[Federal Register: May 20, 2005 (Volume 70, Number 97)]
[Proposed Rules]               
[Page 29253-29265]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]



Fish and Wildlife Service

50 CFR Part 17

Endangered and Threatened Wildlife and Plants; 90-Day Finding on 
a Petition To List the Pygmy Rabbit as Threatened or Endangered

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Notice of 90-day petition finding.


SUMMARY: We, the U.S. Fish and Wildlife Service (Service), announce a 
90-day finding on a petition to list the pygmy rabbit (Brachylagus 
idahoensis) as threatened or endangered under the Endangered Species 
Act of 1973, as amended. We find the petition does not provide 
substantial information indicating that listing the pygmy rabbit may be 
warranted. Therefore, we will not be initiating a further status review 
in response to this petition. We ask the public to submit to us any new 
information that becomes available concerning the status of the species 
or threats to it.

DATES: The finding announced in this document was made May 20, 2005. 
You may submit new information concerning this species for our 
consideration at any time.

ADDRESSES: The complete file for this finding is available for public 
inspection, by appointment, during normal business hours at the Nevada 
Fish and Wildlife Office, U.S. Fish and Wildlife Service, 1340 
Financial Boulevard, Suite 234, Reno, NV 89502. Submit new information, 
materials, comments, or questions concerning this species to us at the 
above address.

FOR FURTHER INFORMATION CONTACT: Robert D. Williams, Field Supervisor, 
Nevada Fish and Wildlife Office (see ADDRESSES) (telephone 775/861-
6300; facsimile 775/861-6301).



    Section 4(b)(3)(A) of the Endangered Species Act of 1973, as 
amended (16 U.S.C. 1531 et seq.), requires that we make a finding on 
whether a petition to list, delist, or reclassify a species presents 
substantial scientific or commercial information to indicate that the 
petitioned action may be warranted. We are to base this finding on 
information provided in the petition. To the maximum extent 
practicable, we are to make this finding within 90 days of our receipt 
of the petition, and publish our notice of this finding promptly in the 
Federal Register.
    Our standard for substantial information within the Code of Federal 
Regulations (CFR) with regard to a 90-day petition finding is ``that 
amount of information that would lead a reasonable person to believe 
that the measure proposed in the petition may be warranted'' (50 CFR 
424.14(b)). If we find that substantial information was presented, we 
are required to promptly commence a review of the status of the 
species, if one has not already been initiated under our internal 
candidate assessment process.
    In making this finding, we relied on information provided by the 
petitioners and evaluated that information in accordance with 50 CFR 
424.14(b). Our process of coming to a 90-day finding under section 
4(b)(3)(A) of the Act and section 424.14(b) of our regulations is 
limited to a determination of whether the information in the petition 
meets the ``substantial information'' threshold.
    On April 21, 2003, we received a formal 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 that the pygmy rabbit (Brachylagus 
idahoensis) found in California, Idaho, Montana, Nevada, Oregon, Utah, 
and Wyoming be listed as threatened or endangered in accordance with 
section 4 of the Act.
    Action on this petition was precluded by court orders and 
settlement agreements for other listing actions that required nearly 
all of our listing funds for fiscal year 2003. 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-
    This finding does not address our prior listing of the Columbia 
Basin distinct population segment (DPS) of the pygmy rabbit. 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).

Species Information

    The pygmy rabbit is a member of the family Leporidae, which 
includes rabbits and hares. This species has been placed in various 
genera since its type specimen was described in 1891 by Merriam (1891), 
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; WDFW 1995); this is the taxonomy accepted by the Service. The 
analysis of blood proteins (Johnson 1968, cited in Washington 
Department of Fish and Wildlife (WDFW) 1995) suggests that the pygmy 
rabbit differs greatly from species within both the Lepus or Sylvilagus 
genera. Halanych and Robinson (1997) supported the

[[Page 29254]]

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; Davis 1939; 
Larrison 1967; Green and Flinders 1980a; Janson 2002).
    The pygmy rabbit is the smallest North American rabbit. 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) (Dice 
1926; Grinnell et al. 1930; Bailey 1936; Orr 1940; Janson 1946; Durrant 
1952; Ingles 1965; Bradfield 1974; Holt 1975; Campbell et al. 1982). 
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).
    Pygmy rabbits typically occur in areas of tall, dense sagebrush 
(Artemisia spp.) cover, and are highly dependent on sagebrush to 
provide both food and shelter throughout the year (Dice 1926, Grinnell 
et al. 1930; Orr 1940; Green and Flinders 1980a, b; Janson 1946; Wilde 
1978; Katzner et al. 1997). The winter diet of pygmy rabbits is 
comprised of up to 99 percent sagebrush (Wilde 1978; Green and Flinders 
1980b), which is unique among rabbits (White et al. 1982). During 
spring and summer in Idaho, their diet consists of roughly 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). 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 its use during spring and summer (Green and Flinders 1980b). 
The specific diets of pygmy rabbit likely vary by region (68 FR 10388).
    The pygmy rabbit is one of only two rabbits in North America that 
digs its own burrows (Nelson 1909; Bailey 1936; Janson 1946; Bradfield 
1974; Wilde 1978). 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; Bradfield 1974). The burrows frequently have multiple 
entrances, some of which are concealed at the base of larger sagebrush 
plants (Dice 1926). Burrows are relatively simple and shallow, often no 
more than 6.6 feet (ft) (2 meters (m)) in length and usually less than 
3.3 ft (1 m) deep with no distinct chambers (Bailey 1936; Bradfield 
1974; Green and Flinders 1980a; Gahr 1993). Burrows are typically dug 
into gentle slopes or mound/inter-mound areas of more level or 
dissected topography (Wilde 1978; Gahr 1993). In general, the number of 
active burrows in a colony increases over the summer as the number of 
juveniles increases. 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 
1946; Gahr 1993; Heady 1998).
    Pygmy rabbits occasionally make use of burrows abandoned by other 
species, such as the yellow-bellied marmot (Marmota flaviventris) or 
badger (Taxida taxus) (Borell and Ellis 1934; Bradfield 1974; Wilde 
1978; Green and Flinders 1980a). As a result, they may occur in areas 
of shallower or more compact soils that support sufficient shrub cover 
(Bradfield 1974). Natural cavities (such as holes in volcanic rock), 
rock piles, stone walls and around abandoned buildings may also be used 
(Janson 1946). During winter pygmy rabbits make extensive use of snow 
burrows, possibly as access to sagebrush forage (Bradfield 1974; 
Katzner and Parker 1997), as travel corridors among their underground 
burrows, for protection from predators, and/or as thermal cover 
(Katzner and Parker 1997).
    Pygmy rabbits begin breeding their second year (Wilde 1978; Fisher 
1979). In some parts of the species' range, females may have up to 
three litters per year and average six young per litter (Davis 1939; 
Janson 1946; Green 1978; Wilde 1978). Breeding appears to be highly 
synchronous in a given area and juveniles are often identifiable to 
cohorts (Wilde 1978). No evidence of nests, nesting material, or 
lactating females with young has been found in burrows (Janson 1946; 
Bradfield 1974; Gahr 1993). Individual juveniles have been found under 
clumps of sagebrush, although it is not known precisely where the young 
are born in the wild, nor is it known if they may be routinely hidden 
at the bases of scattered shrubs or within burrows (Wilde 1978). 
Current information on captive pygmy rabbits indicates females may 
excavate specialized natal burrows for their litters in the vicinity of 
their regular burrows (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 (Bradfield 1974; Green and 
Flinders 1980a; Gahr 1993). 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 (Bailey 1936; Severaid 1950; Bradfield 
    Pygmy rabbits tend to have relatively small home ranges during 
winter, remaining within 98 ft (30 m) of their burrows (Janson 1946). 
Bradfield (1974), Katzner and Parker (1997), and Flath and Rauscher 
(1995) 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; Gahr 1993). 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). These home range 
estimates in Washington are considerably larger than for pygmy rabbit 
populations in other areas of their historic range (Katzner and Parker 
1997). Pygmy rabbits are known to travel up to 0.75 mile (mi) (1.2 
kilometers (km)) from their burrows (Gahr 1993), and there are a few 
records of individuals moving up to 2.2 mi (3.5 km) (Green and Flinders 
1979; Katzner and Parker 1998).
    A wide range of pygmy rabbit population densities has been 
reported. Janson (1946) reported an estimated pygmy rabbit density of 
0.75 to 1.75 per ac (1.9 and 4.3 per ha) in Utah. In another area in 
Utah, he estimated 3.5 pygmy rabbits per ac (8.6 per ha). Green (1978) 
reported an estimate of 18.2 pygmy rabbits per ac (45 per ha) in Idaho. 
Gahr (1993) estimated 0.09 pygmy rabbits per ac (0.22 per ha) in a 
grazed area and 0.11 per ac (0.27 per ha) in an ungrazed area in 
Sagebrush Flat, Washington. In Montana, Rauscher (1997) estimated pygmy 
rabbit density as 1.2 per ac (3.0 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). However, the mortality 
rates of adult and juvenile pygmy rabbits can vary considerably between 
years, and even between juvenile cohorts within years (Wilde 1978). 
Predation is the main cause of pygmy rabbit mortality (Green

