Endangered and Threatened Wildlife and Plants; 12-Month Finding on a Petition To List a Distinct Population Segment of the Fisher in Its United States Northern Rocky Mountain Range as Endangered or Threatened With Critical Habitat, 38504-38532 [2011-16349]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 76, Number 126 (Thursday, June 30, 2011)]
[Proposed Rules]
[Pages 38504-38532]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-16349]



[[Page 38503]]

Vol. 76

Thursday,

No. 126

June 30, 2011

Part III





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 a Distinct Population Segment of the Fisher in Its 
United States Northern Rocky Mountain Range as Endangered or Threatened 
With Critical Habitat; Proposed Rule

Federal Register / Vol. 76 , No. 126 / Thursday, June 30, 2011 / 
Proposed Rules

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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[Docket No. FWS-R6-ES-2010-0017; MO 92210-0-0008]


Endangered and Threatened Wildlife and Plants; 12-Month Finding 
on a Petition To List a Distinct Population Segment of the Fisher in 
Its United States Northern Rocky Mountain Range as Endangered or 
Threatened With Critical Habitat

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Notice of 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 a distinct population segment 
(DPS) of the fisher (Martes pennanti) in its U.S. Northern Rocky 
Mountain range, including portions of Montana, Idaho, and Wyoming, as 
endangered or threatened and designate critical habitat under the 
Endangered Species Act of 1973, as amended (Act). After review of all 
available scientific and commercial information, we find that listing 
the fisher in the U.S. Northern Rocky Mountains as threatened or 
endangered is not warranted at this time.

DATES: The finding announced in this document was made on June 30, 
2011.

ADDRESSES: This finding is available on the Internet at https://www.regulations.gov at Docket Number FWS-R6-ES-2010-0017. Supporting 
documentation we used in preparing this finding is available for public 
inspection, by appointment, during normal business hours at the U.S. 
Fish and Wildlife Service, Montana Field Office, 585 Shepard Way, 
Helena, MT 59601; telephone (406) 449-5225. We ask the public to submit 
any new information that becomes available concerning the status of, or 
threats to, the fisher, in addition to new information, materials, 
comments, or questions concerning this finding, to the above address. 
No information will be accepted by facsimile. The petition finding, 
related Federal Register notices, and other pertinent information, may 
be obtained online at https://www.fws.gov/mountain-prairie/species/mammals/fisher/.

FOR FURTHER INFORMATION CONTACT: Mark Wilson, Field Supervisor, Montana 
Ecological Services Field Office (see ADDRESSES); or by telephone at 
(406) 449-5225. If you use a telecommunications device for the deaf 
(TDD), call the Federal Information Relay Service (FIRS) at (800) 877-
8339.

SUPPLEMENTARY INFORMATION: 

Background

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

Previous Federal Actions

U.S. Northern Rocky Mountains
    On March 6, 2009, we received a petition dated February 24, 2009, 
from the Defenders of Wildlife, Center for Biological Diversity, 
Friends of the Bitterroot, and Friends of the Clearwater (petitioners) 
requesting that the fisher in the Northern Rocky Mountains of the 
United States (USNRMs) be considered a DPS and listed as endangered or 
threatened, and critical habitat be designated under the Act (Defenders 
of Wildlife et al. 2009, entire). In an April 9, 2009, letter to the 
petitioners, we responded that we had reviewed the information 
presented in the petition and determined that issuing an emergency 
regulation temporarily listing the species under section 4(b)(7) of the 
Act was not warranted (Guertin 2009, entire). We informed the 
petitioners that due to staffing and funding constraints in Fiscal Year 
2009, we would not be able to further address the petition at that 
time, but would complete the action when resources allowed. We 
published a 90-day finding on April 16, 2010, stating that the petition 
presented substantial information that listing a DPS of fisher in the 
USNRMs may be warranted, and initiated a status review of the species 
(75 FR 19925). The notice of a 90-day finding and commencement of a 12-
month status review for the USNRMs DPS was published in the annual 
Candidate Notice of Review on November 10, 2010 (75 FR 69222).
    Fishers in the USNRMs were previously petitioned for listing with a 
U.S. Pacific States' population in 1994 (see below).
U.S. Pacific States
    On June 5, 1990, we received a petition dated May 29, 1990, from 
Mr. Eric Beckwitt, Forest Issues Task Force, Sierra Biodiversity 
Project, and others requesting that the Pacific fisher (Martes pennanti 
pacifica) be listed as an endangered species in California, Oregon, and 
Washington under the Act. On January 11, 1991, we published a 90-day 
finding (56 FR 1159) indicating that the fisher in the Pacific States 
is a distinct population that is geographically isolated from 
populations in the Rocky Mountains and British Columbia and represents 
a listable entity under the Act. The finding also indicated that the 
petition had not presented substantial information indicating that a 
listing may be warranted because of a lack of information on fisher 
habitat needs, population size and trends, and demographic parameters 
(56 FR 1159).
    On December 29, 1994, we received a petition dated December 22, 
1994, from the Biodiversity Legal Foundation requesting that two fisher 
populations in the western United States, including the States of 
Washington, Oregon, California, Idaho, Montana, and Wyoming, be listed 
as threatened under the Act. Based on our review, we found that the 
petition did not present substantial information indicating that 
listing the two western United States fisher populations as a DPS was 
warranted (61 FR 8016, March 1, 1996). The best available scientific 
evidence at that time indicated that the range of the fisher was 
contiguous across Canada with some areas having abundant populations, 
and through southward peninsular extensions, was contiguous with the 
U.S. Rocky Mountain and Pacific populations (61 FR 8016). No evidence 
was presented in the petition to support physical, physiological, 
ecological, or behavioral separations (61 FR 8016).
    On December 5, 2000, we received a petition dated November 28, 
2000, from 12 organizations, with the lead organizations identified as 
the Center for Biological Diversity and the Sierra Nevada Forest 
Protection Campaign, requesting that the West Coast DPS of

[[Page 38505]]

the fisher, including portions of California, Oregon, and Washington, 
be listed as endangered and critical habitat be designated under the 
Act. A court order was issued on April 4, 2003, by the U.S. District 
Court, Northern District of California, that required the Service to 
submit for publication in the Federal Register a 90-day finding on the 
2000 petition (Center for Biological Diversity, et al. v. Norton et 
al., No. C 01--2950 SC). On July 10, 2003, we published a 90-day 
petition finding that the petition provided substantial information 
that listing may be warranted and initiated a 12-month status review 
(68 FR 41169).
    On April 8, 2004, we published a warranted 12-month finding for 
listing of the fisher's West Coast DPS (69 FR 18770). A listing action 
was precluded by higher priorities and the West Coast DPS was added to 
our candidate species list. On April 8, 2010, the Center for Biological 
Diversity, Sierra Forest Legacy, Environmental Protection Information 
Center, and Klamath-Siskiyou Wildlands Center filed a complaint in the 
United States District Court for the Northern District of California 
seeking an order for the Service to withdraw the 2004 warranted-but-
precluded finding and proceed with a proposed rule to list the species 
under the Act (Center for Biological Diversity, et al. v. Salazar, et 
al., No. CV 10--1501). A resolution of the complaint is pending.
    The West Coast fisher was included in the Service's candidate 
notices of review in 2005, 2006, 2007, 2008, 2009, and 2010 (70 FR 
24870, May 11, 2005; 71 FR 53756, September 12, 2006; 72 FR 69034, 
December 6, 2007; 73 FR 75176, December 10, 2008; 74 FR 57804, November 
9, 2009; 75 FR 69222, November 10, 2010).

