[Federal Register Volume 75, Number 189 (Thursday, September 30, 2010)]
[Proposed Rules]
[Pages 60516-60561]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2010-24349]



[[Page 60515]]

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Part II





Department of the Interior





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Fish and Wildlife Service



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50 CFR Part 17



Endangered and Threatened Wildlife and Plants; 12-Month Finding on a 
Petition to List the Pygmy Rabbit as Endangered or Threatened; Proposed 
Rule

Federal Register / Vol. 75, No. 189 / Thursday, September 30, 2010 / 
Proposed Rules

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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[Docket No. FWS-R8-ES-2007-0022]
[MO 92210-0-0008-B2]


Endangered and Threatened Wildlife and Plants; 12-Month Finding 
on a Petition to List the Pygmy Rabbit as Endangered or Threatened

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Notice of a 12-month petition finding.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), announce a 
12-month finding on a petition to list the pygmy rabbit (Brachylagus 
idahoensis) as endangered or threatened under the Endangered Species 
Act of 1973, as amended. After review of all available scientific and 
commercial information, we find the listing of the pygmy rabbit is not 
warranted at this time. However, we ask the public to submit to us any 
new information that becomes available concerning the threats to the 
pygmy rabbit or its habitat at any time.

DATES: The finding announced in the document was made on September 30, 
2010.

ADDRESSES: This finding is available on the Internet at http://www.regulations.gov at Docket Number FWS-R8-ES-2007-0022. Supporting 
documentation we used to prepare this finding is available for public 
inspection, by appointment, during normal business hours at the U.S. 
Fish and Wildlife Service, 1340 Financial Boulevard, Suite 234, Reno, 
NV 89502. Please submit any new information, materials, comments, or 
questions concerning this species to the Service at the above street 
address.

FOR FURTHER INFORMATION CONTACT: Robert D. Williams, State Supervisor, 
U.S. Fish and Wildlife Service, Nevada Fish and Wildlife Office (see 
ADDRESSES); by telephone (775) 861-6300 or by facsimile (775) 861-6301. 
Persons who use a telecommunications device for the deaf (TDD) may call 
the Federal Information Relay Service (FIRS) at (800) 877-8339.

SUPPLEMENTARY INFORMATION:

Background

    Section 4(b)(3)(B) of the Endangered Species Act of 1973, as 
amended (Act) (16 U.S.C. 1531 et seq.), requires that, for any petition 
to revise the List of Endangered and Threatened Wildlife and Plants 
that contains substantial scientific or commercial information that the 
listing may be warranted, we make a finding within 12 months of the 
date of the receipt of the petition. In this finding, we will determine 
that the petitioned action is either: (1) Not warranted, (2) warranted, 
or (3) warranted, but the immediate proposal of a regulation 
implementing the petitioned action is precluded by other pending 
proposals to determine whether species are endangered or threatened , 
and expeditious progress is being made to add or remove qualified 
species from the Lists of Endangered and Threatened Wildlife and 
Plants. Section 4(b)(3)(C) of the Act requires that we treat a petition 
for which the requested action is found to be warranted but precluded 
as though resubmitted on the date of such finding; that is, requiring a 
subsequent finding to be made within 12 months. We must publish these 
12-month findings in the Federal Register.

Previous Federal Actions

    On November 21, 1991, we added the pygmy rabbit to our list of 
candidate species as a category 2 candidate species (56 FR 58804). A 
category 2 candidate species was a species for which we had information 
indicating that a proposal to list it as threatened or endangered under 
the Act may be appropriate, but for which additional information on 
biological vulnerability and threat was needed to support the 
preparation of a proposed rule. In the February 28, 1996, Candidate 
Notice of Review (CNOR) (61 FR 7595), we adopted a single category of 
candidate species defined as follows: ``Those species for which the 
Service has on file sufficient information on biological vulnerability 
and threat(s) to support issuance of a proposed rule to list but 
issuance of the proposed rule is precluded.'' In previous CNORs, 
species matching this definition were known as category 1 candidates 
for listing. Thus, the Service no longer considered category 2 species 
as candidates and did not include them in the 1996 or any subsequent 
CNORs. The decision to stop considering category 2 species as 
candidates was designed to reduce confusion about the status of these 
species and to clarify that we no longer regarded these species as 
candidates for listing.
    On April 21, 2003, we received a petition dated April 1, 2003, from 
the Committee for the High Desert, Western Watersheds Project, American 
Lands Alliance, Oregon Natural Desert Association, Biodiversity 
Conservation Alliance, Center for Native Ecosystems, and Mr. Craig 
Criddle requesting the pygmy rabbit found in Oregon, Idaho, Montana, 
Wyoming, California, Nevada, and Utah be listed as endangered or 
threatened in accordance with section 4 of the Act (Committee for the 
High Desert et al. 2003, entirety). The petition was clearly identified 
as a petition and contained the names, signatures, and addresses of the 
requesting parties. The petitioners requested designation of critical 
habitat concurrent with the listing. Included in the petition was 
supporting information regarding the species' taxonomy and ecology, 
historical and current distribution, and perceived threats to the pygmy 
rabbit.
    On June 10, 2003, we acknowledged in a letter the receipt of the 
petition and stated we determined an emergency listing was not 
warranted for the pygmy rabbit. We also stated if our ongoing status 
review of the species indicates that an emergency listing is warranted, 
we would act accordingly. In addition, we advised the petitioners that 
we would not be able to process the petition in a timely manner. On May 
3, 2004, we received a 60-day notice of intent to sue, and on September 
1, 2004, we received a complaint regarding our failure to carry out the 
90-day and 12-month findings on the status of the pygmy rabbit. On 
March 2, 2005, we reached an agreement with the plaintiffs to submit to 
the Federal Register a completed 90-day finding by May 16, 2005, and to 
complete, if applicable, a 12-month finding by February 15, 2006 
(Western Watersheds Project et al. v. U.S. Fish and Wildlife Service 
(CV-04-0440-N-BLW) (D. Idaho).
    On May 20, 2005, we published a 90-day finding in the Federal 
Register (70 FR 29253) stating that the petition did not present 
substantial information indicating that listing the pygmy rabbit may be 
warranted. On March 28, 2006, we received a complaint regarding alleged 
violations of the Act and the Administrative Procedure Act with regard 
to our May 20, 2005, 90-day finding (Western Watersheds Project et al. 
v. Gale Norton and U.S. Fish and Wildlife Service (CV 06-CV-00127-S-
EJL) (D. Idaho)). On September 26, 2007, the court issued an order 
remanding our May 20, 2005, 90-day finding and required the Service to 
issue a new 90-day finding on or before December 26, 2007. On January 
8, 2008, we published a new 90-day finding (73 FR 1312), and determined 
that the petition presented substantial information indicating that the 
petitioned action may be warranted. Additionally in that notice, we 
indicated that we would be initiating a status review of the pygmy 
rabbit and opening a 60-day public comment period.

[[Page 60517]]

    This finding does not address our prior listing of the Columbia 
Basin distinct population segment (DPS) of the pygmy rabbit which 
occurs in the State of Washington. On November 30, 2001, we published 
an emergency listing and concurrent proposed rule to list this DPS of 
the pygmy rabbit as endangered (66 FR 59734 and 66 FR 59769, 
respectively). We listed the Columbia Basin DPS of the pygmy rabbit as 
endangered in our final rule dated March 5, 2003 (68 FR 10388). This 
finding addresses the petitioned action that requests listing of the 
pygmy rabbit as endangered or threatened in the remainder of its range 
in Oregon, Idaho, Montana, Wyoming, California, Nevada, and Utah.

Species Information

Species Description

    The pygmy rabbit is the smallest North American Leporid. Adult 
weights range from 0.54 to 1.2 pounds (245 to 553 grams); adult lengths 
range from 9.1 to 12.1 inches (in) (23.1 to 30.7 centimeters (cm)) 
(Dice 1926, p. 28; Grinnell et al. 1930, p. 554; Bailey 1936, p. 110; 
Orr 1940, p. 194; Janson 1946, pp. 21, 23; Durrant 1952, p. 88; Ingles 
1965, p. 143; Bradfield 1974, pp. 10-11; Holt 1975, pp. 125-126; 
Campbell et al. 1982, p. 100). Adult females are generally larger than 
adult males. The species can be distinguished from other rabbits by its 
small size, gray color, short rounded ears, small hind legs, and the 
absence of white on the tail (66 FR 59734).

Taxonomy

    The pygmy rabbit is a member of the family Leporidae, which 
includes rabbits and hares. This species has been placed in various 
genera positions since its type specimen was described in 1891 by 
Merriam (1891, pp. 76-78), who classified the ``Idaho pygmy rabbit'' as 
Lepus idahoensis. Currently, the pygmy rabbit is generally placed 
within the monotypic genus Brachylagus and classified as B. idahoensis 
(Green and Flinders 1980a, p. 1; Washington Department of Fish and 
Wildlife (WDFW) 1995, p. 1); this is the taxonomy accepted by the 
Service. The analysis of blood proteins (Johnson 1968, cited in WDFW 
1995, p. 1) suggests that the pygmy rabbit differs greatly from species 
within both the Lepus and Sylvilagus genera. Halanych and Robinson 
(1997, p. 301) supported the separate generic status as Brachylagus for 
the pygmy rabbit based on phylogenetic position and sequence divergence 
values. The pygmy rabbit has no recognized subspecies (Grinnell et al. 
1930, p. 555; Davis 1939, p. 364; Larrison 1967, p. 64; Green and 
Flinders 1980a, p. 1; Janson 2002, p. 4).

Ecology and Life History

    Pygmy rabbits are typically found in areas of tall, dense Artemisia 
spp. (sagebrush) cover and are considered a sagebrush obligate species 
because they are highly dependent on sagebrush to provide both food and 
shelter throughout the year (Dice 1926, p. 27; Grinnell et al. 1930, p. 
553; Orr 1940, pp. 194-197; Hall 1946, p. 615; Janson 1946, pp. 39-40, 
53; Wilde 1978, p. 46; Green and Flinders 1980a, pp. 1-3 and b, pp. 
137-141; Weiss and Verts 1984, pp. 569-570; Katzner et al. 1997, p. 
1,053). Anthony (1913, p. 22) also mentioned he found pygmy rabbits in 
``little draws and flats'' in Oregon, where the tall sagebrush was 
thick and where Chrysothamnus spp. (rabbit brush) grew in extensive 
patches, and occasionally they were found on ``sparsely brushed flats 
and hills.''
    The winter diet of pygmy rabbits is composed of up to 99 percent 
sagebrush (Wilde 1978, p. 46; Green and Flinders 1980b, p. 138), which 
is unique among leporids (rabbits and hares) (White et al. 1982, p. 
107). During spring and summer in Idaho, their diet consists of 
approximately 51 percent sagebrush, 39 percent grasses (particularly 
native bunch-grasses, such as Agropyron spp. and Poa spp.), and 10 
percent forbs (Green and Flinders 1980b, p. 138). There is evidence 
that pygmy rabbits preferentially select native grasses as forage over 
other available foods during this period. In addition, total grass 
cover relative to forbs and shrubs may be reduced within the immediate 
areas occupied by pygmy rabbits as a result of their use during spring 
and summer (Green and Flinders 1980b, pp. 138-141). The specific diets 
of pygmy rabbit likely vary by region (68 FR 10388).
    Pygmy rabbits may be active at any time of the day or night, and 
appear to be most active during mid-morning (Anthony 1913, p. 23; 
Bailey 1936, p. 111; Bradfield 1974, pp. 14-15; Green and 
Flinders1980a, p. 3; Gahr 1993, pp. 45-46). Flinders et al. (2005, p. 
27) found pygmy rabbits to be 72 percent more active during twilight. 
Larrucea (2007, p. 79) found pygmy rabbits were most active during dawn 
and dusk (a bimodal diel activity pattern). Activity at dawn was 
greatest except for during winter when dusk activity was higher. Lee 
(2008, p. 33) found pygmy rabbits were active during all time periods 
of the day, but the greatest activity occurred at night.
    Pygmy rabbits maintain a low stance, have a deliberate gait, and 
are relatively slow and vulnerable in more open areas. They can evade 
predators by maneuvering through the dense shrub cover of their 
preferred habitats, often along established trails, or by escaping 
among their burrows (Anthony 1913, pp. 22-23; Bailey 1936, p. 111; 
Severaid 1950, p. 3; Bradfield 1974, pp. 26-27). Due to their small 
size, behavior, and habitat, these small rabbits can be easily 
overlooked (Merriam 1891, p. 75; Grinnell et al. 1930, p. 553; Janson 
1940, p. 1; Severaid 1950, p. 3; Holt 1975, p. 135; Janson 2003, p. 
71).
    The pygmy rabbit is one of only two rabbits in North America that 
digs its own burrows (Nelson 1909, p. 22; Bailey 1936, p. 111; Hall 
1946, p. 617; Janson 1946, p. 43; Bradfield 1974, p. 28; Wilde 1978, p. 
17). Pygmy rabbit burrows are typically found in relatively deep, loose 
soils of wind-borne or water-borne (e.g., alluvial fan) origin. Pygmy 
rabbits, especially juveniles, likely use their burrows as protection 
from predators and inclement weather (Bailey 1936, p. 111; Bradfield 
1974, pp. 26-27). Some burrows have only one entrance. Others have 
multiple entrances, some of which are concealed at the base of larger 
sagebrush plants (Dice 1926, p. 27). A single entrance burrow may be 
referred to as a ``burrow'' while single entrance burrows, multi-
entrance burrows, or an entire site may be referred to as a ``burrow 
system''. Burrows are relatively simple and shallow, often no more than 
2.2 yards (yd) (2 meters (m)) in length and usually less than 1.1 yd (1 
m) deep with no distinct chambers (Bailey 1936, p. 111; Bradfield 1974, 
pp. 29-30; Green and Flinders 1980a, p. 2; Gahr 1993, p. 63). Burrows 
are typically dug into gentle slopes or mound or inter-mound areas of 
more level or dissected topography (Wilde 1978, p. 26; Gahr 1993, pp. 
77-80).
    In general, the number of active burrows in an area increases over 
the summer as the number of juveniles increase. However, the number of 
active burrows may not be directly related to the number of individuals 
in a given area because some individual pygmy rabbits appear to 
maintain multiple burrows and some individual burrows are used by 
multiple individuals (Janson 1940, p. 21; Janson 1946, p. 44; Gahr 
1993, pp. 66, 68; Heady 1998, p. 25).
    Pygmy rabbits may also be using more than one burrow or burrow 
system at a specific time or during different times of the year 
(Purcell 2006, p. 96). In Idaho, Sanchez and Rachlow (2008, p. 1306) 
found the number of burrows used by individuals increased with home 
range size. Patterns of burrow system use varied by study area, sex, 
and season (Sanchez and Rachlow 2008, pp. 1306-

[[Page 60518]]

1307). Larrucea (2007, pp. 96-97) found annual and intra-annual changes 
at three study sites during a 3-year period in the Reese River Valley, 
Nevada. During two of the three years, one site showed lack of activity 
during winter and spring. Pygmy rabbits returned to this site in June 
and many new burrows were found. This site may have been marginal 
habitat and rabbits using the area in June may have been dispersing 
juveniles from other areas. At the other two sites where pygmy rabbits 
were observed year-round, the fewest active burrows were found from 
July to October. With the return of cooler weather in the fall, the 
number of active burrows again increased. Many of these new active 
burrows were ones that had previously been inactive or collapsed.
    Flinders et al. (2005, p. 25) reported distances between burrow 
systems. They found burrow systems with multiple entrances averaged 
124.6 yd (114.0 m) away from the next nearest multiple entrance system, 
while distances between systems with multiple entrances to single 
entrance burrows averaged 57.1 yd (52.2 m) away. Single entrance burrow 
systems averaged 14 yd (12.8 m) away from the nearest single entrance 
system.
    Pygmy rabbits occasionally make use of burrows abandoned by other 
species, such as the yellow-bellied marmot (Marmota flaviventris), 
badger (Taxida taxus), or Utah prairie dog (Cynomys parvidens) (Borell 
and Ellis 1934, p. 41; Hall 1946, p. 617; Bradfield 1974, p. 28; Green 
and Flinders 1980a, p. 2; Flinders et al. 2005, p. 30). As a result, 
they may occur in areas of shallower or more compact soils that support 
sufficient shrub cover (Bradfield 1974, p. 29). Natural cavities (such 
as holes in volcanic rock), rock piles, stone walls, and areas around 
abandoned buildings may also be used (Janson 1946, pp. 44-46). During 
winter, pygmy rabbits make extensive use of snow burrows, possibly for 
access to sagebrush forage (Bradfield 1974, p. 17; Katzner and Parker 
1997, p. 1,069), as travel corridors among their underground burrows, 
for protection from predators, and/or as thermal cover (Katzner and 
Parker 1997, pp. 1,063, 1,069-1,070).
    Pygmy rabbits tend to have relatively small home ranges during 
winter, remaining within 98 ft (30 m) of their burrows (Janson 1946, p. 
75). Bradfield (1974, p. 20), Katzner and Parker (1997, p. 1,066), and 
Flath and Rauscher (1995, p. 3) found pygmy rabbit tracks in snow 
indicating movements of 262 to 328 ft (80 to 100 m) or more from their 
burrows. They have larger home ranges during spring and summer (Janson 
1946, p. 75; Gahr 1993, pp. 103-105). During the breeding season in 
Washington, females tend to make relatively short movements within a 
small core area and have home ranges covering roughly 6.7 acres (ac) 
(2.7 hectares (ha)); males tend to make longer movements, traveling 
among a number of females, resulting in home ranges covering roughly 
49.9 ac (20.2 ha) (Gahr 1993, p. 118). Katzner (1994, pp. 14-15) found 
home range size extremely variable in Wyoming; home ranges were from 
0.12 to 0.86 ac (0.05 to 0.35 ha) for females and 0.82 to 4.4 ac (0.33 
to 1.8 ha) for males. Burak (2006, p. 22) found in Owyhee County, 
Idaho, that pygmy rabbit home range sizes based on Minimum Convex 
Polygons differed between the sexes and ranged from 49.9 to 69.7 ac 
(20.2 to 28.2 ha) for males and from 4 to 5.4 ac (1.6 to 2.2 ha) for 
females during the breeding season. Crawford (2008, p. 47) found that 
pygmy rabbit annual home ranges in southeastern Oregon and northwestern 
Nevada differed between the sexes and ranged from 1.2 to 25.8 ac (0.49 
to 10.46 ha) for males and 0.27 to 18.7 ac (0.11 to 7.55 ha) for 
females. During the breeding season, home ranges for males ranged from 
0.27 to 18.5 ac (0.11 to 7.49 ha) and from 0.15 to 17.5 ac (0.06 to 
7.10 ha) for females.
    Sanchez and Rachlow (2008, p. 1307) in Idaho found range use 
between consecutive seasons and between seasons over 2 years was highly 
variable; some pygmy rabbits shifted seasonal ranges markedly, but most 
ranges showed overlap between seasons and years. One male shifted his 
range center by 8,013.9 yd (7,332 m), but other males shifted their 
range centers between 33 and 122 yd (30 and 112 m). Females shifted 
their range centers between 58 and 144 yd (53 and 132 m) (Sanchez and 
Rachlow 2008, p. 1307). Distances shifted between like seasons over the 
2 years were similar to those observed between consecutive seasons. 
Males showed a distance shift of between 47 and 269 yd (43 and 246 m) 
and females showed a shift of between 0 and 150 yd (0 and 137 m) 
(Sanchez and Rachlow 2008, p. 1307).
    Earlier reports indicated pygmy rabbits were known to have traveled 
up to 0.75 mile (mi) (1.2 kilometers (km)) from their burrows (Gahr 
1993, p. 108), and there are a few records of individuals moving up to 
2.17 mi (3.5 km) (Green and Flinders 1979, p. 88; Katzner and Parker 
1998, p. 73). Rauscher (1997, p. 5) reported that pygmy rabbits crossed 
500 yd (457.2 m) of relatively open grassland habitat to reach a 
sagebrush stringer in Montana. Katzner (1994, p. 105) accounted for all 
the rabbits within a range of 0.62 mi (1 km) of his study area. When 
pygmy rabbits not previously observed appeared, he concluded these 
individuals must have traveled a ``considerable distance.'' More 
recently, Estes-Zumpf and Rachlow (2009, p. 367) radio-tagged juvenile 
pygmy rabbits in Idaho and found median dispersal movements of 0.93 mi 
(1.5 km) and 3.9 mi (6.2 km) and maximum dispersal movements of 4.0 mi 
(6.5 km) and 7.4 mi (11.9 km) by male and female rabbits, respectively. 
Burak (2006, p. 27) indicated the maximum distance a male pygmy rabbit 
moved was 1,662.5 yd (1,521 m) and 1,112.7 yd (1,018 m) for a female. 
Crawford (2008, p. 54) in Nevada and Oregon reported that 24 radio-
marked rabbits moved greater than 0.3 mi (0.5 km) with a maximum long-
distance movement of 5.3 mi (8.5 km) recorded by a juvenile female. 
Twenty-one of the individuals that traveled greater than 0.3 mi (0.5 
km) were juveniles.
    Pygmy rabbits may begin breeding the year following their birth 
(Wilde 1978, pp. 64-66, 127; Fisher 1979, p. 13). In some parts of the 
species' range, females may have up to three litters per year and 
average six young per litter (Davis 1939, p. 365; Hall 1946, p. 618; 
Janson 1946, pp. 67-69; Green 1978, pp. 35-36; Wilde 1978, p. 69). 
Breeding appears to be highly synchronous in a given area and juveniles 
are often identifiable to cohorts (Wilde 1978, pp. 69-70). Prior to 
publication of a study in 2005, no evidence of nests, nesting material, 
or lactating females with young had been found in burrows (Bailey 1936, 
p. 111; Janson 1940, p. 23; Janson 1946, p. 69; Bradfield 1974, p. 29; 
Gahr 1993, p. 82 Rauscher 1997, p. 11). Recent studies have found that 
natal burrows are constructed by pygmy rabbits. Rachlow et al. (2005, 
pp. 137-138) provide information on seven natal burrows found in Lemhi 
Valley, Idaho. Females were observed digging and subsequently back-
filling burrows with soil. Fine grasses, shredded sagebrush bark, and 
hair were the primary components used in the nesting material. Larrucea 
(2007, pp. 89-90) found three natal burrows in Reese River Valley, 
Nevada, but did not describe them. Burak (2006, p. 29) found female 
pygmy rabbits construct natal burrows outside of their original home 
range core area. Three of the four natal burrows he found were located 
outside of the core area; the fourth female stayed within a second core 
area that included the natal burrow and when the burrow became 
inactive, she returned to her original core area (Burak 2006, p. 29). 
Individual juveniles have been found under clumps of sagebrush, 
although it is not known if they are

[[Page 60519]]

routinely hidden at the bases of scattered shrubs or within burrows 
(Wilde 1978, p. 115).
    A wide range of pygmy rabbit population densities has been 
reported. Janson (1946, p. 84) reported estimated pygmy rabbit 
densities of 0.75 to 1.75 per ac (1.9 to 4.3 per ha) and 3.5 pygmy 
rabbits per ac (8.6 per ha) in Utah. Flinders et al. (2005, p. 16) 
reported 0.3 rabbits per ac (0.79 rabbits per ha) in Grass Valley, 
Utah. Green (1978, p. 62) reported an estimate of 18.2 pygmy rabbits 
per ac (45 per ha) in Idaho. In Montana, Rauscher (1997, p. 10) 
estimated pygmy rabbit density as 0.67 rabbits per burrow or 1.2 per ac 
(3.0 per ha). Based on fecal dropping counts, Larsen et al. (2006, pp. 
26-27) estimated rabbit density in Deep Creek watershed, Utah, as 0.07 
per ac (0.17 rabbits per ha). Using line transects in Wyoming, Purcell 
(2006, pp. 100, 105) reported a range of burrow systems per mi (km) for 
systematic transects (1.7 to 18.2 per mi, 2.7 to 29.3 per km) and 
random transects (0.8 to 7.4 per mi, 1.33 to 11.97 per km) in 10 study 
areas. Larrucea (2007, p. 89) estimated, using transect counts, that 
the relative density at five study areas in California and Nevada 
ranged from 0.4 to 1.7 rabbits per ac (0.9 to 4.2 rabbits per ha).
    The annual mortality rate of adult pygmy rabbits may be as high as 
88 percent, and more than 50 percent of juveniles can die within 
roughly 5 weeks of their emergence (Wilde 1978, pp. 139-140). Estes-
Zumpf and Rachlow (2009, p. 367) found mortality rates were 69.2 
percent and 88.5 percent for male and female juvenile pygmy rabbits, 
respectively, in their study area in east-central Idaho. The mortality 
rate was highest within two months of emerging from the natal burrow. 
However, the mortality rates of adult and juvenile pygmy rabbits can 
vary considerably between years, and even between juvenile cohorts 
within years (Wilde 1978, pp. 85-95, 138-140). Predation is the main 
cause of pygmy rabbit mortality (Green 1979, p. 25). Sanchez (2007, pp. 
90-91) attributed 42 percent of natural mortalities to mammalian and 
avian predation. She was unable to determine the cause of death in 58 
percent of the mortalities.
    Predators of the pygmy rabbit include badgers, long-tailed weasels 
(Mustela frenata), coyotes (Canis latrans), bobcats (Felis rufus), 
great horned owls (Bubo virginianus), long-eared owls (Asio otus), 
ferruginous hawks (Buteo regalis), northern harriers (Circus cyaneus), 
and common ravens (Corvus corax) (Borell and Ellis 1934, p. 42; Janson 
1946, pp. 89-90; Gashwiler et al. 1960, p. 227; Green 1978, p. 37; 
Wilde 1978, pp. 96, 141-143; Johnson and Hanson 1979, p. 952; WDFW 
1995, p. 6).
    Sanchez (2007, p. 92) estimated that for known-aged rabbits, the 
average lifespan was 1.16 years. For rabbits captured as adults, 
assuming a birth date of May 1 of the previous year, estimated average 
life expectancy was 1.7 years, and the maximum lifespan achieved was 
3.3 years.
    Population cycles are not known in pygmy rabbits, although local, 
relatively rapid population declines have been noted in some States 
(Janson 1946, p. 84; Bradfield 1974, p. 39; Weiss and Verts 1984, p. 
569). Janson (2003, p. 71) remarked that pygmy rabbits likely undergo 
local, if not regional, fluctuations. After initial declines, pygmy 
rabbit populations may not have the same capacity for rapid increases 
in numbers in response to favorable environmental conditions as 
compared to other rabbit species. This may be due to their close 
association with specific components of sagebrush ecosystems, and the 
relatively limited availability of their preferred habitats (Wilde 
1978, p. 145; Green and Flinders 1980b, p. 141; WDFW 1995, p. 13). No 
study has documented rapid increases in pygmy rabbit numbers in 
response to environmental conditions (Gabler 1997, p. 95). Long-term 
population monitoring studies are not available indicating whether 
population fluctuations or cycles occur for pygmy rabbits or if 
seasonal or other habitat shifts or movements have been misinterpreted 
as declines.
    Literature indicates that pygmy rabbits have never been evenly 
distributed across their range (Bailey 1936, p. 111; Janson 1940 p. 5; 
Holt 1975, pp. 133-134). While the species occurs throughout most of 
the Great Basin, they exhibit extremely specialized habitat 
requirements, and thus occupy only a small subset of locations within 
this range (Larrucea 2007, p. 2). They are found in areas within their 
broader distribution where sagebrush cover is sufficiently tall and 
dense, and where soils are sufficiently deep and loose to allow 
burrowing (Bailey 1936, p. 111; Green and Flinders 1980a, p. 2; 
Campbell et al. 1982, p. 100; Weiss and Verts 1984, p. 563; WDFW 1995, 
p. 15). Sagebrush- dominated communities are naturally subject to 
disturbances of various kinds resulting in a heterogeneous distribution 
of different stand sizes and age classes, and on the landscape scale, 
pygmy rabbit distribution is naturally disjunct (Himes and Drohan 2007, 
p. 380). Local distribution of this habitat and thus pygmy rabbit 
populations likely shift over time due to natural and human 
disturbances including fire, agriculture production, flooding, grazing, 
and weather patterns (Keinath and McGee 2004, p. 5). In the past, dense 
vegetation along permanent and intermittent stream corridors, alluvial 
fans, and sagebrush plains probably provided travel corridors and 
dispersal habitat for pygmy rabbits between suitable use areas (Green 
and Flinders 1980a, p. 1; Weiss and Verts 1984, p. 570; WDFW 1995, p. 
15). Since European settlement of the western United States, dense 
vegetation associated with human activities (fence rows, roadway 
shoulders, borrow ditches, crop margins, abandoned fields) may have 
also acted as avenues of dispersal between local populations of pygmy 
rabbits (Green and Flinders 1980a, p. 1; Rauscher 1997, p. 16).

Distribution, Abundance, and Trends

    The pygmy rabbit's general historical and current geographic range, 
excluding the Columbia Basin DPS, includes most of the Great Basin and 
some of the adjacent intermountain areas of the western United States 
(Green and Flinders 1980a, p. 1), and the boundaries can be described 
as follows: the northern boundary extends into southeastern Oregon and 
southern Idaho. The eastern boundary extends into southwestern Montana 
and south central Wyoming. The southeastern boundary extends into 
southwestern Utah. Central Nevada and eastern California provide the 
southern and western boundaries (Merriam 1891, p. 75; Nelson 1909, p. 
275; Grinnell et al. 1930, pp. 553, 558; Bailey 1936, pp. 110-111; 
Janson 1946, pp. 32-33; Campbell et al. 1982, p. 100; WDFW 1995, pp. 1-
2, Purcell 2006, pp. 1, 7-11, 30). Based on available information, the 
current distribution of the pygmy rabbit indicates a possible range 
contraction in northern California (Larrucea and Brussard 2008a, p. 
696). Because uncertainty remains about whether this possible range 
contraction has occurred due to limited survey efforts in northern 
California both historically and recently, it is not shown in Figure 1. 
Figure 1 illustrates the approximate historical and current range of 
the pygmy rabbit in the seven States discussed in this finding.

[[Page 60520]]

[GRAPHIC] [TIFF OMITTED] TP30SE10.008

    Figure 1. Approximate historical and current range (based on data 
from 1877 to 2008) of the pygmy rabbit (Brachylagus idahoensis) not 
including the Columbia Basin DPS in Washington State.
    To determine the historical and current distribution and trend 
analysis for pygmy rabbits across the seven States discussed in this 
finding, we reviewed published scientific peer-reviewed literature; 
unpublished agency documents; dissertations; theses; databases 
maintained by State heritage programs, State wildlife agencies, and 
Federal agencies; survey data sheets; museum records; electronic mail 
records; and agency notes to the files. Older published literature 
(prior to the mid to late 1990's) generally focused on the species' 
life history, behavior, and some habitat relationships and provided 
location information of study areas. More recent unpublished literature 
(since the mid to late 1990's to 2008) has been primarily related to 
surveys conducted by government agencies or their consultants and 
universities to determine pygmy rabbit occurrence within portions of a 
State and some information regarding species' life history, behavior, 
and habitat relationships. Survey efforts have focused on location of 
pygmy rabbit signs rather than on documenting known or perceived 
threats to the species at these sites. Rarely has revisiting of sites 
occurred with the purpose of monitoring populations over time. While we 
consider this information of limited use to our finding due to its 
local, short-term nature, it is the best scientific information 
available to conduct our analysis.
    We compiled a database of records (location points) of various 
pygmy rabbit signs for each State from these various data sources 
listed above. Some records were not entered into a State database if 
adequate information was

[[Page 60521]]

not provided (e.g., we could not determine a location point because the 
source map did not indicate location or survey data sheet location 
point information was unreadable). Once each State database was 
compiled, we reviewed each location point and eliminated its database 
record if it was not determined to be a reliable data point as 
discussed below. The final databases combined contain approximately 68 
percent of all the location points compiled. We consider the location 
point data retained in these seven State databases to be the best 
scientific information available. We will refer to these created State 
databases as the Service's databases.
    We are aware of concerns related to the use of anecdotal occurrence 
records to determine distribution of species (McKelvey et al. 2008, pp. 
549-554). We are also aware of confidence levels related specifically 
to pygmy rabbit presence and level of activity at particular sites due 
to various factors (e.g., sighting of targeted species vs. only 
targeted species sign or potential targeted species sign observed; if 
burrow activity is uncertain, the site should be revisited; 
uncertainties due to other species or other rabbit species using 
burrows; pellets being misidentified) (Bartels 2003, pp. 47-49; Keinath 
and McGee 2004, pp. 32-34).
    As a result of these concerns, we have based our analysis on what 
we considered to be the more reliable records indicating pygmy rabbit 
presence and activity level. The following types of records were not 
included in the Service's databases for our analysis: database records 
that showed some level of uncertainty for the information being 
provided (e.g., other leporid species data included; uncertainty about 
whether pygmy rabbit was observed or other leporid species; using words 
such as ``possible'', ``potential'', ``maybe'', ``unsure''); records 
that only provided location data or indicated pygmy rabbit sign with no 
additional information indicating what type of sign (e.g., burrow, 
pellet, track, sighting of animal as relates to reliability) had been 
observed; records related to telemetry locations (while informative in 
determining an individual's distribution within its home range, this 
provides little information at the larger landscape scale used here; we 
did include the capture location of any individual pygmy rabbit trapped 
and fitted with a tradio collar); records based solely on pellets or 
tracks due to concerns with species misidentification; those lacking 
key information (e.g., year which is needed for trend analysis) and 
duplicate records.
    For our analysis, we mapped records of ``active'' sites or burrows 
defined as those database records that indicated an activity level (at 
the time of the survey) of current, present, occupied, active, or 
recently active burrows; burrows in combination with fresh pellets; a 
visual sighting; photographic evidence; fecal DNA confirmation; 
specimen collected; trapping effort; in combination with tracks; or any 
combination thereof. All sighting records were included in our analysis 
even if no other information was provided, unless uncertainty was 
expressed about whether it had been a pygmy rabbit observed or another 
leporid species.
    We also mapped records of ``inactive'' sites or burrows defined as 
those database records that indicated an activity level (at the time of 
the survey) of inactive, not recent, old, very old, collapsed, or 
burrow plus old pellets. In addition, we assumed ``inactive'' for site 
or burrow records that did not provide a status and did not provide 
information to support a determination of active, those with an 
``undetermined'' activity status, or were unclear. We reviewed the 
mapped distribution for the ``active'' and ``inactive'' site categories 
across each State.
    In addition, we mapped database records of ``absent'' areas defined 
as points where no sign of pygmy rabbit occupancy was evident. Most 
databases do not include records of areas surveyed but where no pygmy 
rabbit sign was observed. We believe this type of information can be 
valuable; however, we do not assume that pygmy rabbits were or should 
have been present in areas where they were determined to be absent. It 
is possible that an area is unsuitable for pygmy rabbits while 
appearing suitable to surveyors. Conversely, it is possible an area 
that appears unsuitable to surveyors for pygmy rabbits may actually be 
so (Ulmschneider et al. 2004, pp. 2-3). On the ground surveying is 
necessary to positively indicate pygmy rabbit occupancy (Bartels 2003, 
pp. 92-94; Lenard et al. 2005, p. 1; Meisel 2006, pp. 26, 48). The 
``absent'' information indicates locations where survey efforts were 
conducted but pygmy rabbit sign was not evident. Limited ``absent'' 
information was obtained for the States of Oregon, California, Nevada, 
and Wyoming.
    During our analysis we encountered some difficulties in adapting 
data collected for another's purpose for our species' status review, 
and there were several limitations. Overall, survey information 
collected over the years reflects different surveyors, different survey 
methods, different levels of survey intensity, and different amounts 
and types of information recorded. We generally accepted the 
information indicated in a report, data sheet, or database and tried to 
do as little interpretation as possible. For some locations, we 
replaced locational descriptions (Township, Range and Section or a 
narrative description) with Universal Transverse Mercator (UTM) 
coordinates or a center point for a section surveyed or a point was 
buffered to indicate an approximate location. For a portion of records 
from Oregon, we created a point representing the center of a study area 
and ``active'' and ``inactive'' burrows were separated.
    We encountered some difficulties with interpreting data provided 
under different reporting techniques. In general, most surveys for 
pygmy rabbits report location information in terms of point data (i.e., 
legal description or Global Positioning System (GPS)) with qualifiers 
or descriptions for sign, such as burrows (present, absent), activity 
level (occupied, unoccupied, active, inactive, current, recent, old, 
very old), pellets (fresh, old), sightings (actual sightings of pygmy 
rabbits, specimen collection, capture, photographic record), and 
tracks. Some surveyors developed their own rating system or confidence 
level for burrow or site activity (Purcell 2006, p. 38; Himes and 
Drohan 2007, p. 375; Flinders et al. 2005, pp. 8-9). Some efforts 
reported only those sites that were considered positive (confirmed with 
photographic evidence), active, or occupied sites and did not include 
information for areas considered inactive or unoccupied. Location data 
may represent a burrow, a burrow system, or an entire site that was 
surveyed which represents one or more burrows or burrow systems.
    Various techniques have been used to detect pygmy rabbit evidence 
on the landscape. Techniques may include driving and walking transects 
in perceived suitable habitat, winter aerial flights over potential 
habitat with subsequent selection of areas for further ground surveys 
(Rachlow and Witham 2006, pp. 4-8), random searches in perceived 
suitable habitat, or spot lighting at night. Survey efforts have been 
made during all times of the year. It is advised that sites that 
indicate pygmy rabbit sign should be confirmed through sightings or 
photographic evidence; this may or may not have occurred. The Service 
has recommended using draft survey guidelines developed by Ulmschneider 
et al. (2004, entire) in conducting