[[Page 29255]]

1979). 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; 
Janson 1946; Gashwiler et al. 1960; Green 1978; Wilde 1978; Johnson and 
Hanson 1979; WDFW 1995).
    Population cycles are not known in pygmy rabbits, although local, 
relatively rapid population declines have been noted in some States 
(Janson 1946; Bradfield 1974; Weiss and Verts 1984). 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; Green and Flinders 1980b; WDFW 1995). No study 
has documented rapid increases in pygmy rabbit numbers in response to 
environmental conditions (Gabler 1997).
    The pygmy rabbit's 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). The northern boundary extends into southeastern Oregon and 
southern Idaho. The eastern boundary extends into southwestern Montana 
and southwestern Wyoming. The southeastern boundary extends into 
southwestern Utah. Central Nevada and eastern California provide the 
southern and western boundaries (Merriam 1891; Nelson 1909; Grinnell et 
al. 1930; Bailey 1936; Janson 1946; Campbell et al. 1982; WDFW 1995).
    Literature indicates that pygmy rabbits were never evenly 
distributed across their range. Rather, 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; Green and Flinders 1980a; Weiss and Verts 1984; 
WDFW 1995). 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 appropriate use areas (Green and Flinders 1980a; Weiss 
and Verts 1984; WDFW 1995). Since European settlement of the western 
United States, dense vegetation associated with human activities (e.g., 
fence rows, roadway shoulders, crop margins, abandoned fields) may have 
also acted as avenues of dispersal between local populations of pygmy 
rabbits (Green and Flinders 1980a; Pritchett et al. 1987).

Previous Federal Action

    We added the pygmy rabbit to our list of candidate species on 
November 21, 1991, 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 was 
needed to support the preparation of a proposed rule. In the February 
28, 1996, Notice of Review (61 FR 7595), we discontinued the use of 
multiple candidate categories and considered the former category 1 
candidates as simply ``candidates'' for listing purposes. The pygmy 
rabbit was removed from the candidate list at that time. This species 
has no Federal regulatory status.
    As stated above, this finding does not address our prior listing 
with regard to the Columbia Basin DPS of the pygmy rabbit that was 
listed as endangered on March 5, 2003 (68 FR 10388).

Threats Analysis

    Pursuant to section (4) of the Act, we may list a species, 
subspecies, or DPS of vertebrate taxa on the basis of any of the 
following five factors: (A) present or threatened destruction, 
modification, or curtailment of habitat or range; (B) overutilization 
for commercial, recreational, scientific, or educational purposes; (C) 
disease or predation; (D) inadequacy of existing regulatory mechanisms; 
or (E) other natural or manmade factors affecting its continued 
existence. In making this finding, we evaluated whether threats to the 
pygmy rabbit presented in the petition and other information may pose a 
concern with respect to its survival. The Act identifies the five 
factors to be considered, either singly or in combination, to determine 
whether a species may be threatened or endangered. Our evaluation of 
these threats, based on information provided in the petition and 
available in our files, is presented below.

A. Present or Threatened Destruction, Modification, or Curtailment of 
the Species' Habitat or Range

Geographic Range
    The petition estimates that the historic range of the pygmy rabbit 
encompassed 100 million ac (40 million ha) or more of sagebrush habitat 
in the Great Basin and Intermountain West, and that populations may 
currently exist in portions of 7 to 8 million ac (2.8 to 3.2 million 
ha) (Committee for the High Desert et al. 2003). It appears these 
estimates were determined by visually comparing the historic geographic 
range map presented in previous Service Federal Register documents (66 
FR 59734, 68 FR 10388), and a current range map presented in White and 
Bartels (2002). However beyond apparently making a visual comparison of 
these two maps to reach their conclusion the petitioners did not 
provide any data to substantiate this supposed reduction in pygmy 
rabbit range. We are unaware of any estimates from the scientific 
literature in our files regarding a reduction in range for the species. 
Therefore, we conclude that this map comparison is not substantial 
information demonstrating a significant reduction in the range of the 
pygmy rabbit.
    The petition states that there have been rangewide declines in 
pygmy rabbit populations and provides the following State-by-State 
information to support this claim.
    Idaho. According to the petition, Bradfield (1974) speculated that 
the pygmy rabbit population was declining in his study area in Bingham 
County, Idaho, because of the number of abandoned burrows, number of 
skulls indicating death by predation or other means, and fewer observed 
rabbits. In her Idaho study area, Gabler (1997) found 101 burrow sites, 
of which 26 were active. Gabler also revisited Wilde's (1978) three 
study areas, and found two collapsed burrows with no sign of occupancy, 
four active burrows that were abandoned 10 months later, and 34 
abandoned burrows, respectively. Roberts (2001) covered 583,600 ac 
(236,175 ha) in three main river drainages during his 1997-98 survey in 
Idaho and found pygmy rabbits widely scattered in all three of these 
areas. Occupied habitat areas were interrupted by cultivation and burn 
areas. He classified habitat value in his study area as being high 
(2,000 ac (809 ha)), medium (365,200 ac (147,792 ha)), low (175,400 ac 
(70,982 ha)), and nonuse (41,000 ac (16,592 ha)) for pygmy rabbits. All 
of the high-value habitat was located in one of the drainages.
    As included in the petition, Austin (2002) reported that all nine 
of his study areas in Idaho showed past presence of pygmy rabbit use. 
Recent or current signs of occupancy were found at five individual 
sites within three of the nine study areas in 2001 and 2002. Austin 
(2002) states that though it is recognized

[[Page 29256]]

that pygmy rabbits occur in widely scattered and/or isolated clumps 
across the landscape, the large unoccupied areas of lands historically 
used by pygmy rabbits within research areas of Idaho appear to indicate 
a decline in populations and numbers. He reported some level of current 
land use and disturbance in all of his study areas from the following: 
grazing, fire, crested wheatgrass (Agropyron cristatum) seedings, weed 
infestation, residential construction, communication sites, agriculture 
and pasture conversion, fragmentation, gas pipelines, water 
impoundments, off-highway-vehicle (OHV)/off-road vehicle (ORV) use, 
trails, hunting, gravel pit, utility lines, dumping activities, and 
other human influences.
    The petition states that White and Bartels (2002) attempted to 
check 31 historic 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 agriculture, urban 
development, wildfire and reseeding efforts, and five were potentially 
suitable habitat. No active pygmy rabbit burrows were found on any of 
the 13 sites visited. Roberts (2003) investigated 42,000 square mi 
(108,800 square km) of southern Idaho, including lands drained by the 
Snake River (southern Idaho) and Bear River (southeastern Idaho). He 
found only nine currently active pygmy rabbit burrow systems. Roberts 
(2003) states that the pygmy rabbit in Idaho are slowly declining based 
solely on the annual loss of habitat.
    Montana. The petition states that in Montana, Rauscher (1997) 
reported that several previously occupied sites west of Dillon (near 
Dutchman, Montana; Frying Pan Basin) were now vacant. He stated that 
there was no evidence to indicate a significant range decrease had 
occurred. Janson (2002) wrote that the historical range in Montana 
continues to support pygmy rabbits, with some exceptions based on 
limited observations in Beaverhead County, Montana, in 2001.
    Oregon. The petitioners cite Olterman and Verts (1972) as stating 
that pygmy rabbits appeared to occur over the same area in Oregon as 
they did in past collections. However, Weiss and Verts (1984) found 
that of 211 sites suspected of supporting pygmy rabbits in eastern 
Oregon based on records, aerial photographs, soil maps, and interviews, 
only 51 sites showed evidence of occupancy in 1982. In 1983, only 5 of 
15 sites showed recent pygmy rabbit activity. Of 51 burrows found at 5 
sites in 1982, 19 burrows were found open in 1983 and only 8 had fresh 
signs of occupancy (Weiss and Verts 1984). Bradfield (1974) also spent 
time at Ironside, in Malheur County, Oregon. He found evidence of 
previous pygmy rabbit use, but no fresh signs of use or rabbits, 
supporting his belief that they were in decline on a larger geographic 
scale. Bartels (2003) visited 54 previously known pygmy rabbit sites in 
2000 and 2001 in Harney, Malheur, Lake, and Deschutes Counties, Oregon. 
Results from these visits were: Pygmy rabbit occupancy at 12 sites, no 
occupancy at 34 sites, and undetermined presence at 8 sites (Bartels 
2003). Impacts to unoccupied sites included fire, grazing, flooding, 
agriculture, development, and seeding. Of the 69,945 ac (28,306 ha) 
surveyed, 57,485 ac (23,263 ha) were classified as unoccupied. A total 
of 9,589 ac (3,881 ha) were classified as occupied and 2,871 ac (1,162 
ha) were classified as undetermined presence (Bartels 2003). Some of 
these sites included those visited by Weiss and Verts (1984).
    Utah. Janson (1946) reported that in the winter of 1946, pygmy 
rabbits appeared 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. 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) 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. Pritchett et al. (1987) were 
unable to locate a population studied by Holt (1975) near Otter Creek 
    Other States. The petition does not provide specific information on 
population declines for pygmy rabbits in California, Nevada, or 
Evaluation of Information in the Petition
    The data and information presented in the petition has limited use 
in determining rangewide distribution and abundance of the species. 
Little detail is available from records prior to 1950. These records 
may not accurately reflect the species' historic distribution because 
they were not collected in a systematic, comprehensive manner with the 
goal of determining species distribution and abundance. They represent 
a collection of sightings documented through various methods by 
different individuals over time. Recent surveys (post-1950) have not 
been comprehensive in any State within the pygmy rabbit's range. 
Consistent methodologies were not used for those previous surveys. 
Definitions for historic sites versus previously known sites, methods 
for determining occupancy, and definitions that would clearly 
distinguish occupied from unoccupied areas, unoccupied suitable 
habitat, and the extent of occupied or formerly occupied population 
sites, are inconsistent.
    Surveys identified in the petition have reported occupancy at 
different landscape scales, ranging from the individual burrow to the 
broader population level. In many cases, survey areas were not clearly 
identified, and there is a lack of information on the distances between 
adjacent populations, and therefore, on what defines a population. The 
petition does not provide substantial scientific information to 
document the historic or current range of pygmy rabbits within 
sagebrush ecosystems. Although limited data are provided on local 
population declines, particularly in Idaho, the petition does not 
present substantial scientific information that there is a downward 
trend in geographic range or abundance to a level that threatens the 
survival of the pygmy rabbit across all or a significant portion of its 
range. Nor does the petition present substantial information to 
correlate the changes in geographic range and abundance of the species 
to the actual threats to the survival of the species.
    The Service has worked with the States, other Federal agencies, and 
research institutions involved with pygmy rabbit work to create a 
rangewide communication network to coordinate information and 
activities relating to this species. We are aware of continuing survey 
efforts to improve the current knowledge of pygmy rabbit distribution 
across its range, as well as the development of draft survey guidelines 
(Ulmschneider 2004). However, we are unaware of any accurate, 
comprehensive inventories of currently occupied pygmy rabbit habitat 
for any State within the range of the species. Such information is 
critical to any analysis of range and/or population reductions. 
Consequently, we conclude that the petitioners do not present 
substantial information indicating that a reduction in the species' 
numbers or range warrants a status review.

