Lynx: Their ecology and biology and how winter recreation effects them

Authors(s): J. Halfpenny, K. Murphy and D. Reinhart

Publication: Effects of winter recreation on wildlife of the Greater Yellowstone Area: a literature review and assessment. Report to the Greater Yellowstone Coordinating Committee. Yellowstone National Park, Wyoming.

Publisher:

Publication Date: 0000-00-00

Type:

Location:

Abstract: POPULATION STATUS Lynx (Lynx canadensis) historically occupied much of the northern portion of North America, but the loss and degradation of their habitat and the unregulated hunting and trapping that accompanied European settlement reduced their numbers and distribution in the conterminous United States (Jackson 1961, Ruediger 1994). Today, remnant lynx populations persist in some high-elevation boreal forests of the western and Great Lakes states, tied chiefly to the distribution and abundance of snowshoe hares (Lepus americanus) (Koehler and Aubrey 1994). In 1999, the U.S. Fish and Wildlife Service (USFWS) is expected to list the lynx as a threatened species under the authority of the Endangered Species Act (ESA). The listing will culminate a series of actions that included a petition by conservation groups to list the species in 1992 and a series of court decisions. The action will require development of a recovery plan by the USFWS and also require that actions taken by federal wildlife and land management agencies do not jeopardize the species? welfare. Lynx are already treated as a sensitive species by most federal and state wildlife management agencies in the western United States. Montana is the only state in the contiguous United States that still allows trapping of lynx. There is currently a statewide quota of two lynx, with a limit of one per trapper per year. Trapper harvest peaked at 60 in 1979 but was reduced to two lynx per year by legislation. Trapper effort has also declined in spite of high lynx fur prices in the 1980s. Illegal and incidental harvest are thought to be negligible (Giddings et al. 1998). Forest management practices and development of roads and human facilities may adversely affect lynx. However, the rarity and secretiveness of this species make its distribution and habitat requirements difficult to document (Ruediger 1994). The purpose of this report is to review and synthesize current literature on the effects of winter recreation on lynx within the Greater Yellowstone Area (GYA). THE ABUNDANCE AND DISTRIBUTION OF LYNX IN YELLOWSTONE NATIONAL PARK Although reliable information concerning the abundance and distribution of lynx is lacking, historical information suggests that this species was present but uncommon in Yellowstone National Park (YNP) from 1880 to 1980. This condition also describes the status of lynx in YNP today. Lynx were listed among animals that were present and seen by naturalists as early as the 1870s (Grinnell 1876, Blackburn 1879). Consolo Murphy and Meagher (In Press) documented the presence and distribution of lynx in YNP from 1893 to 1995 using sighting records, photographic records, and museum collections. They located 1 museum specimen of a female lynx, 34 sighting reports (39 total lynx), 17 observations of tracks, and 6 other forms of supportive evidence (e.g., photographs). Lynx or their sign were observed parkwide, but visual observations were more common in the southern half of the park and tracks were more common in the north. Most (n=50) sightings and records of tracks occurred after 1930. Consolo Murphy and Meagher (In Press) included a reference to a hide from an illegally trapped lynx that was confiscated by park rangers near Norris Geyser Basin (Harris 1887). In addition to these records, 1 lynx was reported seen and 6 sets of lynx tracks were found in 1887 by T. Hofer, a pioneering naturalist and early visitor to the park (see Field and Stream 1887, April 7 to May 5 issues). Hofer?s observations occurred at Norris Geyser Basin (tracks), Lower and Midway Geyser basins (tracks), Shoshone Lake (sighting), Alum Creek (tracks), and Canyon (tracks). Yellowstone Nature Notes,an in-house periodical of natural history observations made by YNP personnel, also contains 5 records of direct observations of lynx (7 total animals) spanning 1928 to 1958 that were not reported by Consolo Murphy and Meagher. More recently, Halfpenny (unpublished data) identified 1 set of lynx tracks near Snake Hot Springs in February 1979. From 1995 to present, 5 sightings of lynx were reported in YNP, 3 on the northern range and 2 in the park interior (K. A. Gunther, Yellowstone National Park, personal communication). Unfortunately, records of lynx sightings or their tracks carry caveats with regard to reliability. YNP records prior to 1980 typically contained insufficient information to determine observer credibility and to estimate weather and lighting conditions. Consequently, misidentified animals may be represented in the data. In particular, inexperienced observers may easily confuse bobcats (Lynx rufus) with lynx. Numerous researchers have attempted to document the presence of rare carnivores in YNP during this decade. Murphy (unpublished data) found no lynx sign while searching 7,500 km of transect on the northern winter range and vicinity from the winters 1987?88 to 1991?92 incident to cougar studies. No lynx were detected by Harter et al. (1993), who deployed 11 hair snares (387 trap nights) and 21 remote cameras (102 nights), and searched 16 track transects (116 km) on the northern winter range and vicinity from January to March 1993. Similarly, no lynx were found by Gehman et al. (1994), who deployed 20 hair snares (1,609 nights), 12 cameras (961 nights), and 31 track transects (200 km) from December 1993 to February 1994 on the northern winter range and vicinity. Finally, Gehman and Robinson (1998) did not detect lynx when they deployed 4 cameras (4 sites; approx. 