[[Page 60522]]

pygmy rabbit surveys, but it has not always been used since its 
availability.
    Larrucea (2007, p. 3) tested pellet, sighting, burrow, and camera 
survey methods at 20 locations in 4 known, active pygmy rabbit 
populations in California and Nevada. She also assessed road transect 
surveys for detecting and determining relative abundance in an area 
(Larrucea 2007, p. 3). Results indicated that pellets were found at all 
sites, but pellets determined to be fresh were found at only 70 percent 
of the sites. Sighting individual rabbits provided positive results 30 
percent of the time. Burrows were located at 85 percent of the sites, 
but burrows determined to be active were found at only 55 percent of 
the sites. Cameras provided positive results 95 percent of the time 
(Larrucea 2007, p. 6). Photographs were taken of pygmy rabbits at all 
types of active sites including those with only burrows determined to 
be inactive and with pellets determined to be old (Larrucea 2007, p. 
7). During the 10 transect counts, different rabbit and hare species 
were observed 569 times and 545 were identified to genus (Larrucea 
2007, p. 7). Lepus was observed 491 times (90.1 percent); Sylvilagus 44 
times (8.1 percent) and Brachylagus 10 times (1.8 percent) (Larrucea 
2007, p. 7). Photographs taken from the camera locations provided 409 
photos of rabbit and hare species; the number of photographs of Lepus 
was 199 (48.7 percent), Brachylagus 195 (47.7 percent), and Sylvilagus 
15 (3.7 percent) (Larrucea 2007, p. 7).
    Camera surveys are more effective than burrow, pellet, sightings, 
or road transect surveys for determining current pygmy rabbit activity 
at a site (Larrucea 2007, p. 7). Burrows are a good indicator that 
pygmy rabbits may be present, but locating one does not mean pygmy 
rabbits are currently using the site (Larrucea 2007, p. 8). Lack of 
active burrows may not mean that there are no pygmy rabbits in the 
area. Burrows may be used seasonally, may be difficult to locate, or 
may be lacking in dispersal areas (Larrucea 2007, pp. 8-9). Old pellets 
do not confirm current use of a site and pellets may be misidentified 
due to young rabbits of other species cohabiting a site. Not finding 
fresh pellets does not mean pygmy rabbits are not currently using a 
site as environmental conditions can influence how rapidly pellets dry 
and change color (Larrucea 2007, p. 9). Sightings of individual pygmy 
rabbits do confirm current activity, but observers should be 
experienced as the young of cottontails (Sylvilagus spp.) and 
jackrabbits (Lepus spp.) can be confused with pygmy rabbits. Sightings 
of pygmy rabbits are difficult and do not occur often due to the dense 
vegetation inhabited, limited home ranges, and their elusive nature 
(Larrucea 2007, p. 10). Road transect surveys are inefficient for pygmy 
rabbits due to their reluctance to cross open areas and roads 
(Bradfield 1975, p. 3). Pygmy rabbits are more likely to run a short 
distance, sit tight, or disappear into a burrow than to run for a long 
distance making detection more difficult (Larrucea 2007, p. 10).
    We are also aware of difficulties in interpreting site activity 
during surveys. For example, in Montana, Lenard et al. (2005, p. 9) 
commented that comparisons of active to inactive burrows may be 
complicated, stating that burrows exhibiting current rabbit activity 
were easier to locate because tracks in the snow made them very 
apparent. The relative difference in abundance between currently active 
and recently active should not be interpreted to indicate any level of 
past versus current activity. Flinders et al. (2005, p. 33), in Utah, 
commented that single burrow systems are harder to detect than multiple 
entrance burrow systems. The Bureau of Land Management (BLM) (2007a, p. 
1) used the Ulmschneider et al. (2004, entire) method and noted that 
this type of inventory covered large expanses and typically found the 
larger pygmy rabbit populations and a small subset of the actual burrow 
systems on a particular site. However, when sites were re-inventoried 
intensively, BLM found numerous additional burrow systems. Lee et al. 
(2008, pp. 4-5), in Utah, commented that using criteria from Rachlow 
and Witham (2004b, pp. 6-7) or Ulmschneider et al. (2004, entire) is 
somewhat inaccurate in predicting current pygmy rabbit burrow 
utilization. Lee et al. (2008, p. 5) used remote cameras to verify the 
presence or absence of pygmy rabbits in comparison to burrow 
classification. By using both burrow classifications methods along with 
remote cameras, refinement of burrow classifications and census 
techniques may be possible in the future.
    Bartels (undated) compared active and passive survey methods for 
detecting pygmy rabbit burrow occupancy at what she considered isolated 
and low density sites. She compared the use of an active survey method 
(peeper probe) and a passive survey method (surface classification of 
burrows using sign (burrows, pellets) to determine occupancy by pygmy 
rabbits (Bartels undated, pp. 3-4). A total of 233 burrows were 
compared on 27 sites in Oregon and Idaho. Under the passive method, all 
233 burrows were considered occupied (Bartels undated, p. 5). Under the 
active survey method, 122 (52.4 percent) of the burrows were classified 
as occupied and as recently occupied, and 111 (47.6 percent) were 
classified as unoccupied (Bartels undated, p. 5). Bartels (undated, p. 
7) recommended use of an active survey method in areas where pygmy 
rabbit numbers appear to be low and isolated sites are found. Viewing 
the internal attributes of burrows and establishing a standard for 
occupancy increases survey accuracy and could lead to greater accuracy 
when monitoring pygmy rabbit occupancy over time.
    We must also take into consideration complicating factors when 
interpreting current distribution and/or status as we do not have a 
complete understanding of pygmy rabbit habitat use. For example, it 
appears that some habitat use may be seasonal and pygmy rabbits may be 
somewhat migratory as some burrow systems appear occupied during 
certain times of the year and inactive during others, or from year to 
year (Flinders et al. 2005 p. 35; Bockting 2007 p. 2; Larrucea 2007, 
pp. 96-97). Flinders et al. (2005 p. 35) reported that areas where 
pygmy rabbits were relatively abundant in Utah suddenly became sparse 
after the juveniles dispersed. Other areas then appeared to indicate an 
increase in the numbers of pygmy rabbits. In Utah, Flinders et al. 
(2005, p. 32) found active burrows were more common than the other 
activity classifications (i.e., recent, old, very old), and thus 
support statements that pygmy rabbits use more than one burrow system. 
He thought inactive burrows likely play an important role in providing 
escape cover. Cameras placed on burrows classified as old or very old 
documented use by pygmy rabbits. Larrucea (2007, p. 7) also 
photographed pygmy rabbits at sites where burrows were determined to be 
inactive.
    After reviewing the available information, we consider our approach 
in using information to determine the status of the pygmy rabbit to be 
conservative. We have used these data to compare historical (1999 and 
earlier) to current (2000 and later) distribution patterns. We have 
used the data to compare activity levels (active; inactive) of sites or 
burrows during these two time periods. Questions have been raised 
regarding surveyors' abilities to accurately determine activity level 
due to possible detection differences, absence of long-term site 
monitoring, and our incomplete understanding of the pygmy rabbit's life 
history requirements (e.g., possible seasonal use of some areas or 
periods of burrow non-use). We are also aware that some

[[Page 60523]]

survey techniques provide better data than others. Though these data 
are limited in their usefulness for our purposes due to their local, 
short-term nature, they are understood, by the Service to be the best 
available information. This data does provide baseline information that 
could be the foundation for future survey and monitoring efforts.

Models

    To facilitate pygmy rabbit surveys in recent years, models of 
potential habitat have been developed for some States or study areas. 
Eliminating areas in these models that are unsuitable can be important 
as it can concentrate efforts and resources in areas that are more 
likely to support pygmy rabbits (Gabler et al. 2000, p. 763). Large 
areas that seem to be appropriate pygmy rabbit habitat may not be 
suitable based on the specific habitat characteristics needed for pygmy 
rabbits (Gabler et al. 2000, p. 763). To aid pygmy rabbit research in 
Oregon, modeling efforts have been conducted by the following 
researchers: Bartels (2003, p. 35) for the BLM Burns District using 
GIS; Meisel (2006, p. 4) for the Hart Mountain National Antelope 
Refuge; and Hager and Lienkaemper (2007, pp. 1-2) for large blocks of 
State land.
    In Idaho, modeling efforts have been conducted by Rachlow and 
Svancara (2006, p. 828); Bartels (2003, pp. 35-38), and Gabler et al. 
(2000, pp. 762-763; 2001 entirety). In Montana, Lenard et al. (2005, p. 
1) reported on the development of four predictive models in Montana. In 
Wyoming, Purcell (2006, p. 28) used a probabilistic distribution map 
developed by Keinath and Thurston (2005, cited in Purcell 2006, p. 28) 
using the combination of two models, DOMAIN (environmental similarity 
method) and CART (classification and regression tree analysis). Based 
on data collected during Purcell's study, a new predictive distribution 
model was created (Purcell 2006, p. 31).
    In Nevada, a predictive equation was produced based on habitat data 
collected and used as a model to characterize habitat where pygmy 
rabbits or sign occurred. The model explained the occurrence of pygmy 
rabbits or their sign on 56.7 percent of transects (Himes and Drohan 
2007, p. 376). Larrucea and Brussard (2008a, p. 693) used GIS 
coverages. In Utah, Lee et al. (2008, p. 3) used vegetation data from 
the 2004 Southwestern Regional Gap Analysis Project. In general, these 
models are helpful in focusing survey efforts over a large area; 
however, researchers also recognize that due to scale and available 
data for particular attributes such as soils and vegetation, only on 
the ground surveying can positively indicate pygmy rabbit presence 
(Bartels 2003, pp. 92-94; Meisel 2006, pp. 26, 48; Lenard et al. 2005, 
p. 1).
    We believe our large-scale, rangewide analysis, based on the 
Service's databases, represents the best scientific and commercial 
information available on the distribution of pygmy rabbits. As 
mentioned above, many individual records were considered but not 
included in the Service's databases for the following reasons: database 
records showing some level of uncertainty for the information being 
provided (e.g., other leporid species data included; uncertainty about 
whether pygmy rabbit was observed or other leporid species; using words 
such as ``possible'', ``potential'', ``maybe'', ``unsure''); records 
that only provided location data or indicated pygmy rabbit sign with no 
additional information indicating what type of sign (e.g., burrow, 
pellet, track, sighting of animal as relates to reliability) had been 
observed; records related to telemetry locations (while informative in 
determining an individual's distribution within its home range, this 
provides little information at the larger landscape scale used here; we 
did include the capture location of any individual pygmy rabbit trapped 
and fitted with a radio collar); records based solely on pellets or 
tracks due to concerns with species misidentification; those lacking 
key information (e.g., year which is needed for trend analysis); and 
duplicate records.
    Eliminating records with these types of concerns provides for a 
more accurate representation of pygmy rabbit range-wide distribution 
rather than including all records without considering some level of 
reliability of the data. While pygmy rabbits likely occur in additional 
unsurveyed areas and even in some areas that have been surveyed (pygmy 
rabbit sign can be easily overlooked), we have made our finding based 
on our review of these databases, which represent the best scientific 
and commercial information available.

Distribution by State

    The following distribution and trend discussion is based on 
information obtained from published and unpublished literature and an 
interpretation of the survey location point data compiled in the 
Service's databases. The following review does not discuss every 
document from the various information sources due to the volume, but a 
selection of literature that provides substantive historical 
information and survey information on a large scale. The literature is 
generally, but not entirely, associated with records included in the 
Service's databases. This is because not all reports provided specific 
location points and not all location points are associated with a 
report, and as stated earlier, some records are not included in the 
Service's databases. This analysis compares our understanding of the 
historical and current ranges of the pygmy rabbit discussed in this 
finding.

Oregon

    The earliest pygmy rabbit records for the State of Oregon include: 
two specimens collected in Callow Valley, Harney County, Oregon (Nelson 
1909, p. 278); specimens collected near Ironsides, Malheur County, 
Oregon in 1911-1912 (Anthony 1913, pp. 20-21); and 10 specimens 
collected near Baker, Baker County, Oregon (Dice 1926, p. 27).
    Bailey (1936, pp. 110-111) indicated that pygmy rabbits in Oregon 
extended from the southern foothills of the Blue Mountain Plateau and 
eastern base of the Cascade Range over the southeastern quarter of the 
State. He reported that they were absent from areas of open country 
where sagebrush and rabbit brush were not abundant. As a result, there 
are numerous wide gaps in their range.
    Brodie and Maser (1966, pp. 11-12) reported the contents from owl 
pellets collected in 1966 at Lower Bridge, Deschutes County, Oregon. 
Prey animals consisted of pygmy rabbits. This location was reported as 
a new location for the pygmy rabbit as the nearest previously 
documented location was Redmond, Oregon (Hall and Kelson 1959, cited in 
Brodie and Maser 1966, p. 12) about 10 miles (16.1 km) east of Lower 
Bridge.
    Olterman and Verts (1972, p. 25) listed 37 museum records for 
Oregon which occurred in general near the following areas: Baker, Baker 
County; Paulina, Crook County; Redmond, Deschutes County; Beakley, 
Beaties Butte, Burns, Rock Creek Ranch, Crane, Drewsey, Narrows, 
Sageview, Mud Lake, Steens Mountain, Voltage, and Waverly, Harney 
County; Fremont and Klamath Falls, Klamath County; Adel, Ft. Rock, 
Guano Creek, Guano Valley, Rabbit Creek, andSilver Lake, Lake County; 
and Cold Springs, Cow Creek Lake, Ironside, Mahogany Mountains, 
Malheur, McDermitt, Riverside, and Rome, Malheur County. At the time of 
their writing, Olterman and Verts (1972, p. 25) indicated recent 
observations by biologists demonstrated that pygmy

[[Page 60524]]

rabbits were occurring over the same area as in the past. Pygmy rabbits 
were observed near Hines, Wagontire, Lakeview, Hart Mountain National 
Antelope Refuge, Hampton, Ft. Rock, and Lower Bridges.
    Bradfield (1974, p. 39) also spent time at Ironside, in Malheur 
County, Oregon. He found evidence of previous pygmy rabbit use, but no 
fresh sign of use or rabbits, which supported his belief that they were 
in decline on a larger geographic scale.
    Weiss and Verts (1984, p. 563) attempted to search for pygmy 
rabbits in Oregon based on museum record information for sites listed 
in Olterman and Verts (1972, p. 25). Because of the generality of the 
location descriptions provided, they also reviewed aerial photography 
and soil maps to assist in narrowing searches in the areas described 
where pygmy rabbits had been collected previously (Weiss and Verts 
1984, p. 564). Evidence of pygmy rabbits was found at 51 of 211 areas 
searched in 1982 (Weiss and Verts 1984, p. 566). In 1983, only 5 of the 
15 sites that had been sampled for soil and vegetation information in 
1982 showed recent pygmy rabbit activity (Weiss and Verts 1984, p. 
566). Of 51 burrows found at 5 of the sites occupied in 1982, 19 
burrows were found open in 1983 and 8 had fresh pellets (Weiss and 
Verts 1984, p. 568). Only the locations of the 15 occupied sites in 
Grant and Lake Counties where Weiss and Verts (1984, p. 566) recorded 
vegetation and soil data are provided in their document.
    Since 2000, additional survey efforts have been conducted. Bartels 
(2003, p. 70) visited 54 previously known pygmy rabbit sites located on 
BLM lands in 2000 and 2001 in Harney, Malheur, Lake, and Deschutes 
Counties, Oregon. Results from these visits showed 12 sites were 
occupied, 8 were of undetermined occupancy, and 34 showed no occupancy. 
Three additional sites were surveyed off of BLM lands. One site was 
occupied, one showed no evidence of pygmy rabbit use, and one was 
considered undetermined and warranted further investigation (Bartels 
(2003, p. 86). Some of these sites included those visited by Weiss and 
Verts (1984, p. 564) (Bartels 2003, p. 91).
    BLM conducted surveys on their Lakeview and Vale Districts in 
Harney and Lake Counties, Oregon in 2002 and 2003 (BLM 2003a, p. 1). 
Forty-five sites were surveyed in fall of 2002 and winter 2003 on the 
Lakeview District with 19 sites indicating pygmy rabbit activity (10 
active, 9 inactive). Twenty sites were surveyed in fall of 2002 and 
winter 2003 on the Vale District with two sites indicating pygmy rabbit 
activity (1 active, 1 inactive). The remaining sites surveyed (44) on 
the two districts in fall of 2002 and winter 2003 showed no evidence of 
pygmy rabbit use (BLM 2003a, p. 1). During the summer of 2003, 23 
additional sites were surveyed and 19 showed pygmy rabbit activity (11 
active, 8 inactive); 4 sites showed no evidence of pygmy rabbit use 
(BLM 2003a, no page number provided). BLM continued to conduct surveys 
on their Burns and Lakeview Districts in Harney and Lake Counties, 
Oregon, respectively, in 2005 and 2006 (BLM 2006a, pp. 3-4); active 
pygmy rabbit use was found at four of the seven sites surveyed. In 2006 
and 2007, BLM surveyed 12 additional sites on the Lakeview District, 
and active pygmy rabbit use was found at 8 sites (BLM 2007b, p. 1). 
Various numbers of burrow systems were found at the different sites 
(BLM 2003a, p. 3; BLM 2006a, pp. 3-4; BLM 2007b, pp. 3-6).
    Meisel (2006, p. 4), improved the known distribution of pygmy 
rabbits at Hart Mountain National Antelope Refuge, Lake County, during 
2004 and 2005. The sagebrush habitat on the refuge has been protected 
from development and other human disturbances for at least 70 years 
(Meisel 2006, p. 9). Remote infrared 35-mm cameras were used to confirm 
occupancy by pygmy rabbits (Meisel 2006, p. 12). Habitat 
characteristics were measured at 45 occupied burrows (Meisel 2006, p. 
18). In 2005, refuge staff found approximately 99 occupied burrows near 
burrow locations that were found in 2004 by Meisel (R. Huddleston-
Lorton, cited in Meisel 2006, p. 27). Location information on these 99 
burrows was not included in Meisel (2006). It is possible that a large 
population inhabits the northeast portion of the refuge (Meisel 2006, 
p. 27). Meisel (2006, p. 27) recommends future research be conducted in 
areas of Wyoming big sagebrush to locate all burrows and document the 
population status on the refuge which is currently unknown.
    Hager and Lienkaemper (2007, p. 1) conducted surveys to determine 
the presence or absence of pygmy rabbits on State lands in Malheur, 
Harney, Lake, and Deschutes Counties. One hundred and fifty-seven sites 
were ground surveyed during 2004 and 2005 (Hager and Lienkaemper 2007, 
p. 3). Of the 157 sites, 18 were determined to be active, 14 inactive, 
and 125 showed no evidence of pygmy rabbit presence (Hager and 
Lienkaemper 2007, pp. 4-5).
    Most historical records (1999 and earlier) for Oregon occur in the 
following counties: Malheur, Harney, and Lake. A few historical records 
also occur in Baker, Grant, Crook, Deschutes, and Klamath Counties. 
There is also a 1992 database sighting record for Jefferson County. 
Current information (2000 and later) indicates Malheur, Harney, and 
Lake as well as Klamath and Deschutes Counties continue to support 
pygmy rabbit activity. We are unaware of information indicating any 
recent survey efforts have been conducted to determine pygmy rabbit 
activity for Baker, Grant, or Jefferson Counties. Baker County 
indicated some activity in 1926. Grant County indicated inactivity 
during 1982 and 1983. Jefferson County had some activity in 1992. The 
southeastern portion of Crook County was searched during 2005 by BLM, 
but pygmy rabbit evidence was not found. In general, pygmy rabbit 
activity continues to occur in southeastern Oregon in a similar 
distributional pattern as compared with historical information.

Idaho

    Merriam (1891) was the first to describe the ``Idaho pygmy rabbit 
(Lepus idahoensis)'' based on a specimen collected on September 16, 
1890, along the upper part of the Pahsimeroi River by Basil Dutcher 
(Merriam 1891, pp. 7, 13, 75-78). Merriam (1891, p 75) indicated that 
the general distribution for the pygmy rabbit was the ``Sage Plains'' 
along the Snake River, and in Birch Creek and Lemhi Valleys, Little 
Lost River Valley, Pahsimeroi Valley and Big Lost River Valley, Idaho 
and into northern Nevada to the south, and to the west ``probably'' 
into eastern Oregon and Washington.
    Other early records include: six specimens collected from Big Lost 
River Valley, Birch Creek, Junction, Lost River Mountain, and 
Pahsimeroi Valley, Idaho (Nelson 1909, p. 278); and a report of two 
pygmy rabbits collected from 1 mi (1.6 km) west of Schutt's Mine in 
November 1930 (Whitlow and Hall 1933, p. 269). In May 1931, a female 
was collected near Trail Creek (Whitlow and Hall 1933, p. 270). These 
records extended the known range by 75 mi (120.7 km) to the southeast 
(Whitlow and Hall 1933, p. 270). Observations of pygmy rabbits in Idaho 
occurred near the head of the Pahsimeroi River, Idavada, Pahsimeroi 
Valley, Riddle, and Pocatello (Davis 1939, p. 364). Davis lists 
locations of 10 specimens examined: Owyhee County, near Riddle, 2; 
Cassia County, Elba, 1; Butte County, Craters of the Moon National 
Monument, 1; Power County, near Michaud, 3; Bannock County, near 
Schutt's Mine, 2; Trail Creek near Pocatello, 1. Additional records 
mentioned included Nelson's (1909)

[[Page 60525]]

records of Lemhi County, Junction; Custer County, Pahsimeroi Valley. 
Additional locations included Minidoka County, Minidoka (Seton 1929, 
cited in Davis 1939, p. 366); Cassia County, Burley (Grinnell et al. 
1930, cited in Davis 1939, p. 366); Clark County, Birch Creek; Butte 
County, Big Lost River Valley; Lost River Mountains (Lyon 1904, cited 
in Davis 1939, p. 366). Lyon (1904, cited in Davis 1939, p. 366) also 
includes a record from Ione Valley. Davis (1939, p. 366) was unable to 
find Ione Valley in Idaho and thought the specimen may have been from 
Nevada.
    Bradfield (1974, p. 39) speculated that the pygmy rabbit population 
was declining in his study area in Bingham County, Idaho. This was 
based on the number of abandoned burrows, number of skulls indicating 
death by predation or other means, and fewer observed rabbits.
    In her Idaho study area in portions of Idaho National Engineering 
and Environmental Laboratory (Laboratory) in Butte and Jefferson 
Counties, Gabler (1997, p. 42) found 101 burrow sites, of which 26 were 
active. Gabler (1997, p. 94) also revisited Wilde's (1978) three study 
areas on Laboratory lands, and found two collapsed burrows with no sign 
of occupancy; four active burrows which were abandoned 10 months later; 
and 34 abandoned burrows, respectively.
    Several surveys were conducted by Roberts between 1997 and 2004. In 
1997 and 1998, Roberts (2001, pp. 4-6) conducted surveys on BLM lands 
administered by the Salmon and Challis Field Offices (FO) in Lemhi and 
Custer Counties. The 3 areas occurred in the upper Lemhi River and 
upper Birch Creek Valleys; upper Pahsimeroi River and upper Little Lost 
River Valleys; and the upper Warm Springs Creek and upper Big Lost 
River Valleys. He found that pygmy rabbits were found widely scattered 
in all 3 of these areas (Roberts 2001, pp. 10-11). In addition, Roberts 
(2001, p. 11) mentioned an occupied area in Railroad Canyon adjacent to 
Bannock Pass. This may be contiguous with habitat found in Horse 
Prairie Creek, Montana reported by Rauscher (1997, p. 13). Other areas 
of occupied rabbit habitat were found in Hawley Creek and in Bradshaw 
Basin (Roberts 2001, p. 11). During 2002, Roberts (2003a, pp. 3, 5) 
conducted surveys in the Snake River Plains area in southern Idaho. 
Surveys were conducted on BLM lands within Idaho Falls, Pocatello, 
Shoshone, Owyhee, Jarbidge, and Burley FO areas, on U.S. Forest Service 
(USFS) lands within Targhee, Caribou, Cache, Sawtooth, Salmon, and 
Challis National Forests, and the Curlew National Grasslands. Roberts 
(2003a, p. 6) found 9 currently active pygmy rabbit burrow systems. 
Four were found on the Owyhee FO, two on the Pocatello FO and one each 
in Idaho Falls and Jarbidge FO areas. One was found on the Curlew 
National Grasslands. Two systems were classified as recently active. 
One was found on the Owyhee FO area and the other on the Shoshone FO 
area.
    During the summer of 2003, Roberts (2003b, p. 3) searched areas in 
Big Lost River Valley, Little Lost River Valley, Birch Creek, and 
Medicine Lodge Creek for pygmy rabbits. He found three currently and 
recently active burrow sites in Big Lost River Valley; seven currently 
and recently active burrows in Little Lost River Valley; seven 
currently active burrow sites in Birch Creek where five pygmy rabbits 
were observed; and one currently active burrow site at Medicine Lodge 
Creek area. Another active burrow site was found in upper Medicine 
Lodge Creek (Targhee National Forest 3 miles from Bannock Pass).
    In 2004, Roberts (2004, p.2) continued to survey areas in Big Lost 
River Valley, Little Lost River Valley, Birch Creek, and Medicine Lodge 
Creek located in Butte and Clark Counties. He was unable to find pygmy 
rabbit evidence in the areas he searched in Big Lost River (Roberts 
2004, pp. 3-4). He found 11 currently active sites in Little Lost River 
area. In the Birch Creek area he found 7 currently and recently used 
sites. He saw 6 pygmy rabbits at one of these areas. In this area, the 
pygmy rabbits were using cracks and crevices in and around large rocks 
and boulders as their burrows. In the Medicine Lodge Creek area he 
found 10 new burrow sites. He found 2 active burrows on the Targhee 
National Forest. Two additional active burrow sites were found on the 
U.S. Sheep Experiment Station.
    White and Bartels (2002, p. 1) surveyed for pygmy rabbits on 11 
grazing allotments in Twin Falls and Cassia Counties on BLM lands 
administered by the Burley FO. Results included 35 burrows found on 6 
of the allotments (White and Bartels 2002, p. 5). Twenty-four of the 
burrows were revisited with a peeper probe and six burrows located on 
two allotments were considered occupied by pygmy rabbits (White and 
Bartels 2002, p. 5). In addition, White and Bartels (2002, p. 7) 
attempted to visit 31 historical locations for pygmy rabbits in Cassia, 
Minidoka, Blaine, Power, and Oneida Counties, Idaho. Eighteen sites 
were too vague to relocate, eight were disturbed due to various 
factors, and five were potentially suitable habitat (White and Bartels 
2002, pp. 7-8). No active pygmy rabbit burrows were found on any of the 
13 disturbed or potentially suitable sites visited.
    Red Willow Research Inc. conducted several surveys between 1999 and 
2004. In 1999, Red Willow Research Inc. (2000, pp. 5-6) reported on 
sightings of pygmy rabbits at five locations in Cassia and Oneida 
Counties. Red Willow Research Inc. (2002, pp. 99-100) reported that all 
nine study areas within the BLM Shoshone FO area showed presence of 
pygmy rabbit use. Recent or current signs of occupancy were found at 
five individual sites along transects within three of the nine study 
areas in 2001 and 2002. Red Willow Research Inc. (2004, p. 3) continued 
surveys in and adjacent to the nine study areas identified in the 2002 
study. The 2004 survey resulted in one sighting and one possible 
sighting of a pygmy rabbit, one inactive burrow system, and 
identification of additional areas for future survey efforts (Red 
Willow Research Inc. 2004, p. 4).
    North Wind, Inc. (2004, p. 2) surveyed for pygmy rabbits on BLM 
lands in eight areas located in the northern portions of the BLM Idaho 
Falls District. Five sites indicated recent or past pygmy rabbit use, 
including a pygmy rabbit sighting (North Wind, Inc. 2004, p. 13).
    Rachlow and Witham conducted several surveys between 2003 and 2006. 
Rachlow and Witham (2004a, p. 2) surveyed 12 locations in Camas, 
Blaine, and Gooding Counties, south central Idaho that had been 
identified as potential habitat in 2003. Two sites were confirmed to 
support pygmy rabbit populations. Witham and Rachlow (2004, p. 3) 
surveyed three potential sites at Craters of the Moon National Monument 
and Preserve in 2004 and found no evidence of pygmy rabbit presence. 
Rachlow and Witham (2005, p. 1) conducted a pilot study to test whether 
pygmy rabbit sign could be detected during aerial surveys in the Camas 
Prairie of south central Idaho. The study area included the two 
previously known locations found in 2003 and confirmed in 2004 by 
Rachlow and Witham (2004a, pp. 2-3) (Rachlow and Witham 2005, p. 2). 
The aerial surveys identified 25 potential sites and 21 were ground 
checked (Rachlow and Witham 2005, p. 7). Seven of the 21 sites were 
confirmed to support pygmy rabbit populations (Rachlow and Witham 2005, 
p. 7). Rachlow and Witham (2006, p. 1) surveyed a portion of the Camas 
Prairie in south central Idaho by fixed-wing aircraft during February 
2006. They identified 67 potential sites from the air and evaluated 64 
of them on the ground. Presence of pygmy rabbits was

[[Page 60526]]

confirmed at 32 sites. Sign at the remaining sites was attributed to 
cottontail rabbits or other species. These new locations expanded the 
known distribution of pygmy rabbits in the Shoshone FO area.
    BLM (2005a, p. 1) reported on surveys conducted between 2002 and 
2005 on BLM lands within the Boise District (Owyhee FO). In 2002, four 
survey routes were walked and pygmy rabbit evidence was observed on 
each route (BLM 2005a, p. 2). Two sites were at or near previously 
known locations and two were new locations. One site was considered 
active. In 2003, 25 routes were walked and 12 locations found (7 active 
or recent, 5 inactive) (BLM 2005a, p. 2). In 2004, 14 routes were 
walked and 2 new populations were found (1 active or recent, 1 
unrecorded activity level) (BLM 2005a, p. 2). In 2005, 242 routes were 
walked with 16 new populations found (9 active or recent, 7 inactive) 
(BLM 2005a, p. 2).
    Bartels (2005, p. 2) conducted pygmy rabbit surveys in the southern 
portion of BLM's Jarbidge FO area during 2005. Sixteen pygmy rabbit 
burrows were identified with an additional 25 documented as potential 
pygmy rabbit burrows. Burrows were generally located near Coonskin 
Butte, Pigtail Butte, Dorsey Table, Worley Draw, and Signal Butte. 
During the survey four pygmy rabbits were confirmed observed. These 
rabbits were observed at Worley Draw and Coonskin Butte.
    Waterbury (2005, p.3) conducted winter surveys in late 2004 and 
early 2005 for pygmy rabbits in areas previously identified as 
potentially suitable habitat but where their presence or absence had 
not been conclusively determined on BLM (Salmon and Challis FO) and 
USFS (Leadore, North Fork, and Challis Ranger Districts) lands. Of the 
38 locations surveyed, pygmy rabbits were present at 12 of them 
(Waterbury 2005, p. 4). Waterbury (2006, p. 5) expanded search areas 
compared with previous efforts on BLM lands (Challis FO) located in 
Custer and Lemhi Counties. Surveys documented 269 positive detections 
of pygmy rabbits (burrows, tracks, pellets, sightings) over 20 areas 
(Waterbury 2006, pp. 9, 27-32). The areas of greatest concentrations 
occurred in Big Lost River Valley, Thousand Springs Valley, Pahsimeroi 
River Valley, Upper Spar Canyon, and Upper Road Creek (Waterbury 2006, 
p. 9). Forty-six pygmy rabbits were observed during the study 
(Waterbury 2006, p. 9). Of the 265 positive detections associated with 
burrow systems, 91 percent were at active or recently active systems 
(Waterbury 2006, p. 9). These surveys expanded the known pygmy rabbit 
locations in the Challis FO and confirmed the persistence of historical 
populations in the Upper Pahsimeroi and Thousand Springs Valleys 
(Waterbury 2006, p. 11).
    Wackenhut (2008, pp. 4, 6, 7) conducted pygmy rabbit surveys across 
much of Bear Lake Plateau, Bear Lake County, Idaho between December 
2006 and March 2007. Information was collected on 568 active burrows in 
19 different locations across the plateau. Ten pygmy rabbits were 
sighted during the study. Fecal pellets were collected at 19 individual 
burrows. DNA analysis for pygmy rabbit was positive for 13 of these 
samples; 5 samples were positive for mountain cottontail and 1 sample 
failed (Wackenhut 2008, p. 4).
    Most of the historical records (1999 and earlier) for Idaho occur 
in the following counties: Owyhee, Cassia, Minidoka, Bannock, Bingham, 
Butte, Custer, and Lemhi. Additional records are from Canyon, Ada, Twin 
Falls, Lincoln, Power, Oneida, Blaine, Bear Lake, and Clark. Current 
information (2000 and later) indicates the following 11 counties 
continue to support pygmy rabbit activity: Owyhee, Twin Falls, Cassia, 
Bear Lake, Lincoln, Blaine, Bingham, Butte, Custer, Lemhi, and Clark. 
Active areas were also found in the following counties without previous 
records: Washington, Gooding, Camas, Jefferson, and Fremont. Payette 
County indicated a recent inactive area.
    We are uncertain of the current pygmy rabbit activity in Canyon, 
Ada, and Bannock Counties because we are unaware of any survey efforts 
in 2000 or later occurring in these counties. Limited recent survey 
effort in Minidoka, Power, and Oneida Counties indicate inactivity at 
previously known sites. Records from Canyon and Ada Counties indicate 
activity in 1915 and 1982, respectively. Power and Minidoka Counties 
indicate activity in the 1930's and 1940's, respectively. Both Bannock 
and Oneida Counties indicate activity in the 1990's. However, recent 
survey efforts have expanded the known distribution in this State. 
Numerous previously unknown locations currently show signs of pygmy 
rabbit occupancy including locations in previously undocumented 
counties.

Montana

    The pygmy rabbit was first documented in Montana in 1918 (Hoffman 
et al. 1969, cited in Rauscher 1997, p. 1). In 1963, a specimen was 
collected in Big Sheep Basin (Rauscher 1997, p. 1). Between 1963 and 
1997 no additional documentation regarding the pygmy rabbit in Montana 
occurred (Rauscher 1997, p. 1).
    Rauscher (1997, entirety) documented the results of pygmy rabbit 
surveys in Montana during 1996 and 1997. Pygmy rabbits occupied 
suitable habitat in most of Beaverhead County, the extreme southern end 
of Deer Lodge County, and the western edge of Madison County (Rauscher 
1997, p. 5). Because of the discontinuous distribution of pygmy 
rabbits, every occupied site may not have been found, and as a result 
pygmy rabbits may occur outside of this range (Rauscher 1997, p. 5). 
Five of six historical sites were searched and four showed signs of 
occupation (Rauscher 1997, p. 6). He mentioned some sites were found 
that no longer appeared to be occupied. These occurred west of Dillon, 
at the southern end of Dutchman Mountain, and at the northern edge of 
Frying Pan Basin (Rauscher 1997, p. 6). Rauscher concluded pygmy 
rabbits appeared to occupy much of the historical range (Rauscher 1997, 
p. 13).
    Janson (2002, p. 33) wrote that the historical range in Montana 
continues to support pygmy rabbits, with some exceptions. This was 
based on his limited observations in Beaverhead County, Montana in 
2001.
    During 2004 and 2005, the Montana Natural Heritage Program 
conducted pygmy rabbit surveys for BLM (Dillon FO) to assess current 
distribution in the State (Lenard et al. 2005, p. 1). These surveys 
focused on Beaverhead (2004) and Madison (2005) Counties in areas of 
known use and areas where no activity had been previously documented 
(Lenard et al. 2005, p. 1). Due to snow, known locations in Horse 
Prairie, Medicine Lodge Creek (south of Ayers Canyon), Badger Gulch/
Sagebrush Creek, and Upper Ermont Creek were inaccessible (Lenard et 
al. 2005, p. 1). New areas of pygmy rabbit activity were identified, 
expanding the current known distribution of the species (Lenard et al. 
2005, p. 1). In 2004, five previously known locations were surveyed and 
four of the five indicated current activity in Beaverhead County. The 
fifth showed recent activity (Lenard et al. 2005, pp. 9-10). Seven new 
areas were surveyed and all showed current pygmy rabbit activity 
(Lenard et al. 2005, p. 10).
    In Madison County, five areas were surveyed in 2005. Although a few 
pygmy rabbit locations had been previously documented in one of these 
areas, the remaining areas were previously unknown to surveyors 
regarding pygmy rabbit occupancy. Of these five areas, three areas 
showed current activity; two areas showed recent activity (Lenard et 
al. 2005, p. 12). Four new areas were surveyed and

[[Page 60527]]

three areas were reported as showing no pygmy activity; one area could 
indicate a dispersal area as pellets were found but no burrows (Lenard 
et al. 2005, pp. 12-13).
    In Montana, during the winter of 2007, pygmy rabbit surveys were 
conducted in areas where no prior surveys had been conducted or where 
recent activity had not been documented in Beaverhead and Deer Lodge 
Counties (Hendricks et al. 2007, p. 3). Twenty-four sites were surveyed 
and four sites were found to have current pygmy rabbit activity 
(Hendricks et al. 2007, p. 9). Twelve sites had no evidence of pygmy 
rabbit activity, eight were considered unsuitable habitat for pygmy 
rabbits, and two were considered potential but were inaccessible due to 
snow (Hendricks et al. 2007, p. 9). Two active sites in Big Hole Valley 
were notable as they indicated current activity at sites that had not 
been resurveyed since they were active in 1997 (Hendricks et al. 2007, 
p. 10). The two other active sites were previously undocumented pygmy 
rabbit sites (Hendricks et al. 2007, p. 11). These new sites occurred 
in gaps between other locations suggesting additional locations may be 
found between those currently known (Hendricks et al. 2007, p. 13). The 
distribution and status of pygmy rabbits in Montana has become clearer 
since 1997 (Hendricks et al. 2007, p. 15). However, Hendricks et al. 
(2007, p. 15) suggested additional surveys should occur in Centennial 
Valley, Jefferson River corridor north of Twin Bridges, Frying Pan 
Basin west of Dillon, and the Ruby River and Sweetwater Creek 
corridors.
    Most of the historical and recent records for Montana occur in the 
following two counties: Beaverhead and Madison. Current information 
(2000 and later) indicates these two counties, as well as Deer Lodge 
County, continue to support pygmy rabbit activity. There is a notable 
increase in the current distribution of the pygmy rabbit to the 
northeast in Madison County.