Species Information

    This ``Species Information'' section concentrates on general 
biology and fisher studies conducted in the USNRMs area. Additional 
information regarding fisher biology in the western portion of its 
range can be found in the Service's 12-month finding on a petition to 
list the West Coast DPS of the fisher (69 FR 18770).
Description
    The fisher is a forest-dwelling, medium-sized mammal, light brown 
to dark blackish-brown in color, with the face, neck, and shoulders 
sometimes being slightly gray (Powell 1981, p. 1). The chest and 
underside often have irregular white patches. The fisher has a long 
body with short legs and a long bushy tail. Males range in length from 
90 to 120 centimeters (cm) (35 to 47 inches (in.)), and females range 
from 75 to 95 cm (29 to 37 in.) in length. At 3.5 to 5.5 kilograms (kg) 
(7.7 to 12.1 pounds (lbs)), male fishers weigh about twice as much as 
females (2.0 to 2.5 kg (4.4 to 5.5 lbs)) (Powell et al. 2003, p. 638). 
Heavier males have been reported across the range, including 
individuals within the USNRMs (Sauder 2010 unpublished data; Schwartz 
2010 unpublished data); an exceptional specimen from Maine weighed 9 kg 
(20.1 lbs) (Blanchard 1964, pp. 487-488). Fishers may show variation in 
typical body weight regionally, corresponding with latitudinal 
gradients. For example, fishers in the more southern latitudes of the 
U.S. Pacific States may weigh less than fishers in the eastern United 
States and Canada (Seglund 1995, p. 21; Dark 1997, p. 61; Aubry and 
Lewis 2003, p. 87; Lofroth et al. 2010, p. 10).
Taxonomy
    The ``Fisher of Pennant,'' or Mustela pennantii, was formally 
described by Erxleben in 1777, based on accounts of the same specimen 
from either the eastern United States or eastern Canada, by Buffon in 
1765 and the naturalist Thomas Pennant in 1771 (Rhoads 1898 as cited in 
Goldman 1935, p. 177; Powell 1981, p. 1). Taxonomic stability was not 
attained until 80 years after Buffon's original description, when 
taxonomists transferred the fisher to the genus Martes and changed the 
spelling of the species to pennanti (Hagmeier 1959, p. 185; Powell 
1981, p. 1; Powell 1993, pp. 11-12).
    The fisher is classified in the order Carnivora, family Mustelidae, 
a family that also includes weasels, mink, martens, and otters 
(Anderson 1994, p. 14). It is the largest member of the genus Martes, 
classified as subgenus Pekania, and occurs only in North America 
(Anderson 1994, pp. 22-23). Its geographic range overlaps extensively 
with that of the American marten (Martes americana--subgenus Martes), 
the only other Martes species in North America (Gibilisco 1994, p. 59). 
Characteristic of the subgenus Pekania is large body size compared with 
other Martes and the presence of an external median rootlet on the 
upper carnassial (fourth) premolar (Anderson 1994, p. 21).
    Goldman (1935, p. 177) recognized three subspecies of fisher based 
on differences in skull dimensions, although he stated they were 
difficult to distinguish: (1) Martes pennanti pennanti in the east and 
central regions; (2) M. p. columbiana in the central and northwestern 
regions that include the USNRMs; and (3) M. p. pacifica in the western 
coast States of the United States. A subsequent analysis questioned 
whether there is a sufficient basis to support recognition of different 
subspecies based on numerous factors, including the small number of 
samples available for examination (Hagmeier 1959, p. 193). Regional 
variation in characteristics used by Goldman to discriminate subspecies 
appears to be clinal (varying along a geographic gradient), and the use 
of clinal variations is ``exceedingly difficult to categorize 
subspecies'' (Hagmeier 1959, pp. 192-193). Although subspecies taxonomy 
as described by Goldman (1935, p. 177) is often used in literature to 
describe or reference fisher populations in different regions of its 
range, and recent consideration of genetic variation indicates patterns 
of population subdivision similar to the earlier described subspecies 
(Kyle et al. 2001, p. 2345; Drew et al. 2003, p. 59), it is not clear 
whether Goldman's designations of subspecies are taxonomically valid. 
Therefore, for the purposes of this finding, we are evaluating the 
fisher in the USNRMs as a DPS of a full species (i.e., M. pennanti).
Biology
    Fishers are opportunistic predators, primarily of snowshoe hares 
(Lepus americanus), squirrels (Tamiasciurus, Sciurus, Glaucomys, and 
Tamias spp.), mice (Microtus, Clethrionomys, and Peromyscus spp.), and 
birds (numerous spp.) (reviewed in Powell 1993, pp. 18, 102). Carrion 
and plant material (e.g., berries) also are consumed (Powell 1993, p. 
18). The fisher is one of the few predators that successfully kills 
porcupines (Erethizon dorsatum), and porcupine remains have been found 
more often in the gastrointestinal tract and scat of fisher than in any 
other predator (Powell 1993, p. 135). There is only one study reporting 
the food habits of an established fisher population in the USNRMs, and 
that study confirms that snowshoe hares, voles (Microtus and 
Clethrionomys spp.), and red squirrels (Tamiasciurus hudsonicus) are 
similarly important prey in north-central Idaho as they are in other 
parts of the range (Jones 1991, p. 87). Fishers from Minnesota 
relocated to the Cabinet Mountains of Montana subsisted primarily on 
snowshoe hare and deer (Odocoileus spp.) carrion (Roy 1991, p. 29). As 
dietary generalists, fishers across their range tend to forage in areas 
where prey is both abundant and vulnerable to capture (Powell 1993, p. 
100). Fishers in north-central Idaho exhibit seasonal shifts in habitat 
use to forests with younger successional structure plausibly linked to 
a concurrent

[[Page 38506]]