[[Page 29257]]

    The petition claims the pygmy rabbit has been subject to population 
losses and declines due to various land management practices such as 
conversion of sagebrush habitat to agricultural purposes, sagebrush 
eradication to increase forage for livestock, livestock grazing, weed 
invasions, prescribed burns and wildfires, urban and rural development, 
mining and energy exploration and development, power lines, fences and 
roads, military facilities, and recreational activities. The petition 
states that sagebrush once covered approximately 270 million ac (109 
million ha) in western North America. Today, because of various land 
uses, about 150 million ac (61 million ha) of sagebrush habitat remain 
(American Lands Alliance 2001). However, pygmy rabbits do not occur in 
Arizona, Colorado, North or South Dakota, or New Mexico, and only in 
the southwest portions of Montana and Wyoming. So the amount of 
suitable sagebrush habitat for pygmy rabbits is considerably less than 
the 150 million ac (61 million ha) of sagebrush currently distributed 
across western North America. The petitioners claim that pygmy rabbit 
populations may occur over 7 to 8 million acres within the sagebrush 
ecosystem but do not present substantial information to substantiate 
this estimate, nor are we aware of any such estimates in the scientific 
    The petition cites the following general information on threats of 
agriculture to sagebrush habitat. Large-scale conversions of western 
rangelands to agricultural lands began under the Homestead Acts of the 
1800s (Todd and Elmore 1997, cited in Braun 1998). More than 70 percent 
of the sagebrush shrub-steppe habitat has been converted to 
agricultural crops in some States (Braun 1998). 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 
(Quigley and Arbelbide 1997, cited in Committee for the High Desert et 
al. 2003). Development of irrigation projects to support agricultural 
production also resulted in sagebrush habitat loss (Braun 1998). 
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 to 
agriculture. As irrigation techniques have improved, additional land 
has been irrigated, and more big sagebrush (Artemisia tridentata) 
cleared. Shrub-steppe habitat continues to be converted to dry land and 
irrigated cropland but at a much lower rate (Braun 1998).
    Pritchett et al. (1987) reported that a portion of the Sevier River 
Valley between Kingston and Otter Creek, Utah, containing one of the 
last large patches of sagebrush, had been plowed. The authors 
speculated this may have been a dispersal route for pygmy rabbits from 
Iron County to Wayne County, Utah. Rauscher (1997) 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 historic record had been converted to irrigated 
farmland. Williams (1986) indicated that loss of sagebrush habitat in 
California to agriculture was less of a concern than loss of habitat 
from overgrazing. Bartels and Hays (2001) indicated that large portions 
of the pygmy rabbit range in Oregon and Idaho had been converted to 
agricultural use; they found that burning, plowing, and other 
undetermined causes continue to result in loss of pygmy rabbit habitat. 
White and Bartels (2002) believe that the pygmy rabbit historically was 
impacted by sagebrush removal for agricultural purposes in Idaho; they 
found that 8 of 13 locatable historic pygmy rabbit sites in Twin Falls 
and Cassio Counties, Idaho, were disturbed due to agriculture, urban 
development, wildfire, and seeding efforts. Of the 583,600 ac (236,175 
ha) Roberts (1998) inventoried in Idaho for pygmy rabbit occupancy, 
122,300 ac (49,493 ha) had been permanently removed due to agriculture 
Evaluation of Information in the Petition
    The information in the petition suggests that agricultural 
production has been responsible for a loss of sagebrush habitat, 
including some used by pygmy rabbits, particularly in certain areas and 
in Idaho. However pygmy rabbits are not distributed uniformly across 
the full range of the sagebrush ecosystem in western North America. In 
large areas of the sagebrush ecosystem, the pygmy rabbit does not occur 
at all, and in those areas where it does occur it is patchily 
distributed (Green and Flinders 1980a; Weiss and Verts 1984). The 
species only occurs in areas of the sagebrush ecosystem where, at a 
minimum, the habitat has sufficiently dense sagebrush and deep, loose 
soils (Green and Flinders 1980a; Weiss and Verts 1984). The petitioners 
only provide general characterizations of sagebrush habitat loss, or 
cite specific examples of losses in specific areas, particularly in 
Idaho and Oregon. However, they do not provide substantial information 
that clearly documents that the areas where these habitat losses have 
occurred are also the areas where pygmy rabbits are found. Also, the 
petition does not present substantial information on the magnitude and 
the extent of degradation and loss of habitat to agriculture such that 
we can conclude that the continued existence of the pygmy rabbit 
throughout all or a significant portion of its range may be threatened.
Conversion of Sagebrush
    The petition identifies the conversion of sagebrush by mechanical 
and chemical methods (herbicide) primarily for rangeland improvement 
and grazing management as a negative impact to pygmy rabbit habitat, 
and cites the following information to support this claim. Large 
expanses of sagebrush have been removed and seeded with nonnative 
grasses, such as crested wheatgrass, to increase forage production for 
domestic and wild ungulates. This practice results in the elimination 
of many native grasses and forbs that were present before the seedings. 
Olterman and Verts (1972) and Wilde (1978) 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. They 
note that land changes should be closely monitored and adequate 
``safeguards'' implemented to reduce excessive clearing of large areas.
    Roberts (1998) calculated that of the 583,600 ac (236,175 ha) he 
inventoried for pygmy rabbit occupancy in Idaho, 49,000 ac (19,830 ha) 
were lost due to sagebrush eradication. Rauscher (1997) reported that 
sagebrush removal was a ``popular'' rangeland improvement practice in 
southwestern Montana. Sagebrush in the Coyote Creek area of the Big 
Sheep Creek basin has been extensively treated, and only one active 
burrow was located. In lower Badger Gulch, Bureau of Land Management 
(BLM) lands border private lands. Pygmy rabbits are found on public 
lands but absent on private lands where sagebrush had been removed.
Evaluation of Information in the Petition
    Information in the petition indicates that some pygmy rabbit 
habitat has been lost to sagebrush eradication for rangeland and 
grazing management. However, as mentioned under agriculture in the 
previous section, the pygmy rabbit is not distributed uniformly across 
the full range of the