Wyoming

    During the 1980's and 1990's a few reports documented pygmy rabbits 
in Wyoming. Campbell et al. (1982, p. 100) were the first to confirm 
the existence of pygmy rabbits in Wyoming. In 1981, 6 specimens were 
collected, 17 individuals were observed, and 2 skulls and many pellets 
were found at 2 sites in Uinta and Lincoln Counties in southwestern 
Wyoming (Campbell et al. 1982, p. 100). These two new locations found 
in Wyoming extended the known range of the pygmy rabbits about 149 mi 
(240 km) to the southeast and 90 mi (145 km) to the northeast (Campbell 
et al. 1982, p. 100). Clark and Stromberg (1987, p. 75) reported three 
sites from Lincoln and Uinta Counties located in southwestern Wyoming. 
Garber and Beauchaine (1992, p. 3) compiled previously reported 
observations from Campbell et al. (1982, p. 100) and information from 
the Wyoming Game and Fish Department database. Although, this report 
does not indicate locations, which ones were revisited, or their 
status, several sites were revisited and new sites were found in 1990. 
Eleven new observations were recorded which increased records to 50 
site confirmations (Garber and Beauchaine 1992, p. 4). Documented 
observations expanded the known distribution in Wyoming by including 
two additional counties: Sublette and Sweetwater (Garber and Beauchaine 
1992, p. 8).
    In 2004 and 2005, Purcell (2006, pp. 1, 7-11, 30) conducted her 
study in 10 areas in Lincoln, Sublette, Sweetwater, Fremont, and Carbon 
Counties. She found pygmy rabbits more widely distributed in 
southwestern and south central Wyoming than formerly thought due to 
previously unknown locations being found in Fremont and Carbon 
Counties. Purcell (2006, p. 32) suggested pygmy rabbits in Wyoming 
could occur as far east as Rawlins, as far north as Riverton, and as 
far south as Baggs.
    Western EcoSystems Technology, Inc. (2006, p. 1) conducted a pygmy 
rabbit survey in Lincoln and Uinta Counties, Wyoming. During the 
survey, 88 pygmy rabbit points indicating sign of pygmy rabbit presence 
were documented.
    Aster Canyon Consulting, Inc. conducted several surveys between 
2005 and 2007 in relation to proposed oil and gas facilities in 
Wyoming. These surveys provide pygmy rabbit sightings and signs in 
Lincoln, Sublette, and Sweetwater Counties.
    Grasslands Consulting, Inc. (2007, pp, 1,2) conducted pygmy rabbit 
surveys in 2007 in relation to three proposed oil and gas facilities in 
Sweetwater and Uinta Counties, Wyoming. These surveys provided pygmy 
rabbit sightings and signs in these counties.
    Most of the historical and recent records for Wyoming occur in the 
following four counties: Uinta, Lincoln, Sublette, and Sweetwater. 
Current information (2000 and later) indicates these counties continue 
to support pygmy rabbit activity. Recent survey efforts have expanded 
the known distribution in this State considerably as numerous 
previously unknown areas have been found in southern Sublette, southern 
Fremont, and eastern Sweetwater Counties. Areas in western Carbon 
County indicate a further range extension of the known distribution.

California

    Early records indicate that pygmy rabbits were documented in 
eastern Modoc, Lassen, and Mono Counties. Henshaw (1920, p. 9) 
mentioned obtaining rabbit specimens in northeastern California at 
Goose Lake, Modoc County, in 1877 (at the time identified as 
Trowbridge's hare (Lepus trowbridgei) but later determined to be 
Brachylagus idahoensis as described by Merriam). Grinnell et al. (1930, 
p. 553) collected 20 pygmy rabbit specimens during 1926 and 1928 in the 
vicinity of Ravendale, Lassen County. Orr (1940, p. 195) observed pygmy 
rabbits on the south edge of the Madeline Plains, located east of 
Ravendale, in October 1931. Severaid (1950, pp. 1-2) recorded 
observations and collection in 1948 of pygmy rabbits at Bodie, a famed 
gold mining ghost town, located in northern Mono County. The southern 
limit of their distribution in California was documented in 1955 in the 
vicinity of Crowley Lake in southern Mono County (Jones 1957, p. 274).
    During 2004, surveys were conducted on lands managed by BLM (Eagle 
Lake FO) in northern California (Sequin 2004, entirety). Twenty 
historical records are documented within the boundaries of the Eagle 
Lake FO and were located near Ravendale based on information provided 
by Grinnell et al. (1930) and Orr (1940). Pygmy rabbits were not found 
at any of the historical sites; no evidence of old or fresh pellets or 
burrows were seen (Sequin 2004, p. 6). Sequin (2004, p. 6) also 
surveyed 356 potential sites for pygmy rabbit sign within the Eagle 
Lake FO boundary. No pygmy rabbit activity, either old or current, was 
found at any of these potential sites (Sequin 2004, p. 6). As all 
potential pygmy rabbit habitat was not surveyed, it is possible that 
pygmy rabbits may still be found within the Eagle Lake FO boundary 
(Sequin 2004, p. 8).
    Larrucea and Brussard (2008a, pp. 692, 694-695), surveyed locations 
in Nevada and California between 2003 and 2006 which includes 
information reported in Sequin (2004). In California, active sites were 
found in Mono County, but not in Modoc or Lassen Counties (Larrucea and 
Brussard 2008a, p. 694). This area is on the edge of the pygmy rabbit's 
western range (Larrucea and Brussard 2008a, p. 694). It is possible 
that pygmy rabbits have been extirpated from Modoc and Lassen Counties. 
A range contraction would be more expected in a peripheral area, such 
as northern California, if it were to occur

[[Page 60528]]

(Larrucea and Brussard 2008a, p. 696). The Mono County populations may 
be isolated from other known populations because they appear to be 
separated by a distance of approximately 100 mi (162 km) from the 
nearest known populations in Nevada (Larrucea and Brussard 2008a, 
p.694). These pygmy rabbit populations may have become isolated from 
more eastern populations at the end of the Pleistocene (Grayson 2006, 
pp. 2969-2970).
    There are only a few historical (1999 and earlier) records for 
California which included Modoc, Lassen, and Mono Counties. Current 
information (2000 and later) indicates that while pygmy rabbit activity 
continues to occur in Mono County, pygmy rabbits may have been 
extirpated from both Modoc and Lassen Counties in northeastern 
California. Due to limited survey efforts in northern California 
overall, uncertainty remains whether this contraction has actually 
occurred. Therefore, Figure 1 does not depict this possible range 
contraction.

Nevada

    The earliest pygmy rabbit records for Nevada include a collection 
of 12 pygmy rabbits from Paradise, Humboldt County, Nevada in 1908 and 
1909 (Nelson 1909, p. 278). Nelson also indicated he examined 23 
additional specimens from Halleck, Ione Valley, Monitor Valley, Reese 
River, and Skelton, Nevada.
    Hall (1946, p. 618) indicates he examined 56 pygmy rabbit specimens 
and sight records from several locations throughout the State. The 
years of these collections and sightings are not included but were 
recorded for the following eight counties: Washoe, Humboldt, Pershing, 
Churchill, Lander, Nye, Elko, and White Pine. The range map for Nevada 
also included Eureka County and a portion of Lincoln County (Hall 1946, 
p. 615).
    During 1993 and 1994, surveys were conducted on Sheldon National 
Wildlife Refuge lands located in Washoe and Humboldt Counties. Twenty-
four surveys were completed; 17 locations were found to be occupied by 
pygmy rabbits (Service 1995, p. 1). In 2002, surveys were conducted on 
the refuge and locations reported in 1993 and 1994 were also revisited 
(Service 2004, p. 1). In total, 41 sites were surveyed for pygmy 
rabbits and 18 had pygmy rabbit sign of which 15 sites were confirmed 
with photography (Service 2004, p.2). Ten of the sites from the mid 
1990's had pygmy rabbit sign in 2003. Fifteen new sites were surveyed 
in 2003; eight of these showed pygmy rabbits and/or their sign (Service 
2004, p. 2).
    Marriott (2005, p. 4) reported conducting surveys for pygmy rabbits 
in all or portions of 23 units on the Ruby Lakes National Wildlife 
Refuge and an area immediately adjacent to refuge lands, located in 
Elko and White Pine Counties in 2004 and 2005. Evidence of pygmy 
rabbits was found in seven units. The populations reported by Ports and 
Ports (1989, p. 127) were found in the sand dune area adjacent to two 
of the refuge units (Marriott (2005, p. 4). It was confirmed that at 
least 27 burrows were active (Marriott (2005, p. 4). Three pygmy 
rabbits were observed (Marriott 2005, p. 5). The surveyors were 
confident that they had not found all the burrow systems within the 
refuge boundaries (Marriott 2005, p. 7). They also suspected that more 
pygmy rabbits occur in the sand dune area as they were unable to survey 
the entire area (Marriott 2005, p. 8). In 2006, Wienke (2006) reported 
conducting pygmy rabbit surveys in two areas of the Ruby Lakes National 
Wildlife Refuge and adjacent BLM lands. The sand dune area survey found 
44 pygmy rabbit burrow systems of which 20 appeared to be active 
(Wienke 2006, p. 2). Three pygmy rabbits were observed (Wienke 2006, p. 
2). In the Unit II-D area, 162 burrow systems were found; 53 were 
active (Wienke 2006, p. 2). Ten pygmy rabbits were observed (Wienke 
2006, p. 2).
    Etzelmiller (2003, p. 1) conducted 33 survey transects in 
northwestern Nye County, Nevada in 2003 and 10 showed evidence of pygmy 
rabbit sign. Pygmy rabbits appear to be concentrated in Indian, Eastern 
Ione, and Upper Reese River Valleys (Etzelmiller 2003, p. 3).
    In 2003 Himes and Drohan (2007) surveyed for pygmy rabbits in White 
Pine, Lincoln, and Nye Counties in eastern and central Nevada. Pygmy 
rabbit sign (individuals, burrow, pellets) was found along 261 of 642 
transects (40.7 percent) walked (pygmy rabbits and/or fresh burrows and 
pellets on 89 transects (13.9 percent); fresh pellets only on 33 
transects (5.1 percent); old burrows and pellets on 113 transects (17.6 
percent); old pellets only on 26 transects (4.0 percent)). No sign was 
observed on 381 transects (59.3 percent) (Himes and Drohan 2007, p. 
376). The southern limit of the previously known record in Nevada was 
extended by about 7.5 mi (12 km) south (Himes and Drohan 2007, p. 376). 
All transects where pygmy rabbits and/or sign of pygmy rabbit presence 
were observed in the study area were considered new locations. Due to 
the extreme remoteness and fairly inaccessible terrain in the survey 
area, additional localities are almost certain to remain undocumented 
(Himes and Drohan (2007, p. 380).
    During surveys conducted between 2003 and 2006, a total of 1,474 
locations were surveyed in Nevada and California (Larrucea and Brussard 
2008a, pp. 692, 694-695). Pygmy rabbits were documented at 258 sites 
(Larrucea and Brussard 2008a, p. 694). The current distribution of 
active sites in Nevada is similar to the historical distribution 
(Larrucea and Brussard 2008a, p. 694). Active sites were found 
throughout the historical range (Larrucea and Brussard 2008a, pp. 694-
695). Positive (confirmed) locations for pygmy rabbits in Larrucea 
(2007) should be considered as minimum occurrence because it occurred 
on a large, state-wide basis (Larrucea 2007, p. 28). Information from 
Larrucea (2006) was incorporated into the Larrucea (2007) study. 
Associated with the previous study (Larrucea 2007), Larrucea and 
Brussard (2008b, p. 1638) revisited 105 sites based on 118 historical 
records from Nevada (109) and California (9) dated between 1877 and 
1946 for current pygmy rabbit presence. Pygmy rabbits were found to be 
present at 36 percent of the historical sites (Larrucea and Brussard 
2008b, p. 1638). When a radius (buffer) around a positive location was 
increased to 3.1 mi (5 km) around a historical site, positive locations 
increased to 48 percent, and when a radius of positive location was 
increased to 6.2 mi (10 km) around a site, positive locations increased 
to 60 percent (Larrucea 2007, p. 56). As indicated in Larrucea and 
Brussard (2008a) many additional sites were found throughout the 
historical range.
    The Southern Nevada Water Authority (2007, p. 5) conducted pygmy 
rabbit surveys in 2005 and 2006 in Dry Lake, Cave, Lake, and Hamlin 
Valleys in Lincoln County and Spring, Snake, and Steptoe Valleys in 
White Pine County, Nevada. Fifty-six locations were surveyed and 15 had 
pygmy rabbit sign (SNWA 2007, p. 5). There was one confirmed and one 
potential pygmy rabbit sightings observed (SNWA 2007, p. 5). Pygmy 
rabbit sign occurred in Cave, Dry Lake, and Lake Valleys, Lincoln 
County and Spring Valley, White Pine County (SNWA 2007, pp. 5-10).
    Most of the historical records (1999 and earlier) for Nevada 
document occurrences in the following counties: Elko, Eureka, Lander, 
White Pine, and Nye Counties. There are fewer records from Washoe, 
Humboldt, Pershing, and Churchill Counties. Current information (2000 
and later) indicates all of these counties, with the exception of 
Pershing County, continue to support pygmy

[[Page 60529]]

rabbit activity, and across a broader area within those counties than 
historically noted. Pershing County is an exception because we are 
unaware of any recent survey efforts being conducted in the County, and 
therefore do not know if pygmy rabbits continue to exist there. In 
addition, pygmy rabbit activity has been found in Lincoln County. The 
recent survey efforts have located populations over a greater area 
within the State and the expansion of the known range has occurred most 
notably in Washoe, Lincoln, and Nye Counties.

Utah

    Early reports of pygmy rabbits occurring in Utah include the first 
reporting in 1932 after having been detected in 1931 (Stanford 1932, 
cited in Oliver 2004, p. 14). Janson (1940, p. 6) collected pygmy 
rabbits from Blue Creek Hills 10 miles (16.1 km) west of Tremonton and 
in Iron County about 5 miles (8 km) west of Cedar City. He observed 
them in the valley bottom west of Parowan. Anecdotal reports to Janson 
indicated that pygmy rabbits occurred at the foot of Lake Mountains 
west of Utah Lake. Janson (1940, p. 6) thought it was ``probable'' the 
pygmy rabbit occurred in ``a more or less broken strip through the 
Upper Sonoran sagebrush areas of western Utah from the northern 
boundary of the State nearly to the Iron-Washington County line 
southwest of Cedar City.'' In 1946, Janson (1946, p. 32) wrote that the 
pygmy rabbit ``appears'' to extend through Utah west of the Wasatch 
Mountains from the Idaho border to the northern border of Washington 
County. He reported specimens had been collected near Clarkston, Cache 
County; Blue Spring Hills and Grouse Creek, Boxelder County; and near 
Modena, Lund, Kanarraville, and Cedar City, Iron County. Pygmy rabbits 
or their sign had been observed near Snowville, Lucin, and Promontory, 
Boxelder County; and Parowan, Iron County. He mentioned a reliable 
report of their presence west of Utah Lake, Utah County, and a 
questionable report west of Trout Creek (county unknown). Schantz 
(1947, p. 187) noted, based on three specimens collected by Janson in 
1938, a 270 mile (434.4 km) southern expansion of known pygmy rabbit 
distribution in Utah from Promontory, Boxelder County, to Cedar City, 
Iron County.
    Janson (1946, p. 84) reported that in the winter of 1946, pygmy 
rabbits appeared to be more scarce than in 1941 based on two study 
areas in Utah (near Cedar City, Iron County; near Tremonton, Box Elder 
County). Areas where he considered pygmy rabbits common in Utah in 1941 
were found to have no pygmy rabbits occupying them in 1946.
    Durrant (1952, p. 88) reported that the pygmy rabbit range in Utah 
included Boxelder, Cache and Iron Counties and ``probably'' occurred 
between areas along the eastern margin of Pleistocene Lake Bonneville. 
He also listed additional records provided by Janson (1946, pp. 32-33) 
and included Juab County (Durrant 1952, p. 89).
    Holt (1975, p. 131) indicated considerable information was obtained 
that altered the distributional range of the species. Populations from 
Sevier River tributaries and surrounding areas indicated that the pygmy 
rabbit was not restricted to the Upper Sonoran life zone (Holt 1975, p. 
132). Holt (1975, pp. 136-138) indicated additional specimens have been 
examined from Boxelder, Tooele, Millard, Sevier, Beaver, Piute, 
Garfield, and Washington Counties. These are in addition to Janson's 
(1946, pp. 32-33) records or sightings from Boxelder, Cache, Utah, 
Juab, and Iron Counties.
    Pritchett et al. (1987, p. 231) reported pygmy rabbit records 
outside of the published range in the Bonneville Basin. One record is 
near Panguitch, Garfield County (Stephenson 1966, cited in Pritchett et 
al. 1987, p. 231). They mention Holt's (1975, p. 137) record of a 
population south of Fish Lake on Parker Mountain and a collection and 
sighting of pygmy rabbits south of Fish Lake Ranger Station and west of 
Loa, Wayne County. In addition, Pritchett et al. (1987, p. 231) 
reported collecting six live individuals and two skulls from the Parker 
Mountain region of the Awapa Plateau, Wayne County. The Awapa Plateau 
is part of the Fremont River watershed and is outside of the 
Pleistocene Lake Bonneville drainage. During 1986, Pritchett et al. 
(1987, p. 233) looked for pygmy rabbits or their sign and were able to 
find evidence from Burrville, about 0.5 mi (0.8 km) northwest of Parker 
Mountains, south through Grass Valley to north of Otter Creek 
Reservoir. They were unable to find Holt's (1975, p. 137) population 
west of Otter Creek Reservoir Pritchett et al. (1987, p. 233). They 
wrote that the valley between Kingston and Otter Creek is narrow and 
disturbed. They found no evidence of pygmy rabbits from Sigurd to 
Burrville or through Emery Valley.
    Based on the two previous study areas in Utah between 1938 and 
1946, and limited observations in Utah (near Clarkston, Cache County; 
near Snowville and Grouse Creek, Box Elder County) in 2001, Janson 
(2002, p. 32) wrote that recent information indicated pygmy rabbit 
populations had declined in some areas where they were previously more 
abundant, mostly as a result of human actions. He states that 
residential and commercial development, farming, and range improvements 
for grazing, especially near Cedar City, had impacted the sagebrush 
habitat. He found no recent sign of occupancy near Cedar City, Utah.
    Oliver (2004 pp. 16-18) provides a review of pygmy rabbit in Utah 
and lists location records for the pygmy rabbit between 1946 and 2003 
which includes the following 14 counties: Washington, Boxelder, 
Garfield, Piute, Iron, Sevier, Cache, Beaver, Rich, Wayne, Toole, 
Millard, Juab, and Utah.
    In 2005, Welch (2005, pp. 15-17, 36) conducted walking surveys of 
48 big sagebrush stands or sites in Utah (41 sites in Box Elder, Rich, 
Tooele, Davis, Utah, Wasatch, Duchesne, Uintah, Juab, Carbon, Sevier, 
Beaver, Piute, Wayne, Iron, and Washington Counties), Idaho (4 sites in 
Cassia and Oneida Counties), and Nevada (3 sites in Elko and White Pine 
Counties) in 2003 and 2004. Twelve of these sites were known to have 
supported pygmy rabbits in the past, 26 possibly supported pygmy 
rabbits in the past, and 10 sites had no record of past use (Welch 
2005, p 2). Of the 12 sites known to have supported pygmy rabbits in 
the past, 4 were found to support pygmy rabbits or current sign (Cassia 
County, Idaho; Piute and Rich Counties, Utah; Elko County, Nevada); of 
the 26 possible historical sites, 1 was found to support current pygmy 
rabbit activity during his study (Iron County, Utah) (Welch 2005, pp. 
9, 14-17, 36). In addition, he surveyed 13 other sites previously 
listed by Janson (2002, pp. 10-11) (Welch 2005, p 2). Of these 13 
sites, none showed signs of current use; only 5 had some remaining 
suitable habitat (Welch 2005, p 10).
    Flinders et al. (2005, p. 7) surveyed habitat in Grass Valley in 
Piute, Sevier, and Wayne Counties located in south central Utah. Pygmy 
rabbit surveys were conducted in areas slated for sagebrush treatment 
but where pygmy rabbit surveys had not been previously conducted as 
well as revisiting areas where pretreatment pygmy rabbit surveys had 
been completed by BLM employees (Flinders et al. 2005, p. 13). 
According to Flinders et al. (2005, p. 13), BLM surveys identified 118 
active burrow systems and 85 inactive ones. Flinders et al. (2005, p. 
13) found 14 locations with active burrow systems and all others found 
in treatment areas were determined to be inactive.
    During 2005 and 2006, Larsen et al. (2006) surveyed for pygmy 
rabbits in Deep Creek watershed, Tooele County.

[[Page 60530]]

 This watershed is located on the Utah-Nevada border and the closest 
known extant pygmy rabbit population in Nevada occurs about 52 miles 
(84 km) to the northwest (Larsen et al. 2006, p. 4). The Nevada 
population had been surveyed within the past 5 years (Larsen et al. 
2006, p. 4). Four historical (1905-2002) sites showed no evidence of 
present occupation by pygmy rabbits (Larsen et al. 2006, p. 5). In 
addition, three active pygmy rabbit locations (confirmed with 
photography) and three inactive ones were found within the watershed 
(Larsen et al. 2006, pp. 5-6). Pygmy rabbits were not photographed at 
the inactive sites and fresh pellets were lacking; however, given the 
recent activity and the potential for reoccupation, the authors 
believed these inactive sites are important to the species in the 
watershed (Larsen et al. 2006, p. 15). Interestingly, based on the map 
provided by Larsen et al. (2006, p. 16), the three inactive sites and 
the three active sites are located north and south of the historical 
sites, respectively.
    Flinders (2007, pp. 2-3) indicates discovery of fairly extensive 
populations in Hamlin Valley located on the Utah-Nevada border in Iron 
and Beaver Counties. Numerous burrows systems classified as current or 
recently current have been found in the area. This area may provide a 
corridor between Utah and Nevada pygmy rabbit populations. Pygmy rabbit 
use was found on both sides of the border.
    In summary, most historical records (1999 and earlier) for Utah 
occurred in the following six counties: Boxelder, Iron, Washington, 
Garfield, Piute, and Wayne Counties. Fewer records occurred in Beaver, 
Millard, Juab, Tooele, Sevier, Utah, Rich, and Cache Counties. Current 
information (2000 and later) indicates Boxelder, Tooele, Beaver, Iron, 
Washington, Garfield, Piute, Wayne, Sevier, and Rich Counties continue 
to support pygmy rabbit activity. Current pygmy rabbit activity is 
uncertain in Cache, Utah, and Juab because we are unaware of any recent 
survey efforts occurring in these counties. A new area in Millard 
County was searched in 2003 and activity was not observed. The recent 
survey efforts have located active population in Sanpete County and in 
additional areas previously unknown within the other counties where 
surveys have occurred.

Abundance

    We are unaware of any historical or current population estimates 
being made for the pygmy rabbit by individual States or for the range 
considered in this finding. Any figures related to numbers of pygmy 
rabbits provided in the literature have been reported as individuals 
collected (Dice 1926 p. 27 (10 in Oregon); Grinnell et al. 1930, pp. 
553-554 (20 in California), p. 555 (35 in Nevada); Bailey 1936, p. 111 
(8 in Oregon); Severaid 1950, p. 2 (4 in California); Borell and Ellis 
1934, pp. 41-42 (7 in Nevada)), or individuals observed (Grinnell et 
al. 1930, p. 553 (1 in California); Bailey 1936, p. 111 (40 in Oregon); 
Jones 1957, p. 274 (1 in California); Bartels 2003, p. 88 (5 in 
Oregon); Rachlow and Witham 2004a, p. 3 (20 in Idaho); Flinders et al. 
2005 p. 45 (250 in Utah)), or individuals photographed (Flinders et al. 
2005 p. 45 (241 in Utah)) or individuals live trapped (Rauscher 1997, 
p. 9 (58 in Montana); Rachlow and Witham 2004a, p. 3 (25 in Idaho); 
Crawford 2008, p. 22 (337 in Nevada and Oregon)), or mortalities 
reported related to study efforts (Rauscher 1997, p. 9 (11 in Montana)) 
in various parts of its range by researchers.
    Other authors used qualifying statements to indicate abundance 
(Anthony 1913, p. 22, in Oregon wrote, ``On account of the thick growth 
and the animal's habit of circling about under cover an accurate count 
of the inhabitants of such a locality was difficult to obtain.'' 
Anthony (1913, p. 21) also stated that the species was ``not uncommon'' 
around Ironside, Malheur County, Oregon; Bailey (1936, p. 111) stated 
that Oregon pygmy rabbits are locally abundant only where conditions 
are favorable. Janson (1940, p. 41) wrote that pygmy rabbits in Utah 
occur in scattered communities which are limited by characteristics 
favorable to the pygmy rabbit. In these areas where characteristics 
favorable to the pygmy rabbit are found, the pygmy rabbit may be quite 
abundant.
    Under the species description provided above, several researchers 
have reported a variety of density estimates for pygmy rabbits on 
individual sites. However, the number of active burrows may not be 
directly related to the number of individuals in a given area because 
some individual pygmy rabbits appear to maintain multiple burrows, 
while some individual burrows are used by multiple individuals (Janson 
1940, pp. 21, 29; Janson 1946, p. 44; Gahr 1993, pp. 66, 68; Heady 
1998, p. 25). It is not appropriate to extrapolate any of these 
reported densities beyond the local scale due to the patchy 
distribution of suitable habitat and the variable amount of habitat 
actually occupied (Keinath and McGee 2004, p. 20). Efforts to model the 
amount and distribution of suitable habitat have met with minimal 
success and are useful mainly for focusing future survey efforts 
(Keinath and McGee 2004, p. 20).
    More recently, attempts have been made to estimate pygmy rabbit 
abundance by different methods. Rachlow and Witham (2004b, pp. 2-13) in 
Idaho evaluated several census techniques for pygmy rabbits (thermal 
imagery, burrow surveys, live trapping, line transect surveys, fecal 
pellet counts). They found several techniques were infeasible due to 
cost or the likelihood of providing imprecise estimates. Surveys of 
burrow systems provide an obtainable index of activity, but more work 
is needed to associate this index with population density estimates 
(Rachlow and Witham 2004b, p. 13). Price (2008, p. 2) in Idaho is 
attempting to develop a standardized method to monitor abundance of 
pygmy rabbits. Price is attempting to calibrate an index of abundance 
based on burrow systems by correlating the index with estimates of 
population density. Sanchez (2007, p. 108) states that tools used for 
estimating relative abundance of pygmy rabbits rely on locating and 
assessing burrows and fecal pellets. Sanchez evaluated the temporal 
changes in fecal pellets and burrow systems to assess their potential 
usefulness as indicators of relative abundance of pygmy rabbits 
(Sanchez et al. 2009, p. 427). The persistence and detectability of 
pellets and burrows over time may be influenced by factors such as 
weather, soil microorganisms, invertebrates, vertebrates, vegetative 
growth, or the soil's susceptibility to slumping or compaction (Sanchez 
et al. 2009, p. 427). Sanchez et al. (2009) determined that next to 
actual sightings of pygmy rabbits, burrow systems and pellets are the 
most reliable evidence of pygmy rabbit presence in an area; together 
they may provide an indirect index of population trend but depend on 
the objectives of the investigator as multiple factors can affect 
changes in pellets and burrows over time (Sanchez et al. 2009, p. 433). 
Therefore, reliably estimating the abundance of pygmy rabbits on a 
statewide or range wide basis is not currently possible.

Trend

    Population trends are normally defined in terms of distribution or 
abundance. In the case of the pygmy rabbit, the available scientific 
information does not allow for an analysis of abundance over time. 
Abundance trends for the pygmy rabbit in each State and throughout its 
range are unknown and how impacts to the sagebrush habitat from various 
events or actions have affected pygmy rabbit abundance remain unclear.

[[Page 60531]]

    Distribution information obtained from early literature and records 
represent a collection of sightings documented by different individuals 
over time. These early records were not collected in a systematic, 
comprehensive manner with the goal of determining the pygmy rabbit's 
distribution. However, they do reflect the species historical 
distribution known or suggested at that time, which was modified as 
previously unknown locations were found. Our understanding of the 
distributional trend throughout the species' range has improved only 
recently.
    Surveys have concentrated on documenting populations within a 
particular State by revisiting historical sites and looking for 
previously unknown sites. It is important to understand that 
considering only contemporary surveys of historical sites is likely to 
result in an apparent loss of a species from any number of locations 
regardless of whether the species has suffered a decline in numbers or 
not (Shaffer et al. 1998, cited in Larrucea and Brussard 2008b, p. 
1639). Populations naturally fluctuate locally so some historical sites 
are expected to disappear due to chance alone (Hanski 1991, cited in 
Larrucea and Brussard 2008b, p. 1639). In addition, it is often 
difficult to determine whether pygmy rabbit activity continues in a 
particular area because many historical site descriptions are vague.
    With the possible exception of California and Nevada, recent survey 
efforts have not been comprehensive in individual States. Due to 
funding limitations, various individuals from various agencies have 
selected different areas in each State to survey. As a result, 
different methodologies were developed for these surveys. Some 
individual sites or locations have been destroyed while some 
populations may have relocated to other areas across the landscape 
because of various factors. Appropriately, surveys have also expanded 
into new areas and have found previously undocumented pygmy rabbit 
populations. These efforts have improved our understanding of the 
species' current distribution across its range. Because of the emphasis 
in determining where pygmy rabbits occur on the landscape, monitoring 
of known sites over time has essentially not occurred for pygmy rabbit 
populations.
    Historical records provide no information on the amount of area 
where pygmy rabbits were collected or observed. Rarely do recent survey 
efforts report the amount of acreage attributed to occupied or 
unoccupied pygmy rabbit burrow systems. Therefore, we are unable to 
compare changes in the amount of acres used historically or currently 
by pygmy rabbits.
    Because of this lack of long-term distributional data, we have 
compared active and inactive (occupied versus unoccupied) records in 
the Service's databases from 1877 to 1999 to active and inactive 
records from 2000 to 2008. Based on a comparison of these two groups of 
records, the distribution of pygmy rabbits is quite similar to our 
understanding of the historical range in all States except California 
as discussed in more detail above. Not only do pygmy rabbits continue 
to occupy the general areas previously known, new areas of current 
activity have been documented due to increased survey efforts in recent 
years. We are encouraged by recent survey efforts and that researchers 
continue to find populations where they occurred historically. These 
survey efforts have also lead to the discovery of active areas in 
previously unknown or undocumented locations, and assist in improving 
our understanding of the distribution of the pygmy rabbit across its 
range.
    In some States (Montana, Nevada, and most notably Wyoming) these 
increased survey efforts have led to an extension of the current 
distribution of pygmy rabbits within these States. We are not 
suggesting that these populations have expanded in these States, only 
that increased survey efforts have located previously unknown or 
undocumented populations of this species. It appears that recent survey 
efforts have not occurred in the peripheral counties in Oregon so we 
are unsure of current pygmy rabbit activity in these areas. Idaho also 
shows some uncertainties because of some inactive areas and we are 
unaware of previous areas being revisited; however, active areas have 
also been found in previously unknown areas and counties. Utah shows 
some uncertainties because we are unaware of previous areas being 
revisited. Active areas have been found in previously unknown areas and 
counties in Utah. It is possible that California has experienced a 
relatively small range contraction in the northeast in Modoc and Lassen 
Counties. Because we eliminated undesirable records from our analysis, 
as explained above, we believe we have presented a conservative look at 
our current understanding of the distribution of the pygmy rabbit 
across its range. The pygmy rabbit not only occurs generally throughout 
its historical range, it also occurs in previously unknown or 
undocumented areas, thus increasing our understanding of the species' 
current distribution.

Habitat

    Sagebrush is the most widespread vegetation in the western United 
States' intermountain lowlands (West and Young 2000, p. 259). A number 
of species and subspecies of sagebrush are recognized (Connelly et al. 
2004, p. 5-2) and each has unique habitat requirements and responses to 
disturbances (West and Young 2000, pp. 259-261). Sagebrush species and 
subspecies occur in areas dictated by local soil type, soil moisture, 
and climatic conditions (West 1983, pp. 333, 355-357; West and Young 
2000, pp. 259-261). The degree of dominance by sagebrush varies with 
local site conditions and disturbance history. Plant associations, 
typically defined by perennial grasses, further describe distinctive 
sagebrush communities (Miller and Eddleman 2001, p. 14; Connelly et al. 
2004, p. 5-3) and are influenced by soil type, elevation, topography, 
and precipitation.
    Sagebrush species are long-lived with some surviving to 100 years 
(West and Young 2000, p. 259). Allelopathic chemicals are produced that 
reduce seed germination, seedling growth and root respiration of 
competing plant species and inhibit the activity of soil microbes and 
nitrogen fixation. Sagebrush species are resistant to environmental 
extremes, with the exception of fire and on occasion defoliating 
insects (West 1983, p. 341). Most species of sagebrush are killed by 
fire (Miller and Eddleman 2001, p. 17; West and Young 2000, p. 259). 
The natural re-colonization of sagebrush in burned areas depends on the 
presence of adjacent live plants for a seed source or on a seed bank, 
if present (Miller and Eddleman 2001, p. 17).
    Sagebrush species are typically divided into two groups, tall 
sagebrush (also known as ``big'') and low sagebrush, based on their 
affinities for different soil types (West and Young 2000, p. 259). 
Within tall sagebrush, there are three subspecies, Artemesia tridentata 
ssp. wyomingensis (Wyoming big sagebrush), A. t. ssp. tridentata (basin 
big sagebrush), and A. t. ssp. vaseyana (mountain big sagebrush) which 
are the most widely distributed (Knick et al. 2003, p. 614). There are 
two primary species in the low sagebrush group: A. arbuscula (low 
sagebrush) and A. nova (black sagebrush) (Knick et al. 2003, p. 614). 
Big sagebrush occurs in coarse-textured and/or well drained sediments, 
while low sagebrush typically occurs where erosion has exposed clay or 
calcified soil horizons (West and Young 2000, p. 261). Big sagebrush 
will die if saturated long

[[Page 60532]]

enough to create anaerobic conditions for 2 to 3 days (West and Young 
2000, p. 259). Some low sagebrush species are more tolerant of 
occasionally supersaturated soils, and many low sagebrush sites are 
partially flooded during spring snowmelt. Sagebrush species do not 
tolerate high salinity soils (West and Young 2000, p. 270).
    Sagebrush and sagebrush ecosystem response to natural and human 
influenced disturbances varies based on the sagebrush species and its 
understory, as well as abiotic factors such as soil type and 
precipitation. Mountain big sagebrush, for example, generally can 
recover more quickly and robustly than Wyoming big sagebrush following 
a disturbance (Miller and Eddleman 2001, p. 22) likely due to its 
occurrence on moist, well drained soils as compared to the very dry 
soils typical of Wyoming big sagebrush communities. Soil associations 
have resulted in disproportionate levels of habitat conversion across 
different sagebrush communities. Basin big sagebrush occurs at lower 
elevations, in soils that retain moisture two to four weeks longer than 
in well drained, but dry and higher elevation soils typically occupied 
by Wyoming big sagebrush. As a result, sagebrush communities dominated 
by basin big sagebrush have been converted to agriculture more 
extensively than communities found on poorer soils (Winward 2004, cited 
in 70 FR 2254). The effects of disturbance on sagebrush species are not 
constant across their range.
    Within the sagebrush ecosystem, there are two primary features of 
pygmy rabbit habitat: relatively taller and denser big sagebrush and 
deep soils (Ulmschneider et al. 2004, p. 2). Pygmy rabbit burrows are 
usually found in the taller and denser sagebrush within an area. The 
height of the sagebrush can vary greatly, from approximately 1.5 to 7 
ft (0.46 to 2.1 m). Sagebrush density can also vary, but it is common 
that the sagebrush canopy cover at burrows is greater than 30 percent 
(within a 20-ft (6.1 m) radius of burrow) (Ulmschneider et al. 2004, 
pp. 2, 23). Occupied habitat includes various subspecies of sagebrush, 
including Wyoming, mountain, and basin. Other shrub species may also be 
present, including Purshia tridentata (bitterbrush), rabbit brush, 
Sarcobatus vermiculatus (greasewood), Symphoricarpos spp. (snowberry), 
and Juniperus spp. (juniper). In Oregon and Nevada, some areas occupied 
by pygmy rabbits include rabbit brush as dominant or co-dominant with 
sagebrush and burrows have been found under large, dense rabbit brush 
and greasewood (Ulmschneider et al. 2004, p. 2).
    Pygmy rabbits can also occupy habitat that does not appear ideal. 
These areas include sagebrush that is short in height and ``bad'' soil. 
In east central Idaho, pygmy rabbits occupy ``mima mounds'' (mounds of 
soil several feet (ft) high and approximately 20 to 30 ft (6.1 to 9.1 
m) in diameter) with taller and denser sagebrush dotted in a landscape 
of shorter and thinner sagebrush. In Montana, the average sagebrush 
height in occupied sites can be about 15 in (38.1 cm). In Montana, 
pygmy rabbits have been found in areas where the sagebrush is not very 
dense and is about 30 in (76.2 cm) high, especially in mountain bowls 
and where sagebrush has been manipulated. In Utah, pygmy rabbits have 
been found to occupy 12 to 120-inch (30.5 to 304.8 cm) tall sagebrush. 
Regardless of the absolute height of the vegetation, pygmy rabbits will 
almost always burrow in the tallest and densest sagebrush on the 
landscape (Ulmschneider et al. 2004, pp. 2-3).
    Generally, pygmy rabbits burrow in loamy soils deeper than 20 in 
(50.8 cm). Soil composition needs to be soft enough for digging, yet be 
able to support a burrow system. In southwest Idaho, pygmy rabbits 
occur in areas with soils classified as stony sandy loam, and sandy 
loam over sandy clay and clay loam. In east central Idaho, soils are 
gravelly outwash plains with lime-coated rocks. On the lava plains of 
southeast Idaho, rabbits will often burrow between or under lava 
boulders. In Nevada, soils are light-colored and friable (easily 
crumbled) (Ulmschneider et al. 2004, p. 3).
    Occupied pygmy rabbit habitats in Oregon are very similar to those 
in Idaho (below). Most habitat occurs where big sagebrush inclusions 
are mixed with low sagebrush, rabbit brush, or shorter stature big 
sagebrush. Mounding similar to ``mima mounding'' occurs in most of 
these sites. Sagebrush on the mounds is usually 1 to 3 ft (0.30 to 0.91 
m) taller than those in the surrounding area. Another common type of 
occupied habitat in Oregon is small draw bottoms where deeper soils 
have collected. Most of these sites are vegetated with basin big 
sagebrush in the drainage bottom, surrounded by Wyoming big sagebrush, 
low sagebrush, or mountain big sagebrush in the surrounding uplands. 
Some areas utilized by pygmy rabbits are dominated by rabbit brush. 
Some soil mounding can occur in these areas, but can be subtle. Burrows 
in these areas seem to be restricted to the very bottom of the 
drainages or the lower inside slopes of the drainage (Ulmschneider et 
al. 2004, p. 4).
    In Oregon, Weiss and Verts (1984, p. 567) found mean shrub cover in 
areas occupied by pygmy rabbits was about 29 percent and mean shrub 
height was about 33.1 in (84 cm). Mean shrub cover best distinguished 
occupied sites from adjacent sites (29 versus 18 percent), followed by 
mean soil depth (51 versus 31 cm), and mean shrub height (84 versus 53 
cm). Percent basal area of perennial grasses, density of annual 
grasses, density of forbs, and components of soil texture were found to 
contribute little to the difference between occupied areas and adjacent 
sites. Meisel (2006, p. 21) found average sagebrush height 2.1 ft (0.65 
m) and percent sand content in the soil (50.2 percent) as the two 
variables that determined occupied burrows. Unoccupied burrows had an 
average sagebrush height of 1.0 ft (0.32 m) and 45.5 percent sand in 
the soil sample.
    In Idaho, pygmy rabbits are found in mima mound areas. In the 
Salmon, Idaho area, pygmy rabbits are found on alluvial plains dotted 
with mounds about 20 to 30 ft (6.1 to 9.1 m) in diameter, 1 to 2 ft 
(0.3 to 0.61 m) tall, several hundred ft or yd apart, where the 
sagebrush is taller than in the surrounding inter mound spaces. In 
southwest Idaho, a similar habitat is occupied by pygmy rabbits where 
big sagebrush islands are intermingled with low sagebrush. In the 
Owyhees of southwest Idaho, pygmy rabbits are found in swales of taller 
sagebrush. Soil mounding is present, but it does not form distinctive 
mima mounds. In the Bruneau Plateau, pygmy rabbits are found in the 
bottoms and lower slopes of small drainages where the sagebrush is 
denser and taller, indicating deeper soils (Ulmschneider et al. (2004, 
p.3). In the Owyhees of southwestern Idaho, Burak (2006, pp. 63-64) 
found occupied pygmy rabbit areas had significantly greater total 
shrub, sagebrush (A. t. ssp. vaseyana), forbs, and litter cover, and 
significantly less bare soil and rock than in unoccupied areas. Total 
shrub, sagebrush (A. t. ssp. vaseyana) and snowberry cover was greater 
in occupied pygmy rabbit habitat. Height of total shrubs and sagebrush 
was also significantly higher in occupied areas. Total shrub cover 
values ranged from 41 to 67 percent. Sagebrush cover values ranged from 
12 to 60 percent. These differences in total shrub cover and sagebrush 
cover suggest that total shrub cover does not need to be comprised of 
sagebrush primarily. It is unknown what minimum amount of sagebrush 
cover is needed for pygmy rabbit survival. Burak (2006, p. 65) found in 
his study areas