seasonal shift in habitat use by their prey species (Jones and Garton 
1994, p. 383).
    Fishers are estimated to live up to 10 years (Arthur et al. 1992, 
p. 404; Powell et al. 2003, p. 644). Both sexes reach maturity their 
first year but may not be effective breeders until 2 years of age 
(Powell et al. 2003, p. 638). Fishers are solitary except during the 
breeding season, which is generally from late February to the middle of 
May (Wright and Coulter 1967, p. 77; Frost et al. 1997, p. 607). The 
breeding period in north-western Montana and north-central Idaho is 
approximately late February through April based on observations of 
significant changes of fisher movement patterns and examination of the 
reproductive tracts of harvested specimens (Weckwerth and Wright 1968, 
p. 980; Jones 1991, pp. 78-79; Roy 1991, pp. 38-39). Uterine 
implantation of embryos occurs 10 months after copulation; active 
gestation is estimated to be between 30 and 60 days; and birth occurs 
nearly 1 year after copulation (Wright and Coulter 1967, pp. 74, 76; 
Frost et al. 1997, p. 609; Powell et al. 2003, p. 639).
    Litter sizes for fishers range from one to six, with a mean of two 
to three kits (Powell et al. 2003, pp. 639-640). Potential litter sizes 
in the USNRMs are between two to three per female, based on the 
frequency of embryos recovered from harvested females (Weckwerth and 
Wright 1968, p. 980; Jones 1991, p. 84). Newborn kits are entirely 
dependent and may nurse for 10 weeks or more after birth (Powell 1993, 
p. 67). Kits develop their own home ranges by 1 year of age (Powell et 
al. 2003, p. 640). Populations of fisher fluctuate in size, and 
reproductive rates may vary widely from year to year in response to the 
availability of prey (Powell and Zielinski 1994, p. 43).
    An animal's home range is the area traversed by the individual in 
its normal activities of food gathering, mating, and caring for young 
(Burt 1943, p. 351). Only general comparisons of fishers' home range 
sizes can be made, because studies across the range have been conducted 
by different methods. Generally, fishers have large home ranges, male 
home ranges are larger than females, and fisher home ranges in British 
Columbia and the USNRMs are larger than those in other areas in the 
range of the taxon (reviewed in Powell and Zielinski 1994, p. 58; 
reviewed in Lofroth et al. 2010, pp. 67-70). Fisher home ranges vary in 
size across North America and range from 16 to 122 square kilometers 
(km\2\) (4.7 to 36 square miles (mi\2\)) for males, and from 4 to 53 
km\2\ (1.2 to 15.5 mi\2\) for females (reviewed by Powell and Zielinski 
1994, p. 58; Lewis and Stinson 1998, pp. 7-8; Zielinski et al. 2004, p. 
652). In north-central Idaho, the movements of a small number of radio-
collared fishers indicated that males range from approximately 30 to 
120 km\2\ (8.7 to 35 mi\2\) year round, and females range from 6 to 75 
km\2\ (1.7 to 22 mi\2\), with a slight reduction in summer (Jones 1991, 
pp. 82-83). Fishers in Idaho have home ranges larger than any other 
home ranges reported within the range of the taxon (Idaho Office of 
Species Conservation (IOSC) 2010, p. 4).
    The abundance or availability of vulnerable prey may play a role in 
home range selection (Powell 1993, p. 173; Powell and Zielinski 1994, 
p. 57). Fishers exhibit territoriality, with little overlap between 
members of the same sex; in contrast, overlap between opposite sexes is 
extensive, and size and overlap are possibly related to the density of 
prey (Powell and Zielinski 1994, p. 59). Male fishers may extend or 
temporarily abandon their territories to take long excursions during 
the breeding season from the end of February to April presumably to 
increase their opportunities to mate (Arthur 1989a, p. 677; Jones 1991, 
pp. 77-78). However, males who maintained their home ranges during the 
breeding season were more likely to successfully mate than were 
nonresident males encroaching on an established range (Aubry et al. 
2004, p. 215).
    It is not known how fishers maintain territories; it is possible 
that scent marking plays an important role (Leonard 1986, p. 36; Powell 
1993, p. 170). Direct aggression between individuals in the wild has 
not been observed, although signs of fishers fighting and the capture 
of male fishers with scarred pelts have been reported (Douglas and 
Strickland 1987, p. 516). Combative behavior has been observed between 
older littermates and between adult females in captivity (Powell and 
Zielinski 1994, p. 59).
    There is little information available regarding the long-distance 
movements of fishers, although long-distance movements have been 
documented for dispersing juveniles and recently relocated individuals 
before they establish a home range. Fishers relocated to novel areas in 
Montana's Cabinet Mountains and British Columbia moved up to 163 km 
(100 mi) from release sites, crossing large rivers and making 700-m 
(2,296-ft) elevation changes (Roy 1991, p. 42; Weir and Harestad 1997, 
pp. 257, 259).
    Juveniles dispersing from natal areas are capable of moving long 
distances and navigating various landscape features such as highways, 
rivers, and rural communities to establish their own home range (York 
1996, p. 47; Weir and Corbould 2008, p. 44). In Maine and British 
Columbia, juveniles dispersed from 0.7 km (0.4 mi) to 107 km (66.4 mi) 
from natal areas (York 1996, p. 55; Weir and Corbould 2008, p. 44). 
Dispersal characteristics may be influenced by factors such as sex, 
availability of unoccupied areas, turnover rates of adults, and habitat 
suitability (Arthur et al. 1993, p. 872; York 1996, pp. 48-49; Aubry et 
al. 2004, pp. 205-207; Weir and Corbould 2008, pp. 47-48). Long-
distance dispersal by vulnerable, less experienced individuals is made 
at a high cost and is not always successful. Fifty-five percent of 
transient fishers in a British Columbia study died before establishing 
home ranges, and only one in six juveniles successfully established a 
home range (Weir and Corbould 2008, p. 44). One dispersing juvenile 
female traveled an unusually long distance of 135 km (84 mi) over 
rivers and through suboptimal habitats before succumbing to starvation 
(Weir and Corbould 2008, p. 44). Individuals traveling longer distances 
are subject to greater mortality risk (Weir and Corbould 2008, p. 44), 
and very few establish the stability of a home range, which improves 
the chance of successful recruitment (Aubry et al. 2004, p. 215).
Habitat
    The occurrence of fishers at regional scales is consistently 
associated with low- to mid-elevation environments of mesic (moderately 
moist), coniferous and mixed conifer and hardwood forests with abundant 
physical structure near the ground (reviewed by Hagmeier 1956, entire; 
Arthur et al. 1989a, pp. 683-684; Banci 1989, p. v; Aubry and Houston 
1992 p. 75; Jones and Garton 1994, pp. 377-378; Powell 1994, p. 354; 
Powell et al. 2003, p. 641; Weir and Harestad 2003, p. 74). Fishers 
avoid areas with little or no cover (Powell and Zielinski 1994, p. 39; 
Buskirk and Powell 1994, p. 286); an abundance of coarse woody debris, 
boulders, shrub cover, or subterranean lava tubes sometimes provide 
suitable overhead cover in non-forested or otherwise open areas 
(Buskirk and Powell, 1994, p. 293; Powell et al. 2003, p. 641). In the 
understory, the physical complexity of coarse woody debris such as 
downed trees and branches provides a diversity of foraging and resting 
locations (Buskirk and Powell 1994, p. 295).
    Forest succession is a dynamic continuum that begins with an event 
such as wildfire, windthrow (areas of downed trees due to high winds) 
or

[[Page 38507]]