[[Page 29258]]

sagebrush ecosystem in western North America. It is absent from large 
areas of the sagebrush ecosystem, and in those areas of the sagebrush 
ecosystem where it does occur it is patchily distributed (Green and 
Flinders 1980a; Weiss and Verts 1984), in areas where, at a minimum, 
there is sufficiently dense sagebrush and deep, loose soils. The 
petitioners only provide general characterizations of sagebrush habitat 
loss due to conversion, or cite examples of losses in specific areas. 
They do not provide substantial information that clearly documents that 
the areas where these habitat losses have occurred are also the areas 
where pygmy rabbits are found. Also, the petition does not present 
substantial information on the magnitude and the extent of loss of 
habitat due to sagebrush conversion such that we can conclude that the 
continued existence of the pygmy rabbit throughout all or a significant 
portion of its range may be threatened.
Livestock Grazing
    The petition identifies livestock grazing as an important factor in 
sagebrush habitat destruction and alteration in pygmy rabbit habitat. 
The petition mentions not only the direct loss of vegetation, but 
habitat degradation due to associated facilities or actions such as the 
construction of fences, wells, water tanks, and pipelines which can 
concentrate livestock or redistribute livestock and predators; seeding 
of crested wheatgrass to increase livestock forage; and weed 
infestations. The petition also claims that grazing disturbs pygmy 
rabbits, increases their vulnerability to predation, and increases 
stress during winter or harsh weather periods. In addition, the 
petition claims trampling of burrows may cause injury or death of pygmy 
rabbits. The petition cites the following information to support these 
    The pygmy rabbit likely did not evolve with intensive grazing by 
large native herbivores such as bison (Bison bison), elk (Cervus 
canadensis), pronghorn (Antilocapra americana), and mule deer 
(Odocoileus hemionus) (Mack and Thompson 1982, cited in Connelly et al. 
2000; Belsky and Gelbard 2000). Belsky and Gelbard (2000) and Paige and 
Ritter (1999) discuss impacts of livestock grazing on the arid west. 
These impacts can include selective grazing for native species, 
trampling of plants and soil, damage to soil crusts, reduction of 
mycorrhizal fungi, increases in soil nitrogen, increases in fire 
frequency, and contribution to nonnative plant introductions. When the 
sagebrush-grass vegetation is overgrazed, native perennial grasses can 
be eliminated, and shrubs, such as big sagebrush, tend to form dense 
monotypic (single species) stands when the sagebrush-grass vegetation 
is overgrazed (Blaisdell 1949, cited in Yensen 1982; Tisdale and 
Hironaka 1981, cited in Paige and Ritter 1999). In addition, the 
understory becomes sparse with unpalatable perennials (Tisdale and 
Hironaka 1981, cited in Paige and Ritter 1999), and invasions of annual 
species like cheatgrass (Bromus tectorum) can occur (Gabler 1997; 
Rauscher 1997).
    The magnitude of grazing effects is determined by season, timing, 
duration, and intensity of the event, in addition to other factors. 
Overgrazing can break down individual sagebrush plants, which opens up 
interstitial (small, narrow) spaces, allowing invasion of annual 
grasses and forbs (Daubenmire 1970, cited in Rauscher 1997). Livestock 
grazing can result in sagebrush seedling trampling and mortality 
(Connelly et al. 2000). Water developments also influence livestock 
distribution in sagebrush habitat that would otherwise not be used. 
While water developments may provide a more uniform livestock 
distribution over the landscape, they may also distribute habitat 
impacts over a larger area. The associated facilities (tanks, 
pipelines, roads) may also allow predators (Braun 1998), OHV/ORV users, 
and hunters to access new terrain.
    Livestock can physically damage sagebrush by rubbing, battering, 
breaking, and trampling seedlings. Katzner and Parker (1997) state 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 plant structural 
complexity and may not support pygmy rabbit populations adequately. 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; Orr 1940; Wilde 1978; Katzner 1994; Siegel 
    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). Siegel (2002) found more active burrows in ungrazed areas than 
grazed areas. Gahr (1993) found male pygmy rabbits had longer movements 
in a grazed area in Washington during the breeding season compared with 
an ungrazed area. Rauscher (1997) and Janson (2002) 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 (Austin 2002).
    Trampling of burrows by livestock has been reported in Montana by 
Rauscher (1997), in Idaho by Austin (2002), and in Washington by Siegel 
(2002) and Herman (2002). This could cause the death of young rabbits 
in natal burrows or injury or mortality of adults. Austin (2002) 
reported a burrow system in Idaho that was subjected to cattle trailing 
on at least two separate occasions within a period of 2 months or less. 
After the initial event, only 2 of 10 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'' (Austin 
Evaluation of Information in the Petition
    The petition describes various impacts associated with livestock 
and grazing management that could affect pygmy rabbits, and cite 
specific cases in isolated areas where impacts to the species have 
resulted from these practices. However, the petitioners did not provide 
substantial information that clearly documents that areas impacted by 
grazing management practices are regularly also the areas where pygmy 
rabbits are found. Also, the petition does not present substantial 
information on the magnitude and the extent of degradation and loss of 
habitat to livestock grazing such that we could conclude that the 
continued existence of the pygmy rabbit throughout all or a significant 
portion of its range may be threatened.
Invasive Plants
    The petition claims weed invasions pose a threat to pygmy rabbits 
throughout their range and provides the following information to 
support this claim. The spread of weeds by several factors 
(recreationists, ORV/OHV users, trucks, logging, road construction, 
wildfire, wild animals, wind, and floods, livestock and associated 
facilities, among others) (Belsky and Gelbard 2000) across the range of 
the pygmy rabbit results in nonnative plants replacing native grasses 
and shrubs used by pygmy rabbits. Weed infestations can also hinder 
pygmy rabbit movement and increase predator detection. Quigley and

[[Page 29259]]