[[Page 60533]]

average total shrub and sagebrush height to be 160 in (63 cm) and 167.6 
in (66 cm), respectively.
    Pygmy rabbits in Montana are found in habitats similar to those in 
Idaho and Oregon- large intermountain valley bottoms, alluvial fans, 
mountain valleys and bowls, drainage bottoms, plateaus, rolling 
sagebrush plains and isolated patches of sagebrush in grasslands. 
Preferred habitat in Montana appears to be gently sloping or nearly 
level floodplains where adequate sagebrush and appropriate soils exist. 
However, many occupied sites have marginal sagebrush cover and 
shallower soils. If pygmy rabbits are found in areas containing mima-
like mounds, they generally occur throughout the continuous sagebrush 
coverage at varying densities and into sagebrush drainages 
(Ulmschneider et al. 2004, p. 4).
    In Wyoming, pygmy rabbits occur in swales of taller, denser 
sagebrush in a setting of hillsides with thinly distributed, shorter 
sagebrush. The general areas used by pygmy rabbits have evenly 
distributed, taller, and more structurally diverse sagebrush with a 
dense canopy. Three subspecies of big sagebrush can be present, basin, 
Wyoming, and mountain (Ulmschneider et al. 2004, p. 5). In Wyoming, 
Purcell (2006, p. 62) found that the proportion of bare ground and 
shrub cover may influence habitat features used by pygmy rabbits. Of 
the 10 study areas, 6 had significantly less bare ground at use sites 
than at non-use sites. Six of the 10 study areas had significantly 
greater shrub cover at use sites compared with non-use sites. Although 
sagebrush was the dominant shrub in all study areas, other shrubs 
contributed to the shrub cover. In relation to soils, Purcell (2006, 
pp. 64-65) found 8 of the 10 study areas showed a higher fine fraction 
of soil in both the surface and subsurface levels at use sites. The 
amount of coarse material in the soil may not inhibit digging if the 
soil is soft. Both surface and subsurface samples indicated that softer 
soils occurred at the use sites compared with the non-use sites. There 
did not appear to be a relationship between soil texture and areas used 
by pygmy rabbits (Purcell 2006, p. 65).
    Western EcoSystems Technology, Inc. (2008, pp. 18, 20, 22-23) found 
the dominant habitat types within 6.6 ft (2 m) of pygmy rabbit burrows 
along three pipeline routes in 2007 were tall sagebrush (42 percent), 
low sagebrush (48 percent), and desert scrub (10 percent). The average 
percent of different shrub types located within 16 ft (5 m) of pygmy 
rabbit burrows along two of the pipeline routes in 2006 indicated tall 
sagebrush at 56.6 percent, low sagebrush at 34.7 percent, and 
greasewood at 7.7 percent. Average percentages of shrub cover within 
6.6 ft (2 m) of burrows along the three routes in 2007 show 58 percent 
of burrows had between 26 and 50 percent shrub cover. Twenty-eight 
percent had a shrub cover of between 11 and 25 percent. Along two of 
the routes in 2006, pygmy rabbit burrows were found in 33.3 percent 
loam, 30.2 percent clay, and 20.3 percent sand.
    In California, pygmy rabbits occupy areas near Mono Lake in islands 
of big sagebrush and loamy soils, similar to areas in Nevada, but with 
sandier soils. Burrows tend to be in sandy loam soils, which are often 
surrounded by very sandy soils. Near Bodie, an abandoned mining town 
approximately 10 mi (16.1 km) north of Mono Lake, the habitat includes 
shorter, more uniform sagebrush, often less than 3 ft (0.9 m) tall, 
with less clumping of the sagebrush. Pygmy rabbit habitat in 
northeastern California is very similar to habitat in adjacent Nevada 
(Ulmschneider et al. 2004, p. 5).
    In Nevada, pygmy rabbits are found in broad valley floors, drainage 
bottoms, alluvial fans, and other areas with friable soils. Burrows can 
be located in mounds (either natural or human caused) when they are 
available in these types of soils. Pygmy rabbit burrows are easiest to 
find in light colored, friable soils. These soils are usually found in 
valley bottoms and can be associated with rabbit brush or sagebrush 
vegetation. The understory of grasses and forbs can vary from almost 
none to dense (Ulmschneider et al. 2004, p. 4). In California and 
Nevada, Larrucea and Brussard (2008a, pp. 695-697) found mean sagebrush 
cover at occupied sites was 44.7 percent. Mean sagebrush height at 
occupied sites was 38.8 in (98.4 cm), but it was not found to be a 
significant factor. Pygmy rabbits were more likely to occupy sites 
within clusters of sagebrush located higher than the surrounding 
sagebrush or in sagebrush islands. These islands occurred in a range of 
surrounding sagebrush heights of 4.7 to 46.1 in (12 to 117 cm). These 
islands also had greater sagebrush cover. Occupied sites were located 
on loamy soils with a mean sand and clay content of 39.1 percent and 
20.4 percent, respectively. Pygmy rabbits occupied sites with little or 
no understory.
    In Utah, site characteristics inhabited by pygmy rabbits vary 
considerably, because they occupy three different ecoregions: Central 
Basin and Range, Wyoming Basin, and the Wasatch and Uintah Mountain. 
These ecoregions vary in latitude, elevation, precipitation, and 
geologic history. Pygmy rabbits are found in the western half of the 
state in alluvial deposits and in favorable micro sites on ``bench 
tops''. Habitat in northern Utah is characterized by Wyoming, mountain, 
and basin big sagebrush, and bitterbrush and snowberry present at the 
higher elevations. Pygmy rabbit habitat in southern areas is often 
limited to the bottom of gentle drainages supporting Wyoming sagebrush 
with black sagebrush, Atriplex confertifolia (shadscale), and Kochia 
americana (gray molly) community of minimal height (11.0 in, 28 cm) 
(Ulmschneider et al. 2004, p. 5).

Evaluation of Information Pertaining to the Five Threat Factors

    Section 4 of the Act (16 U.S.C. 1533) and implementing regulations 
(50 CFR part 424) set forth procedures for adding species to, removing 
species from, or reclassifying species on the Federal Lists of 
Endangered and Threatened Wildlife and Plants. Under section 4(a)(1) of 
the Act, a species may determine to be endangered or threatened on the 
basis of any of the following five factors:
    (A) The present or threatened destruction, modification, or 
curtailment of its habitat or range;
    (B) Overutilization for commercial, recreational, scientific, or 
educational purposes;
    (C) Disease or predation;
    (D) The inadequacy of existing regulatory mechanisms; or
    (E) Other natural or manmade factors affecting its continued 
existence.
    In making this 12-month finding, information pertaining to the 
pygmy rabbit in relation to the five factors provided in section 
4(a)(1) of the Act is discussed below. In making our 12-month finding 
on the petition, we considered and evaluated the best scientific and 
commercial information available.
    In considering what factors might constitute threats to a species, 
we must look beyond the exposure of the species to a factor to evaluate 
whether the species may respond to the factor in a way that causes 
actual impacts to the species. If there is exposure to a factor and the 
species responds negatively, the factor may be a threat and we attempt 
to determine how significant a threat it is. The threat is significant 
if it drives, or contributes to, the risk of extinction of the species 
such that the species warrants listing as endangered or threatened as 
those terms are defined in the Act.

[[Page 60534]]

Factor A: The Present or Threatened Destruction, Modification, or 
Curtailment of the Species' Habitat or Range

    The following potential factors that may affect the habitat or 
range of the pygmy rabbit are discussed in this section, including: (1) 
Habitat conversion, (2) agriculture, (3) sagebrush treatment, (4) 
livestock grazing, (5) nonnative invasive plants, (6) fire, (7) pinyon-
juniper woodlands encroachment, (8) urban and rural development, (9) 
mining (10) energy exploration and development, (11) habitat 
fragmentation, (12) habitat manipulation conducted to benefit greater 
sage-grouse (Centrocercus urophasianus urophasianus), and (13) 
conservation strategies and actions.
Habitat Conversion
    Sagebrush once covered approximately 270 million ac (109 million 
ha) in western North America within 13 States (Washington, Oregon, 
Idaho, Montana, Wyoming, North and South Dakota, Colorado, New Mexico, 
Arizona, Utah, Nevada and California (American Lands Alliance 2001, p. 
3). Today, because of various land uses, about 150 million ac (61 
million ha) of sagebrush habitat remain (American Lands Alliance 2001, 
p. 3). Pygmy rabbits occur within a portion of this area, but they are 
not known to occur in Arizona, Colorado, North or South Dakota, or New 
Mexico. The amount of sagebrush acres suitable for supporting pygmy 
rabbits is a subset of the remaining acres in the states they are known 
to occur, based on the species' specific habitat needs within the range 
of the sagebrush ecosystem. Therefore, the amount of suitable sagebrush 
habitat for pygmy rabbits has always been less than the total amount of 
sagebrush acreage distributed across western North America.
    A number of activities have been identified as potentially 
impacting pygmy rabbit habitat and individuals or populations across 
the species' range. These activities most commonly include land 
management practices which result in the direct loss of sagebrush 
habitat (e.g., conversion of sagebrush habitat to agricultural 
purposes, sagebrush treatment to increase forage for livestock); 
livestock grazing; invasive nonnative plant species; fire; urban and 
rural development; mining; energy exploration and development; 
fragmentation of sagebrush habitat, and sagebrush modification for 
other species such as greater sage-grouse (Roberts 2001, p. 17; Red 
Willow Research Inc. 2002, pp. 58-59, 64-65; Bartels 2003, pp. 101-104; 
Keinath and McGee 2004, pp. 14, 23-25; Hayden Wing Associates, Inc. 
2008b, p. 1; Larrucea 2006, p. 7; Larrucea and Brussard 2008b, p. 
1636).
    As discussed in the background section, the pygmy rabbit is a 
sagebrush obligate, but it occurs within a subset of the sagebrush 
ecosystem within its range. Pygmy rabbits are found where sagebrush 
cover is sufficiently tall and dense and where soils are sufficiently 
deep and loose to allow burrow construction (Bailey 1936, p. 111; Green 
and Flinders 1980a, p. 2; Campbell et al. 1982, p. 100; Weiss and Verts 
1984, p. 563; WDFW 1995, p. 15). Thus, pygmy rabbits are not 
distributed uniformly across the full range of the sagebrush shrub-
steppe ecosystem. In large areas of the sagebrush habitat, pygmy 
rabbits are not known to occur, and in those areas where it does occur 
it is patchily distributed. For each of the following potential threats 
listed in Factor A, the available information provides general 
characteristics of sagebrush habitat degradation or provides examples 
of impacts in site-specific areas resulting in possible impacts to 
pygmy rabbits.

Agriculture

    Large-scale conversions of western rangelands to agricultural lands 
began under the Homestead Acts of the 1800's (Todd and Elmore 1997, 
cited in Braun 1998, p. 4). More than 70 percent of the sagebrush 
shrub-steppe habitat has been converted to agricultural crops in some 
States (Braun 1998, p. 2). Hironaka et al. (1983, cited in 70 FR 2255) 
estimated that 99 percent of basin big sagebrush habitat in the Snake 
River Plain has been converted to cropland. Across the Interior 
Columbia Basin of southern Idaho, northern Utah, northern Nevada, 
eastern Oregon and Washington, about 15 million ac (6 million ha) of 
shrub-steppe habitat has been converted to agricultural cropland 
(Altman and Homes 2000, p. 10). Development of irrigation projects to 
support agricultural production also resulted in sagebrush habitat loss 
(Braun 1998, p. 4). Reservoirs have been constructed to facilitate 
these irrigation projects, impacting native shrub-steppe habitat 
adjacent to rivers, as well as supporting the conversion of more upland 
shrub-steppe habitat to agriculture. As irrigation techniques have 
improved, additional land has been irrigated, and more big sagebrush 
(A. tridentata) cleared. Shrub-steppe habitat continues to be converted 
to dry land and irrigated cropland but at a much lower rate (Braun 
1998, p. 4).
    Review of current sagebrush steppe habitat and agricultural lands 
within Great Basin sagebrush among states within the range of the pygmy 
rabbit show that less than 10 percent is impacted by agriculture for 
Oregon, Montana, Wyoming, California, Nevada and Utah. Only Idaho has a 
greater percentage of agricultural lands within Great Basin sagebrush 
at about 18 percent (75 FR 13925).
    The loss or modification of sagebrush habitat due to agricultural 
conversion and impacts to pygmy rabbits across its range could include 
injury or death at the time of vegetation clearing, reduction in forage 
and shelter, temporary or permanent home range abandonment, increased 
habitat fragmentation, increased dispersal barriers, increased 
predation, and population declines. As a sagebrush-dependent species, 
complete loss of sagebrush over a large area could have long-term 
impacts to pygmy rabbits. According to Roberts (1998, p. 11), of the 
583,600 ac (236,180 ha) he inventoried in Lemhi and Custer Counties, 
Idaho for pygmy rabbit occupancy, 122,300 ac (49,494 ha) had been 
permanently removed due to agriculture conversion. However, the acreage 
or percentage of land that had been occupied by pygmy rabbits is 
unknown. White and Bartels (2002, pp. 7-8) believe that the pygmy 
rabbit historically was impacted by sagebrush removal for agricultural 
purposes in Idaho as 3 of 13 historic sites they visited were disturbed 
by agriculture, and pygmy rabbit activity was not observed at these 
sites.
    In Utah, Pritchett et al. (1987, p. 233) reported that a portion of 
the Sevier River Valley between Kingston and Otter Creek, containing 
one of the last large patches of sagebrush, had been plowed. They 
speculated this may previously have been a dispersal route for pygmy 
rabbits from Iron County to Wayne County, Utah. Janson (2002, pp. 31-
32) reported in 2001 that he found wheat acreage had expanded in the 
Blue Springs Hills of Box Elder County and that the sagebrush was 
almost gone. He also stated that the foothills area near Clarkston, 
Cache County had experienced increased farming activity which had 
eliminated sagebrush. Larsen et al. (2006, p. 5) visited four 
historical pygmy rabbit sites in Tooele County, Utah which were 
unoccupied. Some of them (number not indicated) showed evidence of 
conversion to farmland.
    In Utah, Idaho, and Nevada, Welch (2005, p. 10) visited historical 
pygmy rabbit sites in 2003 and 2004. He mentioned 7 of 13 were impacted 
or likely impacted by agricultural conversion to farmland including 
wheat and alfalfa fields.

[[Page 60535]]

    In Montana, Rauscher (1997, p. 16) thought conversion of sagebrush 
to agriculture was minimal in southwest Montana because of the large 
expanses of public land. He documented that the suspected location for 
one historical pygmy rabbit record had been converted to irrigated 
farmland (Rauscher 1997, p. 14).
    In California, Williams (1986, p. 51) indicated that loss of 
sagebrush habitat in California to agriculture was less of a concern 
than loss of habitat to overgrazing. Larrucea and Brussard (2008b, p. 
1638) revisited 105 of 118 historical pygmy rabbit sites from Nevada 
(109) and California (9) dated between 1877 and 1946 to document 
current pygmy rabbit presence. They determined the presence or absence 
of current land use (agricultural conversion, livestock grazing, fire, 
urbanization and presence of pinyon-juniper) at each site. This was to 
determine what type of impacts were presently occurring, and they do 
not imply that these land use practices are what led to the loss of 
pygmy rabbits at any of the extirpated sites (Larrucea and Brussard 
2008b, p. 1638). Larrucea and Brussard (2008b, p. 1639) found 
agricultural fields at 6 of the 105 historical sites. Most historical 
sites occurred in the foothills and not on valley floors where 
vegetation was more meadow-like. This may have changed after 1880 as 
excessive grazing reduced grasses, increased erosion, and lowered water 
tables and fire suppression allowed sagebrush to increase on valley 
floors (Miller and Rose 1999, cited in Larrucea and Brussard 2008b, p. 
1640), creating pygmy rabbit habitat at these lower elevations.

Summary of Agricultural Impacts

    Information indicating loss of sagebrush due to agricultural 
conversion in specific portions of the pygmy rabbit's range has been 
documented. However, because of the pygmy rabbit's patchy habitat 
distribution across the landscape, as discussed earlier, the scope of 
loss or modification of sagebrush habitat in general due to 
agricultural conversion does not equally relate to the loss or 
modification of pygmy rabbit habitat. Based on information in site-
specific areas, agricultural conversion has resulted in some loss of 
sagebrush habitat used by pygmy rabbits and likely has resulted in some 
localized population declines in areas of Idaho, Montana, California, 
Nevada, and Utah.
    As presented above, the examples of conversion of sagebrush habitat 
are few in number across the range and do not indicate a systematic or 
widespread loss of habitat that may have been or is now suitable for 
pygmy rabbits. While there has been some documented loss of historical 
pygmy rabbit sites due to agricultural conversion, the best available 
scientific information does not indicate a significant loss or 
modification of habitat, and measureable population decreases 
attributed to habitat loss or modification due to agriculture impacts 
are not occurring across the range. While sagebrush habitat will 
continue to be converted to agricultural lands in the future, it will 
occur at a much lower rate as much of the appropriate habitat has 
already been converted. Therefore, based on the best available 
scientific information, we conclude that sagebrush loss or modification 
due to agriculture is not a significant threat to the pygmy rabbit now 
or in the foreseeable future.

Sagebrush Treatment

    Treatment of sagebrush by mechanical (mowing, rotobeating, roller 
chopping, grubbing, chaining, bulldozing, cabling, raking, railing, and 
plowing) and chemical methods (herbicide) primarily for rangeland 
improvement and grazing management to increase forage production for 
domestic and wild ungulates has been common in sagebrush ecosystems 
(Connelly et al. 2004, pp. 7-46 to 7-47). Over 5 million ac (2 million 
ha) of sagebrush habitat was mechanically or chemically treated or 
burned by the 1970s (Crawford et al. 2004, p. 12). According to Braun 
(1998, p. 9) mechanical treatments began in the 1930s and continued at 
relatively low levels until the late 1990s. While many square miles of 
sagebrush habitat have been lost during the last 150 years due to 
conversion for agriculture (discussed above), today this conversion 
occurs at relatively low levels (70 FR 2255).
    Possible effects to pygmy rabbits of mechanical or chemical 
sagebrush treatments include injury or death at the time of treatment, 
reduction in forage and shelter, temporary or permanent home range 
abandonment, increased habitat fragmentation, increased dispersal 
barriers, increased predation, and population declines. As a sagebrush 
dependent species, complete loss of sagebrush in a large area could 
have long-term impacts to pygmy rabbits. Olterman and Verts (1972, p. 
25) and Wilde (1978, p. 120) cautioned that the practice of sagebrush 
removal from some livestock ranges in Oregon and Idaho, respectively, 
could be a threat to the pygmy rabbit in the future. The researchers 
noted that land changes should be monitored and adequate ``safeguards'' 
implemented to reduce excessive clearing of large areas.
    Roberts (1998, p. 11) calculated that of the 583,600 ac (236,180 
ha) he inventoried for pygmy rabbit occupancy in Lemhi and Custer 
Counties, Idaho, 49,000 ac (19,830 ha) (8 percent) were lost due to 
sagebrush eradication; Roberts (1998, p. 11) did not estimate the 
amount of lost pygmy rabbit habitat. In Oregon, BLM (2007b, pp. 5-6) 
documented active pygmy rabbit use at one of eight sites that had 
sagebrush strips removed by mowing. It appeared that pygmy rabbits had 
been there prior to the mowing (as evidenced by burrows), with 
residency continuing following mowing. Mowing may have opened the area 
for new growth of herbaceous vegetation which can be beneficial to 
pygmy rabbits (BLM 2007b, p. 7).
    In Montana, Rauscher (1997, pp. 13-14) reported that sagebrush 
removal was a ``popular'' rangeland improvement practice in the 
southwestern portion of the State. Sagebrush in the Coyote Creek area 
of the Big Sheep Creek Basin has been extensively treated, and only one 
active burrow was located. In nearby areas where sagebrush had not been 
treated, pygmy rabbits were more abundant. In lower Badger Gulch, BLM 
lands border private lands, and pygmy rabbits were found on the public 
lands but absent on the private lands where sagebrush had been removed. 
However, it is unclear how much sagebrush removal had occurred on the 
private lands and whether pygmy rabbits had previously occupied these 
same lands.
    In Wyoming, Katzner (1994, p. 106) mentioned that sagebrush 
eradication may have significant adverse effects on the pygmy rabbit 
where they were known to occur in southwestern Wyoming at that time. He 
recommended that if sagebrush management is ``mandated,'' management 
plans should consider the pygmy rabbit and retain large patches of 
sagebrush or corridors connecting areas of suitable habitat.
    Welch (2005, p. 10) visited 13 historical pygmy rabbit sites in 
Utah and Idaho. He indicated one site was no longer occupied by pygmy 
rabbits and had been impacted by range improvement.
    In Utah, Holt (1975, p. 159) mentioned a concern that removing 
large areas of sagebrush by chaining and spraying in order to plant 
grass would harm rabbits, including the pygmy rabbit. Flinders et al. 
(2005, p. 7) surveyed habitat in Grass Valley in Piute, Sevier, and 
Wayne Counties located in south central Utah. Pygmy rabbit surveys were 
conducted in areas slated for sagebrush treatment, but

[[Page 60536]]

where pygmy rabbit surveys had not been previously conducted. Areas 
where pretreatment pygmy rabbit surveys (Oak Springs and Praetor 
Slopes) had been completed by BLM employees (Flinders et al. 2005, p. 
13) were revisited, as well. According to Flinders et al. (2005, p. 
13), BLM surveys identified 118 active burrow systems and 85 inactive 
ones. Flinders et al. (2005, p. 13) found 14 locations with active 
burrow systems and determined all other burrows in treatment areas to 
be inactive. BLM surveyed sites recorded as active were found to be 
``abandoned'' or plowed when revisited (Flinders et al. 2005, p. 13).
    Where pygmy rabbits were still occupying treatment areas, they were 
in wide sections of sagebrush that was intact and connected to adjacent 
remaining sagebrush (Flinders et al. 2005, p. 13). In undisturbed 
sagebrush, pygmy rabbits were in isolated patches (Flinders et al. 
2005, p. 13). Flinders et al. (2005, p. 36) thought treatment projects 
could be beneficial to pygmy rabbits if the sagebrush stands were left 
in wide, connected corridors as this would provide forage as well as 
cover. BLM treatment areas revisited found active burrows only where 
the sagebrush treatment occurred in mosaics that were connected to 
other sagebrush stands or the areas of removal were much smaller and 
distances between the treatments were minimal. Patchy, smaller 
sagebrush removal more likely mimics the natural historical fire 
regime. Flinders (2007, p. 3) reported on his preliminary results from 
a multi-year pygmy rabbit study in Grass Valley, Utah and found a 
reduction in suitable pygmy rabbit habitat due to sagebrush treatments. 
He found pygmy rabbit activity was restricted to a narrow band adjacent 
to mature stands of sagebrush and showed significantly decreased 
activity within the treated areas. Burrow abandonment was noted 
following treatment, and he suggested a 131.2 ft (40 m) buffer between 
active burrows and habitat treatment. In Grass Valley, Piute and Sevier 
Counties, and Parker Mountain, Wayne County, Utah, Lee (2008, pp. 4, 7) 
found lower fecal pellet counts in mechanically-treated sagebrush areas 
as compared to untreated sagebrush areas. Average pygmy rabbit fecal 
pellet counts decreased with distance from sagebrush (Lee 2008, p. 10). 
Lee (2008, p. 11) recommended avoiding treatments of big sagebrush in 
areas occupied by pygmy rabbits and in areas with all suitable habitat 
conditions. If treatments cannot be avoided, they should leave intact 
large swaths of undisturbed mature big sagebrush (Lee 2008, p. 11). Lee 
(2008, p. 14) recommended that corridors between residual stands of 
sagebrush within a treatment area be maintained for connectivity and 
dispersal. Lee (2008, p. 13) recommended that stands of remaining 
mature big sagebrush be about 54 yd (490 m) across in any direction, 
and the areas of big sagebrush removed should be narrow (44 yd; 40 m).
    BLM has proposed a national program to treat vegetation across 
several western States to reduce hazardous fuels, control unwanted 
vegetation and improve habitat and resource conditions through the use 
of prescribed fire, wildland fire, herbicides, manual and mechanical 
methods, and biological controls (BLM 2007c, p. 1-3 Abstract, Executive 
Summary, Chapters 1 through 7, and Appendices). BLM manages 
approximately 261 million ac (105.6 million ha) in 17 western States 
including Alaska (BLM 2007c, p. 1-1 Abstract, Executive Summary, 
Chapters 1 through 7, and Appendices). States encompassing the range of 
the pygmy rabbit are included in this program. BLM estimated that 6 
million ac (2,428,166.7 ha) of vegetation would need to be treated 
annually over the next 10 years (BLM 2007c, p. 1-7 Abstract, Executive 
Summary, Chapters 1 through 7, and Appendices). Estimated acres treated 
annually by the various methods include: 2.2 million ac (890,327.8 ha) 
by mechanical means; 2.1 million ac (849,858.4 ha) by fire; 932,000 ac 
(377,175.2 ha) by herbicides; 454,000 ac (183,731.3 ha) by biological 
control; and 271,000 ac (109,672.2 ha) by manual means (BLM 2007c, p. 
ES-2 Abstract, Executive Summary, Chapters 1 through 7, and 
Appendices). The implementation of this program, methods, acres 
treated, and locations are yet to be determined.

Summary of Sagebrush Treatment Impacts

    Although loss of sagebrush due to sagebrush treatment for rangeland 
and grazing management in specific portions of the pygmy rabbit's range 
has been documented, the examples presented above are few in number 
across the range and are not indicative of a systematic or widespread 
loss of habitat that may have been or is now suitable for pygmy 
rabbits. Because of the pygmy rabbit's patchy habitat distribution 
across the landscape, the scope of loss or modification of sagebrush 
habitat in general due to treatments does not equally relate to loss or 
modification of pygmy rabbit habitat. Sagebrush treatment has been 
documented to be responsible for loss of sagebrush habitat used by 
pygmy rabbits in a few specific areas of Oregon, Idaho, Montana, 
Wyoming, Utah and may have resulted in localized population declines. 
The known presence of pygmy rabbits prior to treatment is not 
documented in all cases and some areas show continued occupancy or use 
by pygmy rabbits at some level after treatments were conducted (e.g. 
Flinders et al. 2005; Lee 2008).
    Depending on the design and size of the sagebrush treatment, 
impacts to pygmy rabbits may be minimized, and if designed 
appropriately, sagebrush treatments may be beneficial to pygmy rabbits. 
We are aware of a BLM proposal to implement sagebrush treatments that 
could impact sagebrush habitat in the western United States, however no 
actions have been implemented at this time (BLM 2007c). Available 
information indicates that a significant loss or modification of 
habitat, and measureable population decreases attributed to habitat 
loss or modification due to treatment impacts and impacts to the pygmy 
rabbit with regard to injury or death, temporary home range abandonment 
or permanent shift to adjacent areas, habitat fragmentation, or 
increased predation are not occurring across the range. Therefore, 
based on the best available scientific and commercial information, we 
conclude that sagebrush loss or modification due to treatments is not a 
significant threat to the pygmy rabbit now or in the foreseeable 
future.

Livestock Grazing

    Livestock grazing is the most widespread land use type across 
sagebrush communities (Connelly et al. 2004, p. 7-29). Excessive 
grazing by domestic livestock during the late 1800s and early 1900s, 
along with severe drought, significantly impacted sagebrush ecosystems 
and the long-term effects involving plant community and soil changes, 
continue today (Yensen 1981, cited in Knick et al. (2003, p. 616). By 
the 1940s, animal unit months (AUM) on all Federal lands were estimated 
to be 14.6 million, increasing to 16.5 million in the 1950s, however 
estimated AUMs decreased to 10.2 million by the 1990s (Miller and 
Eddleman 2001, p. 19). Grazing impacts may be associated with the 
direct loss of sagebrush vegetation through physical damage by rubbing, 
battering, breaking and trampling of seedlings, or habitat degradation 
due to associated facilities or actions such as: construction of 
fences; wells; water tanks; pipelines which concentrate livestock or 
redistribute livestock;

[[Page 60537]]

seeding of crested wheatgrass to increase livestock forage; and weed 
infestations.
    Impacts of livestock grazing on the arid west include selective 
grazing for native species, trampling of plants and soil, damage to 
soil crusts, reduction of mycorrhizae fungi, increases in soil 
nitrogen, increases in fire frequency, and contribution to nonnative 
plant introductions (Belsky and Gelbard (2000, pp. 12-18); Paige and 
Ritter (1999, pp. 7-8)). When sagebrush-grass habitats are overgrazed, 
native perennial grasses can be eliminated, and shrubs, such as big 
sagebrush, tend to form dense monotypic (single species) stands 
(Blaisdell 1949, cited in Yensen 1982, p. 25; Tisdale and Hironaka 
1981, cited in Paige and Ritter 1999, p. 7). In addition, the 
understory becomes sparse with unpalatable perennials (Tisdale and 
Hironaka 1981, cited in Paige and Ritter 1999, p. 7) and invasions of 
annual species like Bromus tectorum (cheatgrass) can occur (Gabler 
1997, p. 96; Rauscher 1997, p. 14). Reduction of native grasses and 
increases in invasive plant species may reduce habitat quality and 
suitability for pygmy rabbits by reducing summer forage and impeding 
their movements or ability to see predators.
    Possible effects of livestock grazing include direct injury or 
death due to trampling, degradation of sagebrush plant structure 
resulting in reduced forage and shelter, habitat fragmentation, 
increased predation, reduced grasses and forbs resulting in loss of 
summer forage, increased visual capabilities and ease of movement, 
trampling of burrows, increased invasive plant species resulting in 
reduced visual capabilities and ease of movement, and population 
declines. However, livestock grazing in pygmy rabbit habitat has been 
noted in the early literature. For example, Dice (1926, p. 27) in 
Oregon, found pygmy rabbits near Baker in an area that was overgrazed 
by domestic sheep. He stated very little vegetation remained except for 
sagebrush and rabbit brush. The patch of habitat being used was about 
300 yd long (274.2 m) by 50 yd (45.7 m) wide and was surrounded by low 
sagebrush (Dice 1926, p 27).
    Flath and Rauscher (1995, p. 2) and Purcell (2006, p. 33) found 
that areas of tall, dense sagebrush inhabited by pygmy rabbits were 
typically located along streams. Livestock can impact these areas 
disproportionately by concentrating in riparian areas where trampling 
and vegetation removal can occur (Red Willow Research Inc. 2002, p. 
107). These researchers do not indicate any specific pygmy rabbit 
locations along streams that have been impacted by livestock grazing.
    In Oregon, Hager and Lienkaemper (2007, p. 6) reported that all 157 
sites, located mostly on State lands, surveyed for pygmy rabbits had 
evidence of cattle grazing. Many areas showed heavy use by cattle which 
had resulted in a decrease in shrub cover. Additionally, many of the 
areas where no evidence of pygmy rabbit presence was found may have had 
potential to support pygmy rabbits, as predicted by a habitat model, 
but the habitat may have been rendered unsuitable due to grazing 
reducing shrub cover (Hager and Lienkaemper 2007, p. 6). However, it is 
unknown whether pygmy rabbits were present previously or were absent 
from these areas based on other factors. The BLM (2007b, p. 4) reported 
livestock use at one of eight occupied sites surveyed in Oregon.
    In Idaho, Red Willow Research Inc. (2000, p. 8) documented pygmy 
rabbit sightings on two separate BLM grazing allotments which 
demonstrated historical and current grazing activities. Another 
sighting occurred on private land subjected to grazing and was also 
close to dwellings and agricultural activities (Red Willow Research 
Inc. 2000, pp. 8, 11). In Idaho, Roberts (2001, p. 18) concluded that 
there was no clear evidence that livestock grazing is detrimental to 
pygmy rabbits. In Idaho, White and Bartels (2002, pp. 6, 15) surveyed 
11 grazing allotments. Of the 6 allotments where pygmy rabbit sign was 
observed, 2 allotments supported active burrows, 2 allotments contained 
inactive burrows, and 2 allotments supported burrows of undetermined 
status. BLM (2005a, p. 2) found during their surveys, conducted between 
2002 and 2005 that pygmy rabbits occurred on their lands containing 
portions of grazing allotments. In Idaho, North Wind (2004, p. 12) 
mentioned livestock grazing occurred in all areas where pygmy rabbit 
sign or sightings occurred. In Idaho, Waterbury (2005, p. 9) mentioned 
that an occupied site where a pygmy rabbit was observed (Goldburg site) 
in the upper Pahsimeroi Valley was subjected to livestock grazing.
    In Montana, Rauscher (1997, pp. 14, 17) found that most pygmy 
rabbit sites were grazed to some extent. Pygmy rabbits were found to be 
``surviving and even thriving'' at current grazing levels in certain 
areas.
    In Wyoming, Katzner reported that according to Dorn et al. (1984, 
cited in Katzner 1994, p. 5), pygmy rabbits did not occur in his study 
area (Historical Quarry Trail region) at Fossil Butte National 
Monument, Lincoln County in 1983 at the time when domestic livestock 
grazing was terminated in the monument. Katzner and Parker (1997, p. 
1071) stated that the apparent dependence of pygmy rabbits on a dense 
understory, provided in part by dead shrubs and extensive canopies, may 
explain population declines in the pygmy rabbit in grazed sagebrush-
steppe habitat in the western United States. Lands grazed intensively 
by domestic herbivores often have relatively low structural complexity 
and may not support pygmy rabbit populations adequately. The physical 
destruction of dense, structurally-diverse patches of sagebrush, and 
the corridors that connect them, result in fragmented, unsuitable big 
sagebrush habitat for pygmy rabbits (Katzner and Parker 1997, p. 1071). 
For a species that eludes predators in sagebrush habitat, a reduction 
in canopy cover would increase the vulnerability of pygmy rabbits to 
predation (Bailey 1936, p. 111; Orr 1940, p. 197; Wilde 1978, pp. 115-
116; Katzner 1994, pp. 50, 52-53). Clark and Stromberg (1987, p. 76) 
remarked that overgrazing, which has increased the sagebrush-grass 
ratio, may decrease pygmy rabbit populations.
    In Nevada and California, Larrucea (2006 p. 8) stated that 
livestock grazing at inappropriate levels can be detrimental for the 
degradation of sagebrush habitat. At reasonable levels it may be 
beneficial (Larrucea 2006, p. 8; Larrucea 2007, p. 34). Most of the 
pygmy rabbit burrows on the BLM lands in the Surprise FO were in areas 
available to grazing (Larrucea 2006, p. 8). In Nevada and California, 
Larrucea and Brussard (2008b, p. 1638) found cattle grazing occurred at 
83 percent of historical pygmy rabbit sites; 38 percent showed current 
pygmy rabbit activity. If sites with additional impacts were eliminated 
and only cattle grazing impacts are considered, this increased to 62 
percent of sites that supported current pygmy rabbit activity (Larrucea 
and Brussard 2008b, p. 1639). Grazing was compatible with pygmy rabbits 
if grazing occurs at levels that left sagebrush plants intact and soils 
were not overly compacted (Larrucea 2007, p. 58). Larrucea and Brussard 
(2008a, p. 697) found increasing amounts of understory stem density was 
associated negatively with current pygmy rabbit presence at a site. 
Pygmy rabbits, by foraging for forbs and grasses near their burrows, 
may create areas of little understory. An understory that is free of 
grasses and forbs may be beneficial by reducing movement restrictions 
and increasing pygmy rabbit's ability to detect predators (Weiss and 
Verts 1984, p. 568). The Southern Nevada Water

[[Page 60538]]

Authority (SNWA) (2008, p. 15) stated that data collected during their 
surveys conducted in 2005 and 2006 in Nevada (SNWA 2007, entirety) 
found 84 percent of the sites with documented pygmy rabbit occurrence 
existed in areas of moderate grazing. SNWA (2008, p. 15) suggested that 
given that recent occurrence data overlaps with grazing practices, 
there is little evidence to suggest that light to moderate grazing is 
significantly detrimental to pygmy rabbit in Nevada.
    In Utah, Janson (2002, p. 31) did not attempt to measure grazing 
intensity during his earlier studies. While he observed a scarcity of 
grasses and forbs in the Cedar City area compared to the Blue Springs 
area, efforts to collect and observe pygmy rabbits seemed to be similar 
on either site. The difference between the amount of shrubs to 
herbaceous vegetation between the two sites, due to grazing or some 
other factor, did not seem to affect the populations. He did state that 
grazing intensities high enough to break down the sagebrush plants and 
reduce their density would be detrimental to pygmy rabbits. Although it 
is unclear how many of the four sites he considered overgrazed, Larsen 
et al. (2006, p. 5) found historical pygmy rabbit sites in Tooele 
County, Utah that showed evidence of overgrazing.
    Trampling of burrows by livestock has been reported in Montana by 
Rauscher (1997, p. 14) and in Idaho by Red Willow Research Inc. (2002, 
p. 54). This could cause the death of young rabbits in natal burrows or 
injury or death of adults. Red Willow Research Inc., (2002, pp. 54-55) 
reported a burrow system in Idaho that was subjected to cattle trailing 
on at least two separate occasions within a period of two months or 
less. After the initial event, only two of ten active burrows were 
still open. A second visit showed additional trailing activities, and 
no open burrows or recent sign were found, indicating ``that domestic 
livestock can have an immediate and detrimental effect upon burrow 
systems'' (Red Willow Research Inc., 2002, pp. 54). This assumes that 
no other influences were involved, and there was no further monitoring 
of the area to determine if pygmy rabbits returned to the area at a 
later date.