timber harvest that removes or alters major components of an 
environment. Over time the affected environment experiences a series of 
changes or seral stages in vegetation species and structure. In the 
absence of disturbance and over many decades to hundreds of years 
depending on the forest type, mature or late-seral structure and 
species composition may result. Late-seral forests (also known as old-
growth) are generally characterized by more diversity of structure and 
function than younger developmental stages. Specific characteristics of 
late-seral forests vary by region, forest type, and local conditions. 
Fishers are associated more commonly with mature forest cover and late-
seral forests with greater physical complexity than other habitats 
(reviewed by Powell and Zielinski 1994, p. 52). Other forest 
successional stages may suffice if adequate cover and structure is 
provided. For example, extensive, mid-mature, second growth forests are 
used by fishers in the Northeast and Midwest United States (Coulter 
1966, pp. 59-60; Arthur et al. 1989b, pp. 680-683; Powell 1993, p. 92).
    To what extent late successional forests are required to support 
fisher may be dependent on scale (Powell et al. 2003, p. 641). Home 
ranges may be established based on attributes at a landscape scale, 
foraging at a site scale, and resting and denning use based on the 
element or structural scale (Powell 1993, p. 89; Buskirk and Powell 
1994, p. 284; Weir and Corbould 2008, p. 103). Within areas of low and 
mid-elevation forests, the most consistent predictor of fisher 
occurrence at larger spatial scales is moderate to high levels of 
contiguous canopy cover rather than any particular forest plant 
community (Buck 1982, p. 30; Arthur et al. 1989b, pp. 681-682; Powell 
1993, p. 88; Jones and Garton 1994, p. 41; Weir and Corbould 2010, p. 
408). In north-central Idaho, mature to old-growth mesic forests of 
grand and subalpine fir in close proximity to riparian areas are used 
extensively (Jones 1991, pp. 90, 113; Jones and Garton 1994, p. 381); 
fishers in this study avoided forests with less than 40 percent crown 
cover and drier upland sites composed of Abies grandis (grand fir), 
Abies lasiocarpa (subalpine fir), Pseudotsuga menziesii (Douglas fir), 
and Pinus ponderosa (ponderosa pine) (Jones 1991, p. 90). A preliminary 
analysis of habitat associations in the USNRMs indicates that in 
summer, fishers select areas with larger diameter trees and landscapes 
with a higher proportion of large trees, and avoid dry areas typically 
populated by ponderosa pine (Schwartz 2010, unpublished data). Winter 
detections of fisher are more likely in drainages with a high amount of 
canopy cover, and winter avoidance of dry areas is similar to summer 
(Schwartz 2010, unpublished data). Fishers in Idaho include forested 
environments of differing configurations in their home range including 
roadless areas, industrial forest, and national forests managed for 
multiple uses (Albrecht and Heusser 2009, p. 19; IOSC 2010, p. 4).
    The physical structure of the forest and prey associated with 
forest structures are thought to be critical features that explain 
fisher habitat use, rather than specific forest types (Buskirk and 
Powell 1994, p. 286), and the composition of individual fisher home 
ranges is usually a mosaic of different forested environments and 
successional stages (reviewed by Lofroth et al. 2010, p. 94). Further, 
fishers are opportunistic predators with a relatively general diet, and 
the vulnerability of prey may be more important to the use of an area 
for foraging than the abundance of a particular prey species (Powell 
and Zielinski 1994, p. 54). In north-central Idaho, fishers expand 
their use of young forest stages in winter, likely in response to a 
seasonal shift in habitat use by their prey or an increase in prey 
vulnerability in these areas (Jones and Garton 1994, p. 383). 
Individuals translocated to the Cabinet Mountains of Montana from 
Minnesota and Wisconsin exhibit winter habitat use similar to that 
reported for fishers in north-central Idaho (Roy 1991, p. 60). Fishers 
in north-central Idaho and Montana also select forest riparian areas 
and draws or valley bottoms that have a strong association with spruce, 
which tend to have dense cover, high densities of snowshoe hare, and a 
diversity of other prey types (Powell 1994, p. 354; Jones 1991, pp. 90-
93; Heinemeyer 1993, p. 90).
    Fishers are more selective of habitat for resting than they are 
about foraging or traveling habitat (Arthur et al. 1989b, p. 686; 
Powell and Zielinski 1994, p. 54; Powell 1994, p. 353). Across the 
range, fishers select resting sites with characteristics of late 
successional forests--higher canopy closure, large-diameter trees, 
coarse downed wood, and singular features of large snags, tree 
cavities, or deformed trees (Powell and Zielinski 1994, p. 54; Lofroth 
et al. 2010, pp. 101-103). Rest sites may be selected for their 
insulating or thermoregulatory qualities and their effectiveness at 
providing protection from predators (Weir et al. 2004, pp. 193-194). 
Resting locations for fishers in north-central Idaho are predominately 
in mature forest types (Jones and Garton 1994, p. 383). When fishers 
use younger forest types, they will select large-diameter trees or 
snags, if present, that are remnants of a previously existing older 
forest stage (Jones 1991, p. 92). Because of this selectivity for 
mature forest type or structure, resting and denning sites may be more 
limiting to fisher distribution than foraging habitats, and should 
receive particular consideration in managing habitat for fishers 
(Powell and Zielinski 1994, pp. 56-57).
    Cavities and branches in trees, snags, stumps, rock piles, and 
downed timber are used as resting sites, and cavities in large-diameter 
live or dead trees are selected more often for natal and maternal dens 
(Powell and Zielinski 1994, pp. 47, 56). Fishers do not appear to 
excavate their own natal or maternal dens; therefore, other factors 
(i.e., heartwood decay of trees, excavation by woodpeckers, broken 
branches, frost or fire scars) are important in creating cavities and 
narrow entrance holes (Lofroth et al. 2010, p. 112). The tree species 
may vary from region to region based on local influences. In regions 
where both hardwood and conifers occur, hardwoods are selected more 
often, although they may be a minor component of the area (Lofroth et 
al. 2010, p. 115). Den trees tend to be older and larger in diameter 
than other available trees in the vicinity (reviewed by Lofroth et al. 
2010, pp. 115, 117). Little is known of natal or maternal den use or 
selection in the USNRMs. A habitat study conducted in north-central 
Idaho found no kits or evidence of denning (Jones 1991, p. 83). A 
female introduced into Montana's Cabinet Mountains used a downed hollow 
log for a natal den only months after release, and it is likely that 
this suboptimal site was selected only because of the female's 
unfamiliarity with the area (Roy 1991, p. 56).
    Snow conditions and ambient temperatures may affect fisher activity 
and habitat use. Fishers in eastern parts of the taxon's range may be 
less active during winter and avoid areas where deep, soft snow 
inhibits movement (Leonard 1980, pp. 108-109; Raine 1981, p. 74). 
Historical and current fisher distributions in California and 
Washington are consistent with forested areas that receive low or lower 
relative snowfall (Krohn et al. 1997, p. 226; Aubry and Houston 1992, 
p. 75). Fishers in Ontario, Canada, moved from low-snow areas to high-
snow areas during population increases, indicating a possible density-
dependent migration to less suitable habitats factored by snow 
conditions (Carr et al. 2007, p. 633). These distribution and activity 
patterns

[[Page 38508]]

suggest that the presence of fisher and their populations may be 
limited by deep snowfall. However, the reaction to snow conditions 
appears to be variable across the range, with fishers in some locations 
not affected by snow conditions or increasing their activity with fresh 
snowfall (Jones 1991, p. 94; Roy 1991, p. 53; Weir and Corbould 2007, 
p. 1512). Thus, fishers' reaction to snow may be dependent on a myriad 
of factors, including, but not limited to, local freeze-thaw cycles, 
the rapidity of crust formation, snow interception by the forest 
canopy, and prey availability (Krohn et al. 1997, p. 226; Mote et al. 
2005, p. 44; Weir and Corbould 2007, p. 1512).
Historical Distribution Across the Range of the Species
    Fishers occur only in North America, appearing in the fossil record 
approximately 30,000 years ago in the eastern United States throughout 
the Appalachian Mountains, south to Georgia, Alabama, and Arkansas, and 
west to Ohio and Missouri (Anderson 1994, p. 18). No fossil evidence of 
a fisher range expansion to the north or west exists until the middle 
Holocene (4,000 to 8,000 years ago) in southern Wisconsin, and only 
within the past 4,000 years is there evidence that fishers inhabited 
northwestern North America (Graham and Graham 1994, pp. 46, 58). 
Although there is limited fossil evidence available from central 
Canada, fishers' expansion westward and northward likely coincided with 
glacier retreat and the subsequent development of the boreal spruce 
forests (Graham and Graham 1994, p. 58). Fossil remains of early fisher 
in the northwest have been found in British Columbia, Washington, and 
Oregon, and no fossil remains have been discovered in the USNRMs region 
(Graham and Graham 1994, pp. 50-55).
    Our present understanding of the historical (before European 
settlement) distribution of fishers is based on the accounts of natural 
historians of the early 20th century and general assumptions of what 
constitutes fisher habitat. The presumed fisher range prior to European 
settlement of North America (c. 1600) was throughout the boreal forests 
across North America in Canada from approximately 60[deg] north 
latitude, extending south into the United States in the Great Lakes 
area and along the Appalachian, Rocky, and Pacific Coast Mountains 
(Figure 1) (Hagmeier 1956, entire; Hall 1981, pp. 985-987; Powell 1981, 
pp. 1-2; Douglas and Strickland 1987, p. 513; Gibilisco 1994, p. 60).
    The distribution of fishers has been described by numerous authors, 
and the distribution boundaries vary depending on the evidence used for 
occurrences. The presumed presence of fishers has been drawn along the 
lines of forest distribution, and the species has been consistently 
described as an associate of boreal forest in Canada, mixed deciduous-
evergreen forests in eastern North America, and coniferous forest 
ecosystems in the west (Lofroth et al. 2010, p. 39). Subsequently, 
range maps of historical distribution typically portray large areas of 
continuous occurrence, although it is likely that the suitability of 
habitat to support fishers within the portrayed range varied over time 
and spatial scales, subject to climatic variation, large-scale 
disturbances, and other ecological factors (Giblisco 1994, p. 70; 
Graham and Graham 1994, pp. 57-58). Fishers do not occur in all 
forested habitats today, and evidence would indicate they did not 
occupy all forest types in the past (Graham and Graham 1994, p. 58). 
Based on the contemporaneous assemblages of fossilized remains, it is 
likely that habitat selection by fishers has historically been 
influenced by the availability of specific types of prey (Graham and 
Graham 1994, p. 58).
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Post-European Settlement Distribution Across the Range of the Species

