experiences with Sonoran pronghorn to fine tune and improve capture 
methodologies, with the goal of minimizing stress and the possibility 
of injury or mortality of captured animals, while increasing efficiency 
of capture operations.
    (2) Comment: Although habitat modeling to identify habitat suitable 
for reestablished populations is adequate at the landscape scale, 
additional work is needed to pinpoint the adequacy of habitat prior to 
releases. Cholla is a key forage plant that is missing or scarce north 
of Interstate 8. Supplemental feeding may be necessary in that area 
during prolonged drought.
    Our Response: As discussed under ``Reestablishment Areas'' above, 
an IDT was tasked with identifying and ranking possible reestablishment 
areas within the historical range of the Sonoran pronghorn. Areas A and 
D ranked first and second of seven areas identified. Potential 
locations for a captive pen at Kofa NWR are somewhat limited by 
extensive wilderness designation that precludes construction and 
operation of that facility. Hence a block of non-wilderness, large 
enough to accommodate the pen, was selected in northern King Valley. 
This is a good location, because the pen will be located off well-
traveled roads, yet it is relatively close to Highway 95, the access 
route from Yuma, and its location in the northern part of the valley 
provides an opportunity for pronghorn released directly from the pen to 
spread out throughout King Valley before moving off-refuge to areas of 
Yuma Proving Grounds or BLM lands. The IDT considered the absence of 
chain fruit cholla on Kofa NWR in its rankings of the seven areas. One 
of the seven criteria used to rank the areas was forage quality. The 
absence of chain fruit cholla is a concern; however, the value of that 
plant in the diet of the Sonoran pronghorn is primarily as a source of 
preformed water; it provides little nutrition (Fox 1997, pp. 76, 79). 
As a result, if freestanding water is available or can be provided 
dependably, the importance of chain fruit cholla in the diet is much 
reduced. Five water sources outside of the pen at Kofa NWR will be 
built to provide dependable water for Sonoran pronghorn. Water sources 
and chain fruit cholla are available on BMGR-E in Area D near where the 
holding pen will be constructed, and, if needed, additional water 
sources will be constructed; hence, water for drinking is not 
anticipated to be a limiting factor at BMGR-E.
    (3) Comment: The movement of released Sonoran pronghorn might be 
underestimated, particularly as the populations grow. In particular, 
there is a possibility of Sonoran pronghorn moving south in Area D into 
Organ Pipe Cactus NM east of Highway 85, and then west into the areas 
occupied by the wild population.
    Our Response: Some of the young male Sonoran pronghorn released 
from the pen in Cabeza Prieta NWR have moved extraordinary distances, 
and across barriers including, on at least two occasions, the right-of-
way fence along Highway 85, a vehicle barrier constructed on the U.S./
Mexico border, and Highways 2 and 8 in Sonora, Mexico. Released Sonoran 
pronghorn that wander over large areas tend to continue these long-
distance movements until they find and join an existing herd or another 
Sonoran pronghorn. Although such movements are expected to be unusual, 
we agree that as Sonoran pronghorn are released and as populations 
grow, individuals will periodically make long-distance movements and 
some animals could potentially move across Highway 85 from Area D into 
areas occupied by the wild herd. Similarly, Sonoran pronghorn released 
from the pen at Cabeza Prieta NWR may occasionally move across Highway 
85 into Area D.
    Although these movements could occur more frequently as populations 
on both sides of Highway 85 increase, we do not anticipate they will 
ever be more than rare events for the reasons discussed in 
``Reestablishment Areas'' above, hence we do not anticipate overlap of 
the wild population and the NEP. Lone dispersers do not constitute a 
population or even part of a population, because they are not in 
``common spatial arrangement'' sufficient to interbreed with other 
members of a population (see discussion under ``Reestablishment 
Areas''). Furthermore, the likelihood of a Sonoran pronghorn moving 
from the release site on BMGR-E south to the area east of Highway 85 in 
OPCNM is remote, because a Sonoran pronghorn would have to traverse 
miles of rugged terrain from the holding pen at Midway Wash through the 
Batamote/Coffee Pot Mountain region to reach the Hickiwan Valley or 
Pozo Redondo Valley, and then move south and west from there across 
Highway 86 and through the Gunsight Hills, then down the western bajada 
of the Ajo Mountains. Years of surveys have shown that Sonoran 
Pronghorn do not use the rugged slopes and mountainous terrain 
characteristic of this area (Hervert et al. 2005, p. 12).
    (4) Comment: One peer reviewer expressed concern that there is a 
remote possibility of a Sonoran pronghorn moving through Area D south 
and east to Buenos Aires NWR, where a population of Mexican pronghorn 
(Antilocapra americana mexicana) currently exists.
    Our Response: Buenos Aires NWR is in the southeastern portion of 
the NEP area, and is within the historical range of the Sonoran 
pronghorn (Service 2002, p. 17). The NEP area includes all regions into 
which Sonoran pronghorn could