Arbelbide (1997, cited in Committee for the High Desert et al. 2003) 
describe the effects of weeds in the Interior Columbia River Basin as 
able to alter ecosystem processes, including productivity, nutrient 
cycling, decomposition, and natural disturbance patterns such as 
frequency and intensity of wild fires. Altering these processes can 
result in the displacement of native plant species, eventually 
impacting wildlife and native plant habitats.
    Paige and Ritter (1999) suggest that the most harmful 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 persistent in replacing native species (Mack 1981, 
Yensen 1981, and Whisenant 1990, cited in Paige and Ritter 1999). 
Cheatgrass alters fire and vegetation patterns in sagebrush habitats as 
it creates a continuous fine fuel that easily carries fire (Paige and 
Ritter 1999). Where it dominates, it can carry fires over large 
distances, and burns more frequently than native vegetation (Paige and 
Ritter 1999). 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). Pellant and Hall (1994) reported on the 1992 
distribution of cheatgrass and medusahead wild rye (Taeniatherum 
asperum), the primary alien grass invaders of disturbed and fire-
altered rangelands in the Intermountain area of the western United 
States. Data indicated that 3.3 million ac (1.3 million ha) of 
rangeland administered by the BLM in Nevada, Oregon, Utah, Washington, 
and Idaho were dominated by these two species. Another 76.1 million ac 
(30.8 million ha) of public rangeland were classified as infested or 
susceptible to infestation by these two species. The petition states 
that this distribution corresponds to areas of the pygmy rabbit's 
    The petition provides the following specific information on the 
threat of invasive weeds to pygmy rabbits and their habitat. In Oregon, 
2 of 51 sites occupied by pygmy rabbits in 1982 contained appreciable 
stands of cheatgrass (Weiss and Verts 1984). This led the authors to 
suspect that pygmy rabbits avoid areas containing annual grasses 
because it can restrict their movements or vision, especially when they 
are attempting to escape predators. Weeds were reported for all nine 
study areas investigated by Austin (2002) in Idaho. Gabler (1997) 
predicted 10 sites on Idaho National Environmental Engineering 
Laboratory (INEEL) lands would be used by pygmy rabbits, but later 
found large patches of invasive cheatgrass on 8 of those sites, and 
that the species 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 their nonuse.
Evaluation of Information in the Petition
    The petitioners provide information about weed invasions within the 
sagebrush ecosystem in general, and provide a few specific cases where 
the presence of weeds may have been the reason why pygmy rabbits were 
absent from an area. However, petitioners did not provide substantial 
information that clearly documents that areas impacted by invasive 
species are regularly also the areas where pygmy rabbits are found. 
Furthermore, the petitioners do not provide substantial information on 
the magnitude and the extent of habitat impacts by invasive weeds such 
that we might conclude that they may threaten the continued existence 
of the pygmy rabbit throughout all or a significant portion of its 
    The petition contends that fire, either wild or prescribed, can 
result in long-term habitat loss and fragmentation of pygmy rabbit 
habitat across its range. Fire can result in death, increased 
predation, or home range abandonment. The petition cites the following 
information to support this claim.
    Fire intervals during presettlement times have been estimated at 20 
to 25 years in wetter regions, where fuels (vegetation) are more 
abundant. In the arid sagebrush steppe of Idaho, intervals have been 
estimated at 60 to 110 years because fuels are less abundant (Tisdale 
and Hironaka 1981 and Whisenant 1990, cited in Paige and Ritter 1999). 
Burning typically kills big sagebrush (Artemisia tridentata tridentata, 
A. t. vaseyana, A. t. wyomingensis) (Pechanec et al. 1954, cited in 
Yensen 1982), fire it and does not resprout after burning (Wright et 
al. 1979, cited in Braun 1998; Paige and Ritter 1999). As a result, big 
sagebrush habitat takes a long time to recover following burns. 
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 preburn 
densities (Bunting 1984; Britton and Clark 1984, cited in Paige and 
Ritter 1999). Billings (1994) documented slow shrub succession 
following a burn in western Nevada, with little sagebrush recovery 
after 45 years.
    Burning can also damage perennial grasses, allowing cheatgrass to 
increase (Stewart and Hull 1949; Wright and Britton 1976, cited in 
Yensen 1982). The presence of cheatgrass extends the fire season and 
can carry a fire into areas where burning would not normally occur 
(Yensen 1982; Billings 1994). Though it is not known when cheatgrass 
became so abundant in the sagebrush ecosystem as to allow extensive 
fires in the western Great Basin, these fires were common as early as 
the mid-1930s (Billings 1994). Range fire intervals on the Snake River 
Plain in Idaho may have been 50 to 100 years (Whisenant 1990, cited in 
Gabler 1997). Whisenant (1990, cited in Gabler 1997) indicates this 
interval currently occurs at 3 to 5 years, and that the burns are more 
extensive and leave fewer patches of unburned habitat within the burned 
areas. With cheatgrass cover, fire frequency increases and sagebrush 
are unable to reestablish (Whisenant 1990, cited in Gabler 1997).
    The petition states that numerous and extensive fires have occurred 
in States where pygmy rabbits occur. Wildfires have reduced more than 
50 percent of sagebrush acreage in some areas in Idaho and Nevada (BLM 
2000). In Idaho a number of fires have occurred during the last decade 
that have exceeded 100,000 ac (40,469 ha) (Roberts 2003). In Nevada, 
1,277 fires in 2001, impacted 654,253 ac (264,768 ha) on public and 
private lands (BLM 2001a). In 2002, BLM reported 771 fires that 
impacted 77,551 ac (31,384 ha) on public and private lands in Nevada 
(BLM 2002).
    According to Gabler (1997), range fires may be a more serious 
threat to pygmy rabbit populations now than in the past. Roberts (1998) 
stated that of the 583,600 ac (236,175 ha) he inventoried in Idaho, 
about 2,500 ac (1,012 ha) had been temporarily removed due to fire (a 
loss of 0.4 percent). White and Bartels (2002) indicated that of the 
133,067 ac (53,851 ha) surveyed, 23,660 ac (9,575 ha) had been affected 
by wildfire within the last 15 years. Gabler (1997) mentions that 12.5 
percent of her predicted pygmy rabbit habitat in Idaho was destroyed by 
fires during 1994-1996.
    The petition cites several instances of fire impacting pygmy rabbit 
populations locally across its range. In Idaho, Austin (2002) indicated 
a burrow system was no longer occupied by pygmy rabbits following an 
escaped BLM controlled burn. White and Bartels (2002) discuss that 
wildfires in the 1990s at INEEL severely affected the pygmy rabbit 
population, though some individuals remained. Gates and Eng (1984, 
cited in Tesky 1994) reported that 2 months following a fire in big 
sagebrush-grassland community in Idaho, only 3 of

[[Page 29260]]

11 located 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 abandoned their home 
ranges and moved to new home ranges in adjacent unburned sites. Of the 
six rabbits remaining on the burn site, only one survived the winter. 
Pygmy rabbit habitat in Benton County, Washington, was destroyed by 
fire soon after its discovery in 1979 (WDFW 1995). The population at 
the Coyote Canyon site in Washington showed a dramatic decline in 1999 
following a fire (WDFW 2001).
    Roberts (2003) suggests that sagebrush habitat can be regenerated 
within 30 to 50 years but how long it takes for pygmy rabbits to 
recolonize is unknown. Roberts (2001) mentions a 1966 burn near Gilmore 
Summit, Idaho, that has not regenerated to suitable habitat and which 
pygmy rabbits have not recolonized. White and Bartels (2002) state that 
after the removal of sagebrush habitat along the Snake River Plain, the 
area from Jerome to Idaho Falls, Idaho, became important pygmy rabbit 
habitat. This area was recently burned and reseeded with crested 
wheatgrass. Rauscher (1997) 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 pre-burn levels. White and Bartels (2002) suggest 
that the current low abundance and populations of the species is likely 
due to recent wildfires and slow rate of habitat recovery.
Evaluation of Information in the Petition
    The information in the petition indicates that fire has impacted 
sagebrush ecosystems, that there have been increased numbers of fires 
in this system, and that pygmy rabbits have been negatively affected in 
some local areas within their range due to fire. But pygmy rabbits are 
not distributed uniformly across the full range of the sagebrush 
ecosystem in the western United States, and only occur in areas where, 
at a minimum, dense sagebrush and deep, loose soils are found (Green 
and Flinders 1980a; Weiss and Verts 1984). The petitioners did not 
provide substantial information that demonstrates that the areas of the 
sagebrush ecosystem impacted by fires, and those subject to increased 
fire frequency, are also the areas occupied by pygmy rabbits, with the 
exception of a limited number of cases, mostly from Idaho. Also, the 
petition does not provide substantial information to document how much 
of the sagebrush ecosystem where pygmy rabbits occur has been impacted 
by fire. Therefore, we conclude that the petition has not presented 
substantial information that fire in the sagebrush ecosystem is a 
factor that may threaten the continued existence of the pygmy rabbit 
throughout all or a significant portion of its range.
Urban and Suburban Development
    The petition identifies habitat loss from rural and urban 
development as a negative impact to pygmy rabbits and their habitat. 
This includes the infrastructure that accompanies such development. 
(i.e., roads, powerlines, pipelines). Historic destruction of sagebrush 
habitat for urban development has occurred (Braun 1998). More recent 
expansion into rural areas is resulting in additional sagebrush habitat 
loss (Braun 1998), as well as introducing nonnative predators such as 
domestic pets to these areas (Connelly et al. 2000). Janson (2002) 
discovered that one of his 1940s pygmy rabbit study areas was impacted 
by residential and commercial development near Cedar City, Utah, when 
revisited in 2001. White and Bartels (2002) also found that urban 
development had impacted historic pygmy rabbit locations in Idaho.
Evaluation of Information in the Petition
    The petition indicates that some sagebrush habitat has been lost 
due to development, and that in some specific instances pygmy rabbits 
have been impacted locally. With the exception of these few local 
examples, the petitioners do not provide substantial information to 
document that the areas impacted by development are the same as those 
where the pygmy rabbit occurs, nor do they provide any documentation 
that indicates how much pygmy rabbit habitat has been lost to urban and 
suburban development across its range. Therefore, we conclude that the 
petition has not presented substantial information that urban and 
suburban development in the sagebrush ecosystem is a factor that may 
threaten the continued existence of the pygmy rabbit throughout all or 
a significant portion of its range.
    The petition contends that mining and associated facilities 
threaten sagebrush habitats, thereby negatively impacting pygmy 
rabbits. The petition provides the following information to support 
this claim. Sagebrush habitat throughout the west has been impacted by 
gold, coal, and uranium mining (Braun 1998). Immediate impacts include 
direct loss from mining and construction of associated facilities, 
roads, and power lines (Braun 1998). In western North America, 
development of mines and energy resources began before 1900 (Robbins 
and Wolf 1994, cited in Braun 1998). Mining occurs across large areas 
in northern Nevada where pygmy rabbits are known to occur (Nevada 
Natural Heritage Program 2002). In California, pygmy rabbits have been 
observed in the area around Bodie, a mining town that was abandoned in 
the mid-1930s (Severaid 1950).
Evaluation of Information in the Petition
    Though the petition provides general information on mining 
activities where pygmy rabbit habitat may occur, it does not present 
substantial information that correlates mining activities with the 
direct loss of pygmy rabbits or their habitat, nor does it quantify the 
extent of this effect across the range of the species.
Energy Development
    The petition contends that energy development and associated 
facilities threaten sagebrush habitats thereby negatively impacting 
pygmy rabbits. The petition identifies habitat loss from energy 
development (i.e., oil, gas, and geothermal energy) as a negative 
impact to the pygmy rabbit. Millions of acres of western lands are in 
production for oil and gas energy. Other western lands have been 
developed for geothermal energy, but the number of acres is much lower 
than for oil and gas. Energy development involves construction of well 
pads, roads, pipelines, and other associated facilities. The 
petitioners specifically mention concerns with oil, gas, and coal bed 
methane development in Wyoming and they cite proposals for energy 
production in sagebrush habitats in this State. The Jack Morrow Hills 
Supplemental Draft Environmental Impact Statement (DEIS) (2002, cited 
in Committee for the High Desert et al. 2003) proposes oil, gas, and 
coalbed methane production in sagebrush habitats north of Rock Springs, 
Wyoming. The scoping notice for the South Piney Natural Gas Development 
Project (2002, cited in Committee for the High Desert et al. 2003) 
proposes the possible development of 210 new natural gas wells on 
31,000 ac (12,545 ha) in southwestern Wyoming. The Pinedale Anticline 
DEIS (2002, cited in Committee for the High Desert et al. 2003) 
indicates that large areas of Lincoln, Uinta, Sublette and Sweetwater 
Counties with existing and potential oil and gas development are 
planned. The Upper Green River Valley Coalition