    In the late 1800s and early 1900s, fishers experienced reductions 
in range, decreases in population numbers, and local extirpations 
attributed to overtrapping, predator control, or habitat destruction in 
the United States, including the USNRMs, and to a lesser extent in 
Canada (Weckwerth and Wright 1968, p. 977; Brander and Books 1973, p. 
53; Douglas and Strickland 1987, p. 512; Powell and Zielinski 1994, p. 
39). Since the 1950s, fishers have

[[Page 38510]]

recovered in some of the central (Minnesota, Wisconsin, Michigan) and 
eastern (Northeastern States and West Virginia) portions of their 
historical range in the United States as a result of trapping closures 
and regulations, habitat regrowth, and reintroductions (Brander and 
Books 1973, pp. 53-54; Powell 1993, p. 80; Gibilisco 1994, p. 61; Lewis 
and Stinson 1998, p. 3; Proulx et al. 2004, pp. 55-57; Kontos and 
Bologna 2008, entire). Fishers have not returned to the areas south of 
the Great Lakes to the southern Appalachian States (Proulx et al. 2004, 
p. 57). The historical, early European settlement, and contemporary 
distribution of fishers in the USNRMs is discussed in detail in the 
following sections.
Current Distribution Outside of the U.S. Northern Rocky Mountains
    Presently, fishers are found in all Canadian provinces and 
territories except Newfoundland and Prince Edward Island (Proulx et al. 
2004, p. 55) (Figure 1). The fisher range in Quebec, Ontario, and 
eastern Manitoba is contiguous with currently occupied areas in New 
England, northern Atlantic States, Minnesota, Wisconsin, and the Upper 
Peninsula of Michigan in the United States (Proulx et al. 2004, pp. 55-
57). In Saskatchewan and Alberta, fishers are found primarily north of 
52 degrees and 54 degrees north latitude, respectively, and form no 
known breeding population with the United States (Proulx et al. 2004, 
p. 58). In Alberta, trapping data indicate that a rare fisher may occur 
to the south of high-density population areas to approximately 32 km 
(20 mi) north of the United States border along the Continental Divide 
near Waterton Lakes National Park, (Corrigan 2010, pers. comm.; Hale 
2010, pers. comm.)--an area contiguous with the USNRMs. However, there 
is no indication that there is a population of fisher in southern 
Alberta or whether the source of the occasional rare fisher detected 
there is the distant fisher population of central Alberta, central 
British Columbia, or the USNRMs. Fishers occupy low- to mid-elevation 
forested areas throughout British Columbia, but are rare or absent from 
the coast and from the southern region for at least 200 km (125 mi) to 
the border with the United States (Weir et al. 2003, p. 25; Weir and 
Lara Almuedo 2010, p. 36).
    After reviewing known distribution records for fishers in 1956, 
Hagmeier (p. 156) noted that there were no known records from 
southeastern British Columbia, which includes the Rocky Mountains in 
the eastern Kootenay Region contiguous with northern Idaho and 
northwest Montana. A reintroduction of fishers to the Kootenay Region 
of southeast British Columbia, an area just north of the USNRMs, was 
attempted in the 1990s (Fontana et al. 1999, entire), but ``the 
observed survival rate of translocated adults and the few cases of 
confirmed reproduction in the area were not likely sufficient for the 
population to expand and become self-sustaining'' (Weir et al. 2003, p. 
25). The South Thompson Similkameen area of south-central British 
Columbia, bordering north-central Washington, produced 88 legally 
harvested fishers between 1928 and 2007, and 13 since 1985 (Lofroth et 
al. 2010, p. 48). Because the northern boundary of the South Thompson 
Similkameen is considered the southern extent of the fisher population 
distribution in the province (Weir and Lara Almuedo 2010, p. 36), the 
significance of the trapping data to fisher distribution is not clear 
without more specific location information. Harvest data could indicate 
that individuals were captured at the periphery of larger, established 
populations, that there is a low-density population in south-central 
British Columbia, or that individuals represent transient or 
extralimital (outside an established population area) records.
    In the western United States outside of the USNRMs, fishers occur 
in a few disjunct and relatively small areas of their former range in 
the Cascade Mountains of southwest Oregon, the Klamath and Coastal 
Ranges of southwest Oregon and northwest California, and the Southern 
Sierra Nevada Mountains in east-central California (Proulx et al. 2004; 
Lofroth et al. 2010, pp. 47-49). A reintroduction program is underway 
on the Olympic Peninsula of Washington State, and the program's 
objective of establishing a self-sustainable population of fisher has 
yet to be achieved (Lewis et al. 2009, p. 3).
Historical Distribution and Early European Settlement Distribution in 
the U.S. Northern Rocky Mountains
    Presumed historical distribution of fishers in the USNRMs is 
depicted as continuous with eastern British Columbia and southwestern 
Alberta in Canada, bounded on the east by the forested areas of the 
front range of the Rocky Mountains at approximately 113 degrees west 
longitude in Montana, the south at approximately 44 degrees north 
latitude, and the west in Idaho at approximately 116.5 degrees west 
longitude, extending to the northwest, north of the Palouse Prairie in 
Idaho to include the forested Pend Oreille River area of northeastern 
Washington (Hagmeier 1956, entire; Hall 1981, pp. 985-987; Gibilisco 
1994, p. 64) (Figure 1). The described historical distribution also 
includes individually isolated areas in the present-day Greater 
Yellowstone Ecosystem (northwest Wyoming, southern Montana and east-
central Idaho), and north-central Utah (Gibilisco 1994, p. 64). The 
representation of historical fisher distribution in the USNRMs by the 
sources above should be viewed cautiously, because it is based on 
limited information and records collected in the late 1800s to mid-
1900s (Hagmeier 1956, pp. 154, 156, 161, 163; Hall 1981, p. 985) after 
European settlement had influence in the area. In addition, as stated 
previously, fishers have been consistently described as associates of 
coniferous forest ecosystems in the west, and the presumed historical 
presence of fishers was drawn along the lines of forest distribution, 
with little physical evidence of whether fishers occupied those 
habitats.