[[Page 25601]]

potentially move from release sites. Although over 90 miles southeast 
of the release site, we agree there is a small probability that Sonoran 
pronghorn could reach Buenos Aires NWR at some point in the future. The 
major barrier between the two areas is likely a complex of rugged 
terrain between the release site and Sonoran pronghorn habitat to the 
east and south, formed by the Batamote, Sauceda, Sand Tank, and other 
ranges. If a Sonoran pronghorn could get past that barrier, then 
potentially it could move through the valleys of the Tohono O'odham 
Nation, and then around the north end of the Quinlan Mountains, across 
Highway 86 and south through the Altar Valley to Buenos Aires NWR. 
Historically a more direct route probably existed south of the 
Baboquivari Mountains in Mexico, but a vehicle barrier and livestock 
fence on the United States/Mexico border now block that route.
    In the unlikely event that a Sonoran pronghorn reached Buenos Aires 
NWR, the Service would be required to assess the effects of its actions 
at the refuge, including managing herds of Mexican pronghorn, and 
conduct intra-Service section 7 consultation if those activities may 
affect the Sonoran pronghorn. A decision on how to proceed would emerge 
from that process and would be based on the circumstances at the time.
    (5) Comment: The proposed rule stated that success criteria would 
be developed by the recovery team prior to release of any Sonoran 
pronghorn into areas A or D. Success criteria drive the types of 
monitoring needed. Some parameter(s) of success need to be identified.
    Our Response: Broadly defined, success will be measured by our 
ability to achieve the purpose of the program, which, as stated in the 
EA (p. 19) and our recovery plan (Service 2002, p. 38), is to 
contribute to recovery of the Sonoran pronghorn by establishing 
additional populations in suitable habitat within its historical range 
in Arizona. In accordance with 50 CFR 17.81(c)(4), a technical 
definition of what it means to establish a population of Sonoran 
pronghorn will, as the commenter notes, be forthcoming; however, it 
will almost certainly involve the presence of Sonoran pronghorn 
surviving and breeding in the wild to an extent that, at some point, 
release of additional animals to augment the population--either via the 
captive breeding pen at Kofa NWR or the holding pen in Area D-- is no 
longer needed to sustain the population.
    (6) Comment: If the reestablished populations cannot be sustained 
into the future without intensive management, this needs to be clearly 
stated.
    Our Response: Some level of management will always be needed to 
maintain the reestablished herds. These management actions will be 
undertaken by the Service, in conjunction with our partners, including 
AGFD. The Sonoran pronghorn will need to be monitored to track their 
status, water sources will need to be maintained for them, and the 
lands they occupy must remain as habitat capable of supporting a viable 
herd. However, once a population is established to the degree that 
additional augmentation is no longer needed to sustain it, we 
anticipate that some intensive management actions, including the 
maintenance of a captive rearing pen, will no longer be necessary.
    (7) Comment: Not enough information is presented to determine if 
the proposed monitoring will be adequate to determine whether the 
program is successful, and to better determine the role of water and 
forage enhancement plots in recovery, mortality, and recruitment rates; 
causes of mortality by age and sex, movements; and the role of habitat 
in the life history of the Sonoran pronghorn.
    Our Response: The monitoring should not only allow us to determine 
whether the program is a success, but if it is failing to meet its 
objectives, the reason(s) why it is failing must emerge from the 
monitoring data. The latter is crucial for making appropriate changes 
in management to correct problems and ensure we achieve sustainable 
herds in Areas A and D. Although our monitoring plan is not yet 
complete, released animals in Area D will be monitored primarily via 
aircraft to determine survival, reproduction, and other measures of 
success. We acknowledge that all of the parameters noted by the 
commenter above are important in terms of tracking the status of 
Sonoran pronghorn populations. All of these factors will be carefully 
considered in the development of the monitoring program in Areas A and 
D.

Public Comments

    (8) Comment: Establishment of additional herds of Sonoran pronghorn 
in the Uni