[[Page 29261]]

(2003, cited in Committee for the High Desert et al. 2003) predicts 
that the Green River Valley will be a major natural gas production 
region in the United States. In addition, BLM's Kemmerer Field Office 
contains a log of 100 oil, gas, and other energy related actions, and 
the Rock Springs Field Office contains a register of over 70 oil, gas, 
coal, and other energy related actions (Committee for the High Desert 
et al. 2003).
    The petition contends that wind energy and geothermal energy 
development threaten sagebrush habitats and, therefore, pygmy rabbits 
in Idaho and Nevada. The petition cites a proposed wind power project 
to be located west of Salmon Falls Reservoir, Idaho (Jarbidge BLM 
Environmental Assessment (EA) 2003, cited in Committee for the High 
Desert et al. 2003). On adjacent BLM lands, along the Nevada/Idaho 
border, meteorlogical towers have been installed to determine the 
feasibility of these areas for wind energy development. Both White and 
Bartels (2002) and Roberts (2003) found pygmy rabbit populations in 
this region. The petition cites a Battle Mountain Geothermal 
environmental assessment (2002, cited in Committee for the High Desert 
et al. 2003) which could authorize geothermal leasing and exploration 
on 4.3 million (1.7 million ha) of BLM lands in Nevada, including areas 
of occupied pygmy rabbit habitat. Nielsen et al. (2002) indicates 
geothermal development sites located in big sagebrush habitats in all 
western states in portions of pygmy rabbit habitat except in Wyoming.
Evaluation of Information in the Petition
    While the petition provides some information regarding oil, gas, 
and coal bed methane production in Wyoming, it does not present 
substantial information that this development has resulted in losses of 
large amounts of pygmy rabbit habitat. Much of the information in the 
petition identifies potential impacts rather than actual impacts. And 
while information in the petition indicates that wind power and 
geothermal energy development projects are occurring or planned in 
areas of pygmy rabbit habitat, the petition does not present 
substantial information to correlate this development with reductions 
in pygmy rabbit habitat that may affect their reproduction and survival 
throughout all or a significant portion of their range. Therefore, we 
conclude that the petition has not presented substantial information 
that habitat degradation and loss due to energy development may 
threaten the continued existence of the pygmy rabbit throughout all or 
a significant portion of the range.
Power Lines, Fences, and Roads
    The petition contends that the construction of power lines, fences, 
and roads results in direct sagebrush habitat loss, provides raptor 
perches that facilitate predation, facilitates the spread of weeds, 
disrupts pygmy rabbit dispersal corridors, and increases human access 
for recreational activities, all of which impact pygmy rabbits and 
their habitat. Sagebrush habitat contains power lines, fences, and 
roads associated with urban and rural development, grazing, mining and 
energy development, and recreation. Power poles and fences can provide 
hunting and roosting perches, and nesting support, for many raptor 
species that can prey upon pygmy rabbits. These power lines and fences 
are often accompanied by maintenance roads that may serve as travel 
corridors for predators, spread weeds, and offer access for hunters and 
recreationists. Power lines occur throughout occupied pygmy rabbit 
habitat, such as through the Big Lost Valley and INEEL lands in Idaho 
(Committee for the High Desert et al. 2003).
    The petition also contends roads disrupt the dispersal capabilities 
of pygmy rabbits, and it provides the following information to support 
this claim. Bradfield (1974) suggested that pygmy rabbits were 
reluctant to cross open areas based on the lack of highway mortality 
(Gordon 1932, Sperry 1933, Smith 1943, cited in Bradfield 1974). Others 
(Weiss and Verts 1984; Roberts 2001) have reiterated this comment. 
Rauscher (1997) reported use of a subnivian (layer between snow and 
soil surface) tunnel that extended across a back country road near 
Badger Pass, Montana. Jones (1957) mentions a pygmy rabbit winter road 
kill in California north of Crowley Lake, Mono County. Rauscher (1997) 
found pygmy rabbits crossed relatively small open areas (1,500 ft (457 
m)) to reach suitable habitat in Montana. Katzner and Parker (1998) 
report a pygmy rabbit traveling long distance (2.2 mi (3.5 km)) through 
open habitat likely unsuitable for long-term habitation. This suggests 
that fragmented populations may not be as isolated as previously 
suggested and has implications for recolonization of nearby areas.
Evaluation of Information in the Petition
    The petition does not provide substantial information that directly 
relates the actual and potential impacts of power lines, fences, and 
roads to the significant loss of pygmy rabbits or their habitat. The 
information in the petition does not directly implicate that activities 
related to power lines, fences, and roads are threatening pygmy 
rabbits; the information provided is ``anecdotal'' and/or speculative 
in nature, and not comprehensive. Therefore, we conclude that the 
petition has not presented substantial information that power lines, 
fences, and roads in the sagebrush ecosystem are factors that may 
threaten the continued existence of the pygmy rabbit throughout all or 
a significant portion of their range.
Activities on Military Facilities
    Military facilities occur within the range of the pygmy rabbit. The 
petition claims that impacts of military operations could involve 
direct mortality to pygmy rabbits and cause loss and degradation of 
sagebrush habitats. The U.S Air Force (USAF) has constructed roads and 
an electronic training range site and other facilities in Owyhee 
County, Idaho (USAF 1998, cited in Committee for the High Desert et al. 
2003). According to the petition, one emitter site and access road is 
located less than 2.0 mi (3.2 km) from occupied pygmy rabbit habitat 
reported by Roberts (2003). These facilities increase pygmy rabbit 
habitat degradation and fragmentation by facilitating weed invasion and 
increased fire potential. Noise levels due to training exercises may 
also impact pygmy rabbits.
Evaluation of Information in the Petition
    The petition does not provide substantial information that 
documents the actual loss of pygmy rabbits and their habitat by 
military activities, and how this may threaten the survival of the 
species across its range.
Recreational Activities
    The petition contends that recreation, especially ORV/OHV and 
snowmobile use, threatens pygmy rabbit and sagebrush habitats by 
disturbing individuals, damaging sagebrush, damaging burrows or 
subnivian tunnels, increasing the spread of weeds, and increasing human 
presence and pets in the area. Much of the sagebrush habitat occupied 
by pygmy rabbits is open to recreational use. Bradfield (1974) 
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. Thus, passing vehicle noise may make the 
pygmy rabbit more vulnerable to predation. The petition cites a BLM 
document indicating that a proposed OHV/ORV race in Idaho could

[[Page 29262]]

damage pygmy rabbit burrows (Jarbidge Field Office BLM 2003, cited in 
Committee for the High Desert et al. 2003). Austin (2002) found weed 
infestation highest in areas of greatest disturbance, which included 
ORV use areas in his Idaho study areas.
Evaluation of Information in the Petition
    As presented in the petition, the information on recreational 
impacts is speculative. We conclude that the petition does not provide 
substantial information that describes how recreation activities 
threaten pygmy rabbits and their habitats.
Habitat Manipulations for Other Species
    Connelly et al. (2000) recommend managing sagebrush canopy cover 
for 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, which can be greater than the 10 
to 30 percent range (Green and Flinders 1980b; Weiss and Verts 1984) 
suggested for various sage grouse habitats. Reducing dense sagebrush 
cover to benefit sage grouse may be in conflict with the needs of pygmy 
Evaluation of Information in the Petition
    While we share a concern that large scale vegetation manipulations 
to benefit sage grouse may negatively impact pygmy rabbit habitat, the 
petition does not provide substantial information to document the 
magnitude and extent of this concern for pygmy rabbits throughout their 
Summary of Habitat Threats
    While a variety of anthropogenic activities that affect sagebrush 
(e.g., agriculture, grazing, mining) are occurring across the range of 
the pygmy rabbit, the petition does not provide substantial information 
that these activities, either singly or in combination with one 
another, are destroying or modifying pygmy rabbit habitat over all or a 
significant portion of the species' range. Also, with limited 
exceptions, the petition fails to provide scientific documentation to 
demonstrate that the areas where sagebrush habitat loss and degradation 
are occurring are also the areas where pygmy rabbit populations occur. 
Additionally, the petition does not provide substantial information to 
document what the effects of these anthropogenic changes are on pygmy 
rabbit population numbers across the range of the species. Based on the 
preceding discussion, we do not believe that substantial information is 
available indicating that the present or threatened destruction, 
modification, or curtailment of habitat or range may, either singularly 
or in combination with other factors, rise to the level of a threat to 
the continued existence of the species throughout all or a significant 
portion of the species' range.