Montana

    No reliable records are available for Montana, and historical and 
early settlement distribution in the western forested areas of the 
State was assumed based on the reports of the presence of fishers in 
northwest Wyoming and central Idaho (Hagmeier 1956, p. 156). Vinkey 
(2003, pp. 44-69) investigated fisher records in the Rocky Mountains, 
concentrating on Montana, to determine the fisher distribution post-
settlement and prior to their apparent disappearance in the 1920s 
(Newby and McDougal 1964, p. 487; Weckworth and Wright 1968, p. 977). 
The first reference to fisher in Montana was a shipping record of pelts 
from Fort Benton in 1875 (Vinkey 2003, p. 49). Although shipping 
records are not definitive of the product origin, it is likely some of 
the fisher pelts were of Montana origin because of Montana's prominence 
in the fur trade and Fort Benton's location at the upper reaches of the 
Missouri River (Vinkey 2003, p. 49).
    Reports of fishers in Montana's Glacier National Park in the early 
1900s were dismissed as ``unreliable'' and ``unauthentic'' by Newby 
(cited in Hagmeier 1956, p. 156); nevertheless, these records have been 
cited by other authors, in addition to reports from early trappers, to 
support a distribution of fishers in Montana as far south as Wyoming 
(Hoffman et al. 1969, p. 596; Vinkey 2003, p. 50). Hoffman et al. 
(1969, p. 596) interpreted the lack of reliable records as an 
indication of the fisher's extirpation in Montana and adjacent areas 
before any specimens

[[Page 38511]]

could be preserved. Thus, in Montana, the presumed occurrence of 
fishers before translocations occurred in 1959 is based on trapper 
accounts alone (Weckworth and Wright 1968, p. 977; Hoffman et al. 1969, 
p. 596).

Idaho

    The historical presence of fisher in Idaho was based on an 1890 
specimen from Alturas Lake (originally Sawtooth Lake) in the Sawtooth 
Mountains of Blaine County in central Idaho (Goldman 1935, p. 177; 
Hagmeier 1956, p. 154; Drew et al. 2003, p. 62; Schwartz 2007, p. 922), 
and other 20th century reports of fishers in the ``mountainous parts of 
the state,'' including the Selkirk (north), Bitterroot (northeast), and 
Salmon River (central) ranges (Hagmeier 1956, p. 154). Only two fisher 
specimens document the presence of fishers in the USNRMs prior to their 
presumed extirpation in the 1920s (Williams 1963, p. 9). Both specimens 
originated in Idaho. The above-mentioned 1890 specimen from Alturas 
Lake, Blaine County, in central Idaho is housed in the collection of 
the National Museum of Natural History in Washington, DC, and this 
specimen has been pivotal for supporting historical distribution and 
post-settlement representation, and for suggesting that an indigenous 
population has survived since the 1920s in the USNRMs (Hagmeier 1956, 
p. 154; Hall 1981, p. 985; Drew et al. 2003, pp. 59, 62; Vinkey et al. 
2006, p. 269). An 1896 Harvard Museum specimen collected in Idaho 
County in north-central Idaho west of the Bitterroot Divide, which 
separates Idaho and Montana, further supports the extent of fisher 
distribution in the late 1800s, and supports a close ecological 
connection between north-central Idaho and west-central Montana (Vinkey 
et al. 2006, p. 269; Schwartz 2007, pp. 923-924).

Wyoming and Utah

    The first reported fisher capture in Wyoming is often cited as 
occurring in the 1920s from the Beartooth Plateau east of Yellowstone 
National Park near the Montana State line (Thomas 1954, p. 28; Hagmeier 
1956, p. 163). The pelt of a poached fisher was confiscated in 
Yellowstone National Park in the 1890s, but it is not clear where the 
animal was captured originally (Skinner 1927, p. 194; Buskirk 1999, p. 
169). Fishers have been seldom described in Wyoming (Buskirk 1999, p. 
169), and by the 1950s fishers were considered ``extinct or nearly so'' 
in the Yellowstone area (Thomas 1954, p. 3; Hagmeier 1956, p. 163). As 
early as the 1920s the fisher was considered rare or absent from 
Yellowstone National Park (Skinner 1927, p. 180). The inclusion of Utah 
in the historical range of the fisher was based solely on photographs 
of tracks taken in 1938 (Hagmeier 1956, p. 161).

Location of Restocking Efforts in the U.S. Northern Rocky Mountains

    By 1930, fishers were thought to be extirpated from the USNRMs in 
Montana and Idaho as they were in other parts of the United States 
(Williams 1963, p. 9; Newby and McDougal 1964, p. 487; Weckworth and 
Wright 1968, p. 977). Montana Department of Fish and Game (now Montana 
Fish, Wildlife and Parks (MTFWP)) initiated a restocking program for 
fisher in 1959 with 36 individuals from central British Columbia 
transplanted to the Purcell, Swan, and Pintler Ranges in northwestern 
and west-central Montana (Weckworth and Wright 1968, p. 979). Idaho 
Fish and Game (IDFG) followed with a reintroduction program for fishers 
in 1962. Forty-two fishers from central British Columbia were 
transplanted to areas considered to have been formerly occupied before 
presumed extirpation in north-central Idaho, including the Bitterroot 
divide area (Williams 1963, p. 9; reviewed by Vinkey 2003, p. 55). 
Minnesota and Wisconsin were the sources for 110 fishers transplanted 
to the Cabinet Mountains of northwest Montana between 1989 and 1991 
(Roy 1991, p. 18; Heinemeyer 1993, p. ii). After an absence of 
authenticated records for over 20 years in the USNRMs, areas near 
release sites yielded fisher captures in Montana in the years following 
the first reintroduction efforts in 1959 (Newby and McDougal 1964, p. 
487; Weckworth and Wright 1968, p. 979). No post-release studies were 
conducted in Idaho until the mid-1980s, but marten trappers in the 
State reported inadvertent captures of fishers by the late 1970s (Jones 
1991, p. 1).
Contemporary Distribution in the U.S. Northern Rocky Mountains
    The use of unreliable records to support distribution and 
population extent has led to overestimation of other species' ranges 
(Aubry and Lewis 2003, p. 86; McKelvey et al. 2008, p. 550). Mindful of 
that, we have used the most reliable and verified data in this analysis 
of the fisher in the USNRMs. We base the contemporary (1960 to present) 
record of fisher distribution in the USNRMs on verifiable or documented 
records of physical evidence such as legal harvest or incidentally 
captured specimens, animals captured for scientific study, genetic 
analysis of biological samples, and photographs identified by a 
knowledgeable expert. Eyewitness accounts of a fisher itself, or its 
sign, by the general public or untrained observer also may be found in 
agency databases (IOSC 2010, p. 5-6); however, a correct identification 
of fisher or its sign can be difficult by an untrained observer and 
these unverified records or anecdotal reports should be viewed 
cautiously (Aubry and Lewis 2003, p. 81; Vinkey 2003, p. 59; McKelvey 
et al. 2008, p. 551). Other animals that are similar in appearance and 
share similar habitats, such as the American marten, mink (Mustela 
vison), or domestic cat (Felis catus), may be mistaken for fishers 
(Aubry and Lewis 2003, p. 82; Lofroth et al. 2010, p.11; Kays 2011, p. 
1). Animal signs, such as tracks, can be significantly altered by 
environmental conditions, and fisher tracks can be confused with those 
of the more common American marten (Vinkey 2003, p. 59; Giddings 2010, 
pers. comm.).