Summary of Livestock Grazing Impacts

    Livestock grazing occurs in all seven States where pygmy rabbits 
occur. Researchers suggest that livestock grazing, particularly 
overgrazing, may negatively impact some sagebrush habitat used by pygmy 
rabbits and may result in some localized population declines. The 
potential effects of livestock grazing on sagebrush habitat and pygmy 
rabbit populations, while widespread across the pygmy rabbit's range 
have not been documented to impact pygmy rabbits at the population 
level or result in documented measurable population declines as a 
result of overgrazing.
    As described above, there are several examples where pygmy rabbits 
have been document to continue to occupy areas grazed by livestock, 
which may indicate an apparent compatibility between livestock grazing 
and area use by pygmy rabbits under certain grazing conditions. Other 
documentation suggests possible habitat loss or degradation, site 
abandonment, habitat fragmentation, increased predation, or injury of 
pygmy rabbits due to livestock overgrazing and trampling. However, 
based on survey information, there is no indication of a causal 
relationship between livestock grazing and pygmy rabbit site 
abandonment or avoidance. Studies do not indicate that there is a level 
of livestock grazing that influences pygmy rabbit site occupancy. While 
the Service is aware of a report of burrow trampling, we are not aware 
of any studies relating actual site abandonment, increased predation, 
death, or injury due to livestock grazing or trampling. Reduced grasses 
and forbs may increase the pygmy rabbits' ability to see and evade 
predators. Some survey reports suggest that livestock grazing is 
degrading pygmy rabbit habitat in some locations. Our review of the 
best available scientific data indicate that measureable population 
decreases attributed to habitat modifications from livestock grazing 
are not occurring across the range. Therefore, we conclude that 
livestock grazing is not a significant threat to the pygmy rabbit now 
or in the foreseeable future.

Nonnative Invasive Plants

    Paige and Ritter (1999, p. 8) suggest that the greatest change to 
sagebrush shrub lands has been the invasion of the nonnative grasses 
and forbs, especially cheatgrass. Cheatgrass is a rapid colonizer of 
disturbed areas and is persistent in replacing native species (Mack 
1981, Yensen 1981, and Whisenant 1990, cited in Paige and Ritter 1999, 
p. 8). Cheatgrass alters fire and vegetation patterns in sagebrush 
habitats as it creates a continuous fine fuel that easily carries fire 
(Paige and Ritter 1999, p. 8). Where it dominates, it can carry fires 
over large distances, and it burns more frequently than native 
vegetation (Paige and Ritter 1999, p. 8). It also matures and dries 
earlier than native vegetation, increasing the likelihood of a fire 
earlier in the season (Young and Evans 1978, Whisenant 1990, and Knick 
and Rotenberry 1997, cited in Paige and Ritter 1999, p. 8).
    The total acreage of invasive plant infestations has been reported 
with varying estimates. Pellant and Hall (1994, p. 109) reported on the 
1992 distribution of cheatgrass and Taeniatherum asperum (medusa head), 
the primary alien grass invaders of disturbed and fire-altered 
rangelands in the Intermountain area of the western United States. 
Approximately 3.3 million ac (1.3 million ha) of rangeland administered 
by the BLM in Nevada, Oregon, Utah, Washington, and Idaho are dominated 
by these two species (Pellant and Hall 1994, p. 109). Another 76.1 
million ac (30.8 million ha) of public rangeland was classified as 
infested or susceptible to infestation by these two species (Pellant 
and Hall 1994, p. 109). It has been estimated that 3 million ac (1.2 
million ha) of public lands in the Great Basin have been converted to a 
cheatgrass monoculture with another 14 million ac (5.7 million ha) 
assumed to be infested, and it is likely that conversion is inevitable 
(Knapp 1996, West 1999, cited in Larrucea 2007, p. 61). Though 
estimates of total area supporting cheatgrass vary widely, cheatgrass 
is a significant presence in western rangelands (75 FR 13935).
    BLM (1996, p. 6) estimated invasive plant species covered at least 
8 million ac (3.2 million ha) of BLM lands as of 1994 and predicted 19 
million ac (7.7 million ha) would be infested by 2000. A qualitative 
BLM survey in 1991 covering 98.8 million ac (40 million ha) of BLM-
managed land in Washington, Oregon, Idaho, Nevada, and Utah reported 
introduced annual grasses were a dominant or significant presence on 
17.2 million ac (7 million ha) of sagebrush ecosystems (Connelly et al. 
2004, pp. 5-10). In reference to the same BLM survey, Zouhar (2003, p. 
3 cited in 75 FR 13935) estimated an additional 62 million ac (25 
million ha) had less than 10 percent cheatgrass understory, but were 
considered to be a risk of cheatgrass invasion. BLM has reported that 
as of 2000, invasive plants occupied about 29 million ac (11.7 million 
ha) of BLM lands in the Washington, Oregon, Idaho, Utah, Nevada (BLM 
2007a, pp. 3-28 as cited in 75 FR 13935).
    Connelly et al. (2004, p. 7-15) estimated the risk of cheatgrass 
invasion into sagebrush and other natural vegetation in a portion of 
the southern and northern Great Basin. They projected, based on 
elevation, landform, and south-facing slope parameters, that 80 percent 
of the land area in the Great Basin is susceptible to displacement by

[[Page 60539]]

cheatgrass and of that area, greater than 65 percent is estimated to be 
at moderate or high risk within 30 years (Connelly et al. 2004, pp. 7-
16 to 7-17). Wyoming-basin big sagebrush and salt desert scrub, which 
occupy over 40 percent of the Great Basin, are the vegetation types 
most susceptible to cheatgrass displacement (Connelly et al. 2004, p. 
7-17).
    Restoration or rehabilitation of areas to sagebrush after invasive 
plant species, especially annual grasses, become established is 
difficult. Only about 3 to 34 percent of recent vegetation treatments 
performed by BLM in areas of annual grassland monocultures were 
successful (Carlson 2008b, pers. comm., cited in 75 FR 13937). The 
success of treatments often depends on factors such as precipitation 
received at the treatment site (Pyke, in press, p. 30).
    Nonnative invasive plant species may impact pygmy rabbits 
throughout their range by replacing native grasses and shrubs used by 
pygmy rabbits, hindering their ability to see or move, and increasing 
detection by predators. In Oregon, only 2 of 51 sites occupied by pygmy 
rabbits in 1982 contained appreciable amounts of cheatgrass (Weiss and 
Verts 1984, p. 568). This led the authors to suspect that pygmy rabbits 
avoid areas containing annual grasses because it can restrict their 
movements or ability to see, especially when they are attempting to 
escape predators. However, it is unclear whether annual grasses are 
playing a role in pygmy rabbits not occupying a site. The authors did 
not indicate whether or not unoccupied sites surveyed had cheatgrass.
    In Idaho, invasive plants were reported at all nine study areas 
investigated by Red Willow Research Inc. (2002, pp. 38, 45, 59, 65, 72, 
80, 87, 92, 97). Gabler (1997, p. 94) predicted 10 study sites would be 
used by pygmy rabbits, but later found large patches of cheatgrass on 8 
of those sites, and that the pygmy rabbit did not use these sites. 
Other factors, such as large amounts of dead sagebrush, and/or sparse, 
short sagebrush, and thick grass cover, may have contributed to pygmy 
rabbit absence in those sites (Gabler (1997, p. 94). BLM (2005a, p. 2) 
indicated that no evidence of pygmy rabbits was found at any of the 
sites (no number provided) in Idaho surveyed in 2005 where cheatgrass 
was a major component of the understory. Burak (2006, p. 68) found that 
cheatgrass made up little of the grass community within his entire 
study area; areas occupied by pygmy rabbit had approximately 1 percent 
cheatgrass cover and unoccupied areas had less than 1 percent.
    In Nevada and California, Larrucea and Brussard (2008b, p. 1641) 
stated that wide expanses of cheatgrass monocultures may provide a 
barrier to pygmy rabbit dispersal as they rely on shrub cover for 
protection from predators. Larrucea and Brussard (2008a, p. 697) found 
cheatgrass presence was negatively associated with pygmy rabbit 
presence at a site. Once established it may be difficult for pygmy 
rabbits to burrow into the dense root mats (Larrucea and Brussard 
2008a, p. 697). SNWA overlaid a Nevada Natural Heritage Program 
invasive annual grass index map (most of which was cheatgrass) (NHP 
2006, cited in SNWA 2008, p. 14) with 2000 to 2007 pygmy rabbit 
occurrence data from various sources. The overlay indicates a large 
portion of pygmy rabbit occurrences are within areas of relatively low 
cheatgrass cover. This map serves as a relative density index of 
cheatgrass rather than actual current ground cover because of the 
remote sensing and statistical models from which it is derived. While 
the underlying models tend to underestimate index values for sites with 
high invasive annual grass densities, the general pattern of low to 
high densities is well represented on the map. The map is quite 
accurate for sites where invasive annual grass cover is low or 
nonexistent. SNWA concluded that cheatgrass has not had a major impact 
on pygmy rabbit occurrence or geographic range in east-central Nevada 
(SNWA 2008, p. 14).
    Larsen et al. (2006, p. 5) visited four historical pygmy rabbit 
sites in Tooele County, Utah that were unoccupied by pygmy rabbits. 
They mentioned these sites showed evidence of cheatgrass invasion, but 
it is unclear if all four sites supported cheatgrass.

Summary of Nonnative Invasive Plant Impacts

    Based on information for a few specific areas, presence of invasive 
plant species has been documented and may have some impact on pygmy 
rabbit presence or their movements in Oregon, Idaho, Nevada, 
California, and Utah. These examples, as discussed above, are few in 
number and are not considered to be indicative of a widespread habitat 
condition. It is unclear whether the presence of cheatgrass or other 
invasive plant species caused pygmy rabbits to not occupy an area or if 
other factors may have also played a role. The scope of loss or 
modification of sagebrush habitat in general due to nonnative plant 
invasion does not equally relate to the loss or modification of pygmy 
rabbit habitat because pygmy rabbit's habitat is patchily distributed 
across the landscape.
    Varying estimates have been made regarding the amount of area 
invaded by invasive plant species in the western United States, and 
some predictions indicate it could take decades for cheatgrass to 
invade sagebrush and other natural vegetation in a portion of the Great 
Basin. The Service recognizes that invasion of sagebrush habitat by 
nonnative plant species is a concern based on their ability to 
outcompete sagebrush, the difficulty in controlling them once 
established, and their interaction with other threats, such as fire. 
However, there is no indication of a significant loss or modification 
of habitat, and measureable population decreases attributed to habitat 
loss or modification due to nonnative plant species, especially 
cheatgrass, and pygmy rabbit site abandonment or avoidance are not 
occurring across the range. Available information does not provide a 
causal relationship between a reduction in pygmy rabbit visual 
capabilities and ease of movement due to nonnative plant species. 
Therefore, based on the best available scientific and commercial 
information, we conclude that nonnative invasive plant species in pygmy 
rabbit habitat is not a significant threat to the pygmy rabbit now or 
in the foreseeable future.

Fire

    The effect of fire on sagebrush habitats depend on the sagebrush 
species present, the composition of understory species, and the size, 
frequency, and intensity of the fire. Estimates of mean fire intervals 
indicated in the literature vary widely: 12 to 15 years for mountain 
big sagebrush (Miller and Rose 1999, p. 556), 13 to 25 years (Frost 
1998, cited in Connelly et al. 2004, p. 7-4), greater than 50 years for 
big sagebrush communities (Whisenant 1990, cited in McArthur 1994, p. 
347), 20 to 100 years (Peters and Bunting 1994, p. 33), 35 to 100 years 
(USFS 2000, p. 7), and 10 to 110 years depending on sagebrush species 
and geographic area (Kilpatrick 2000, p. 1).
    Natural fires in sagebrush stands characteristically result in 
incomplete burns leaving areas of unburned sagebrush (Huff and Smith 
2000, cited in 70 FR 2264). These unburned areas appear to be important 
in the future recolonization of the sagebrush community by providing 
sources of sagebrush seed (Huff and Smith 2000, cited in 70 FR 2264). 
Prior to European immigrant settlement, fire patterns in sagebrush 
communities were patchy,

[[Page 60540]]

particularly in Wyoming big sagebrush, due to the limited and 
discontinuous fuels and unburned areas that remained after a fire 
(Miller and Eddleman 2001, p. 17).
    In parts of the Great Basin, a decline in fire occurrence since the 
late 1800's has been reported in several studies coinciding with fire 
suppression and reduction of fuels by introduced livestock (Miller and 
Rose 1999, pp. 556-557; Kilpatrick 2000, p. 6; Connelly et al. 2004, p. 
7-5). Long fire intervals and fire suppression can result in increased 
dominance of conifer species, such as western juniper (Juniperus 
occidentalis) (Wrobleski and Kauffman 2003, p. 82) resulting in almost 
complete loss of shrubs in localized areas (Miller and Eddleman 2001, 
p. 20).
    Burning can also damage perennial grasses, allowing cheatgrass to 
increase (Stewart and Hull 1949; Wright and Britton 1976, cited in 
Yensen 1982, p. 28). The presence of cheatgrass extends the fire season 
and carries a fire into areas where burning would not normally occur or 
can make fires difficult to control (Yensen 1982, pp. 28-29; Billings 
1994, p. 24). The invasion of nonnative annuals, such as cheatgrass and 
medusa head has resulted in increases in the frequency and number of 
fires within sagebrush habitats (USFS 2000, p. 153; Connelly et al. 
2004, pp. 5-9 to 5-10). Sagebrush does not quickly re-establish after 
fires, while nonnative grasses can recover quickly and increase, 
effectively preventing sagebrush return. Due to this relationship 
between fire and the spread of invasive plants, large areas of 
sagebrush in the western United States have been converted to 
cheatgrass (Connelly et al. 2004, p. 7-14).
    Generally, fire tends to extensively reduce the sagebrush component 
within the burned areas. The most widespread species of sagebrush, big 
sagebrush (A. tridentata spp.) (McArthur 1994, p. 347), is killed by 
fire. It does not re-sprout after burning (Agee 1994, p. 14; Braun 
1998, p. 9) and can take over 30 years to recolonize an area (Wambolt 
et al. 2001, pp. 244, 247). Depending on the species, sagebrush can 
reestablish itself within 5 years of a burn, but it may take 15 to 30 
years to return to pre-burn densities (Bunting 1984; and Britton and 
Clark 1984, cited in Paige and Ritter 1999, p. 6). Billings (1994, p. 
26) documented slow shrub succession following a burn in western 
Nevada, with little sagebrush recovery after 45 years. This suggests 
that these sagebrush subspecies evolved in an environment where 
wildfire was infrequent (30 to 50 year intervals) and patchy in 
distribution (Braun 1998, p. 9).
    Connelly et al. (2004, p. 7-6) summarized fire statistics from 
records of wild and prescribed fires in the sagebrush biome and found 
the total area burned and the number of fires increased from 1960 to 
2003. In the 100 million ac (40.5 million ha) sagebrush-steppe 
ecoregion or drier sagebrush areas, fire regimes have become more 
frequent (USFS 2000, p. 195). Miller et al. (2008, p. 39) also mapped 
fires from 1960 through 2007 and found that the number of fires and 
total area burned across the Greater Sage-grouse Conservation Area 
increased in each of the geographic subdivisions except the Snake River 
Plain from 1980 through 2007. Average fire size increased only in the 
Southern Great Basin during this period. Location of fires since 1960 
was related to cheatgrass distribution particularly within the Snake 
River Plain and Northern Great Basin (Miller et al. 2008, p. 39).
    Wildfires have removed large areas of sagebrush in recent years. 
Although fire occurs throughout the sagebrush ecosystem, fire has 
disproportionately affected Idaho, Nevada, Oregon, and Utah (Baker, in 
press, p. 20). In these states combined, about 27 percent of the 
sagebrush habitat has burned since 1980 (Baker, in press, p. 43). Total 
area burned each year on or adjacent to BLM- administered lands was 
variable from 1997 through 2006 (Miller et al. 2008, pp. 39-40); most 
total area burned was in cheatgrass regions in Oregon, Idaho, and 
Nevada (Miller et al. 2008, p. 40). A number of fires have occurred in 
Idaho that have exceeded 100,000 ac (40,469 ha) (Roberts 2003a, p. 14). 
The largest contiguous patch of sagebrush habitat in southern Idaho 
covered about 700,000 ac (283,000 ha) (Michael Pellant, BLM, quoted in 
Healy 2001, p. 3), and during 1999 to 2001 about 500,000 ac (202,000 
ha) of this area burned. In Nevada, 1,277 fires in 2001 impacted 
654,253 ac (264,773 ha) on public and private lands (BLM 2001, p. 3). 
In 2002, BLM reported 771 fires that impacted 77,551 ac (31,384 ha) on 
public and private lands in Nevada (BLM 2002, p. 3). In 2006, over 
988,400 ac (400,000 ha) of sagebrush steppe and potential pygmy rabbit 
habitat was burned in Elko County (Larrucea and Brussard 2008b, p. 
1641). Over 9 fire seasons in Nevada (1999-2007), about 2.5 million ac 
(1.0 million ha) of sagebrush habitat were burned. This represents 
about 12 percent of the extant sagebrush in Nevada (Espinosa and Phenix 
2008, p. 3). Most of these fires occurred in northeast Nevada (75 FR 
13933). The amount of occupied pygmy rabbit habitat impacted by these 
fires is unknown.
    Sagebrush restoration efforts following fire are complicated by 
invasive, nonnative, annual plant species, costs, equipment 
limitations, availability of suitable seeds, limited knowledge of 
appropriate methods, and abiotic factors (Hemstrom et al., 2002, pp. 
1250-1251, Pyke, in press, p. 29). Habitat rehabilitation following 
fire has increased in recent years from 69,436 ac (28,100 ha) in 1997 
to 3.9 million ac (1.6 million ha) in 2002 with treatments primarily 
occurring in Oregon, Idaho, and Nevada (Connelly et al. 2004, p. 7-35). 
While not all burned habitat is rehabilitated, fires which occur on 
public lands will likely experience some level of post-fire restoration 
(75 FR 13934).
    Fire, either wild or prescribed, has been documented within the 
range of the pygmy rabbit and could result in long-term habitat loss or 
modification of pygmy rabbit habitat across its range. Possible impacts 
to pygmy rabbits include injury or death, reduction in forage and 
shelter, increased habitat fragmentation, increased predation, barriers 
to movement, or home range abandonment. Although information is 
available relating fire and its impact to pygmy rabbits, several 
studies have shown pygmy rabbit presence after fires.
    In Idaho, researchers have noted burn areas on the lands they have 
surveyed for pygmy rabbits. For example, Roberts (1998, p. 11) stated 
that of the 583,600 ac (236,175 ha) he inventoried, about 2,500 ac 
(1,012 ha) had been temporarily removed due to fire (a loss of 0.4 
percent). White and Bartels (2002, pp. 8-9) indicated of the 133,067 ac 
(53, 851 ha) they surveyed, 23,660 ac (9,575 ha) had been affected by 
wildfire within the last 15 years and that historical pygmy rabbit 
locations had been impacted. The sagebrush had been burned and habitat 
for the pygmy rabbit was not available. In these studies, researchers 
did not indicate how much of this acreage might have been occupied by 
pygmy rabbits and the number of historical sites where habitat may have 
been removed is unknown. However, Welch (2005, p. 10) visited 
historical pygmy rabbit sites in Utah and Idaho and documented some 
sites (2 of 13) were, or were likely impacted by fire.
    Other researchers have reported impacts of fire on local pygmy 
rabbit populations. For example, Gates and Eng (1984, cited in Tesky 
1994, p. 8) reported the deaths of ``several'' pygmy rabbits in an area 
where the fire advanced rapidly within a prescribed burn in Idaho. They 
thought pygmy

[[Page 60541]]

rabbits may be capable of escaping slow-moving fires but could be 
burned or die of asphyxiation in others (Gates and Eng 1984, cited in 
Tesky 1994, p. 8). Gates and Eng (1984, cited in Tesky 1994, p. 9) also 
reported that 2 months following a fire in big sagebrush-grassland 
community, only 3 of 11 radio-collared pygmy rabbits were alive. Of the 
eight lost, seven were due to predation. They speculated that the loss 
of big sagebrush from their home ranges probably increased 
vulnerability to predation. Some of the surviving pygmy rabbits 
(presumably other uncollared pygmy rabbits) abandoned their home ranges 
and moved to new home ranges in adjacent unburned sites (Gates and Eng 
1984, cited in Tesky 1994, p. 9). Roberts (2001, p. 17) mentioned a 
1966 burn near Gilmore Summit, Idaho, that had not regenerated to 
suitable habitat, and pygmy rabbits had not recolonized the area. 
Rachlow and Witham (2006, p. 6) suggested that large fires that removed 
sagebrush in the Camas Prairie of south central Idaho near the 
locations of known populations may reduce or eliminate successful 
movement of pygmy rabbits among some populations.
    In Nevada, the Service (1995, p. 2) reported that a survey 
conducted after a prescribed fire on the Sheldon National Wildlife 
Refuge in an area previously inhabited by pygmy rabbits found no 
evidence of their use afterwards. Larrucea (2006, p. 5) found no active 
pygmy rabbit sites in areas burned between 1981 and 2002 within the 
Surprise FO boundary; however, few fires occurred, and they were small 
in size (Figure 5 in Larrucea 2006, p. 14). Larrucea and Brussard 
(2008b, p. 1641) found 16 percent of the 105 historical pygmy rabbit 
sites in Nevada and California had been impacted by fire. Larrucea 
(2007, p. 61) found fire to be the strongest predictor of loss of pygmy 
rabbits from a site in Nevada and California; the greater the fire's 
intensity, the fewer the patches of intact sagebrush will remain. Pygmy 
rabbits were found on the edges of large burned areas (Midas-Tuscarora 
Road, NV), but the burned areas had not reverted to suitable pygmy 
rabbit habitat (Larrucea 2007, pp. 61-62).
    In contrast to the above studies, other researchers have mentioned 
burned areas that showed use by pygmy rabbits. In Idaho, a pygmy rabbit 
sighting reported by Red Willow Research Inc. (2000, p. 8) on BLM lands 
that had been impacted by wildfire in 1999 showed active use of the 
site. White and Bartels (2002, p. 13) mentioned that wildfires in the 
1990's severely affected the pygmy rabbit population, though some 
individuals remained. At one of her study sites, Waterbury (2005, p. 
11) found occupied burrows in an area where prescribed burns had 
occurred during 1993 to 1995. Waterbury (2006, p. 13) discovered a 
pygmy rabbit population in an old burn area in upper Spar Canyon.
    In Montana, Rauscher (1997, p. 14) reported that a prescribed burn 
in 1980 near Badger Pass, Montana, had been recolonized by pygmy 
rabbits. He did not know how long this process had taken or if pygmy 
rabbit densities had reached preburn levels. Bockting (2007 p. 1) found 
prescribed burns of about 500 ac (202 ha) have been implemented in 
pygmy rabbit habitat to reduce Pseudotsuga menziesii (Douglas fir) 
encroachment. Fire patterns minimized burning in the dense sagebrush. A 
mosaic burn pattern was allowed. Mechanical treatments (chainsaws) have 
also been used to remove Douglas fir. Within one unit, pygmy rabbit 
burrows were identified prior to the burn and revisited after the burn. 
Where the sagebrush habitat was not burned over, the burrows were still 
occupied (Bockting (2007 p. 1). It appears that small burns that create 
a mosaic do not significantly impact pygmy rabbits as long as 
surrounding habitat is maintained and the entire population is not 
lost.
    In Nevada, SNWA (2008, pp. 14-15) overlaid BLM's 1980 to 1996 and 
1997 to 2007 wildlife data (BLM 2007b, cited in SNWA 2008, p. 14) with 
Nevada's 2000 to 2007 pygmy rabbit occurrence data from various 
sources. They stated that review of their map indicates that a large 
portion of Nevada pygmy rabbit occurrence data falls in areas with 
relatively low numbers and sizes of wildfires, especially in east-
central Nevada. Large numbers and sizes of wildfires have not occurred 
throughout most of the historical and current pygmy rabbit range in 
east-central Nevada. They concluded that wildfires have not caused 
major declines in pygmy rabbits or their habitat, or pygmy rabbit 
occurrence or geographic range in east-central Nevada.

Summary of Fire Impacts

    Fire has impacted sagebrush ecosystems in the past and will 
continue to do so in the future, likely in increasing frequency and 
size of burned area. This increase in frequency is likely to be 
attributed to increases in invasive plant species cover, especially 
cheatgrass, as discussed above, as well as possible impacts of climate 
change as discussed below. Some studies summarized above have shown 
pygmy rabbits to have been negatively affected in some specific areas 
within their range. However, other studies have shown pygmy rabbits are 
not affected or are able to recolonize burned areas. Based on reports 
from site-specific areas in Idaho, Montana, California, Nevada, and 
Utah, fire has resulted in some loss of sagebrush habitat used by pygmy 
rabbits and has likely resulted in some population declines. Of the 
available examples showing loss of habitat, these are few in number 
across the range and are not indicative of systematic or widespread 
loss of habitat that may have been or is now suitable for pygmy 
rabbits. The scope of loss or modification of sagebrush habitat in 
general due to fire does not equally relate to loss or modification of 
pygmy rabbit habitat because the pygmy rabbit habitat occurs in a 
patchy distribution across the landscape. Some fires have resulted in 
loss of individuals, forage, and shelter for pygmy rabbits which may 
have led to an increased vulnerability to predation (Gates and Eng 
1984, cited in Tesky 1994, pp. 8-9). Abandonment of home ranges has 
been indicated at some specific sites but with the surviving 
individuals moving to adjacent unburned areas (Gates and Eng 1984 cited 
in Tesky 1994, p. 9).
    Recolonization or use of burned areas has occurred in other site-
specific areas. It also appears that the adverse impacts of fire may be 
minimized if burns are small, reducing possible habitat fragmentation 
and barriers to movement; if they occur in a mosaic pattern; if 
surrounding habitat is maintained to provide habitat; and if all 
members of a population are not lost. Additionally, studies in Montana 
and Idaho have indicated previously burned areas used or recolonized by 
pygmy rabbits (Rauscher 1997, Red Willow Research Inc. 2000, White and 
Bartels 2002, Waterbury 2005, 2006). Also in Montana a study indicated 
that a small mosaic fire, leaving some surrounding habitat, remained 
occupied by pygmy rabbits (Bockting 2007). Fire effects on sagebrush 
habitats depend on the sagebrush species, the composition and density 
of understory species, as well as the size, frequency, speed, burn 
pattern, and intensity of the fire. While it is not possible to predict 
the location or extent of future fires within pygmy rabbit habitat, the 
numbers of fires are likely to increase in the future; however, pygmy 
rabbits have shown an ability to survive and recolonize areas after 
some fire events. Based on our review of the best available scientific 
information, we conclude habitat loss or modification as a result of 
fire is not a significant threat to the pygmy rabbit now or in the 
foreseeable future.

[[Page 60542]]

Pinyon-Juniper Woodlands Encroachment

    Pinyon-juniper woodlands have increased in the Intermountain West 
an estimated 10 fold since European immigrant settlement (Miller and 
Tausch 2001, p. 15) resulting in the loss of many sagebrush-bunchgrass 
communities. The major factor cited for this increase is the decrease 
in fire return intervals (Miller and Tausch 2001, p. 25). Other factors 
attributed to this expansion include historical livestock grazing 
patterns, which reduced fine fuel buildup that more readily carried 
fire, and possibly climate change (Miller and Rose 1999, p. 551; Miller 
and Tausch 2001, p. 15).
    Connelly et al. (2004, pp. 7-8 to 7-12) estimated the risk of 
pinyon-juniper displacement of sagebrush within 30 years for a large 
portion of the Great Basin based on site elevation, proximity to extant 
pinyon-juniper, precipitation, and topography. They projected that 60 
percent of the sagebrush in the Great Basin was at low risk of being 
displaced by pinyon-juniper, 6 percent was at moderate risk, and 35 
percent was at high risk (Connelly et al. 2004, p. 7-12). It appeared 
that mountain big sagebrush was the type most at risk for pinyon-
juniper displacement (Connelly et al. 2004, p. 7-13). They cautioned 
that additional field research is necessary to support their 
projections (Connelly et al. 2004, pp. 7-14).
    Surveys (BLM 2006a, pp. 4-5) conducted in Oregon found junipers at 
6 of 7 sites surveyed, and pygmy rabbits occupied 5 of these sites with 
an additional site being inconclusive in terms of occupancy. In areas 
where pygmy rabbit burrows were found close to junipers, tree density 
ranged from 5 to 15 mature (70 to 120 years old) trees per ac (2 to 6 
per ha), and trees more than 20 years old were common. The areas still 
had a sagebrush and grass understory. Burrows were within 50 yd (45.7 
m) of junipers. . BLM (2007b, pp. 7-8) mentioned juniper control may 
benefit the pygmy rabbit populations at two of the eight occupied sites 
surveyed in Oregon. Juniper control may benefit pygmy rabbit 
populations at these sites before canopy closure affects the understory 
(BLM 2006a, p. 4; 2007b, p. 7).
    Welch (2005, p. 10) indicated 1 of 13 historical pygmy rabbit sites 
visited in Utah and Idaho were impacted by juniper encroachment. Larsen 
et al. (2006, p. 5) found historical pygmy rabbit sites in Tooele 
County, Utah, showed evidence of pinyon-juniper encroachment, but he 
did not indicate if all four sites had been encroached by pinyon-
juniper or whether there was remaining suitable pygmy rabbit habitat.
    Pinyon-juniper encroachment may have a negative impact on pygmy 
rabbits. In Nevada, pinyon-juniper woodland populations have increased 
almost 250 percent in distribution during the last 150 years (Tausch et 
al. 1981, cited in Larrucea and Brussard 2008b, p. 1640). These 
conifers slowly replace the sagebrush and convert it to woodland 
habitat, eliminating the understory (Miller et al. 2000, cited in 
Larrucea and Brussard 2008b, p. 1640).
    Larrucea and Brussard (2008b, p. 1640) found that a few of these 
trees at a site generally meant that pygmy rabbits were not present. 
Larrucea and Brussard (2008b, p. 1639), surveying sites in California 
and Nevada, showed that 14 percent of historical pygmy rabbit sites 
showed signs of pinyon-juniper woodland conversion. Of these sites, 
only one had current pygmy rabbit activity (Larrucea and Brussard 
2008b, p. 1639). At 6 of the 14 extirpated pinyon-juniper sites, pygmy 
rabbits were known to occur lower in the valley where sagebrush habitat 
existed (Larrucea and Brussard 2008b, p. 1640). However, based on the 
information available a significant loss or modification of habitat and 
measureable population decreases from site abandonment or avoidance 
attributed to pinyon-juniper encroachment are not occurring across the 
range.

Summary of Pinyon-Juniper Woodlands Encroachment Impacts

    Based on our review of the best available information, we found few 
studies which document negative effects of pinyon-juniper expansion on 
pygmy rabbit populations. Based on the studies cited above, pinyon-
juniper expansion has occurred in some occupied pygmy rabbit habitat in 
Oregon, Idaho, California, Nevada, and Utah; however, pygmy rabbits 
continued to be present at a number of these sites. Larrucea and 
Brussard (2008b, p. 1639), surveyed sites in California and Nevada and 
found only 14 percent of historical sites showed signs of pinyon-
juniper woodland conversion, and one had current activity. BLM (2006a, 
p. 4) conducted surveys in Oregon and found junipers at 6 of 7 sites, 
and pygmy rabbits continued to occupy a majority of these sites. Welch 
(2005, p. 10) found only 1 of 13 historical sites in Utah and Idaho 
showed signs of juniper encroachment. Larsen et al. (2006, p. 5) found 
four historical sites in Utah may have showed pinyon-juniper 
encroachment. The encroachment of pinyon-juniper into occupied pygmy 
rabbit habitat is a slow process, and pygmy rabbits may be able to 
inhabit those areas or shift their home range to adjacent areas if 
pinyon-junipers habitat becomes established at a site. Therefore, based 
on the best available scientific and commercial information, we 
conclude that pinyon-juniper expansion is not a significant threat to 
the pygmy rabbit now or in the foreseeable future.

Urban and Rural Development

    Historical destruction of sagebrush habitat for urban development 
has occurred (Braun 1998, pp. 6-7) with more recent expansion into 
rural areas causing additional loss (Braun 1998, pp. 6-7). Since 1950, 
the western United States has experienced rapid human population growth 
with regional rates higher than the national average (Brown et al. 2005 
cited in Leu and Hanser in press, p. 4). Fifty percent of all 
population growth in the United States from 1990 to 2000 occurred in 
western states (Perry and Mackun 2001 cited in Anderson and Woosley 
2005, p. 6). The amount of uninhabited area in the Great Basin (Idaho, 
California, Nevada, and Utah) has decreased from 90,000 km\2\ (34,749 
mi\2\) in 1990 to less than 12,000 km\2\ (4.633 mi\2\) in 2004 (Knick 
et al. in press, p. 20). The petitioner contended that power lines, 
fences, and roads that are associated with urban and rural development 
may have also resulted in the direct loss of sagebrush habitat and 
subsequently affected pygmy rabbits.
    Urban and rural development has impacted and may impact pygmy 
rabbit populations on a local scale. Possible effects to pygmy rabbits 
include loss of food and shelter, home range abandonment, injury or 
death at the time of vegetation clearing, habitat fragmentation, and 
population declines. Power poles and fences can provide hunting and 
roosting perches and nesting support, for many raptor species that are 
known to prey upon pygmy rabbits. In addition to direct habitat loss, 
roads may disrupt pygmy rabbit dispersal movements, and exacerbate 
potential impacts due to habitat fragmentation.
    Some research indicates that pygmy rabbits can occur where humans 
are present, while other research indicates that the human-developed 
habitat is not inhabited by pygmy rabbits. For example, Red Willow 
Research Inc. (2000, p 6) observed a pygmy rabbit under a conifer near 
a main ranch house in Idaho. In Nevada and California, Larrucea and 
Brussard (2008b, p. 1639) found 21 percent of historical sites showed 
signs of urbanization and still had pygmy rabbits present. White and 
Bartels (2002, pp. 7-8) found urban development had impacted 3 of 13

[[Page 60543]]

historical pygmy rabbit locations in Idaho, and no active pygmy rabbit 
burrows were found. Janson (2002, p. 32) discovered that one of his 
1940's pygmy rabbit study areas was impacted by residential and 
commercial development near Cedar City, Utah, when it was revisited in 
2001. He reported that his study area had been ``taken over'' by 
development and no pygmy rabbits or recent sign was seen.
    The petitioners contend that power lines and fences associated with 
urban and rural development result in loss of pygmy rabbit habitat, 
predation, displacement, and creation of movement barriers to pygmy 
rabbit populations. The available information does not document that 
power lines or fences are causing these impacts to pygmy rabbit 
populations.
    Estes-Zumpf and Rachlow (2009, p. 367) found that several radio-
collared pygmy rabbits crossed gravel roads and creeks in Idaho. 
Rauscher (1997, p. 14) reported the use of a subnivian (layer between 
snow and soil surface) tunnel that extended across a back country road 
near Badger Pass, Montana. Western EcoSystems Technology, Inc. (2008, 
p. 28) reported observations of pygmy rabbits crossing open areas, 
including desert grasslands with limited shrub cover, roads, and 
between shrub lands surrounded by grasslands in Wyoming. These few 
studies indicate that roads do not significantly affect pygmy rabbit 
movements.

Summary of Urban and Rural Development Impacts

    Although loss of sagebrush habitat due to development has been 
documented and will continue in the future, the amount of suitable or 
occupied pygmy rabbit habitat lost (or the magnitude of that loss 
across the range) is minimal in scale compared to overall sagebrush 
habitat and will likely remain so. Based on the best available 
information, pygmy rabbits have been reported to have been impacted by 
some development in a few site-specific areas in Idaho and Utah, but 
they have also continued to be present in some other areas. The scope 
of loss or modification of sagebrush habitat in general due to urban 
and rural development does not equally relate to the loss or 
modification of pygmy rabbit habitat because pygmy rabbits are patchily 
distributed across the landscape.
    While power lines, fences, and roads associated with development 
are also known to occur across sagebrush habitat within the range of 
the pygmy rabbit, we have no information regarding the amount of pygmy 
rabbit habitat that has been impacted across the range. The best 
available scientific information does not indicate that power lines, 
fences, and roads are threats to the pygmy rabbit. We do not have 
reports of raptors associated with power lines or fences impacting 
pygmy rabbit populations. The best available scientific information 
indicates that pygmy rabbits will cross roads, suggesting roads may be 
less of a barrier to pygmy rabbit movements than previously thought. 
Therefore, based on the best available scientific and commercial 
information, we conclude that urban and rural development, including 
associated power lines, fences, and roads, in the sagebrush ecosystem 
are not significant threats to the pygmy rabbit now or in the 
foreseeable future.

