Endangered and Threatened Wildlife and Plants; 12-Month Finding on a Petition to List the Pygmy Rabbit as Endangered or Threatened, 60516-60561 [2010-24349]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

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



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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 https://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.

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    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-

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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)

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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 we