Montana and Idaho

    A legal trapping season for fisher was reopened in Montana in 1983 
after a series of fisher transplantations and evidence that fishers 
were reproducing in the State (Weckwerth and Wright 1968, entire; MTFWP 
2010, p. 3). The majority of verified fisher records in the State 
through 2009 result from the harvest program (Vinkey 2003, p. 51; MTFWP 
2010, p. 2, Attachment 3). In addition, Montana agency files include 48 
incidental harvest records between 1968 and 1979 (Vinkey 2003, p. 51). 
Prior to 2002, Idaho records included verified fisher presence by 
targeted live-trapped and incidental captures, or otherwise-obtained 
physical specimens, photographs, and individuals observed directly by 
qualified experts (IOSC 2010, p. 7). From 2004 to the present, multiple 
State and Federal agencies in Montana and Idaho have partnered to 
collect biological data and samples by live-trapping and hair-snares 
for genetic testing (Albrecht and Heusser 2010, p. 23; Albrecht 2010, 
unpublished data; IOSC 2010, pp. 4-6; MTFWP 2010, p. 2); many surveys 
are conducted using a standardized protocol specific to fisher 
(Schwartz et al. 2007, entire). Fisher detections (species 
identification) and genetic analyses to identify individual fishers 
have been provided to us as they become available (Albrecht 2010, 
unpublished data); the results of some targeted fisher surveys are 
pending (IOSC 2010, p. 10). Harvest specimens and targeted studies 
provide confident identification of fishers, but may not represent the 
full extent of fisher

[[Page 38512]]

distribution due to biases of trapper effort, site accessibility, 
nonrandom site selection to increase the efficacy of detection, or a 
lack of either survey or trapping exposure (Vinkey 2003, p. 59; 
Schwartz et al. 2007, p. 6; Albrecht and Heusser 2009, p. 19).
    In western Montana from 1968 to the late 1980s, fishers were known 
to occur in the Bitterroot Mountains bordering north-central Idaho, and 
west of the Continental Divide in the Whitefish Range, Flathead, and 
Swan Mountain Ranges (Vinkey 2003, p. 53). Trapping or targeted 
sampling has not been robust in these areas west of the Continental 
Divide since the early 1990s, but there are verified fisher detections 
over the past two decades (Vinkey 2003, p. 53; MTFWP 2010, Attachment 
2) (Figure 2). Fisher presence has been consistent in the Bitterroot 
Mountains to the present, and in the Cabinet Mountains in northwest 
Montana since the late 1980s introduction (Vinkey 2003, p. 53; MTFWP 
2010, Attachment 2).
    Fishers in Idaho are found in the Selkirk Mountains in the north, 
the Clearwater and Salmon River Mountains in central Idaho, and the 
Bitterroot Range, including the Selway-Bitterroot Wilderness, in the 
north-central portion of the State.
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Wyoming and Utah

    The contemporary distribution of fisher in Wyoming is unknown. Rare 
reports of fisher tracks and harvested specimens are available up until 
the 1950s (Thomas 1954, p. 31; Hagemeier 1956, p. 163; Buskirk 1999, p. 
169). A photograph of an animal near Yellowstone National Park 
described as a fisher was featured in a popular publication in 1995 
(Gehman, p. 2), but to date there has been no professional or expert 
verification that the photographed animal is indeed a fisher. Carnivore 
detection surveys were conducted in the Gallatin National Forest in the 
northern Greater Yellowstone Ecosystem between 1997 and 2000, using 
camera stations, hair-snares, and snow track transects; the surveyors 
reported fisher tracks in snow in the Gallatin and Madison Ranges of 
southern Montana (Gehman and Robinson 2000, p. 7). These records are 
considered unverified, because the use of sighting and track 
measurements alone are dependent on the observer's level of skill, snow 
and weather conditions, and ``notoriously unreliable'' (Vinkey 2003, p. 
59).
    The Wyoming Fish and Game Department (2010, p. IV-2-26) and 
Gibilisco (1994, pp. 63-64) report only two verified records, both 
prior to 1970, in or near Yellowstone National Park. One specimen was 
described from Ucross, Wyoming, in 1965 (Hall 1981, p. 985) over 217 km 
(135 mi) east of the Beartooth Plateau and Yellowstone National Park, 
but most of that distance is open grassland or sagebrush, which is 
unsuitable for fisher. Proulx et al. (2004, p. 59) could not confirm 
the presence of fisher in Wyoming in their status review of Martes 
distribution. Schwartz et al. (2007, p. 1) acknowledge that Wyoming may 
contain fisher, but there is no evidence to confirm that presence. 
Recently, fishers are described as ``accidental'' or ``rare'' in 
Wyoming with assumed breeding or records of breeding in the northwest 
part of the State (Orabona et al. 2009, p. 152; Wyoming Fish and Game 
Department 2010, p. IV-2-26). However, the statement of fisher breeding 
in Wyoming is unsubstantiated and apparently made in error, (Oakleaf 
2010, pers. comm.). The fisher is considered extirpated in Utah 
(Biotics Database 2005, pp. 1-2).
Summary of Contemporary Distribution of Fisher in the U.S. Northern 
Rocky Mountains
    Based on the available verified specimen data, contemporary fisher 
distribution in western Montana and Idaho (Figure 2) covers an area 
similar to that depicted in the historical distribution synthesized by 
Gibilisco in 1994 (p. 64) (Figure 1). The contemporary distribution of 
fishers includes forested areas of western Montana and north-central to 
northern Idaho, and the boundary is further described in the ``Distinct 
Vertebrate Population Segment'' section of the finding. Based on a lack 
of verified records or documentation, we cannot conclude that the 
fisher is present, or if a breeding population was ever present, in 
Wyoming, including the Greater Yellowstone Ecosystem, which includes 
parts of south-central Montana, northwest Wyoming, and south-east 
Idaho.
Distribution Based on Genetic Characteristics
    Recent genetic analyses revealed the presence of a remnant native 
population of fishers in the USNRMs that escaped the extirpation 
presumed to have occurred early in the 20th century (Vinkey et al. 2006 
p. 269; Schwartz 2007, p. 924). Fishers in the USNRMs today reflect a 
genetic legacy of this remnant native population, with unique genetic 
identity found nowhere else in the range of the fisher and genetic 
contributions from fishers introduced from British Columbia and the 
Midwest United States. We discuss the genetic differences due to this 
the native legacy and its significance to the fisher taxon in the 
``Significance'' section of the DPS analysis later in this document.
    Individuals with native genes are concentrated in the Bitterroot 
Mountains of west-central Montana and north-central Idaho, the St. Joe 
and Clearwater Regions, and the Lochsa River corridor in Idaho (Vinkey 
2003, p. 76; Vinkey et al. 2006, p. 267; Albrecht 2010, unpublished 
data). Individuals in these areas appear to form one population based 
on the frequency of gene types (Schwartz 2007, p. 924). The unique 
genetic type also has been identified in the only two existing USNRMs 
fisher specimens from the 1890s (Schwartz 2007, p. 922). The presence 
of this unique variation would indicate that fishers in the USNRMs were 
isolated from populations outside the region by distance, small 
population number, or both, for some time before the influences that 
led to the presumed extirpation in the early 20th century (Vinkey 2003, 
p. 82). Today, a genetic identity more commonly found in British 
Columbia populations also is present in the Bitterroot Divide area, and 
fishers in this region are likely a mix of native and individuals 
translocated from British Columbia (Vinkey 2003, p. 76; Vinkey et al. 
2006, p. 268; Schwartz 2007, p. 924).
    Fishers in northwestern Montana and extreme northern Idaho 
represent the geographically distant source populations from Minnesota 
and Wisconsin that were introduced into the Cabinet Mountains of 
Montana in the late 1980s (Drew et al. 2003, p. 59; Vinkey et al. 2006, 
pp. 268-269; Albrecht 2010, unpublished data). British Columbia types 
also are found in this region, reflecting offspring of a 1959 
introduction from Canada, a remnant native population, or possibly 
natural immigration from Canada (Vinkey et al. 2006, p. 270; Schwartz 
2007, p. 924).
    An assessment of the degree of hybridization between native and 
introduced individuals is difficult based on the assessment techniques. 
Analysis of genetic identity is conducted on mitochondrial DNA, which 
only reflects the genetic contribution of the mother (Forbes and 
Alledorf 1991, p. 1346; Vinkey 2003, p. 82). Males could make a greater 
contribution to distant populations based on their larger home range 
sizes and expanded wanderings during the breeding period (Arthur 1989a, 
p. 677; Jones 1991, pp. 7-78), but based on mitochondrial DNA analysis 
alone, this contribution would not be detected.
Population Status
    Estimates of fisher abundance and vital rates are difficult to 
obtain and often based on harvest records, trapper questionnaires, and 
tracking information (Douglas and Strickland 1987, p. 522), and recent 
information is limited. Habitat modeling and behavioral or other 
natural history characteristics (e.g., home range sizes) also are used 
to estimate population sizes over a geographic area (Lofroth 2004, pp. 
19-20; Lofroth et al. 2010, p. 50). Fisher densities over areas of 
suitable habitat have been reported, but there are no total or 
comprehensive population sizes for the fisher in the eastern United 
States or Canada. In the western range, fisher populations have been 
estimated using habitat models and home range sizes. Late winter 
populations in British Columbia range from 1,403 to 3,715 individuals 
(Lofroth 2004, p. 20). In the Southern Sierra Nevada Mountains, the 
fisher population is estimated between 160 to 598 individuals depending 
on the methods used, and an estimated 4,616 fishers inhabit the 
Southwest Oregon/Northern California area (reviewed by Lofroth et al. 
2010, p. 50).
    As previously noted, fishers in the USNRMs have increased in number 
and distribution since their perceived