Mining

    Sagebrush habitat throughout the west has been impacted by gold, 
coal, and uranium mining (Braun 1998, pp. 5-6). Mining, livestock 
grazing, and ranching are decreasing as a percent of the economics in 
some parts of the western United States (Hansen et al. 2002, 2005 cited 
in Knick et al. in press, p. 56). Immediate impacts from mining to 
sagebrush habitat include direct loss from mining and construction of 
associated facilities, roads, and power lines (Braun 1998, pp. 5-6). In 
western North America, development of mines and energy resources began 
before 1900 (Robbins and Wolf 1994, cited in Braun 1998, p. 5).
    While comprehensive information on the number or surface extent of 
mines across the range of the pygmy rabbit is not known, the 
development of mineral resources is occurring on a large-scale and 
important to the economies of a few of the states in the range. For 
example, Nevada ranked second in the United States in terms of value of 
overall nonfuel mineral production in 2006 (U.S. Geological Survey 
2007, p. 10); Wyoming is the largest coal producer in the U.S. (Wyoming 
Mining Association 2008, p. 2).
    Between 2006 and 2007, surface coal production increased by 1.6 
percent in Wyoming (EIA, http://www.eia.doe.gov/cneaf/coal/page/acr/table1.pdf, accessed October 19, 2008). The number of Wyoming coal 
mines increased from 19 in 2005 to 23 in 2007 (Wyoming Mining 
Association 2005, p 5; 2008, p. 6). Most of these mines are located in 
the Powder River Basin (Wyoming Mining Association 2008, p. 2) which is 
not within the known range of the pygmy rabbit in that State.
    Possible impacts from mining to pygmy rabbits could include injury 
or death, loss or reduction of forage or shelter, temporary or 
permanent home range abandonment, increased habitat fragmentation, 
increased dispersal barriers, increased predation, and population 
declines. Red Willow Research Inc. (2000, p. 6) reported a pygmy rabbit 
sighting near the Historical Tallman Pit on the Sawtooth National 
Forest, Idaho. The individual was observed entering the rocks and 
boulders on the east edge of the pit. In California, pygmy rabbits have 
been observed in the area around Bodie, a mining town that was 
abandoned in the mid 1930's (Severaid 1950, p. 2). In Oregon, two 
survey areas supported active pygmy rabbit burrows at inactive 
diatomaceous earth mines (BLM 2008d, pp. 3, 6). One pygmy rabbit was 
observed at one of the sites (BLM 2008d, p. 6). Still, the best 
available scientific information does not indicate whether pygmy 
rabbits occupied these areas prior to or during the active mining 
period or if the observed individuals colonized or recolonized the 
areas after mining activities ceased.

Summary of Mining Impacts

    Though mining activities occur within sagebrush habitat, we do not 
have an estimate of habitat lost to mining impacts; however the impact 
to pygmy rabbit habitat is likely small compared to the overall range 
of the species and will likely continue to remain so in the future. 
Noted increases in the number of Wyoming coal mines occurred mostly in 
the Powder River Basin outside the known range of the pygmy rabbit in 
that State. We do have some information that indicates pygmy rabbits 
have been observed at specific mining areas in Idaho, California, and 
Oregon which may indicate pygmy rabbits are adaptable and can exist 
near mining sites or reestablish use of mining areas after mining 
activities have ceased. The best available scientific information 
indicates that significant loss or modification of habitat and 
measureable population decreases due to habitat loss or modification 
from mining impacts are not occurring across the range. Therefore, 
based on the best available scientific and commercial information, we 
conclude that habitat loss or modification due to mining is not a 
significant threat to the pygmy rabbit now or in the foreseeable 
future.

Energy Exploration and Development

    Energy exploration and development of non-renewable resources (oil, 
gas, coal) has occurred in sagebrush habitat since the late 1800's 
(Connelly et al. 2004, p. 7-38). Energy development and its associated 
facilities (well pads, access roads, pipelines, compressor

[[Page 60544]]

stations, pumping stations, and power lines) can impact sagebrush 
habitats.
    The exploration and development of fossil fuels in sagebrush 
habitats has increased recently as prices and demand are spurred by 
geopolitical uncertainties and legislative mandates (National Petroleum 
Council 2007, pp. 5-7). Legislative mandates include those of the 
Energy Policy and Conservation Act of 1975 (EPCA), 42 U.S.C. 6201, et 
seq., to secure energy supplies and increase the availability of fossil 
fuels. The EPCA was re-authorized and amended by the Energy Policy Act 
of 2000, P.L. 106-469, and the Energy Policy Act of 2005, PL 109-58, 
mandating inventory of Federal nonrenewable resources, economic 
incentives for energy development, identification of impediments to 
timely granting of leases and post-leasing development, and increased 
development of renewable energy resources (DOE 2005). In addition, the 
Energy Policy Act of 2005 mandated designation of federal lands for 
energy transport corridors (DOE 2005).
    Present and future exploration and development is highly likely to 
focus on areas of highest potential return. Pursuant to the EPCA 
mandates, the BLM as lead Federal agency for EPCA implementation, 
released results in 2003 of the first of a 4-phase survey intended to 
identify onshore oil and gas resources. Phases II and III were 
published in 2006 and 2008, respectively. Phase III supersedes the 
previous phases (DOI et al. 2008, p. 6).
    Available EPCA inventories indicate energy resources (oil and gas) 
in 11 geological basins within the range of the greater sage-grouse as 
identified in the 2006 Conservation Strategy (Stiver et al. 2006, p. 1-
11) for the greater sage grouse. Some of these basins also correspond 
with pygmy rabbit range: the Wyoming Thrust Belt of Wyoming, Utah and 
Idaho; Southwestern Wyoming Basin including portions of Wyoming and 
Utah; and Eastern Great Basin in Nevada, Utah, and Southern Idaho.
    We are aware that many land parcels within the range of the pygmy 
rabbit are leased for oil and gas development. Oil fields have been 
developed in east-central Nevada and western and central Utah. Major 
oil and gas production areas occur in eastern Utah, southwest Wyoming, 
and central California (USFS 2008a, p. 25). We are aware of a number of 
projects related to oil, gas, and coalbed methane production in 
sagebrush habitats---most notably in Wyoming---as can be seen from the 
following list of NEPA documents:
<bullet> Final Environmental Impact Statement (EIS) for the Jack Morrow 
Hills Coordinated Activity Plan/Proposed Green River Resource 
Management Plan Amendment, (BLM 2004a), for Sweetwater, Fremont and 
Sublette Counties, Wyoming;
<bullet> Scoping Notice for South Piney Natural Gas Development 
Project, (BLM undated), for Sublette County, Wyoming;
<bullet> Final Supplemental EIS for the Pinedale Anticline Oil and Gas 
Exploration and Development Project, (BLM 2008a), for Sublette County, 
Wyoming;
<bullet> Record of Decision Jonah Infill Drilling Project, (BLM 2006b), 
for Sublette County, Wyoming;
<bullet> Record of Decision EIS for the Atlantic Rim Natural Gas Field 
Development Project, (BLM 2007d), for Carbon County, Wyoming;
<bullet> Finding of No Significant Impact and Decision Record for the 
Bitter Creek Shallow Oil and Gas Project, Sweetwater County, Wyoming 
(BLM 2005b);
<bullet> Decision Record, Finding of No significant Impact and 
Environmental Assessment for the Copper Ridge Shallow Gas Exploration 
and Development Project, (BLM 2003b), for Sweetwater County, Wyoming;
<bullet> Environmental Assessment, Finding of No significant Impact and 
Decision Record for the Pacific Rim Shallow Gas Exploration and 
Development Project, Sweetwater County, Wyoming (BLM 2004b);
<bullet> Record of Decision for White Pine and Grant-Quinn Oil and Gas 
Leasing Project, (USFS 2007), for White Pine, Nye, and Lincoln 
Counties, Nevada;
<bullet> Final EIS Greater Deadman Bench Oil and Gas Producing Region, 
(BLM 2008b), for Uintah County, Utah.
    Currently, pygmy rabbits could be most affected by an energy 
resources development concentration in the Southwest Wyoming Basin. For 
example, the BLM published the Record of Decision in 2008 for Pinedale 
Anticline Project Area in southwest Wyoming (BLM 2008e). The project 
description included up to 900 drill pads, including dry holes, over a 
10 to 15-year development period (BLM 2008a, p. 4-4). Approximately 250 
new well pads are proposed in addition to pipelines and other 
facilities (BLM 2008e, p. 36). Total initial direct disturbance acres 
for the entire Pinedale project are approximately 25,800 ac (10,400 ha) 
with over 18,000 ac (7,200 ha) in sagebrush land cover type (BLM 2008a, 
pp. 4-52).
    The Jonah Gas Project also occurs in the Pinedale Anticline area of 
the Southwest Wyoming Basin. In 2006, the BLM issued a Record of 
Decision (BLM 2006b, entire) and a final EIS (BLM 2006c, entire) to 
extend the existing project to an additional 3,100 wells and up to 
16,200 ac (6,556 ha) of new surface disturbance (BLM 2006c, p. 2-4). 
Specific features include: at least 64 well pads per 640 ac (259 
km\2\), up to 473 mi (761 km) of pipeline and roads, and 140 ac (56 ha) 
of new surface disturbance for ancillary facilities (BLM 2006c, pp. 2-4 
to 2-5).
    The Pinedale Anticline and Jonah Gas Field Projects as analyzed by 
the BLM's EISs are not the only oil and gas development occurring in 
Wyoming. According to the Wyoming Oil and Gas Commission completed 
wells in Wyoming counties with sagebrush habitats increased from a 
total of 37,144 in 2005 to 42,510 in 2007. An additional 6,209 
applications for permit to drill were approved from January through 
September 2008 in these counties (WOGC 2008, http://wogcc.state.wy.us, 
accessed September 29, 2008).
    The Ruby Pipeline Project, as proposed, involves the construction 
and operation of a 675-mi-(1,086-km)-42-inch (106.7-cm)-diameter 
natural gas pipeline. The pipeline would transport natural gas from 
western Wyoming, through northern Utah and Nevada, to south central 
Oregon (Federal Energy Regulatory Commission (FERC) 2010, pp. 1-2- 1-
3). The project would cross known occupied pygmy rabbit habitat in 
Wyoming, Utah, and Nevada (FERC 2010, p. 4-126). Approximately 62 ac 
(25 ha) of suitable pygmy rabbit habitat was delineated along the 
pipeline route in these three states (FERC 2010, p. 4-147). The 
Applicant has committed to minimize impacts to pygmy rabbits by 
conducting preconstruction surveys, realignment of portions of the 
pipeline to avoid occupied habitat, construction buffers, construction 
timing restrictions, and specific re-vegetation activities, among other 
commitments (FERC 2010, pp. 4-132; 4-159; 5-9).
    Possible impacts to pygmy rabbits due to nonrenewable energy 
exploration and development include injury or death, loss of habitat, 
habitat fragmentation, dispersal barriers, noise, and disturbance due 
to increased human presence. Lance (2008, pp. 5-6) provided information 
on oil and gas development in southwestern Wyoming as it relates to 
pygmy rabbits. He indicated that the greatest number of wells drilled 
to date has occurred in the Pinedale/Jonah fields in southern Sublette 
County (Big Piney area south to Granger; in the Overthrust Belt along 
the Wyoming/Utah border; the Wamsutter area). While oil and gas 
development has been intensive in some portions of

[[Page 60545]]

the pygmy rabbit's predicted range in Wyoming, the majority of the 
range has been subjected to scattered oil and gas exploration and/or 
development, or no exploration or development at all. The pygmy 
rabbit's predicted range in Wyoming is based on a predictive 
distribution model that uses habitat variables and confirmed pygmy 
rabbit records (sightings) from the Wyoming Natural Diversity database 
(Lance 2008, pp. 2-3). Lance (2008, p. 5) estimated that 9,200 oil and 
gas wells have been drilled within the predicted range. Based on an 
average disturbance of 25 ac (10.1 ha) per well (accounting for pad, 
production facility, roads, pipelines, etc.), it was estimated that 4 
percent of the predicted range in Wyoming has been disturbed by 
conventional oil and gas development.
    Coal bed methane development is expected in isolated portions of 
the pygmy rabbit's predicted range in Wyoming. The areas potentially 
suitable for coal bed methane development include the area around 
Atlantic Rim and Baggs in Carbon County, and in the vicinity of Hay 
Reservoir in Sweetwater County.
    While some power lines may cross habitat occupied by pygmy rabbits, 
localized and insignificant impacts are expected given the linear 
nature of these projects (Lance 2008, p. 6). Power poles could be used 
as perches by avian predators preying on pygmy rabbits; however, as 
discussed above, we were not able to find evidence documenting this.
    Purcell (2006, pp. 2, 34) expressed concern for loss of sagebrush 
communities at energy production sites in Wyoming. Purcell (2006, p. 
110) mentioned that oil and gas development in southwestern and south 
central portions of Wyoming may contribute to degradation of suitable 
areas used by pygmy rabbits due to destruction of sagebrush and sodium 
contamination of the soil; and recommended that research be conducted 
to determine pygmy rabbit response to these disturbances.
    In contrast, two studies indicate energy projects and pygmy rabbits 
can co-exist. Hayden-Wing Associates, Inc. (2008b, p. 2) compiled pygmy 
rabbit observations of all sign (visuals, burrows and pellets, burrows 
only, pellets only) they collected during 1994 to 2007 surveys in 
Wyoming. All of their observations were within 109 yd (100 m) of roads 
(Hayden-Wing Associates, Inc. 2008b, p. 3). Observations were recorded 
in the Continental Divide-Wamsutter and Creston-Blue Gap natural gas 
project areas in Carbon and Sweetwater Counties; Moxa Arch natural gas 
development area in Lincoln, Uinta, and Sweetwater Counties; Jonah gas 
field in Sublette County; and Lake Ridge 3D seismic area in Lincoln 
County (Hayden-Wing Associates, Inc. 2008b, p. 2). They recorded 1,151 
pygmy rabbit observations (visuals, n=216; burrows and pellets, n=422, 
pellets only, n=513) (Hayden-Wing Associates, Inc. (2008b, p. 3). The 
majority of observations (50 percent) occurred in Moxa, 26 percent 
occurred within the Continental Divide-Wamsutter and Creston-Blue Gap 
areas, 17 percent in the Jonah gas field, and 6.5 percent in the Lake 
Ridge 3D seismic area (Hayden-Wing Associates, Inc. 2008b, p. 3). They 
acknowledge biases with road-based surveys and possible uncertainties 
in assigning pellets to pygmy rabbits, but concluded that energy 
development and pygmy rabbits do coexist throughout portions of Wyoming 
(Hayden-Wing Associates, Inc. 2008b, p. 3). Pygmy rabbit locations were 
farther away from well pads, but the analysis, in general, suggests 
that pygmy rabbits are capable of tolerating some level of disturbance 
(Hayden-Wing Associates, Inc. 2008b, p. 4). The authors suggest that 
research needs to be conducted to quantify the mechanisms that affect 
pygmy rabbits due to energy development, to understand thresholds at 
which negative impacts occur, and to determine ways the industry can 
avoid impacting populations (Hayden-Wing Associates, Inc. 2008b, p. 4).
    Estes-Zumpf et al. (2009, p. 4) began a pygmy rabbit monitoring 
program in the Pinedale Anticline Project Area (PAPA) (359 plots) and 
in a neighboring Boulder reference area (85 plots), Sublette County, 
Wyoming, in 2009. Surveys confirmed recent or current pygmy rabbit use 
at 83 percent of the plots, and there were 120 confirmed pygmy rabbit 
sightings across both study areas (Estes-Zumpf et al. 2009, p. 9). The 
Boulder reference area contained a greater proportion of active plots 
(81 percent) compared to the PAPA (54 percent) (Estes-Zumpf et al. 
2009, p. 9). One hundred and twelve plots were surveyed in the PAPA 
that occurred within the five oil and gas development areas (Estes-
Zumpf et al. 2009, p. 10). The proportion of active (52 percent) and 
recently active (25 percent) plots within the development zone was 
similar to the proportion of active (54 percent) and recently active 
(26 percent) plots throughout the PAPA (Estes-Zumpf et al. 2009, p. 
10). Thirty-two known plots were surveyed inside the development zone 
and 19 known plots were surveyed in the remainder of the PAPA; the 
proportion of known plots in the development zone that were still 
active (88 percent) was similar to the proportion of known plots still 
active (74 percent) in the remainder of the PAPA (Estes-Zumpf et al. 
2009, p. 10). Only 2 (6 percent) of previously known active plots 
within the development zone showed recent, but not current, pygmy 
rabbit activity (Estes-Zumpf et al. 2009, p. 10).
    Past and present renewable energy development (wind, solar, and 
geothermal) in sagebrush habitats could impact pygmy rabbits. Possible 
impacts to pygmy rabbits could include injury or death, loss of 
habitat, habitat fragmentation, dispersal barriers, noise, and 
disturbance due to increased human presence. The Department of Interior 
(DOI) and Department of Energy (DOE) (2003, pp. 2-17) assessed the 
potential for renewable energy being developed on public lands in 11 
western States. This assessment also indicated which BLM planning areas 
within these States offered the highest potential for each type of 
renewable energy (DOI and DOE 2003, pp. 18-24).
    BLM published a Final Programmatic EIS on Wind Energy Development 
on BLM-administered Lands in the Western United States (BLM 2005c, 
entire). This EIS addresses the environmental, social, and economic 
impacts associated with wind energy development on BLM-administered 
lands in 11 western States under the direction of increasing renewable 
energy production on public lands while minimizing environmental and 
socio-cultural impacts (BLM 2005c, p. ES-1). Future proposed wind 
energy projects may impact sagebrush habitats, and therefore, pygmy 
rabbits within the seven States. The 12-month finding for the greater 
sage-grouse (75 FR 13950) provides acreage of sagebrush habitat with 
wind energy development potential by Greater Sage-grouse Management 
Zone. Selecting those management zones that most appropriately overlap 
with the pygmy rabbit range, the estimated percent of sagebrush with 
developable wind potential in the species range is 3 to 9 percent 
(Greater Sage-grouse Management Zones III, IV, V). Greater Sage-grouse 
Management Zone II has 42 percent of sagebrush habitat with developable 
wind potential, but this incorporates a much larger area of Wyoming 
than is known to be occupied by pygmy rabbits.
    Wind development could occur in the future in the eastern portion 
of the predicted range in Wyoming; most projects are expected to be 
located east of Rawlins, and some may occur between Rawlins and 
Wamsutter in pygmy rabbit habitat with localized impacts (Lance 2008, 
p. 6).

[[Page 60546]]

    Eastern Nevada and the Pinedale area of Wyoming are the areas 
within the pygmy rabbit range with good potential for commercial solar 
development (EIA 2009e, entire cited in 75 FR 13953). The BLM is 
developing a programmatic EIS for leasing and development of solar 
energy on BLM lands (75 FR 13953).
    Geothermal energy facilities occur in pygmy rabbit range in 
California, Nevada, Utah, and Idaho. Geothermal potential occurs across 
pygmy rabbit range in the four mentioned states above as well as in 
southeast Oregon and west central Wyoming (EIA 2009e, entire cited in 
75 FR 13953).
    A Programmatic EIS for the Designation of Energy Corridors on 
Federal Land in the 11 Western States (DOE 2008) was published in 2008. 
This EIS addresses section 368 of the Energy Policy Act of 2005 which 
directs the designation of corridors for oil, gas, and hydrogen 
pipelines, and electricity transmission and distribution facilities on 
Federal lands. Federal agencies are required to conduct environmental 
reviews to complete the designation and incorporate the designated 
corridors into agency land use and resource management plans or 
equivalent plans. This EIS proposes only designation of corridors, and 
no environmental impacts are attributed to this action. Section 368 
does not require agencies to consider or approve specific projects, 
applications for rights-of-way (ROW), or other permits within any 
designated corridor nor does section 368 direct, license, or permit any 
activity on the ground. Any interested applicant would need to apply 
for a ROW authorization and the agency would consider each application 
under the requirements of various laws and related regulations (DOE 
2008, S-1-S-2). The proposed action would designate more than 6,000 mi 
(9,600 km) with an average width of 3,500 ft (1 km) of energy corridors 
across the West (DOE 2008, p. S-17). Federal land not presently in 
transportation or utility right-of-way is proposed for use in Idaho 
(102 mi or 164 km), Montana (149 mi or 240 km), Nevada (373 mi or 600 
km), Oregon (253 mi or 407 km), Utah (166 mi or 268 km), Wyoming (70 mi 
or 113 km), and California (unclear as miles in existing right-of-way 
is greater than miles of proposed corridors) (DOE 2008, p. S-18). 
Although we do not have data on how much of the corridor is in 
sagebrush habitat within the range of pygmy rabbits, based on the 
proposed location, habitat in Wyoming, Idaho, Utah, Nevada, and Oregon 
would be most affected.

Summary of Energy Exploration and Development Impacts

    Energy (nonrenewable and renewable) exploration and development has 
been documented within sagebrush habitat. Pygmy rabbits have been 
reported to occur in areas impacted by energy development in Wyoming 
and have continued to be present in these areas but with unknown 
impacts to population trends and long-term population persistence. The 
scope of loss or modification of sagebrush habitat in general due to 
energy exploration and development does not equally relate to the loss 
or modification of pygmy rabbit habitat because of the pygmy rabbit's 
patchy habitat distribution across the landscape. Available information 
indicates that significant loss or modification of habitat and 
measureable population declines from injuries or mortalities, temporary 
home range abandonment or permanent home range shift to adjacent areas, 
increased habitat fragmentation, increased dispersal barriers, noise, 
or increased human presence due to energy development (nonrenewable and 
renewable) are not occurring across the range.
    Energy exploration and development is occurring, especially within 
a portion of the pygmy rabbit's range in Wyoming. Yet, the available 
information does not indicate that this potential threat is negatively 
impacting pygmy rabbits. Therefore, based on the best available 
scientific and commercial information, we conclude that habitat 
degradation and loss due to energy exploration and development is not a 
significant threat to the pygmy rabbit now or in the foreseeable 
future.

Habitat Fragmentation

    Habitat fragmentation is the separating of previously contiguous, 
functional habitat components that are used by a particular species. 
Habitat fragmentation can result from direct losses that leave 
remaining habitat in discontinuous patches or from alteration of 
habitat such that the habitat becomes unusable to the species (i.e., 
functional habitat loss). This type of loss can result from 
disturbances that change a habitat's successional state or remove one 
or more of its habitat functions; barriers that prevent use of suitable 
areas; and activities that prevent use of habitat due to behavioral 
avoidance. Most extant sagebrush habitat has been altered since 
European immigrant settlement of the West (Braun 1998, p. 2; West and 
Young 2000, Miller and Eddleman 2001, cited in Knick et al. 2003, p. 
614; Connelly et al. 2004, p. 7-1). Sagebrush habitat continues to be 
fragmented (Knick et al. 2003, p. 625) through various factors (natural 
and anthropogenic) and will into the future. Cumulative effects of 
habitat fragmentation have not been quantified over the range of 
sagebrush and most fragmentation cannot be attributed to specific land 
uses (Knick et al. 2003, pp. 614-616). Review of the human- footprint 
intensity within the greater sage-grouse management zones showed that 
the Northern and Southern Great Basin and Snake River Plain sage-grouse 
management zones contained a greater proportion of low-intensity human 
footprint area compared to the range-wide intensity (Leu and Hanser in 
press, p. 14). Sage-grouse management zones with a higher proportion of 
high-intensity human footprint area (Colorado Plateau, Great Plains, 
and Columbia Basin) compared to the range-wide intensity (Leu and 
Hanser in press, p. 14) occurred outside of the range occupied by the 
pygmy rabbit. Thus, in sage-grouse management zones, the range of the 
pygmy rabbit occurs mostly within a low-intensity human footprint area.
    In general, habitat fragmentation has been mentioned as a potential 
threat to pygmy rabbits by several researchers (White and Bartels 2002, 
p. 13; Bartels 2003, p. 99; Roberts 2003a, p. 9). Potential impacts to 
pygmy rabbits include loss of habitat, increased dispersal distance, 
increased predation, and increased isolation. Weiss and Verts (1984, p. 
570), in Oregon, stated that fragmentation of sagebrush posed a threat 
to pygmy rabbit populations by reducing the size of this vegetative 
community and increasing the distances between suitable areas; however, 
the severity of this threat to pygmy rabbits cannot be adequately 
assessed without improved understanding of the dispersal abilities of 
this species and minimum sagebrush patch size requirements. Katzner and 
Parker (1997, p. 1071) stated that fragmentation of habitat can 
influence size, stability, and success of pygmy rabbit populations 
because of their low dispersal capabilities. However, subsequent 
studies by researchers, as indicated below, demonstrate dispersal 
capabilities of pygmy rabbits are greater than initially thought and 
that potential barriers such as perennial creeks and roads do not 
appear to be barriers to gene flow among some populations.
    Pygmy rabbits depend on sagebrush, but there is no information 
available to indicate minimum sagebrush patch size required to support 
populations. In Washington, the Service (2007, p. 54) estimated that a 
subpopulation of at least 500 Columbia Basin DPS pygmy

[[Page 60547]]

rabbits would need an area of between 454 and 3,250 ac (184 and 1,316 
ha) of suitable habitat. Some studies indicate that pygmy rabbit 
populations may not be as isolated as previously thought. This has 
implications for recolonization and genetic exchange between nearby 
areas. In Montana, movement data has shown pygmy rabbits will cross 
relatively small open areas (1,500 ft (457 m)) to reach suitable 
habitat (Rauscher 1997, p. 5). In Wyoming, Katzner and Parker (1998, p. 
73) reported a pygmy rabbit traveled long-distance (2.2 mi (3.5 km)) 
through open habitat likely unsuitable for long-term habitation. In 
Idaho, Estes-Zumpf and Rachlow (2009, p. 367) found median dispersal 
movements of 0.93 mi (1.5 km) and 3.9 mi (6.2 km) and maximum dispersal 
movements of 4.0 mi (6.5 km) and 7.4 mi (11.9 km) by male and female 
juvenile pygmy rabbits, respectively. Crawford (2008, p. 54) in Nevada 
and Oregon reported that 24 radio-marked rabbits moved greater than 0.3 
mi (0.5 km) with a maximum long-distance movement of 5.3 mi (8.5 km) 
recorded by a juvenile female.
    Continued survey efforts in recent years have found new populations 
throughout the pygmy rabbit's range. Rachlow and Witham (2006, p. 6) 
found that the locations of the 32 new sites in the Camas Prairie of 
south central Idaho indicated the possibility that movement can occur 
among several of these sites. The sites are separated by distances of 
less than 3.1 to 4.3 mi (5 to 7 km) which are within dispersal 
capabilities shown by Estes-Zumpf and Rachlow (2009) and Rachlow and 
Witham (2006, p. 6). Because most surveys for pygmy rabbits are limited 
to a single state, it is noteworthy that some reports mention occupied 
sites near state lines. This suggests the possibility that additional 
unreported genetic exchange may be occurring where ranges overlap two 
states. This would further reduce the concern of habitat fragmentation 
and isolation. Roberts (2003a, p. 9) reported that 6 of the 9 active 
burrow systems found were within 15 mi (24.1 km) of the Idaho State 
line. One was within 3 mi (4.8 km) of the Montana border at the head of 
Medicine Lodge Creek, Clark County. Two active burrow sites were within 
8 mi (12.9 km) of both Wyoming and Utah borders on Pegram Creek, Bear 
Lake County. One active burrow site found on the Curlew National 
Grasslands was about 15 mi (24.1 km) north of the Utah border and two 
active burrows sites were about 15 mi (24.1 km) north of the Nevada 
border near Riddle, Idaho. In Montana, Hendricks et al. (2007, p. 13) 
mentioned that two new active sites found during their survey occurred 
in gaps between other locations and suggested pygmy rabbits may exist 
in additional locations in Big Hole Valley. Continued occupancy of 
previously known locations along the east side of Big Hole Valley may 
benefit through connectivity with populations in Grasshopper Valley, 
Argenta Flats, and Horse Prairie located to the south.
    Estes-Zumpf et al. (2010, p. 212) obtained genotypes for 249 pygmy 
rabbits from 8 sample locations in Lemhi Valley (5) and Camas Prairie 
(3), Idaho. They did not document strong evidence of genetic 
substructure based on nuclear microsatellites among pygmy rabbit 
populations within the study areas (Estes-Zumpf et al. 2010, p. 215). 
Lack of strong population structure within the study areas indicates 
that perennial creeks and roads do not appear to create substantial 
barriers to gene flow (Estes-Zumpf et al. 2010, pp. 215-216). Levels of 
genetic diversity in pygmy rabbits were relatively high in the study 
areas (Estes-Zumpf et al. 2010, pp. 214). Sample locations within 8.1 
mi (13 km) of one another in each study area showed sufficient gene 
flow to constitute single populations (Estes-Zumpf et al. 2010, pp. 
215).
    In Utah, Flinders (2007, pp. 2-3) found fairly extensive 
populations in Hamlin Valley located on the Utah/Nevada border in Iron 
and Beaver Counties (Utah). He thought that this area may provide an 
important habitat corridor between the two States as he found pygmy 
rabbit use for several miles on both sides of the border.

Summary of Habitat Fragmentation Impacts

    Although we cannot estimate the amount of suitable or occupied 
pygmy rabbit habitat lost or the magnitude or extent of that loss due 
to habitat fragmentation, the habitat used by pygmy rabbits is 
naturally fragmented and populations occur in a patchy distribution 
across their range. Because of this patchy habitat distribution across 
the range, the scope of loss or modification of sagebrush habitat in 
general due to fragmentation does not equally relate to the loss or 
modification of pygmy rabbit habitat. Naturally fragmented sagebrush 
habitat occupied by pygmy rabbits may not have been more prevalent or 
more contiguous prior to human settlement. Local distribution of this 
habitat and the distribution of the pygmy rabbit likely shifts over 
time due to disturbances from factors such as fire, agriculture 
production, flooding, grazing, and weather patterns.
    Pygmy rabbit populations may be less isolated than previously 
thought based on studies in Idaho, Montana, Wyoming, Nevada, and Utah. 
For example, studies related to movement data indicate pygmy rabbits, 
including juveniles, can move greater distances than initially thought 
(Green and Flinders 1979, p. 88; Gahr 1993, p. 108; Katzner and Parker 
1998, p. 73; Crawford 2008, p. 54; Estes-Zumpf and Rachlow 2009, p. 
367).
    Other studies by Rachlow and Witham (2006, p. 6) and Roberts 
(2003a, p. 9) in Idaho, Hendricks et al. (2007, p. 13) in Montana, and 
Flinders (2007, pp. 2-3) in Utah, as detailed above, suggest 
connectivity may occur among several areas and between states. 
Understanding dispersal capabilities of pygmy rabbits plays an 
important role in addressing the possibility for genetic exchange among 
occupied sites as well as determining whether the characteristics of a 
metapopulation apply to this species.
    The best available scientific information does not indicate that 
fragmented sagebrush habitat is negatively impacting pygmy rabbit 
populations across their range. Available information indicates through 
genetic analysis that current habitat sagebrush distribution does not 
appear to affect dispersal distances, predation, or isolation among 
pygmy rabbit populations. Although the necessary patch size to support 
pygmy rabbit populations has not been determined, this species has been 
reported to historically survive in a naturally fragmented habitat. 
Survey efforts demonstrate that pygmy rabbits have been found in areas 
impacted or fragmented by various potential threats as discussed in 
Factor A and continue to exist in or adjacent to many of these areas 
suggesting that habitat fragmentation is not a significant threat to 
this species. While its habitat may be impacted to some degree by 
current habitat fragmentation, based on the best available scientific 
and commercial information, we conclude that habitat fragmentation is 
not a significant threat to the pygmy rabbit now or in the foreseeable 
future.

Habitat Manipulation Conducted to Benefit Greater Sage-Grouse

    There has been a recent and widespread interest in the protection 
and restoration of sagebrush habitats with an emphasis on greater sage-
grouse conservation (BLM 2004c). It is uncertain whether efforts 
implemented to improve greater sage-grouse habitat will benefit pygmy 
rabbits. Some habitat manipulation to benefit greater sage-grouse could 
benefit pygmy rabbit (e.g.,

[[Page 60548]]

pinyon-juniper removal) (Larrucea 2007, p. 127).
    Connelly et al. (2000, pp. 977, 980) recommend managing sagebrush 
canopy cover for greater sage-grouse habitat at 10 to 25 percent for 
brood-rearing, 15 to 25 percent for breeding habitat, and 10 to 30 
percent for winter habitat. Pygmy rabbits, in general, prefer taller, 
denser sagebrush cover relative to the surrounding landscape (Green and 
Flinders 1980b, p. 138; Weiss and Verts 1984, p. 567), which can be 
greater than the 10 to 30 percent range suggested for greater sage-
grouse habitat needs during their various life history stages. Burak 
(2006, pp. 63-64) found total shrub cover values ranged from 41 to 67 
percent and sagebrush cover values ranged from 12 to 60 percent in 
areas occupied by pygmy rabbits. Reducing dense sagebrush cover to 
benefit greater sage-grouse may be in conflict with habitat needs of 
pygmy rabbits.
    In Nevada, Larrucea (2006, p. 7) raised a concern that sagebrush 
management plans which target areas of mature sagebrush for treatment 
to promote succession (e.g., Greater Sage-Grouse Conservation Plan for 
Nevada and Eastern California (NDOW 2004), cited in Larrucea 2006, p. 
7) do not protect pygmy rabbit habitat. The goal of these plans is to 
create a mosaic of sagebrush stands of differing ages. These plans 
allow for mature sagebrush at the end of the succession, but pygmy 
rabbits use their burrows over many seasons and require stable, long 
lasting, mature sagebrush. Larrucea (2006, p. 7) suggested a 
modification of these plans which would allow protection of habitat for 
pygmy rabbits and recommends either: 1) surveying for areas to be 
managed for pygmy rabbit habitat; or 2) specifying areas of mature, 
clumped, larger than average sagebrush stands within the area to be 
managed and taking a portion of these areas to be mapped and managed as 
stable, mature sagebrush sites with no treatments applied. The 
combination of these two actions (successional and stable) would create 
a mosaic of ages. This would incorporate both the succession desired by 
other plans while protecting the stable type of habitat needed by pygmy 
rabbits. The stable, mature sagebrush would be available for 
colonization and the earlier successional stages would be available for 
pygmy rabbit dispersal. These untreated areas of late-successional 
sagebrush should be included in the actively managed rotational-
successional plan (i.e., NDOW 2004). Larrucea (2006) does not provide 
details of any specific project implemented within sagebrush habitats 
to improve greater sage-grouse habitat and its possible impact to pygmy 
rabbits or their populations.

Summary of Habitat Manipulation Conducted to Benefit Greater Sage-
Grouse

    Sagebrush habitat manipulations to benefit greater sage-grouse have 
occurred within the range of the pygmy rabbit. Habitat manipulation to 
benefit greater sage-grouse or other species was raised as a concern by 
the petitioners and a researcher, but the available information does 
not provide an example of the effects of this activity on pygmy 
rabbits. Additionally, the available information does not indicate 
there has been a systematic or widespread loss of habitat due to 
habitat manipulation that may have been or is suitable habitat for 
pygmy rabbits. Because of the pygmy rabbit's patchy habitat 
distribution across the landscape, the scope of loss or modification of 
sagebrush habitat in general due to habitat manipulation for greater 
sage-grouse does not equally relate to the loss or modification of 
pygmy rabbit habitat.
    Large-scale sagebrush manipulations to benefit greater sage-grouse 
may benefit pygmy rabbit. Based on the similarities with sagebrush 
treatments discussed earlier, the size and design of the manipulated 
area may minimize adverse impacts to pygmy rabbits. If designed 
appropriately, these projects may be beneficial to pygmy rabbits by 
opening up areas for new vegetation growth or to provide dispersal 
areas. Pygmy rabbits have been found in mosaics where large areas of 
sagebrush were left intact and remained connected to adjacent sagebrush 
or where treated areas were small and travel distances between them 
were minimal. Therefore, based on the best available scientific and 
commercial information, we conclude that habitat degradation and loss 
due to habitat manipulations for other species is not a significant 
threat to the pygmy rabbit now or in the foreseeable future.

Conservation Strategies and Actions

    All seven States mention the pygmy rabbit in their Comprehensive 
Wildlife Conservation Strategies. These strategies confer no regulatory 
mechanisms, but indicate that the species or its habitat deserves 
special management considerations (Oregon Department of Fish and 
Wildlife 2006; Idaho Department of Fish and Game 2005; Montana Fish, 
Wildlife & Parks 2005; Wyoming Game and Fish Department 2005; 
California Department of Fish and Game 2005; Nevada Department of 
Wildlife 2006; Utah Division of Wildlife Resources 2006).
    We are not aware of any States implementing conservation actions 
specifically for the pygmy rabbit, though we are aware of initiatives 
to restore the sagebrush ecosystem within the range of the pygmy 
rabbit. For example, the State of Utah Division of Wildlife Resources 
launched the Watershed Initiative in 2003 to implement restoration 
projects designed to prevent and reverse habitat loss. Emphasis has 
been placed on restoration and protection of shrub-steppe and riparian 
habitats in Utah due to their importance to a diversity of wildlife 
species. Completed, current, and proposed projects within the range of 
pygmy rabbit total 35,335 ac (14,300 ha). Monitoring is an important 
component to assessing these treatments (Karpowitz 2008, p. 3). In 
addition, research is being conducted to address impacts of treatments 
for greater sage-grouse, mule deer, and pronghorn on pygmy rabbit 
populations. Preliminary results indicate that at least a 131.2 ft (40-
m) buffer should be established between active pygmy rabbit burrows and 
treatments. Future designs should also implement a mosaic pattern and 
preserve long and wide swaths of undisturbed mature big sagebrush with 
corridors of connectivity between all residual stands. All current and 
future habitat projects in pygmy rabbit habitat follow these 
recommendations (Karpowitz 2008, p. 3). Although it is not known 
whether pygmy rabbits are benefiting from these types of habitat 
restoration actions across their range, some actions implemented for 
other species may benefit pygmy rabbits (e.g., pinyon-juniper removal 
for greater sage-grouse) (Larrucea 2007, p. 127).
    At the State level, control of invasive plant species is sometimes 
encouraged. Some States require landowners to control noxious weeds on 
their property, but the types of plants considered to be noxious weeds 
vary by state. For example, only Oregon, California, Colorado, Utah, 
and Nevada list medusa head as a noxious, regulated weed, but medusa 
head can be problematic in other states (e.g., Idaho). Cheatgrass is 
not considered an official noxious weed within the range of the pygmy 
rabbit. Although we do not know how these regulations affect sagebrush 
habitats, States have regulations regarding invasive species in place.

Summary of Conservation Strategies and Actions

    All seven States within the range of the pygmy rabbit mention this 
species in their Comprehensive Wildlife Conservation Strategies and 
indicate

[[Page 60549]]

that the species or its habitat deserves special management 
considerations now and in the future. While we are not aware of any 
States implementing conservation actions specifically for the pygmy 
rabbit, we are aware of initiatives to restore the sagebrush ecosystem 
within the range of the pygmy rabbit over time. Many states encourage 
the control of invasive plant species. Conservation strategies and 
actions carried out in consideration of the pygmy rabbit will benefit 
it now and in the future.
    Therefore, based on the best available scientific and commercial 
information, we conclude that conservation strategies and actions for 
pygmy rabbits or their habitat do not pose a significant threat to the 
pygmy rabbit now or in the foreseeable future.