B. Overutilization for Commercial, Recreational, Scientific, or 
Educational Purposes

    The petition contends that pygmy rabbit populations at low levels 
could be harmed due to hunting mortality and research activities. The 
petition also notes the difficulty in distinguishing pygmy rabbits from 
other rabbit species, especially cottontails (Sylvilagus spp.) (Garber 
and Beauchaine 1993), and claims that this difficulty could lead to 
accidental shootings. The petition contends that road networks 
associated with energy, pipeline, powerline, mining, and development 
provide travel corridors for hunters, increasing the likelihood of 
pygmy rabbit mortality.
    The following information from the petition summarizes potential 
impacts to the species from hunting. Williams (1986) stated that 
although hunting impacts were not known in California, he thought that 
hunters probably did not kill many because the species was quite 
secretive and rarely left dense brush. Rauscher (1997) reported pygmy 
rabbit hunting in southwestern Montana, but stated that hunting did not 
appear to be a significant mortality factor. Fisher (1979) recommended 
that bag limits be monitored in Idaho, 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. Pritchett et al. (1987) reported that, according to locals 
near Loa, in 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) found spent shotgun 
shells. He thought it was probable that some pygmy rabbits were shot 
because most hunters do not distinguish between pygmy rabbits and 
    The petition also contends that shooting or poisoning likely caused 
pygmy rabbit population declines in the past even though jackrabbits 
were primarily taken. While we are aware that rabbit drives occurred 
(Bacon et al. 1959; Jackman and Long 1965), there is little 
documentation on the impacts to pygmy rabbits. Bacon et al. (1959) 
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.
    Currently, only three (California, Montana, and Nevada) of the 
eight States where the pygmy rabbit occurs allow hunting. For those 
States that allow hunting of pygmy rabbits, the State Wildlife Boards 
of Commissioners set hunting regulations yearly. In California the 
hunting season extends from July 1 to the last Sunday in January with a 
bag limit of 5 per day and 10 in possession (Pat Lauridson, California 
Department of Fish and Game, pers. comm. 2005). The 2004 pygmy rabbit 
hunting season in Nevada opened October 9 and closed February 28 with a 
daily limit of 10 and a possession limit of 20 (Sandy Canning, Nevada 
Department of Wildlife, pers. comm. 2005). For Montana, information on 
hunting seasons is more limited. Based on the Montana Fish, Wildlife 
and Parks webpage pygmy rabbits can be hunted year round and there is 
no bag limit. For the three States that allow hunting of this species, 
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.
Evaluation of Information in the Petition
    The petition did not provide, nor are we aware of, any long-term 
historic or recent hunting data that would clarify past or current 
hunting pressure on the pygmy rabbit across its range. This includes a 
lack of information related to poaching and accidental shootings. The 
petition does not provide substantial information indicating that 
hunting may threaten the continued existence of the species across all 
or a significant portion of its range.
    The petition presents the following information on the threat of 
research activities to pygmy rabbits. Research activities on the 
species that involve trapping, handling, and holding them for a period 
of time can result in mortality from exposure, injury, trap

[[Page 29263]]

predation, intraspecific fighting, and capture stress (Wilde 1978; Gahr 
1993; Rauscher 1997). Mortality rates reported for captured pygmy 
rabbits have been 3 percent (Gahr 1993), 5 percent (Wilde 1978), and 19 
percent (Rauscher 1997). Investigations may also involve digging out of 
burrows, stepping on burrows accidentally, measuring vegetation and 
other site characteristics near burrows, and other general disturbance 
in the study area (Janson 1946; Bradfield 1974; Green 1978; Wilde 1978; 
Gahr 1993; Katzner 1994; Gabler 1997; Rauscher 1997). Katzner (1994) 
reported that all of his radio-collared rabbits (10) died. He suggested 
the weight of the radiocollars, and increased grooming as a result of 
their presence, may have increased a rabbits' vulnerability to 
Evaluation of Information in the Petition
    While these actions can be of concern for small populations such as 
in Washington (66 FR 59734, 68 FR 10388), the petition did not 
adequately describe how conducting research activities within pygmy 
rabbit habitats may threaten the continued existence of the species. 
Therefore, we conclude that the petition does not present substantial 
information to indicate that conducting research activities within 
pygmy rabbit habitat threatens the existence of pygmy rabbits 
throughout all of a significant portion of their range.

C. Disease or Predation

    The petition contends that disease likely poses a serious threat to 
remaining pygmy rabbit populations. A lack of adequate food or an 
increase in stress associated with altered sagebrush habitat throughout 
its range, could increase the species' susceptibility to disease. It 
also states predation may not represent a significant threat to 
relatively large well-distributed populations, but may have an impact 
on small pygmy rabbit populations in degraded habitats. The petition 
also mentions West Nile Virus as a growing concern for all native 
wildlife including pygmy rabbits. The petition cites the following 
information to support these claims.
    Pygmy rabbits can harbor high parasite loads (Janson 1946; Wilde 
1978; Gahr 1993; WDFW 1995; 66 FR 59734). These parasites include 
ticks, fleas, lice, and bot flies (Dice 1926; Janson 1946; Larrison 
1967; Wilde 1978; Gahr 1993; Rauscher 1997), which can be vectors of 
disease. Reports of episodes of plague and tularemia from these vectors 
in populations of other leporid species indicate they often spread 
rapidly and can be fatal (Quan 1993, cited in 68 FR 10388). There have 
been no reports of severe disease epidemics occurring in pygmy rabbits 
(68 FR 10388). Parasites and disease have not been regarded as a major 
threat to pygmy rabbits (Wilde 1978; Green 1979, cited in 68 FR 10388).
    Gahr (1993) found bot flies only on pygmy rabbits located in the 
grazed area of her study, indicating that cattle may act as a vector 
for spreading parasites and possibly disease. She only had two rabbits 
with bot flies. 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. Siegel (2002) and Austin (2002) also 
expressed concern that disease transport and transmission by domestic 
livestock to pygmy rabbits could be a threat. Austin (2002) raised the 
concern that a calicivirus, such as Rabbit Hemorrhagic Disease, could 
explain declines in pygmy rabbit populations and suggests additional 
research is needed. Janson (2002) reported that no obviously diseased 
pygmy rabbits were seen in his earlier work in the 1940s. He thought it 
may be likely that disease reduced pygmy rabbit populations 
periodically when they reached high densities.
    Predation is the main cause of pygmy rabbit mortality (Wilde 1978; 
Green 1979, cited in 68 FR 10388). As discussed in the background 
section, pygmy rabbits have numerous predators and have adapted to 
their presence (Janson 1946; Gashwiler et al. 1960; Green 1978; Wilde 
1978). The petition contends that habitats degraded by grazing and its 
associated facilities, or other actions can damage the structural 
components of the sagebrush habitat as well as increase or redistribute 
predators, thus increasing the pygmy rabbit's vulnerability to 
predation. Weiss and Verts (1984) thought that use of denser and taller 
sagebrush habitats by pygmy rabbits was related to predator avoidance. 
Katzner (1994) documented that raptors were a cause of mortality and 
denser sagebrush cover deterred these avian predators. The petition 
also includes vertical structures, such as fences and powerlines, as 
features providing raptor perches and possibly impacting pygmy rabbit 
populations, as discussed earlier. Siegel (2002) suggested that 
artificial livestock watering possibly increased coyote numbers in 
Evaluation of Information in the Petition
    Disease and predation may be significant threat factors to small 
pygmy rabbit populations. Habitat degradation and fragmentation may 
increase the effects of disease, parasites, and predation on some 
populations. However, the petition does not adequately describe how the 
species' continued survival over all or a significant portion of its 
range is threatened by disease and predation. The information presented 
indicates that these potential threats have not been evaluated, and 
that further research is needed to determine actual impacts to pygmy 
rabbits. Thus the petition does not provide substantial information to 
indicate that disease or predation may threaten pygmy rabbits over all 
or a significant portion of its range.