[[Page 38515]]

extirpation in the 1920s. However, little is known of the population 
numbers, trends, or vital rates of fishers in the USNRMs today. 
Preliminary work is ongoing to determine the geographic range of the 
species, identify populations with native and introduced genes, and 
determine the abundance of individuals in populations using DNA 
analyses (Schwartz et al. 2007, pp. 1-2). An evaluation of the 
translocation effort in the Cabinet Mountains of northwest Montana 
between 2001 and 2003 yielded only 4 live-trapped individuals and 28 
track detections over 25 survey weeks, indicating that the population 
there is likely small and limited in distribution (Vinkey 2003, p. 33) 
(Figure 2). Based on genetic similarities, fishers in the Selkirk 
Mountains of northern Idaho, just south of the Canadian border, are 
likely associated with the fishers from Minnesota and Wisconsin 
introduced to Montana's Cabinet Mountains to the east (Cushman et al. 
2008, p. 180). Efforts to detect fisher in the Selkirk Mountains 
between 2003 and 2005 using hair-snares for genetic analysis produced 
26 samples identified as fisher, although the number of unique 
individuals is likely much smaller than the number of samples (Cushman 
et al. 2008, p. 180).
    A review of historical records and carnivore research in Montana 
indicates that the fisher is one of the lowest-density carnivores in 
the State (Vinkey 2003, p. 61). What is known of fisher populations 
today in Montana is primarily derived from harvest data and winter 
furbearer track surveys (MTFWP 2010, p. 2, Attachment 8, pp. 2-3). A 
Montana habitat model based on 30 years of fisher presence data (the 
majority being harvest data) conservatively estimates that there is 
high habitat suitability capable of supporting 216 individuals 
concentrated in the Bitterroot Mountains along the Idaho border, the 
Swan and Flathead River drainages, and the Whitefish and Cabinet 
Mountains just south of the Canada border (MTFWP 2010, Attachment 8, 
pp. 2-3; Montana Natural Heritage Program (MTNHP) 2010a, entire; 2010b, 
entire).
    Most of the recent USNRMs fisher survey effort has targeted the 
Coeur d'Alene, St. Joe, Clearwater, and Lochsa areas of northern and 
north-central Idaho. In 2006 and 2007, 10 individual fishers were 
identified in an area of approximately 8,951 km\2\ (3,456 mi\2\) of 
potentially suitable habitat in the St. Joe and Coeur d'Alene areas, 
north and south of Interstate 90 in northern Idaho (Albrecht and 
Heusser 2009, pp. 6, 8, 15). The St. Joe and Coeur d'Alene projects 
were not intended to elucidate fisher presence in the entire area of 
potentially suitable habitat, but simply to detect the presence of 
fisher; therefore, traps were placed in areas highly likely to support 
fisher (Albrecht and Heusser 2009, p. 19). Thirty-four fisher were 
identified in a 1,295-km\2\ (500-mi\2\) (one fisher per 38 km\2\ (14.7 
mi\2\)) area of the Lochsa River corridor of north-central Idaho during 
a targeted live-trap study between 2002 and 2004 (Schwartz 2010, 
unpublished data). Thirty individual fishers were captured in the 
Clearwater area north of the Lochsa River in north-central Idaho 
between 2007 and 2010 (Sauder 2010, unpublished data). Based on genetic 
data, it appears that individuals in these areas of north-central Idaho 
and fishers in west-central Montana represent a single population 
(Schwartz 2007, p. 924) (Figure 2). We have no additional information 
on the Lochsa River or Clearwater surveys to determine if these reports 
are indicative of comprehensive population numbers. No habitat 
suitability or capacity model is available for Idaho.

Evaluation of Listable Entities

    Under section 3(16) of the Act, we may consider for listing any 
species, including subspecies, of fish, wildlife, or plants, or any DPS 
of vertebrate fish or wildlife that interbreeds when mature (16 U.S.C. 
1532(16)). Such entities are considered eligible for listing under the 
Act (and, therefore, are referred to as listable entities), should we 
determine that they meet the definition of an endangered or threatened 
species. In this case, the petitioners have requested that the fisher 
in the USNRMs be considered as a DPS of a full species for listing as 
endangered or threatened under the Act. We concluded in our 90-day 
finding on the petition that there is support for a DPS of fisher in 
the USNRMs (75 FR 19925), and we analyze this possibility further in 
the following section after reviewing the best available information.

Distinct Vertebrate Population Segment

    Under the Service's DPS policy (61 FR 4722, February 7, 1996), 
three elements are considered in the decision concerning the 
establishment and classification of a possible DPS. These are applied 
similarly for additions to, or removal from, the Federal List of 
Endangered and Threatened Wildlife. These elements include:
    (1) The discreteness of a population in relation to the remainder 
of the species to which it belongs;
    (2) The significance of the population segment to the species to 
which it belongs; and
    (3) The population segment's conservation status in relation to the 
Act's standards for listing, delisting, or reclassification (i.e., is 
the population segment endangered or threatened).
    In evaluating the distribution of fisher and the geographic extent 
of a possible DPS in the USNRMs, we examined information cited in the 
petition (Defenders et al. 2009, pp. 11-24), published range maps, 
published works that included historical occurrences, unpublished 
studies related to fisher distribution, and other data submitted to us 
subsequent to the request for information pub