Summary of Factor A

    We have assessed the best available scientific and commercial data 
on the magnitude and extent of the impacts of agriculture, sagebrush 
treatment, livestock grazing, nonnative and invasive plant species, 
fire, urban and rural development (and associated facilities), mining, 
energy exploration and development (and associated facilities), habitat 
fragmentation, greater sage-grouse conservation actions and other 
conservation actions on pygmy rabbit habitat. We find that these 
threats do not significantly, either singly or cumulatively, impact the 
pygmy rabbit to such an extent within the foreseeable future such that 
listing under the Act as an endangered or threatened species is 
warranted. While sagebrush habitat loss and fragmentation has occurred 
within the range of the pygmy rabbit due to various anthropogenic and 
natural activities as discussed above and likely will continue at some 
level in the future; our review of the best available information 
reveals only a handful of specific areas where sagebrush loss or 
degradation is occurring in occupied pygmy rabbit habitat. Due to the 
pygmy rabbit's patchy habitat distribution across the landscape, the 
scope of loss or modification of sagebrush habitat in general does not 
equally relate to loss or modification of pygmy rabbit habitat. The 
activities listed above are likely to continue into the future with 
some increases occurring. However, pygmy rabbit populations continue to 
occur throughout the species' current known range, including 
historically occupied locations, and some new populations have been 
found in recent years, despite numerous activities occurring within its 
habitat.
    We conclude that the best scientific and commercial information 
available indicates that the pygmy rabbit is not now, or in the 
foreseeable future, threatened by the present or threatened 
destruction, modification, or curtailment of its habitat or range to 
the extent that listing under the Act as an endangered or threatened 
species is warranted at this time.

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

    We have no information that the pygmy rabbit is being used for 
commercial or educational purposes.
Hunting
    Impacts due to hunting include injury or death with the potential 
for impacting population numbers. Some individuals have suggested that 
pygmy rabbits were not readily hunted in the past. Bailey (1936, p. 
112) indicated an individual from Nevada reported that pygmy rabbits 
were not eaten by locals because of the strong sage taste. Later 
Larrison (1967, p. 64) said, ``[Pygmy rabbits] flesh tastes of 
sagebrush, rendering it unfit as food.''
    In Idaho, Fisher (1979, p. 29) recommended that bag limits be 
monitored, especially where habitat was declining, because with the 
pygmy rabbit's lower reproductive potential as compared to other 
rabbits, fewer surplus animals may be available to hunters. Sanchez 
(2007, p. 90) reports of an illegal harvest of two pygmy rabbits in her 
Idaho study area during 2004 to 2005. Rauscher (1997, pp. 10-11) 
reported pygmy rabbit hunting in southwestern Montana, but stated that 
hunting did not appear to be a significant mortality factor. Williams 
(1986, p. 52) stated that although hunting impacts were not known in 
California, he thought that hunters probably did not kill many pygmy 
rabbits because the species was quite secretive and rarely left dense 
brush. Pritchett et al. (1987, p. 231) reported that, according to 
locals near Loa, Wayne County, Utah, pygmy rabbits have been 
``extensively hunted'' along with black-tailed jackrabbits (Lepus 
californicus) and cottontails. Where he was able to access portions of 
his previous study area outside Cedar City, Utah, Janson (2002, p. 32) 
found spent shotgun shells. He thought it was probable that some pygmy 
rabbits were shot because most hunters cannot distinguish between pygmy 
rabbits and cottontails.
    We are aware that rabbit drives occurred (Bacon et al. 1959, p. 
281; Jackman and Long 1964, p. no page number), but there is little 
documentation on the impacts to pygmy rabbits. For example, Bacon et 
al. (1959, p. 281) collected rabbits, mostly by organized drives of 
hunters who shot them, to gather ectoparasitic (parasite on outer 
surface of an animal) information on wild rabbits and rodents in 
eastern and central Washington between 1951 and 1956; of the 1,040 
rabbits collected, representing four species, only one was a pygmy 
rabbit. It is unknown if the single collection indicates pygmy rabbits 
are less vulnerable to drives or if numbers were reduced in that area 
at the time.
    Jackman and Long (1964, p. no page number) documented, with a 
photograph, that a rabbit drive occurred in Oregon in 1911. The drive 
resulted in 1,811 rabbits being captured, but the species of rabbits 
were not identified nor was the location of the drive. The photograph 
is courtesy of the Schminke Museum, Lakeview, Lake County, Oregon, so 
the drive could have occurred in that county. We do not have any 
additional information on rabbit drives occurring within the range of 
the pygmy rabbit.
    Currently, only three (California, Nevada, and Montana) of the 
seven States within the species range allow hunting of pygmy rabbits. 
For these States, the State Wildlife Boards of Commissioners set 
hunting regulations yearly. In California, for the 2009 to 2010 Upland 
Game Season, hunting of pygmy rabbits is allowed from July 1 to January 
31 with a bag limit of 5 per day and 10 in possession (California 
Department of Fish and Game 2010, http://www.dfg.ca.gov/regulations/09-10-upland-sum.html, accessed July 20, 2010). The 2009-2010 pygmy rabbit 
hunting season in Nevada opened October 10 and closed February 28 with 
a daily limit of 10 and a possession limit of 20 (Nevada Department of 
Wildlife, 2009, no page numbers). For Montana, the pygmy rabbit is 
considered a nongame species and there is no protection from hunting. 
Pygmy rabbits can be hunted year-round with no bag limits (Montana 
Department of Fish Wildlife and Parks 2010, http://fwp.mt.gov/wildthings/livingWithWildlife/rabbits/rab_ctrl.html). For these three 
States, harvest data are collected through hunter surveys but the 
various rabbit species are not distinguished from one another so the 
number of pygmy rabbits harvested in these States per year is not 
known.
Summary of Hunting Impacts
    While it has been reported that pygmy rabbits have been hunted over 
the years and specifically in Idaho, Nevada, and Utah, only three 
(Montana, California,

[[Page 60550]]

and Nevada) of the seven States within the range of the pygmy rabbit 
currently allow hunting of this species. Historical harvest records are 
not available, but information indicates a reluctance to eat pygmy 
rabbits due to their strong sage taste as well as difficulty in hunting 
them due to their secretive nature. The number of pygmy rabbits taken 
more recently through hunting is not discernable because of the method 
by which present-day data are collected in States that allow hunting. 
Based on the best scientific information available, we conclude that 
hunting is not a significant threat to the pygmy rabbit now or in the 
foreseeable future.
Research
    Research activities on pygmy rabbits that involve trapping, 
handling, and holding them for a period of time can result in mortality 
from exposure, injury, trap predation, intra-specific fighting, and 
capture stress (Bailey 1936, pp. 111-112; Severaid 1950, p. 2; Wilde 
1978, p. 96; Gahr 1993; Rauscher 1997, p. 9). Mortality rates for 
captured pygmy rabbits have been reported as 3 percent (Gahr 1993, p. 
37), 5 percent (Wilde 1978, p. 96), and 19 percent (Rauscher 1997, p. 
9). Individuals may be killed for specimen collections (Grinnell et al. 
1930, pp. 553-555; Bailey 1936, p. 111; Severaid 1950, p. 2). 
Investigations may also involve digging out burrows, stepping on 
burrows accidentally, measuring vegetation and other site 
characteristics near burrows, and other general disturbance in the 
study area (Janson 1946, p. 69; Bradfield 1974, pp. 17, 21-22, 26; 
Green 1978, pp. 4-6; Gahr 1993, pp. 54-60; Katzner 1994, pp. 6-12; 
Rauscher 1997, pp. 6, 12). Katzner (1994, p. 111) reported that all of 
his collared rabbits (10) died. He suggested the weight of the radio 
collars, and increased grooming as a result of their presence, may have 
increased a rabbits' vulnerability to predation. Rachlow and Witham 
(2004a, p. 3) reported 1 pygmy rabbit mortality out of the 15 trapped 
during their survey efforts. The trap contained a long-tailed weasel 
(Mustela frenata), and it was unclear if the weasel killed the rabbit 
prior to entering the trap, entered the trap after the rabbit was 
captured in the trap, or entered the trap with the rabbit 
simultaneously. Sanchez (2007, p. 90) reported two deaths related to 
her study due to collars entrapping the lower jaw of the pygmy rabbit. 
Flinders et al. (2005, p. 36) captured two pygmy rabbits, placing 
radio-collars and ear tags on them. They reported one died due to a 
loose collar; the other bit the collar off but was captured by a remote 
camera 339 yd (310 m) away from the initial capture site.
Summary of Research Impacts
    The documented mortalities due to research activities are 
relatively few in number, occur in limited areas, and occur over 
limited time periods. Most of these reported mortalities are documented 
in studies conducted before 1997 and few mortalities have been reported 
in recent documents. Therefore, based on our review of the best 
available scientific information, we conclude that research activities 
are not a significant threat to the pygmy rabbit now or in the 
foreseeable future.

Summary of Factor B

    Currently only three States allow hunting of pygmy rabbits; this is 
a reduction from the historic condition where all of the states 
considered in this finding allowed hunting. We found no data regarding 
long-term historical or recent hunting data that would clarify past or 
current hunting pressure on the pygmy rabbit across its range. While 
there is a potential for populations at low levels to be harmed by 
hunting and poaching mortality, our review of the best scientific and 
commercial information indicates hunting is not a significant threat to 
the pygmy rabbit.
    Research activities have been a source of mortality for pygmy 
rabbits, although our review of the best scientific information 
suggests this is a very minor level of mortality and does not pose a 
significant threat to the species.
    We have assessed the best available scientific and commercial data 
on the magnitude and extent of the impacts of hunting and research 
activities on pygmy rabbits. Based on that information, we conclude 
that the best scientific and commercial information available indicates 
that the pygmy rabbit is not now, or in the foreseeable future, 
threatened by the overutilization for commercial, recreational, 
scientific, or educational purposes to the extent that listing under 
the Act as an endangered or threatened species is warranted at this 
time.

Factor C: Disease or Predation

Disease
    Possible effects of disease include weakening of individuals which 
may increase their vulnerability to predation. Serious disease 
outbreaks can impact population size and number. Pygmy rabbits 
reportedly can harbor high parasite loads (Janson 1946, p. 90; Wilde 
1978, p. 107; Gahr 1993; WDFW 1995; 66 FR 59734). These parasites 
include ticks (e.g., Dermacenter paramapterus, D. anersoni, 
Haemaphysalis leporis-palustris), fleas (e.g., Cediopsylia inaequalis, 
Odontopysilys dentatus), lice (not specified), and bot flies (e.g., 
Cuterebra maculata) (Davis 1939, p. 365; Janson 1940, pp. 25-27; Janson 
1946, p. 90; Larrison 1967, p. 64; Wilde 1978, pp. 13-16; Gahr 1993; 
Rauscher 1997, p. 12) which can be vectors of disease.
    Plague and tularemia can be found in leporid populations, but they 
have not been confirmed in pygmy rabbits. Plague is a bacterial disease 
that is transmitted by fleas infected with the bacterium, Yersinia 
pestis. Tularemia is caused by the bacterium Francisella tularensis and 
is commonly transmitted by ticks. These diseases often spread rapidly 
and can be fatal (Quan 1993, p. 54). Hall (1946, p. 618), in Nevada, 
thought that pygmy rabbits were killed by tularemia based on his 
general observations which were not specified. Gahr (1993, p. 22) found 
bot flies on two pygmy rabbits located in the grazed area of her study 
in Washington, indicating cattle may act as a vector for spreading 
parasites and possibly disease. She commented that parasitism by bot 
flies is not necessarily detrimental to the rabbit, and additional 
study is needed to determine if cattle presence increases the incidence 
of ectoparasites for pygmy rabbits.
    Red Willow Research Inc. (2002, p. 108) expressed concern that the 
transport and transmission of diseases by domestic livestock to pygmy 
rabbits could be a threat. Red Willow Research Inc. (2002, p. 108) 
raised the concern that a calicivirus, such as Rabbit Hemorrhagic 
Disease (RHD), could explain declines in pygmy rabbit populations and 
suggests additional research is needed. The Committee for the High 
Desert et al. (2003, p. 150) indicated that West Nile Virus is a 
growing concern for native wildlife, including pygmy rabbits. We have 
no reports of disease epizootics (outbreaks) occurring in pygmy rabbits 
in the range considered in this finding. Janson (2002, p. 30) did not 
observe any obviously diseased pygmy rabbits in his earlier work in the 
1940's. Oliver (2004, p. 36) reported that in Utah, the effects of 
parasites and disease on pygmy rabbit populations are not known. 
Parasites and disease have not been regarded as a major threat to pygmy 
rabbits (Wilde 1978, p. 141; Green 1979, p. 25). The final rule for the 
Columbia Basin DPS pygmy rabbit indicated disease, including plague, 
was a significant potential threat to the remaining, small populations 
(68 FR 10405). A number of captive Columbia Basin pygmy rabbits have 
died of mycobacteriosis and

[[Page 60551]]

coccidiosis (WDFW 2005a; Harrenstien et al. 2006 cited in Service 2007, 
p. 21). It is unclear if these two diseases were introduced into the 
captive breeding population from wild caught individuals or by some 
other means. Mycobacteriosis and coccidiosis have not been reported in 
pygmy rabbits occurring in the rest of its range.
Summary of Disease Impacts
    Though pygmy rabbits can harbor high parasite loads, there is no 
evidence that this is negatively impacting pygmy rabbit populations. 
Through our review of the best scientific and commercial information we 
found no reports of disease epizootics occurring in pygmy rabbit 
populations anywhere within the range of the species. Therefore, based 
on our review of the best available information, we conclude that 
disease is not a significant threat to the pygmy rabbit now or in the 
foreseeable future.
Predation
    Predation of pygmy rabbits has been reported in Idaho, Nevada, and 
Utah. According to Green (1979, p. 25) predation is the main cause of 
pygmy rabbit mortality. The annual mortality rate of adult pygmy 
rabbits may be as high as 88 percent, and one researcher found that 
more than 50 percent of juveniles can die within about 5 weeks of their 
emergence (Wilde 1978, pp. 139-140). Estes-Zumpf and Rachlow (2009, p. 
367) found mortality rates were 69 percent and 88.5 percent for male 
and female juvenile pygmy rabbits, respectively, in their study area in 
east-central Idaho. The mortality rate was highest within two months of 
emerging from the natal burrow. However, mortality rates for adult and 
juveniles can vary considerably between years and for juveniles between 
cohorts within years (Wilde 1978, pp. 85-95, 138-140).
    While pygmy rabbits have numerous predators, they have adapted to 
their presence (Janson 1946, pp. 28-29; Gashwiler et al. 1960, p. 227; 
Green 1978, p. 37; Wilde 1978, pp. 141-143). Junipers provide perches 
for avian predators and may provide habitat for mammalian predators 
(Larrucea and Brussard 2008b, p. 1640). However, Larrucea and Brussard 
(2008b) do not provide actual losses of pygmy rabbits to predators 
utilizing pinyon-juniper habitat. If levels of predation are too high, 
local populations may be suppressed below a point at which they can be 
maintained. Sagebrush habitat with damaged structural components may 
increase the pygmy rabbit's vulnerability to predation. Weiss and Verts 
(1984, p. 569) thought that use of denser and taller sagebrush habitats 
by pygmy rabbits was related to predator avoidance. Katzner (1994, p. 
52) documented that raptors were a cause of mortality and denser 
sagebrush cover deterred these avian predators. In Idaho, Sanchez 
(2007, pp. 90-91) attributed 42 percent of natural mortalities to 
mammalian and avian predation; the cause of death in 58 percent of the 
mortalities could not be determined.
Summary of Predation Impacts
    Pygmy rabbits are a prey species and predation has been stated by 
some researchers as the main cause of mortality. Annual mortality rates 
for adult and juvenile pygmy rabbits can be high, but these rates can 
vary considerably between years and between juvenile cohorts within 
particular years. Predation is a natural part of population dynamics 
for any species and results in the death of individuals. Based on our 
review of the best available scientific information, we did not find 
any indication of predation being a significant threat to the pygmy 
rabbit in all or a significant portion of its range. The Service is not 
aware of any predators that potentially pose a significant threat to 
the species. We therefore conclude that the available information 
indicates that the pygmy rabbit is not threatened by predation now or 
in the foreseeable future.

Summary of Factor C

    Disease and predation may be significant threat factors to local or 
isolated pygmy rabbit populations; however, based on our review of the 
best available scientific information, we did not find any information 
to indicate significant threats from either disease or predation 
Habitat degradation and fragmentation may increase the effects of 
parasites, disease, and predation on some populations. We do not have 
any reports indicating that RHD or West Nile Virus is a significant 
threat to pygmy rabbits, nor are we are aware of reports of disease 
epizootics occurring in wild pygmy rabbits anywhere within the species' 
range. Therefore, we conclude that the best scientific and commercial 
information available indicates that the pygmy rabbit is not now, or in 
the foreseeable future, threatened by disease or predation to the 
extent that listing under the Act as an endangered or threatened 
species is warranted at this time.

Factor D: Inadequacy of Existing Regulatory Mechanisms

Local Laws and Regulations
    We are not aware of any county or city ordinances that provide 
protection specifically for pygmy rabbits or their habitat on private 
lands. We recognize that county or city ordinances that address 
agricultural lands, transportation, and zoning for various land uses 
have the potential to influence pygmy rabbits or their habitat (zoning 
that protects open space might retain suitable pygmy rabbit habitat; a 
housing development and associated roads might destroy or fragment 
habitat). We found no detailed information regarding the nature or 
extent of zoning efforts within the species' range and its direct or 
indirect effects on pygmy rabbit habitat or populations.
State Laws and Regulations
    Currently, hunting of pygmy rabbits is allowed in three of the 
seven States within the species' range (California, Nevada, and 
Montana). In California, for the 2009 to 2010 Upland Game Season, 
hunting of pygmy rabbits is allowed from July 1 to January 31 with a 
bag limit of 5 per day and 10 in possession (California Department of 
Fish and Game, 2010, http://www.dfg.ca.gov/regulations/09-10-upland-sum.html, accessed July 20, 2010). In Nevada, the 2009-2010 pygmy 
rabbit hunting season opened on October 10 and closed on February 28 
with a daily limit of 10 and a possession limit of 20 (Nevada 
Department of Wildlife, 2009, no page numbers). For Montana, the pygmy 
rabbit is considered a species of concern, nongame species and there is 
no protection from hunting. Pygmy rabbits can be hunted year-round with 
no bag limits (Montana Department of Fish Wildlife and Parks 2010, 
http://fwp.mt.gov/wildthings/livingWithWildlife/rabbits/rab_ctrl.html). Due to the manner of data collection, the numbers of pygmy 
rabbits harvested in these States each year is not known.
    Hunting of pygmy rabbits is not allowed in Idaho or Wyoming where 
they are considered a species of special concern, or in Utah where they 
are considered a sensitive species. Nor is hunting allowed in Oregon 
where the pygmy rabbit is considered a sensitive species and protected 
under State law.
    In Wyoming, many oil and gas development projects occurring on 
private lands fall under the jurisdiction of the Wyoming Industrial 
Siting Act (cited in Lance 2008, p. 6). This requires the Industrial 
Siting Administration to consult with Wyoming Game and Fish

[[Page 60552]]

Department to address impacts; and appropriate mitigation is required 
prior to issuance of permits (Lance 2008, pp. 5-6). As mentioned above, 
monitoring for restoration and mitigation activities are in the early 
stages. We do not know whether pygmy rabbits are benefiting from any 
mitigation that may have been required under reviewed projects, but 
restoration of sagebrush habitat is likely to positively impact pygmy 
rabbits.
Summary of State Laws and Regulations Impacts
    Hunting of pygmy rabbits is allowed in three of the seven States. 
In Wyoming, many oil and gas projects located on private lands will be 
reviewed by that state's wildlife agency with appropriate mitigation 
required that may benefit pygmy rabbits. The best available information 
indicates that the inadequacy of existing State laws do not threaten 
the pygmy rabbit.
Federal Laws and Regulations
    A large portion of the sagebrush community with the potential to 
support pygmy rabbits occurs on BLM lands. The Federal Land Policy and 
Management Act of 1976 (FLPMA) (43 U.S.C. 1701 et seq.) is the primary 
Federal law governing most land uses on BLM-administered lands. Section 
102 (a)(8) of FLPMA specifically recognizes that wildlife and fish 
resources are the uses for which these lands are to be managed.
    We acknowledge that data to evaluate the effectiveness of BLM's 
programs on pygmy rabbit conservation are not available. Whether the 
various BLM stipulations issued related to oil and gas activities 
specific to the greater sage-grouse (75 FR 13978) also reduce impacts 
from these activities to pygmy rabbits and their habitats is unknown. 
The BLM has management and permitting authorities to regulate and 
condition oil and gas lease permits under FLPMA and the Mineral Leasing 
Act (MLA) (30 U.S.C. 181 et seq.). BLM usually incorporates 
stipulations as a condition of issuing leases. The BLM's planning 
handbook has program-specific guidance for fluid materials (including 
oil and gas) that specifies that Resource Management Plan (RMP) 
decision-makers will consider restrictions on areas subject to leasing, 
including closures, and lease stipulations (BLM 2000, Appendix C, p. 
16). The handbook also specifies that all stipulations must have 
waiver, exception, or modification criteria documented in the plan, and 
indicates that the least restrictive constraint to meet the resource 
protection objective should be used (BLM 2000, Appendix C, p. 16).
    BLM's RMPs are the basis for all actions and authorizations 
involving BLM-administered land and resources. They establish allowable 
resource uses; resource condition, goals and objectives to be attained; 
program constraints and general management practices needed to attain 
the goals and objectives; general implementation sequences; and 
intervals and standards for monitoring and evaluating each plan to 
determine its effectiveness and the need for amendment or revision (43 
CFR 1601.0-5(k)).
    RMPs provide a framework and programmatic guidance for site-
specific activity plans. These plans address livestock grazing, oil and 
gas field development, travel management (managing vehicle routes and 
access), wildlife habitat management, and other activities. Activity 
plan decisions normally require National Environmental Policy Act 
(NEPA) (42 U.S.C. 4321 et seq.) analysis.
    BLM has designated the pygmy rabbit as a special status species/
bureau assessment species in five (Idaho, Montana, Nevada, Oregon, and 
Wyoming) of the seven States in which it occurs. BLM policy and 
guidance for species of concern occurring on BLM managed land is 
addressed under BLM's 6840 Manual, ``Special Status Species 
Management'' (BLM 2008c entirety). This manual provides agency policy 
and guidance for the conservation of special status plants and animals 
and the ecosystems on which they depend, but it is not a regulatory 
document. The objectives for BLM special status species are `` to 
conserve and/or recover ESA-listed species and the ecosystems on which 
they depend so that ESA protections are no longer needed for these 
species and to initiate proactive conservation measures that reduce or 
eliminate threats to Bureau sensitive species to minimize the 
likelihood of and need for listing of these species under the ESA.'' 
(BLM 2008c, p. 3).
    There has been an increased focus on the roles that state, county, 
and private entities have in controlling invasive plants. For example, 
the Noxious Weed Control and Eradication Act was passed in 2004 and 
incorporated into the Plant Protection Act. This Act is intended to 
assist eligible weed management entities to control or eradicate 
harmful nonnative weeds on both public and private lands. Additionally, 
Executive Order 13112 was signed on February 3, 1999, establishing an 
interagency National Invasive Species Council in charge of creating and 
implementing a National Invasive Species Management Plan. The 
Management Plan directs federal efforts, including overall strategy and 
objectives, to prevent, control, and minimize invasive species and 
their impacts (National Invasive Species Council 2008, p. 5). However, 
the Order also directs the Council to encourage planning and action at 
local, tribal, state, regional, and eco-system levels to achieve the 
goals of the National Invasive Species Management Plan, in cooperation 
with stakeholders (e.g., private landowners, states) and existing 
organizations addressing invasive species.
    Noxious and invasive weed treatments on BLM lands involving 
reseeding can occur through the Emergency Stabilization and Burned Area 
Rehabilitation Programs. Invasive species control is a stated priority 
in many RMPs. For example, 76 of the RMPs included in BLM's response to 
a data call claim that the RMP (or supplemental plans/guidance 
applicable to the RMP) require treatment of noxious weeds on all 
disturbed surfaces to avoid infestations of BLM-managed lands in the 
planning area (Carlson 2008a cited in 75 FR 13977). We also note that 
it is possible that more RMPs specifically address invasive species 
under another general restoration category (75 FR 13977).
    BLM commonly uses herbicides on lands to control invasive plant 
species. In 2007, the BLM completed a programmatic EIS (BLM 2007c) and 
Record of Decision for vegetation treatments on BLM-administered lands 
in the western United States. This program approves the use of four new 
herbicides, provides updated analysis of 18 currently used herbicides, 
and identifies herbicides that the BLM will no longer use on public 
lands. Information is unavailable on how frequently the programmatic 
EIS has been used for most states or whether actions implemented under 
this EIS have been effective; and while not authorizing any specific 
on-the-ground actions, it guides the use of herbicides for field-level 
planning. Site-specific NEPA analysis is still required at the project 
level (BLM 2007c, p. ES-1 to ES-2).
    Another voluntary approach to control invasive plant species is the 
development of Cooperative Weed Management Areas (CWMAs). CWMAs are 
partnerships between federal, state, and local agencies, tribes, 
individuals, and interested groups to manage both regulatory noxious 
weeds and invasive plants in a county or multi-county geographical 
area. They function under a mutually developed memorandum of 
understanding and a locally developed

[[Page 60553]]

strategic plan. The CWMAs can utilize federal funds for invasive plant 
control on non-federal land. As of 2005, Oregon, Nevada, and Utah had 
between 75 and 89 percent of their state covered by CWMAs and/or county 
weed districts, while Idaho, Montana, Wyoming, and California had 
between 90 and 100 percent coverage (Center for Invasive Plant 
Management 2008, www.weedcenter.org/weed_mgmt_areas/wma_overview.html).
    BLM regulatory authority for grazing management is provided at 43 
CFR part 4100 (Regulations on Grazing Administration Exclusive of 
Alaska). Livestock grazing permits and leases contain terms and 
conditions determined by BLM to be appropriate to achieve management 
and resource condition objectives on the public lands and other lands 
administered by the BLM, and to ensure that habitats are, or are making 
significant progress toward being restored or maintained for BLM 
special status species (43 CFR 4180.1(d)). Grazing practices and 
activities include the development of grazing related portions of 
implementation or activity plans, establishment of terms and conditions 
of permits, leases and other grazing authorizations, and range 
improvement activities such as vegetation manipulation, fence 
construction, and development of water for livestock.
    BLM grazing administration standards for a particular state or 
region must address habitat for endangered, threatened, proposed, 
candidate, or special status species, and habitat quality for native 
plant and animal populations and communities (43 CFR 4180.2 (d)(4) and 
(5). The guidelines must address restoring, maintaining or enhancing 
habitats of BLM special status species to promote their conservation, 
and maintaining or promoting the physical and biological conditions to 
sustain native populations and communities (43 CFR 4180.2(e)(9) and 
(10).
    Information regarding assessments of rangelands is not available. 
During 2004 through 2008, BLM conducted a national data call to collect 
information on the status of rangelands, rangeland health assessments, 
and measures that have been implemented to address rangeland health 
issues under their jurisdiction. The information collected was unusable 
to make broad generalizations about the status of rangelands or 
management actions because of inconsistency across the range regarding 
how questions were interpreted and answered. This limited the ability 
to use this information in understanding habitat conditions on BLM 
lands (75 FR 13976).
    Since 2005, the BLM has developed or is in the process of 
developing guidances to minimize impacts of renewable energy production 
on public lands. A Record of Decision for ``Implementation of a Wind 
Energy Development Program and Associated Land Use Plan Amendments'' 
was issued in 2005. The Record of Decision outlines the Best Management 
Practices for the siting, development, and operation of wind energy 
facilities on BLM lands. A final programmatic EIS and Record of 
Decision for geothermal development were issued in 2008. The BLM is in 
the process of developing programmatic-level guidance for the 
development of solar energy projects. The draft programmatic EIS for 
solar energy is under development -available at http://www.blm.gov/wo/st/en/prog/energy/epca_chart.html).
    Although we are uncertain which management direction the USFS is 
taking for the pygmy rabbit or whether pygmy rabbit habitat objectives 
and conservation measures have been incorporated into grazing allotment 
plans or Land and Resource Management Plan (LRMPs), the pygmy rabbit is 
designated as a USFS Sensitive Species in the Intermountain Region (R4) 
(USFS 2008b, p. 1). This includes southern Idaho, western Wyoming, 
Utah, and Nevada; the Northern Region (R1) which includes Montana (USFS 
2005, p. 2); and the Pacific Northwest Region (R6) which includes 
Oregon (USFS 2008c, p. 2). Sensitive species receive special management 
to ensure viability and to preclude trends that may lead to the need 
for Federal listing. There must be no impacts to sensitive species 
without an analysis of the significance of adverse impacts on 
populations, habitat and on the viability of the species as a whole 
(USFS Manual 2672.1, cited in USFS 2008b, p. 1).
    Management of Federal activities on National Forest System lands is 
guided principally by the National Forest Management Act (NFMA) 16 
U.S.C. 1600-1614, August 17, 1974, as amended. NFMA specifies that all 
national forests and grasslands must have a LRMP (16 U.S.C. 1604(a)) to 
guide and set standards for natural resource management activities. 
NFMA also requires the USFS to incorporate standards and guidelines 
into LRMPs (16 U.S.C. 1604(c)). This has historically been done through 
a NEPA process. In order to meet overall multiple-use objectives, 
provisions are developed to manage plant and animal communities for 
diversity, based on the suitability and capability of a specific land 
area.
    The 1982 NFMA implementing regulations for land and resource 
management planning under which all existing forest plans were 
prepared, requires the USFS to manage habitat in order to maintain 
viable populations of existing native vertebrate species on National 
Forest System lands (47 FR 43037, September 30, 1982). A new USFS 
planning regulation was published on April 21, 2008 (73 FR 21,468) 
which superseded the 1982 rule. Plans developed under the new 
regulations would be more strategic and less prescriptive in nature 
than those developed under the 1982 planning rule. However, on June 30, 
2009, the U.S. District Court for the Northern District of California 
vacated the new rule, and as a result, the rule is not currently in use 
by the USFS.
    Through the NFMA, LRMPs, and the On-Shore Oil and Gas Leasing 
Reform Act (1987; implementing regulations at 36 CFR 228, subpart E), 
the USFS has the authority to manage, restrict, or include protective 
measures to mineral and other energy permits on their lands. Similar to 
BLM, existing protective standard stipulations on USFS lands occur for 
greater sage-grouse (75 FR 13980). The USFS is a partner agency with 
the BLM on the draft programmatic EIS for geothermal energy development 
mentioned above. If finalized, the programmatic EIS will amend relevant 
LRMPs and will expedite the leasing of USFS lands with geothermal 
energy potential.
    Pygmy rabbit habitat also occurs on lands managed by other Federal 
agencies such as the Service and National Park Service (NPS). The 
National Wildlife Refuge System Administration Act (16 U.S.C. 668dd-
668ee) provides guidelines and directives for administration and 
management of all areas in the National Wildlife Refuge system. Refuges 
are managed for species conservation, consistent with direction in the 
National Wildlife Refuge System Administration Act, as amended, and 
related Service policies and guidance. The National Park Service 
Organic Act (16 U.S.C. Sec. 1, et seq.) states that the NPS will 
administer areas under their jurisdiction ``*** by such means and 
measures as conform to the fundamental purpose of said parks, 
monuments, and reservations, which purpose is to conserve the scenery 
and the natural and historical objects and the wildlife within and to 
provide for the enjoyment of the same in such manner and by such means 
as will leave them unimpaired for the enjoyment of future 
generations.''

[[Page 60554]]

Summary of Federal Laws and Regulations Impacts
    A large portion of pygmy rabbit habitat occurs on lands 
administered by Federal agencies, including BLM, USFS, Service, and 
NPS. Numerous policies, guidance, and laws have been developed to 
assist the different agencies in management of these lands. The Bureau 
of Land Management policies and guidance address species of concern, 
actions covered by RMPs, and regulatory authority for grazing and oil 
and gas leasing and operating. The USFS policies and guidance address 
sensitive species and actions covered by LRMPs. The Service uses 
guidelines and directives under the National Wildlife Refuge System 
Administration Act for management of lands in the National Wildlife 
Refuge system. The National Park Service Organic Act provides 
management guidance to the NPS for management of lands administered by 
this agency.
    As discussed under Factors A and E, the best available information 
indicates that activities such as livestock grazing, mining, energy 
exploration and development, and recreational activities that are 
regulated by various policies, guidance, and laws on Federal lands are 
not significantly impacting pygmy rabbits. Therefore, we conclude that 
available information indicates that the existence of inadequate 
Federal laws and regulations are not a significant threat to the pygmy 
rabbit.

Summary of Factor D

    Our assessment of threats based on the best available scientific 
and commercial data regarding the past, present and future loss or 
modification of pygmy rabbit habitat as discussed in Factor A, hunting 
activities as discussed in Factor B, and intra and inter-specific 
competition or recreational and non recreational vehicle use as 
discussed under Factor E lead us to conclude that the inadequacy of 
existing regulatory mechanisms is not a threat to the pygmy rabbit. 
Therefore, the best available scientific and commercial information 
indicates that the pygmy rabbit is not now, or in the foreseeable 
future, threatened by the inadequacy of existing regulatory mechanisms 
to the extent that listing under the Act as an endangered or threatened 
species is warranted at this time.