D. Inadequacy of Existing Regulatory Mechanisms

    The petition contends that State and Federal agencies have failed 
to conduct monitoring for the species in most of its range and to 
protect it from numerous direct and indirect impacts associated with 
livestock grazing, prescribed and wild fires, energy exploration and 
development, vegetation manipulation, weed invasion, roads, and OHV/ORV 
proliferation (see Factor A). The petition contends that mechanisms to 
regulate and control these various activities have failed to prevent 
harm to pygmy rabbit habitat in a significant portion of its range. The 
petition cites the following information to support these claims.
    A large portion of pygmy rabbit habitat occurs on BLM lands. BLM 
has designated the pygmy rabbit as a special status species/bureau 
assessment species in five of the seven States in which it occurs 
(Idaho, Montana, Nevada, Oregon, and Wyoming). Special status species 
management is discussed in BLM's 6840 Manual, ``Special Status Species 
Management'' (BLM 2001b). 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. Currently, there are no regulations requiring BLM land use 
plans to address the conservation needs of special status species (BLM 
    According to the petition, the U.S. Forest Service (USFS) does not 
include the pygmy rabbit as a Management Indicator Species in any of 
the States where the pygmy rabbit occurs (Committee for the High Desert 
et al. 2003) on USFS lands. Pygmy rabbit habitat also occurs on lands 
managed by other Federal agencies such as the Service and National Park 
    Currently, hunting of pygmy rabbits is allowed in three of the 
eight States within the species' range (Committee for the High Desert 
et al. 2003). Hunting of pygmy rabbits is not allowed in Idaho

[[Page 29264]]

or Wyoming, where they are considered a species of special concern, or 
in Utah where they are considered a sensitive species. Hunting is also 
not allowed in Oregon, where the pygmy rabbit is protected from take. 
In Montana, the pygmy rabbit is also considered a species of concern, 
but there is no protection from take. According to the petition, 
Wyoming is the only state that has a management plan for the pygmy 
rabbit (Committee for the High Desert et al. 2003). In Washington, the 
pygmy rabbit was listed as threatened in 1990 by the Washington 
Wildlife Commission (Commission). In 1993, the Commission reclassified 
the species as endangered (WDFW 1995). A recovery plan for the species 
was completed in 1995, and an addendum to the plan was prepared in 2001 
(WDFW 1995, 2001).
Evaluation of Information in the Petition
    Based on the information in the petition, the primary concern 
expressed by the petitioners regarding the inadequacy of existing 
regulatory mechanisms is related to pygmy rabbit habitat conservation. 
Sagebrush habitat degradation and loss, discussed under Factor A, is 
due mostly to human activities as opposed to natural events. However, 
the petition does not provide substantial scientific information that 
quantifies impacts to pygmy rabbit habitat rangewide, or the level of 
significance of these threats to pygmy rabbit populations. Thus, we 
conclude that the petition does not present substantial information to 
indicate that pygmy rabbits are threatened by the inadequacy of 
existing regulatory mechanisms across all or a significant portion of 
its range.

E. Other Natural or Manmade Factors Affecting the Species Continued 

    The petition contends that several other factors, not discussed 
above, negatively impact pygmy rabbit populations. These include: 
intra- and interspecific competition, habitat fragmentation, natural 
stochastic (random) events such as floods and drought; mortality caused 
by collisions with OHV/ORV, snowmobiles, and automobiles; and life 
history traits. The petitioners are also concerned that habitat 
manipulations taken to benefit sage grouse may negatively impact pygmy 
rabbit. Lastly, the petition claims that predator control to benefit 
livestock may have a negative impact on pygmy rabbits.
    The petition suggests that because pygmy rabbits are extreme 
habitat specialists, intraspecific competition among individuals may be 
exacerbated under environmental stress such as drought. The petition 
also contends interspecific competition with other herbivores for 
sagebrush such as jackrabbits (Wilde 1978), pronghorn, and mule deer, 
could occur. Large populations of jackrabbits from past decades are 
likely gone, but as sagebrush is reduced across the range, they may 
compete with pygmy rabbits at lower population levels. Conde (1982) 
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) 
and jackrabbits on 2-year old woody stems (Currie and Goodwin 1966, 
cited in Conde 1982). Spatial distribution and exploitation of 
different vegetation in the summer allow a sympatric relationship to 
occur between these two species (Conde 1982).
    Siegel (2002) at Sagebrush Flat, Washington, found cottontails 
inhabited burrows dug by pygmy rabbits, but it is unclear if 
cottontails were displacing pygmy rabbits. Cottontails may use burrows 
after they are abandoned by pygmy rabbits, because 60 percent of the 
burrows used by cottontails had not shown pygmy rabbit use on the date 
the burrow was last checked. Siegel (2002) found pygmy rabbits reused 
burrows in summer that had been occupied by cottontails the previous 
    Grazing competition with livestock will depend on the range 
conditions and grazing practices that vary across the range of the 
pygmy rabbit. At Sagebrush Flat, Washington, Siegel (2002) determined 
that livestock grazing seasonally reduced the quantity of preferred 
vegetation by pygmy rabbits as well as reduced the nutritional quality 
of the forage. By spring, fewer differences were noted, likely 
reflecting the new spring growth. 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 winter range, other 
sagebrush winter ranges, and the range of pygmy rabbits. Hence, 
interspecific competition may result (Janson 2002). No substantial 
scientific information regarding the effects of intra- and 
interspecific competition on pygmy rabbits has been provided.
    The petition identifies habitat fragmentation as a threat to pygmy 
rabbits as it results in small, isolated populations surrounded by vast 
areas of inhospitable lands (Austin 2002; White and Bartels 2002; 
Roberts 2003). Habitat fragmentation can influence size, stability, and 
success of pygmy rabbit populations because of their low dispersal 
capabilities (Katzner and Parker 1997). Bartels (2003) suggested that 
pygmy rabbit distribution may be more fragmented than previously 
thought due to the limited availability of suitable habitat and their 
absence from large areas of sagebrush. Bartels (2003) suggested other 
disturbances, such as habitat fragmentation, seeding after wildfires, 
improper range improvements, sagebrush removal, development, 
agriculture, sagebrush diseases, and floods, are all contributing 
    The petition claims that because most of the remaining pygmy rabbit 
populations are small, they are vulnerable to environmental and 
demographic stochasticity. Natural stochastic events can significantly 
impact local populations if they result in high mortality, habitat 
loss, or little or no possibility of recolonization. They are most 
significant for small or fragmented populations. Small, isolated 
populations are also at a greater risk to the deleterious effects of 
demographic and genetic problems (Schaffer 1981). The petition cites a 
concern with flooding which may cause burrow abandonment, mortality, 
and erosion of deep soils. Pygmy rabbits are known to use deeper soils 
found along drainages for burrows (Flath and Rauscher 1995). Bartels 
and Hays (2001) state that historic pygmy rabbit habitat was lost in 
Oregon and Idaho due to flooding. White and Bartels (2002) reported 
that uncontrolled floods at the Sagebrush Flat site in Washington were 
a major reason for loss of individuals during 1996 to 1997. Bartels 
(2003) mentions a large flood event in pygmy rabbit habitat in the 
Harney Basin, Oregon, in 1984. Natural stochastic events have not been 
reported as types of events that have played a significant role in 
population abundance and/or trends for the pygmy rabbit range wide, nor 
did the petition provide substantial scientific information that 
current pygmy rabbit populations are small or isolated.
    Because the pygmy rabbit is a habitat specialist, and its climax-
type habitat is highly fragmented and occurs across the landscape, the 
petition contends the species' life history traits could affect 
population viability. Pygmy rabbits have small home ranges, are not 
evenly distributed across the species' range, and appear to have poor 
dispersal and low reproduction capabilities. Pygmy rabbits do not 
respond to abundant spring food supply by producing

[[Page 29265]]

additional litters like other rabbits (Wilde 1978). These factors may 
explain the slow recolonization of vacated habitat even under normal 
conditions (Heady et al. 2001). However, though the pygmy rabbit is a 
habitat specialist, the petition does not present substantial 
information on how the pygmy rabbit's natural history characteristics 
have limited the species across its range.
    Lastly, the petition does not provide supporting documentation that 
supports the claim that predator control for livestock benefits 
increases predation on pygmy rabbits.
    Based on the foregoing discussion, we do not believe that the 
petition has presented substantial scientific information to indicate 
that natural or manmade factors threaten the continued existence of 
pygmy rabbits throughout all or a significant portion of the species' 
    We have reviewed the petition and literature cited in the petition, 
and evaluated that information in relation to other pertinent 
literature and information available in our files. After this review 
and evaluation, we find the petition does not present substantial 
information to indicate that listing the pygmy rabbit may be warranted 
at this time. Although we will not be commencing a status review in 
response to this petition, we will continue to monitor the species' 
population status and trends, potential threats, and ongoing management 
actions that might be important with regard to the conservation of the 
pygmy rabbit across its range. We encourage interested parties to 
continue to gather data that will assist with the conservation of the 
species. If you wish to provide information regarding the pygmy rabbit, 
you may submit your information or materials to the Field Supervisor, 
Nevada Fish and Wildlife Office (see ADDRESSES section above).

References Cited

    A complete list of all references cited herein is available, upon 
request, from the Nevada Fish and Wildlife Office (see ADDRESSES 


    The primary author of this notice is Marcy Haworth, U.S. Fish and 
Wildlife Service, Nevada Fish and Wildlife Office (see ADDRESSES).


    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: May 12, 2005.
Marshall P. Jones, Jr.,
Acting Director, Fish and Wildlife Service.
[FR Doc. 05-10056 Filed 5-19-05; 8:45 am]