Factor E: Other Natural or Manmade Factors Affecting the Species 
Continued Existence

    Several other potential threats have been mentioned as possibly 
negatively impacting pygmy rabbit populations including: (1) intra- and 
inter-specific competition; (2) small or isolated populations; (3) 
natural stochastic (random) events such as floods and drought; (4) 
climate change; (5) recreational activities; (6) mortality caused by 
collisions with vehicles; and (7) life history traits of a habitat 
specialist.
Intra- and Inter-specific Competition
    While intra-specific competition likely occurs both under normal 
and stressful environmental conditions, we are not aware of any 
scientific information documenting or suggesting that such competition 
for food and space is negatively impacting pygmy rabbits at this time.
    As pygmy rabbits are habitat specialists, inter-specific 
competition with other herbivores for sagebrush such as jackrabbits, 
pronghorn, and mule deer could occur. Numerous researchers have 
mentioned other leporid species, namely black-tailed and white-tailed 
(Lepus townsendii) jackrabbits, and mountain cottontails (Silvilagus 
nuttallii) as occurring in the same areas with pygmy rabbits throughout 
their range.
    In Oregon, Anthony (1913, p. 23) mentioned that cottontails and 
black-tailed jackrabbits were observed in the same areas with pygmy 
rabbits. Bartels (2003, p. 93) also mentioned these two species were 
observed in areas used by pygmy rabbits.
    In Idaho, Merriam (1891, p, 13) mentioned white- and black-tailed 
jack rabbits and mountain cottontails in Pahsimeroi Valley where the 
pygmy rabbit also occurred. Roberts (2004, p. 4) mentioned that at one 
site in the Birch Creek area he flushed pygmy rabbits along with 
cottontails. Waterbury (2006, p. 10) found other rabbit and hare 
species (black-tailed and white-tailed jackrabbits, mountain 
cottontails) in association with pygmy rabbits in several locations, 
including Pahsimeroi and Big Lost River Valleys.
    In Montana, Rauscher (1997 p. 11) mentioned mountain cottontails 
and jack rabbits were observed at most pygmy rabbit sites. It was 
unclear if cottontails and pygmy rabbits were sharing burrows, if 
cottontails were replacing pygmy rabbits at burrows, or if cottontails 
were taking advantage of burrow availability.
    In California and Nevada, Larrucea and Brussard (2008a, p. 697) 
found cottontail rabbits may compete with pygmy rabbits and influence 
the relationship between understory growth and pygmy rabbit presence. 
Cottontails appear to occur more in areas with greater understory 
(Larrucea and Brussard 2008a, p. 697). Though pygmy rabbits consume 
primarily sagebrush, they will also eat forbs and grasses (Green and 
Flinders 1980b, p. 138).
    In California, Severaid (1950, p. 4) commented that white- and 
black-tailed jackrabbits and cottontails occupied the same habitats as 
pygmy rabbits. In northern Utah, Janson (1946, p. 40) also mentioned 
that these three species were occupying the same areas as pygmy 
rabbits.
    Grinnell et al. (1930, pp. 557-558) also noted the overlap of pygmy 
rabbit's range with other leporids, namely mountain cottontail and 
black-tailed jackrabbit ranges. The other species occurred within or 
near the same territories as pygmy rabbits throughout all of their 
ranges, but mountain cottontails and black-tailed jackrabbits ranged 
over a much larger area than the pygmy rabbit. They suggested that the 
differentiation of each is mainly due to conditions outside of the 
range of the pygmy rabbit and these conditions may limit the territory 
of the pygmy rabbit.
    Conde (1982, p. 4) compared pygmy rabbit and black-tailed 
jackrabbit use in sagebrush-greasewood habitat in Cassia County, Idaho. 
She found in summer that pygmy rabbits selected areas with abundant 
grass while jackrabbits selected areas with abundant forbs. During the 
fall-winter period shrubs played an important role for both species, 
but pygmy rabbits fed on sagebrush leaves and young stems (Johnson 
1979, cited in Conde 1982, p. 19) and jackrabbits on 2-year old woody 
stems (Currie and Goodwin 1966, cited in Conde 1982, p. 19). Spatial 
distribution and exploitation of different vegetation in the summer 
allowed a sympatric relationship to occur between these two species 
(Conde 1982, p. 3).
    Grazing competition with livestock will depend on the range 
conditions and grazing practices that vary across the range of the 
pygmy rabbit. While researchers have documented pygmy rabbit in 
livestock use areas and the potential impacts to pygmy rabbits under 
Factor A, we are unaware of studies documenting aspects of potential 
forage competition between the two species within the range of the 
pygmy rabbit. We are aware of one study conducted at Sagebrush Flat, 
Washington, by Siegel Thines et al. (2004, p. 532) that found Columbia 
Basin pygmy rabbits selected ungrazed areas over grazed areas when 
constructing burrows. Livestock grazing during late summer and fall 
reduced the availability of grass (and likely forbs) by about 50 
percent in the grazed units until the following growing season. Grasses 
provided greater than 50

[[Page 60555]]

percent and forbs greater than 30 percent of the pygmy rabbit's diet in 
winter at Sagebrush Flat. They did not find that Columbia Basin pygmy 
rabbits ate less grass in grazed areas or that they chose different 
diets relative to the availability between ungrazed and grazed areas 
before the yearly grazing. However, after yearly grazing the Columbia 
Basin pygmy rabbits may have had a harder time finding grasses and 
forbs in the grazed areas. Grazing reduced the nutritional quality of 
grasses in winter and spring. On grazed areas, grasses had less protein 
and more fiber than ungrazed areas. Shrubs were more fibrous in grazed 
areas than ungrazed areas in winter. However, grasses may not have been 
providing a more nutritious food source for Columbia Basin pygmy 
rabbits in winter as they provided about 50 percent less of the crude 
protein and 50 percent more fiber than sagebrush or rabbit brush. It is 
unclear why the Columbia Basin pygmy rabbits avoided grazed areas and 
may not be due to diet-related reasons not measured in the study. Other 
impacts of cattle grazing in pygmy rabbit habitat have been previously 
discussed under Factor A.
    In Montana, there is spatial overlap between big game (elk Cervus 
elaphus, mule deer Odocoileus hemionus, antelope Antilocapra americana) 
winter range, jack rabbits and greater sage-grouse, and the range of 
pygmy rabbits. Hence, inter specific competition with pygmy rabbits may 
result (Janson 2002, pp. 16-17).
Summary of Intra- and Inter-specific Competition Impacts
    Most authors only mention observing these other rabbit and hare 
species while they were studying or searching for pygmy rabbits in 
Oregon, Idaho, Montana, California, Nevada, and Utah; few authors 
suggest that there is possible competition between or among the species 
that negatively impacts pygmy rabbits. One study demonstrates a 
sympatric relationship between pygmy rabbits and black-tailed 
jackrabbits in Idaho. It has been suggested in Montana that competition 
may occur between big game species and pygmy rabbits where they 
coexist. While livestock grazing occurs throughout the range of the 
pygmy rabbit, its impact on the species remains unclear as discussed 
under Factor A. Any possible negative impacts to pygmy rabbits may be 
related more to loss or degradation of sagebrush structure as opposed 
to loss or reduction of the grass or forbs understory. The best 
scientific and commercial information available does not provide any 
documentation that pygmy rabbits are adversely affected by intra-
specific competition for food or space across their range. We know from 
numerous reports that there appears to be a long history of pygmy 
rabbits co-existing across their range, with other species, especially 
other rabbit and hare species. The available information does not 
document adverse effects of inter-specific competition on pygmy rabbits 
from other species of rabbits or hares or other species. Therefore, 
based on the best available scientific and commercial information, we 
conclude that the intra- or inter-specific competition is a not a 
significant threat to the pygmy rabbit now or in the foreseeable 
future.
Small or Isolated Populations
    Small, restricted populations are more vulnerable to risks and more 
susceptible to extinction from naturally occurring stochastic 
environmental causes than populations with large numbers occurring over 
a large area (Shaffer 1981, pp. 131-132). Small, isolated populations 
are also at a greater risk to the deleterious effects of demographic 
and genetic problems (Schaffer 1981, p. 133). Random demographic 
effects (e.g., skewed sex ratios) and loss of genetic variability may 
result in individuals and populations being less able to cope with 
environmental change.
    As discussed in the Background Section, accurately estimating pygmy 
rabbit population size is complex because the number of active burrows 
may not be directly related to the number of individuals in a given 
area. Some individual pygmy rabbits appear to maintain multiple burrows 
and conversely some individual burrows are used by multiple individuals 
(Janson 1940, p. 21; Janson 1946, p. 44; Gahr 1993, pp. 66, 68; Heady 
1998, p. 25). Pygmy rabbits may also use more than one burrow or burrow 
system at a specific time or during different times of the year 
(Purcell 2006, p. 96).
    It is possible that pygmy rabbits have a metapopulation structure 
and therefore, populations located across the range are not small or 
isolated because they are able to interact with neighboring populations 
if distance is not too great. Recent studies as mentioned in the 
Background section above, indicate that pygmy rabbit home ranges and 
dispersal capabilities are greater than previously thought. Genetic 
research has occurred in some areas of the species' range, and we have 
information documenting little population substructure in areas 
supporting pygmy rabbit in Idaho indicating these populations are not 
isolated (Estes-Zumpf et al. 2010, p. 215).
Summary of Small or Isolated Populations
    The impacts of various potential threats can be more pronounced on 
small or isolated populations. However, the best available scientific 
and commercial information does not indicate that pygmy rabbit 
populations are isolated or occurring in small populations across the 
range, or that these are significant threats now or in the foreseeable 
future.
Stochastic Events
    Natural stochastic events can significantly impact populations if 
they result in high mortality, habitat loss, or offer little or no 
possibility of recolonization. They are most significant for small or 
fragmented populations (Gilpin and Soule 1986, p. 25). Flooding which 
may cause burrow abandonment, mortality, and erosion of deep soils has 
been mentioned as a concern for pygmy rabbits. Pygmy rabbits are known 
to use deeper soils found along drainages for their burrows (Flath and 
Rauscher 1995, p. 2). Bartels (2003, p. 103) mentions a large flood 
event in pygmy rabbit habitat in the Harney Basin, Oregon, in 1984, 
though it is not reported if animals were actually killed. Drought can 
reduce vegetative cover, potentially resulting in increased soil 
erosion and subsequent reduced soil depths, decreased water 
infiltration, and reduced water storage capacity (Connelly et al. 2004, 
p. 7-19), Pygmy rabbit populations could be impacted directly by loss 
of habitat (food and shelter) or indirectly through possible increased 
predation. Drought has not been reported as having a direct negative 
effect on pygmy rabbits.
Summary of Stochastic Events Impacts
    While natural stochastic events most certainly have occurred within 
the range of the pygmy rabbit and may have impacted specific 
populations, such as in Oregon during a flood, they have not been 
documented as types of events that have played a significant role in 
population distribution, abundance, and/or trends for the pygmy rabbit 
within its range. The best available scientific and commercial 
information does not indicate that stochastic events are a significant 
threat to the pygmy rabbit now or in the foreseeable future.
Climate Change
    The Service acknowledges that environmental changes resulting from 
climate change could facilitate invasion and establishment of invasive 
species or exacerbate the fire regime, possibly accelerating the loss 
of sagebrush habitats (Connelly et al. 2004, p. 7-18).

[[Page 60556]]

 Increases in the expansion of pinyon and juniper woodlands in the 
Great Basin may have resulted from poor habitat management and climate 
change (Connelly et al. 2004, p. 7-7). However, the encroachment of 
pinyon-juniper into occupied pygmy rabbit habitat is a slow process, 
and pygmy rabbits may be able to inhabit those areas or shift their 
home range to adjacent areas if pinyon-junipers habitat becomes 
established at a site.
    One researcher has addressed potential impacts to pygmy rabbits due 
to climate change. In California and Nevada, Larrucea and Brussard 
(2008b, p. 1640) found extant historical pygmy rabbit sites averaged 
515 ft (157 m) higher than extirpated sites. With local downward shift 
effect accounted for, overall upward elevation shift of extant sites 
was 721.8 ft (220 m); the researchers attributed this to climate. Over 
the last century, a 0.7 degree Celsius temperature increase has 
occurred, which correlates with a predicted elevational shift upwards 
of 383.9 ft (117 m) (Peters 1989, cited in Larrucea and Brussard 2008b, 
p. 1640). Warmer temperatures are also expected to increase fire 
intensity and frequencies (Westerling et al. 2006, cited in Larrucea 
2007, pp. 63-64). Warming temperatures may continue to shift upward the 
lower elevational boundary of habitable pygmy rabbit sites.
    The prehistoric record for pygmy rabbits in the Great Basin 
indicates a wider distribution than today and declines have occurred 
since the end of the Pleistocene (Kurten and Anderson 1972, p. 21; 
Findley et al., 1975, Gillespie 1984, Harris 1985, 1993a cited in 
Grayson 2006 pp. 2969-2970). The beginning of the middle Holocene in 
the Great Basin also saw a decline in pygmy rabbit abundance (Grayson 
2006, pp. 2971-2972). The decline is attributed to this period 
experiencing elevated temperatures and decreased precipitation in the 
Great Basin (Grayson 2006, p. 2972). A third decline in pygmy rabbit 
abundance in the Great Basin is associated with the development of 
pinyon-juniper woodland within the region (Grayson 2006, pp. 2973-
2974). Establishment of pinyon-juniper in this area and its associated 
decline in pygmy rabbit numbers is best explained by the loss of 
sagebrush-grass habitat (Grayson 2006, p. 2974). Pygmy rabbits occur in 
the prehistoric record in New Mexico (Grayson 2006, p. 2970), but they 
are not currently known to occur in the State, though sagebrush habitat 
does exist there. The habitat may have changed to such an extent since 
prehistoric times that it no longer provides appropriate habitat for 
pygmy rabbits. Butler (1972, p. 52) stated that the population of pygmy 
rabbits on the Eastern Snake River Plain was greater prior to 7,000 
years ago. The decline in abundance of pygmy rabbits and pocket gophers 
(common in grassy meadows) at the beginning of the 7\th\ millennium 
B.P. and accompanied by a proportional increase in the pygmy rabbit may 
indicate a change in climate that had more impact on grasses and forbs 
than on sagebrush (Butler 1972, p. 52).
    A warming trend in the mountains of western North America is 
expected to decrease snow pack, accelerate spring runoff, and reduce 
summer flows (Intergovernmental Panel on Climate Change (IPCC) 2007, p. 
11). Increased summer temperatures may increase the frequency and 
intensity of wildfires (IPCC 2007, p. 13). Recent warming is linked, in 
terrestrial ecosystems, to pole-ward and upward shifts in plant and 
animal ranges (IPCC 2007, p. 2). Climate projections predict the Great 
Basin region is likely to become warmer and drier (Peters and Lovejoy 
1992, cited in Larrucea 2007, p. 63).
    It is difficult to predict local climate change impacts due to 
substantial uncertainty in trends of hydrological variables, 
limitations in spatial and temporal coverage of monitoring networks, 
and differences in the spatial scales of global climate models and 
hydrological models (Bates et al. 2008, p. 3). Climate change models 
that are currently available are not yet capable of making meaningful 
predictions of climate change for specific, local areas (Parmesan and 
Matthews 2005, p. 354). Thus, while the best available information 
indicates that climate change has the potential to affect habitats used 
by pygmy rabbits in the Great Basin in the long-term, there is much 
uncertainty regarding which habitat attributes (including sagebrush, 
grass, and forbs communities) could be affected, and the timing, 
magnitude, and rate of their change as it relates to pygmy rabbits and 
their needs.
Summary of Climatic Change Impacts
    Extant historical populations may indicate an upward shift in 
elevation due to climatic changes or this shift may be due to other 
unknown factors. The prehistoric record shows the range of the pygmy 
rabbit occurred over a larger area than today, and the range 
contraction has been attributed, in part, to increased temperatures and 
decreased precipitation. It is reasonable to assume that pygmy rabbits 
of today may be likewise affected in the Great Basin due to possible 
warmer and drier conditions. Climate change could also facilitate the 
establishment of invasive plant species or exacerbate the fire regime. 
Pinyon and juniper woodland expansion may increase, however this may be 
a slow process and may result in less sagebrush habitat being available 
for the pygmy rabbit in the future. However, while there is some 
evidence to suggest there may be an upward shift in elevation or 
contracted range due to climatic changes, we have no information to 
suggest that climate change will significantly affect the pygmy rabbit. 
Based on our review of the available information, there is no 
demonstrated direct link between predicted climate change and reduced 
abundance and survival of pygmy rabbits. The best scientific and 
commercial information currently available does not indicate that 
climate change is a significant threat to the species now or in the 
foreseeable future.
Recreational Activities
    Recreational activities, especially off-highway vehicle/off-road 
vehicle (OHV/ORV) and snowmobile use, have the potential to be a threat 
to pygmy rabbits and their sagebrush habitat by disturbing individuals 
through excessive noise, damaging sagebrush, or damaging burrows or 
subnivian tunnels. Additionally, recreation could increase the spread 
of weeds, and human presence and pets in a particular area. Much of the 
sagebrush habitat across the range of the pygmy rabbit is open to 
recreational use. Based on our review of the best available 
information, we found one document that indicates pygmy rabbits occupy 
an area used by OHV/ORV users in Oregon (BLM 2008d, p. 6). In addition, 
in Idaho, Bradfield (1974, pp. 35-36) suggested that the pygmy rabbit 
depends on its hearing for predator detection and may be less active 
during windy periods when predator detection may be reduced. This study 
may suggest noise from a passing vehicle could make pygmy rabbits more 
vulnerable to predation.
Summary of Recreational Activities Impacts
    Recreational activities occur in sagebrush habitat within the range 
of the pygmy rabbit, however, our review of the best scientific and 
commercial information available identified only one instance of 
recreational activities or areas where these activities may be directly 
or indirectly impacting pygmy rabbits. This area continued to support a 
number of active pygmy rabbit burrows. Therefore, we conclude that the 
best scientific and commercial information available does not indicate 
that recreational activities are a

[[Page 60557]]

significant threat to the pygmy rabbit now or in the foreseeable 
future.
Vehicle Collisions
    Roads are known to exist throughout the range of the pygmy rabbit. 
Jones (1957, p. 274) mentions a pygmy rabbit winter road kill in 
California north of Crowley Lake, Mono County, and in Wyoming a study 
mentions a previously reported road kill near Pinedale (Purcell 2006, 
p. 8). Bradfield (1974, p. 3) suggested that pygmy rabbits were 
reluctant to cross open areas based on the lack of observed highway 
mortality (Gordon 1932, Sperry 1933, Smith 1943, cited in Bradfield 
1974, p. 3). We are not aware of any documentation of pygmy rabbit 
mortalities due to snowmobiles or OHVs and ORVs. Additionally, there is 
no indication that vehicle mortalities have increased, or will increase 
in the future, as the density of roads have increased across the range 
of the species.
Summary of Vehicle Collisions Impacts
    While we are aware of reports of road mortalities in Wyoming and 
California related to pygmy rabbits, they are few in number with low 
mortalities documented. We conclude that populations are able to 
recover from these types of limited, individual losses. Based on our 
review of the best available information, we conclude that mortality 
due to vehicular collisions is not a significant threat to the pygmy 
rabbit now or in the foreseeable future.
Habitat Specialist
    Because the pygmy rabbit is a habitat specialist and its habitat is 
fragmented across the landscape, the species' life history traits could 
affect population viability. Pygmy rabbits appear to have small home 
ranges, are not evenly distributed across the species' range, and may 
have poor dispersal capabilities (though recent information indicates 
home ranges and dispersal capabilities are greater than originally 
thought) influencing genetic diversity or its ability to move to a more 
favorable location if necessary in reaction to natural or manmade 
factors. Pygmy rabbits do not respond to abundant spring food supply by 
producing additional litters like other rabbits and therefore, may have 
lower reproductive capabilities (Wilde 1978, p. 145). These life 
history traits could contribute to population declines as habitat size 
and quality are reduced, however, they should not be a limiting factor 
to pygmy rabbits across large geographic areas when suitable habitat is 
extensive and in good condition.
Summary of Habitat Specialist Impacts
    The pygmy rabbit is a habitat specialist. Life history traits such 
as small home ranges, uneven distribution across its range, poor 
dispersal capabilities and lower reproductive potential compared to 
other leporid species might suggest a concern for the long-term 
survival of the pygmy rabbit. However, recent studies as mentioned in 
the Background section above indicate that pygmy rabbit home ranges and 
dispersal capabilities are greater than previously thought. Genetic 
research (Estes-Zumpf et al. 2010, p. 214) has occurred in some areas 
of the species' range, and available information indicates the pygmy 
rabbit exhibits relatively high genetic diversity. The best available 
scientific and commercial information does not indicate that the pygmy 
rabbit is negatively impacted by current habitat fragmentation. The 
information available indicates pygmy rabbit populations continue to 
occur over a wide distribution of their current range.
    The pygmy rabbit survives almost exclusively on sagebrush for food 
(especially in winter) and shelter. Sagebrush are long-lived, stable 
species, resistant to most environmental impacts, except fire and some 
insects, and thus do not fluctuate widely in availability. The best 
available information does not indicate how the lack of producing 
additional litters specifically during times of abundant plant growth 
is detrimental to the species. However, as indicated in the background 
section, female pygmy rabbits are capable of producing an average of 
six young per litter with three litters possible in a year. The best 
available information shows that the pygmy rabbit's natural life 
history characteristics have not limited the species across its range. 
Therefore, we conclude that being a habitat specialist is not a 
significant threat to the pygmy rabbit now or in the foreseeable 
future.
Other Potential Threats
    In our 90-day petition finding, we identified other natural or 
manmade factors (facilities associated with grazing (tanks, pipelines, 
roads) may allow predators, OHV/ORV users, and hunters to access new 
terrain; activities on military facilities; and predator control to 
benefit livestock increases predation on pygmy rabbits) that might pose 
a threat to pygmy rabbits. However, for this analysis, we could find no 
supporting information to indicate that any of these factors are 
threatening pygmy rabbit populations.

Summary of Factor E

    We have assessed the best available scientific and commercial data 
on the magnitude and extent of the potential threats of intra- and 
inter-specific relationships, small or isolated populations, stochastic 
events, climate change, recreational activities, vehicle collisions, 
and habitat specialist life history requirements of the pygmy rabbit. 
As discussed above, intra- and inter-specific relationships between and 
among pygmy rabbits and other species are natural and occur but do not 
constitute a significant threat to the species. The best available 
scientific and commercial information does not document that natural or 
anthropogenic pressures are negatively affecting these relationships. 
The best available information indicates that pygmy rabbit populations 
are not small or occurring in isolation across the range. While 
stochastic events have occurred and will continue to occur throughout 
the range of the species, there is no indication that these events are 
a significant threat to the pygmy rabbit largely due to the patchy 
distribution of the species and its preferred habitat. Vehicle 
collisions, while a potential threat, have been rarely reported, and we 
do not consider them to be a significant source of mortality. Projected 
climate change impacts across the range of the pygmy rabbit are 
generalized and are not considered to be a significant threat. The 
potential impact of pinyon-juniper woodland expansion into pygmy rabbit 
habitat is predicted to be slow with pygmy rabbits demonstrating a 
variety of responses. Recreational activities occur within the range of 
the pygmy rabbit, but no information is available to qualify or 
quantify the effect on populations, and we do not considered these 
activities to be a significant threat. There is no indication from the 
available information that the pygmy rabbit has been limited across its 
range based on its natural life history characteristics. There are many 
natural and manmade factors or activities that have occurred and will 
continue to occur within pygmy rabbit habitats within its range. As 
discussed in the distribution and trend section, the available 
information indicates pygmy rabbit populations continue to occur over a 
wide distribution of their current range, including historical 
locations, despite these various factors. Based on the best available 
scientific and commercial information, the pygmy rabbit is not now, or 
in the foreseeable future, threatened by other natural or manmade 
factors affecting the species to the extent that listing as endangered 
or

[[Page 60558]]

threatened under the Act is warranted at this time.

Finding

    As required by the Act, we considered the five factors in assessing 
whether the pygmy rabbit is endangered or threatened throughout all or 
a significant portion of its range. We carefully examined the best 
scientific and commercial information available regarding the past, 
present, and future threats faced by the pygmy rabbit. We reviewed the 
petition, information available in our files, other available published 
and unpublished information, and we consulted with recognized pygmy 
rabbit experts and other Federal, State, and tribal agencies.
    We have identified and evaluated the potential threats as discussed 
under Factor A (agriculture, sagebrush treatment, livestock grazing, 
nonnative invasive plants, fire, urban and rural development, mining, 
energy exploration and development, habitat fragmentation, and greater 
sage-grouse conservation actions), and we acknowledge that most of 
these threats have occurred within the range of the pygmy rabbit and 
may have impacted some areas known to be, or to have been, occupied by 
pygmy rabbits based on site-specific information. Some or all of these 
activities are likely to continue at some level in the future. 
Available information does not indicate that the sagebrush lost or 
degraded due to agriculture, sagebrush treatment, urban and rural 
development, mining, habitat fragmentation, greater sage-grouse 
conservation actions, or other conservation actions has impacted large 
areas of suitable or occupied pygmy rabbit habitat resulting in 
significant occupied habitat or population losses. The impacts 
attributed to livestock grazing, while widespread across the pygmy 
rabbit's range, have not resulted in documented measurable declines in 
pygmy rabbit numbers or populations. Based on the information 
available, we find that the potential threat of increasing energy 
exploration and development as well as the relationship between 
invasive nonnative plant species and fire regimes are not significant 
threats to the pygmy rabbit now or in the foreseeable future. There is 
no available information that indicates the magnitude or extent of 
pygmy rabbit sites that may have been lost or reduced in area or in 
population size due to these activities. Some of these events or 
actions that can result in the complete loss of sagebrush over large 
areas (i.e., sagebrush conversion to agriculture, sagebrush treatments, 
fire) likely resulted in the reduction of occupied habitat and loss of 
some pygmy rabbit populations. However, there is no evidence that this 
will significantly threaten the species in the foreseeable future. 
Therefore, based on our review of the best available scientific 
information, we find these potential threats, either singly or in 
combination with one another, are not significant threats now or in the 
foreseeable future, to pygmy rabbit habitat across its range.
    We have identified and evaluated the risks from overutilization for 
commercial, recreational, scientific or educational purposes. Available 
information indicates that historical or recent hunting pressure has 
not played an important role in population dynamics for the pygmy 
rabbit across its range. Three of the seven States discussed in this 
finding currently allow hunting of pygmy rabbits; this is a reduction 
from the past. Based on the best available information we find that 
hunting was not and is not a significant threat to pygmy rabbit 
populations across its range nor will it be in the foreseeable future.
    Research activities may result in adverse impacts to a species 
(e.g., injury, death, stress, or general habitat disturbance). Negative 
impacts to pygmy rabbits that have been caused by research activities 
have been few in number, occurred in limited areas, and occurred over 
short periods of time. We encourage research activities to continue in 
the future to increase our understanding of this species. With planning 
and care, adverse impacts of research activities can be minimized. 
Based on the best available information we find that research 
activities are not a significant threat now or in the foreseeable 
future, to the pygmy rabbit across its range.
    Disease epizootics in pygmy rabbits have not been reported within 
its range considered in this finding. Research is needed to determine 
if disease could be a threat in the future. Predation has been reported 
as the main cause of mortality in pygmy rabbits. Numerous species have 
been identified as predators of pygmy rabbits. Based on the best 
available information, we find that neither disease nor predation are 
significant threats now or in the foreseeable future, to the pygmy 
rabbit across its range.
    Based on our analysis of the existing regulatory mechanisms, we 
determined that States are managing pygmy rabbit hunting in three 
States while four others protect them hunting as species of concern or 
sensitive species. In Wyoming, many oil and gas projects will be 
reviewed and mitigation provided that may benefit pygmy rabbits.
    A large portion of pygmy rabbit habitat occurs on lands 
administered by Federal agencies and numerous policies, guidance, and 
laws have been developed to assist in managing these lands. We 
determined in the evaluation that other threats would not significantly 
affect the pygmy rabbit now or in the foreseeable future. Thus, we find 
the inadequacy of existing regulatory mechanisms is not a significant 
threat to the pygmy rabbit across its range now or in the foreseeable 
future.
    Other natural or manmade factors have occurred within the range of 
the pygmy rabbit, and these habitat impacts or actions will likely 
continue at some level in the future. As indicated above, intra- and 
inter-specific relationships between pygmy rabbits and among pygmy 
rabbits and other species are natural and occur across the range, but 
there is no indication that these relationships are negatively 
impacting the pygmy rabbit. Though impacts to pygmy rabbits have 
occurred related to stochastic events and vehicle collisions, they have 
been rarely reported. The best available information indicates that 
pygmy rabbit populations are not small or isolated across the range. 
Potential impacts due to climate change are general, and there is no 
demonstrated connection between climate change and reduced abundance or 
survival of pygmy rabbits. Recreational activities occur throughout the 
range of the pygmy rabbit, but there is no indication these activities 
are significantly impacting pygmy rabbit populations. The best 
available information indicates that the pygmy rabbit, as a habitat 
specialist, has not been limited across its range.
    During our status review for this species, it has become evident 
that many of the threat issues raised have been speculative and direct 
impacts to historical and extant pygmy rabbit populations have not been 
documented. Threats exist but do not appear to be significant across 
the range of the species. While the sagebrush ecosystem has been and 
will continue to be impacted by various natural and manmade events and 
activities in parts of the pygmy rabbit's range, we have determined, 
based on the species' current range and distribution, that pygmy rabbit 
populations continue to persist in much of its range, despite the 
numerous activities occurring within their habitat. Pygmy rabbits are 
represented across their current range which is not dissimilar from 
what is known of their historical distribution as

[[Page 60559]]

discussed in the Distribution and Trend section. Our understanding of 
the pygmy rabbit's range has improved, and the current known range has 
been extended in Montana, Nevada, and most notably Wyoming based on 
recent survey efforts.
    Based on our review of the best available scientific and commercial 
information, we find that the threats are not of sufficient imminence, 
intensity, or magnitude to indicate that the pygmy rabbit is in danger 
of extinction (endangered), or likely to become endangered within the 
foreseeable future (threatened) throughout its range. Therefore, 
listing the pygmy rabbit as an endangered or threatened species under 
the Act is not warranted at this time.

Distinct Vertebrate Population Segment (DPS)

    After assessing whether the species is endangered or threatened 
throughout its range, we next consider whether any distinct vertebrate 
populations segment (DPS) exists and meets the definition of endangered 
or is likely to become endangered in the foreseeable future 
(threatened).
    Under the Service's Policy Regarding the Recognition of Distinct 
Vertebrate Population Segments Under the Endangered Species Act (61 FR 
4722, February 7, 1996), three elements are considered in the decision 
concerning the establishment and classification of a possible DPS. 
These are applied similarly for additions to or removal from the 
Federal List of Endangered and Threatened Wildlife. These elements 
include:
    (1) The discreteness of a population in relation to the remainder 
of the taxon to which it belongs;
    (2) The significance of the population segment to the taxon to 
which it belongs; and
    (3) The population segment's conservation status in relation to the 
Act's standards for listing, delisting (removal from the list), or 
reclassification (i.e., is the population segment endangered or 
threatened).
    In this analysis, we will evaluate whether pygmy rabbits in Mono 
County, California, meet the criteria to be considered a DPS. This 
analysis is being conducted because studies have indicated that pygmy 
rabbit populations in Mono County may be separated from the rest of the 
pygmy rabbit range (Grayson 2006, pp. 2969-2970; Larrucea and Brussard 
2008a, pp. 694, 696).

Discreteness

    Under the DPS policy, a population segment of a vertebrate taxon 
may be considered discrete if it satisfies either one of the following 
conditions:
    (1) It is markedly separated from other populations of the same 
taxon as a consequence of physical, physiological, ecological, or 
behavioral factors. Quantitative measures of genetic or morphological 
discontinuity may provide evidence of this separation.
    (2) It is delimited by international governmental boundaries within 
which differences in control of exploitation, management of habitat, 
conservation status, or regulatory mechanisms exist that are 
significant in light of section 4(a)(1)(D) of the Act.
    We note that the standard set forth in the DPS policy is that a DPS 
be ``markedly separated'' from other populations--thus, while absolute 
separation is not required, neither are ``large numbers'' of 
individuals migrating between populations. Nor is absolute isolation 
required for populations to be markedly separated.
    Pygmy rabbits in Mono County appear to be markedly separated from 
other pygmy rabbit populations. The nearest known populations to Mono 
County populations are in western Nevada, approximately 100 mi (162 km) 
away (Larrucea and Brussard 2008a, p. 694). There are no known 
historical pygmy rabbit records for Lyon, Mineral, and Emeralda 
Counties, Nevada, which could provide possible connections between 
California and Nevada in this area. Surveys conducted during 2003 and 
2006 in Lyon and Mineral Counties did not find evidence of pygmy 
rabbits (Larrucea 2007, pp. 165-179). It is possible that the Mono 
County populations have been separated from the rest of the species' 
range since the end of the Pleistocene (Grayson 2006, pp. 2969-2970).
    We determine, based on a review of the best available information, 
that the Mono County populations of pygmy rabbit are markedly separated 
from other pygmy rabbit populations as a consequence of physical 
factors and thus meet the discreteness criterion of the 1996 DPS 
policy.
    There are no international governmental boundaries associated with 
this species that are significant. The pygmy rabbit is found wholly 
within the United States. Because this element is not relevant in this 
case for a finding of discreteness, it was not considered in reaching 
this determination.

Significance

    If a population segment is considered discrete under one or more of 
the conditions described in our DPS policy, its biological and 
ecological significance will be considered in light of Congressional 
guidance that the authority to list DPSs be used ``sparingly'' while 
encouraging the conservation of genetic diversity. In making this 
determination, we consider available scientific evidence of the 
discrete populations segment's importance to the taxon to which it 
belongs. Since precise circumstances are likely to vary considerably 
from case to case, the DPS policy does not describe all the classes of 
information that might be used in determining the biological and 
ecological importance of a discrete population. However, the DPS policy 
does provide four possible reasons why a discrete population may be 
significant. As specified in the DPS policy (61 FR 4722), this 
consideration of the population segment's significance may include, but 
is not limited to, the following:
    (1) Persistence of the discrete population segment in an ecological 
setting unusual or unique to the taxon;
    (2) Evidence that loss of the discrete population segment would 
result in a significant gap in the range of a taxon;
    (3) Evidence that the discrete population segment represents the 
only surviving natural occurrence of a taxon that may be more abundant 
elsewhere as an introduced population outside its historic range; or
    (4) Evidence that the discrete population segment differs markedly 
from other populations of the species in its genetic characteristics.
    A population segment needs to satisfy only one of these criteria to 
be considered significant. Furthermore, the list of criteria is not 
exhaustive; other criteria may be used as appropriate.

(1) Persistence of the discrete population segment in an ecological 
setting unusual or unique to the taxon;

    The available information does not suggest that the ecological 
setting occupied by pygmy rabbits in the Mono County, California, 
portion of its range is unusual or unique when compared to the 
remainder of its range. The available information does not suggest that 
the vegetation, elevation, topography, or climate of the habitat 
occupied by the Mono County, California populations of the pygmy rabbit 
is unusual or unique to the taxon; nor is there any information 
indicating there are physiological or behavioral factors of the Mono 
County populations that are unusual or unique to the taxon.

[[Page 60560]]

(2) Evidence that loss of the discrete population segment would result 
in a significant gap in the range of a taxon;

    The Mono County populations are located on the western periphery of 
the pygmy rabbit's range. We have determined that they occupy less than 
1 percent of the species' range. If the populations in Mono County were 
to be extirpated, the portion of the range lost would be small when 
compared to the remainder of the species' range. Loss of these 
populations would not result in a gap in the pygmy rabbit's range as 
they are located on the edge of the range and may not be providing 
connectivity to other portions of its range. Therefore, we conclude 
that loss of these populations would not be result in a significant gap 
in the range of the species.
    (3) Evidence that the discrete population segment represents the 
only surviving natural occurrence of a taxon that may be more abundant 
elsewhere as an introduced population outside its historic range; or
    The Mono County populations do not represent the only surviving 
natural occurrence of a taxon that may be more abundant elsewhere as an 
introduced population outside its historic range. The pygmy rabbit's 
current distribution is similar to its historic distribution, and the 
species has not been introduced to areas outside of its historic range. 
The Mono county populations represent a small portion of the total 
extent of the species' range.

(4) Evidence that the discrete population segment differs markedly from 
other populations of the species in its genetic characteristics.

    As indicated above, pygmy rabbits in Mono County have not been 
genetically tested. Therefore, there is no information to indicate that 
these populations differ markedly from other populations of this 
species in its genetic characteristics.
    We therefore conclude that pygmy rabbit populations in Mono County 
do not meet the significance element of the Service's DPS policy 
because they do not occur in an ecological setting unusual or unique to 
the taxon; their loss would not result in a significant gap in the 
range of the taxon; they do not represent the only surviving natural 
occurrence of the taxon; and there is no evidence available indicating 
that Mono County populations differ markedly in genetic 
characteristics.
Conclusion of Distinct Population Segment Review
    Based on the best scientific and commercial information available, 
we find that pygmy rabbit populations found in Mono County, California, 
meet the discreteness element of our DPS policy but fail to meet the 
significance element of that policy. Since both discreteness and 
significance are required to satisfy the DPS policy, we have determined 
that Mono County pygmy rabbit populations do not qualify as a DPS under 
our policy. As a result, no further analysis under the DPS policy is 
necessary.

Significant Portion of the Range Analysis

    Having determined that the pygmy rabbit is not endangered or 
threatened throughout all its range, we must next consider whether 
there are any significant portions of the range where the pygmy rabbit 
is in danger of extinction or is likely to become endangered in the 
foreseeable future.
    To identify those portions that may be significant portions of the 
range, we determine whether there is substantial information indicating 
that: (i) The portions may be significant, and (ii) the species may be 
in danger of extinction there or likely to become so within the 
foreseeable future. In practice, a key part of this analysis is whether 
the threats are geographically concentrated in some way. If the threats 
to the species are essentially uniform throughout its range, no portion 
is likely to be a significant portion of the range. Moreover, if any 
concentration of threats applies only to portions of the range that are 
unimportant to the conservation of the species, such portions will not 
be significant portions of the range.
    If we identify any significant portions, we then determine whether 
the species is threatened or endangered in that portion of the range. 
Depending on the biology of the species, its range, and the threats it 
faces, the Service may address either the significance question or the 
status question first. Thus, if the Service considers significance 
first and determines that a portion of the range is not significant, 
the Service need not determine whether the species is threatened or 
endangered there. Likewise, if the Service considers status first and 
determines that the species is not threatened or endangered in a 
portion of its range, the Service need not determine if that portion is 
significant.
    Based on our review of survey information, distributional data, and 
potential threats, we have determined that the pygmy rabbit range in 
Oregon, Idaho, Montana, Nevada, and Utah does not warrant further 
consideration to determine if it is a significant portion of the range 
that is threatened or endangered. We found no areas within this portion 
of the range where threats are geographically concentrated. The 
potential factors that may affect the species are essentially uniform 
throughout this portion of the range. However, we did determine that 
the Mono County, California, and the Wyoming portions of the pygmy 
rabbit's range warranted further consideration to determine if they are 
significant portions of the range that are threatened or endangered. 
The Mono County, California portion was selected due to the possible 
lack of connectivity to populations in Nevada, and therefore, threats 
to it may include population isolation. Regardless of the possible 
extirpation of pygmy rabbit populations in Modoc and Lassen Counties, 
California (Larrucea and Brussard 2008a, pp. 694, 696), populations in 
Mono County may be isolated from the rest of the range. There are no 
known historical pygmy rabbit records for Lyon, Mineral, and Emeralda 
Counties, Nevada, which could provide possible connections between 
California and Nevada in this area. Surveys conducted during 2003 and 
2006 in Lyon and Mineral Counties did not find evidence of pygmy 
rabbits (Larrucea 2007, pp. 165-179). It is possible that the Mono 
County populations have been separated from the rest of the range since 
the end of the Pleistocene (Grayson 2006, pp. 2969-2970) (see our 
discussion regarding DPS above). The Wyoming portion was selected due 
to the concentration of energy exploration and development in the 
southwestern and south central areas of the State and the possible 
threat from these activities to pygmy rabbit populations in those 
areas.
    To assess the significance of these portions of the range, we 
evaluated whether these two areas occupy relatively large or 
particularly high-quality, unique habitat that could be affected, or if 
their locations or characteristics make them less susceptible to 
certain threats than other portions of the species' range such that 
they could provide important population refugia in the event of 
extirpations elsewhere in the species' range. We determined that the 
Mono County populations occupy less than 1 percent of the species 
range, and the available information does not suggest that the habitat 
occupied by pygmy rabbits in this portion is particularly high quality 
or unique when compared to the remainder of the range. The pygmy 
rabbit, in addition to Mono County California, occurs in sagebrush 
habitats located in southeastern Oregon, southern Idaho, southwestern 
Montana,

[[Page 60561]]

western Utah, and northern and eastern Nevada. We did not find that the 
Mono County populations are less susceptible to certain threats than 
other portions of the range. We also evaluated the historical value of 
this portion and how frequently it is used by the species and whether 
the portion contains important concentrations of certain types of 
habitat that are necessary for the species to carry out its life-
history functions, such as breeding, feeding, migration, dispersal, or 
wintering. We found that the Mono County populations are not 
significant because the habitats necessary for breeding, feeding, 
dispersal, or wintering are utilized year round and are found 
throughout the pygmy rabbit's range. These necessary habitats are not 
concentrated in Mono County.
    We determined that the Wyoming populations occupy about 11.5 
percent of the species' range, and available information does not 
suggest that the habitat occupied by pygmy rabbits in this portion is 
particularly high quality or unique when compared to the remainder of 
the range. The pygmy rabbit, in addition to Wyoming, occurs in 
sagebrush habitats located in southeastern Oregon, southern Idaho, 
southwestern Montana, western Utah, and northern and eastern Nevada. We 
did not find that the Wyoming populations are less susceptible to 
certain threats than other portions of the range. We also evaluated the 
historical value of this portion of the range and how frequently it is 
used by the species and whether the portion contains important 
concentrations of certain types of habitat that are necessary for the 
species to carry out its life-history functions, such as breeding, 
feeding, migration, dispersal, or wintering. We found that the Wyoming 
populations are not significant because the habitats necessary for 
breeding, feeding, dispersal, or wintering are utilized year round and 
are found throughout the pygmy rabbit's range. These necessary habitats 
are not concentrated in Wyoming.
    Based on the discussion above, we determined that the Mono County, 
California, and the Wyoming portions of the current range of the pygmy 
rabbit are not significant to the species and therefore do not warrant 
further consideration to determine if they are a significant portion of 
the range that is threatened or endangered.
    We do not find that the pygmy rabbit is in danger of extinction 
now, nor is it likely to become endangered within the foreseeable 
future throughout all or a significant portion of its range. Therefore, 
listing the pygmy rabbit as threatened or endangered under the Act is 
not warranted throughout all or a significant portion of its range at 
this time.
    We request that you submit any new information concerning the 
status of, or threats to, the pygmy rabbit to our Nevada Fish and 
Wildlife Office (see ADDRESSES section) whenever it becomes available. 
New information will help us monitor the pygmy rabbit and encourage its 
conservation. If an emergency situation develops for the pygmy rabbit, 
we will act to provide immediate protection.

References Cited

    A complete list of references cited is available on the Internet at 
http://www.regulations.gov and upon request from the Nevada Fish and 
Wildlife Office (see ADDRESSES).

Authors

    The primary authors of this document are the staff members of the 
Nevada Fish and Wildlife Office, U.S. Fish and Wildlife Service, Reno, 
Nevada.

Authority

    The authority for this action is section 4 of the Endangered 
Species Act of 1973, as amended (16 U.S.C. 1531 et seq.).

    Dated: September 20, 2010
Rowan Gould,
Acting Director, Fish and Wildlife Service.
[FR Doc. 2010-24349 Filed 9-29-10; 8:45 am]
BILLING CODE 4310-55-S