138 nights) and 14 transects (80 total km) along the upper Gallatin River in YNP (see below for their sighting of a probable lynx track 10 km northwest of YNP). THE PRESENCE AND DISTRIBUTION OF LYNX IN THE GYA Museum, trapping, and other agency records indicate lynx distribution in the GYA prior to 1976 (Giddings et al. 1998; Fig. 1) with approximately 107, 6, and 8 occurrences of lynx in Wyoming, Montana, and Idaho, respectively (our counts from Giddings et al. 1998), including 8 records for Grand Teton National Park (GTNP). These records do not include a lynx killed in 1920 by ranger and his hounds in the Hellroaring Creek drainage (Stevenson 1920). In the GYA from 1976 to 1993, there are 122, 19, and 13 occurrences of lynx in Wyoming, Montana, and Idaho, respectively, including four records in GTNP. Lynx reports occur for the Absaroka, Beartooth, Centennial, Gallatin, Gros Ventre, Madison, Teton, Wind River, and Wyoming mountain ranges as well as forested portions of eastern Idaho (Giddings et al. 1998). Laurion and Oakleaf (1998) surveyed 2,055 km of roads and 2,400 km of backcountry trails in 12 areas on the Shoshone (SNF) and Bridger?Teton (BTNF) national forests in western Wyoming during winter 1997?98. Lynx tracks were identified in three locales (four total track observations) on the SNF and one locale (two track observations) on the BTNF. In addition, D. Stevenson (1997) surveyed nine snow-covered transects 29 times (269 total km) near Bridger Lake, BTNF, from February to March 1997, but found no lynx sign. S. Patlas (Wyoming Game and Fish Department, personal communication) surveyed a total of 169 km of transect at nine locales in northern GTNP and vicinity but found no sign of lynx. However, citizen observers have recently seen lynx or their tracks near Big Piney, Kemmerer, Moose, and Dubois, in the Upper Greys River watershed, Wyoming (Laurion and Oakleaf 1998). An adult male and a female lynx were captured in the Wyoming Range near Merna, Wyoming in 1996?97 as part of a research project being conducted by Wyoming Game and Fish Department (see Laurion and Oakleaf 1998). A total of five to seven lynx resided on the study area, including the radio-marked individuals. The radio-marked female produced four kittens during May 1998. In Montana, Gehman and Robinson (1998) surveyed 12 snow-covered transects 39 times (170 total km) and deployed cameras at 15 different sites in the Gallatin National Forest in 1997?98. They identified a probable lynx track in Buck Creek, a tributary of the Gallatin River. LIFE HISTORY The breeding season for lynx spans March to May. Kittens are born in May or June after a 60- to 74-day gestation period. Young are born without teeth, but with closed eyes, folded ears, and a well-developed pelage. Lynx walk by age 24?30 days and are weaned at 3?6 months. However, kittens may consume meat as part of their diet by an age of 30 days. Kittens typically remain with their mothers until about age ten months, but the period of maternal care may extend into the next mating season. Females can breed at age ten months, but usually do not until 22 months. Natural predators of lynx include coyotes (Canis latrans), wolves (Canis lupis) (Banfield 1974), cougars (Felis concolor) (Koehler et al. 1979), wolverines (Gulo gulo), and lynx themselves (Elsey 1954). Lynx contract rabies and distemper, but these diseases do not significantly affect their population dynamics. Dominant mortality factors are malnutrition and starvation of kittens (Brainerd 1985). Malnutrition may dispose lynx to disease and parasites (Quinn and Parker 1987). SOCIAL ORGANIZATION AND SPACING PATTERNS Lynx are solitary carnivores, remaining apart except when mating. Mothers support their altricial young without direct support of fathers. Spatial and temporal separation results from social intolerance and mutual avoidance that is accomplished through scent marking. Intersexual overlap for territories is high. During lows in hare numbers, adults of the same sex are mutually hostile, maintaining exclusive territories (Berrie 1973, Mech 1980). In a Washington study, strong territoriality may have resulted from a varied and relatively stable prey base (Koehler 1990a). As hare populations increase, social intolerance among lynx breaks down, prompting increases in the degree of range overlap (Slough and Mowat 1996). When hares are extremely scarce, lynx may become nomadic or emigrate. Home range sizes differ by sex, prey density, and other factors. Females typically have home ranges that are smaller than males, varying from 10?243 km2, but normally 15?20 km2 in size. Home ranges varied from 36?122 km2 for males in Montana (Koehler et al. 1979, Brainerd 1985). In Wyoming, a male?s range was 131 km2 and a female?s was 137 km2 (Laurion and Oakleaf 1998). In Alaska and Canada, home ranges may exceed 40?80 km2 when hare populations decrease. Large ranges may indicate prey scarcity (Hatler 1988). Inverse relationships between hare numbers and the size of lynx ranges are documented (Brand et al. 1976, Ward and Krebs 1985, Poole 1993). Home ranges may be abandoned at a threshold of low hare densities, prompting lynx to turn nomadic (Ward 1985, Ward and Krebs 1985). The relatively large sizes of lynx home ranges in the Rocky Mountains suggests that the availability of snowshoe hares is low. Lynx typically achieve densities of one per 15?25 km2. In Washington, density was one per 40 km2 (Koehler 1990a). Home range sizes and densities of lynx exhibit regional and local variation that depend on topography and food availability. When hare populations are low, lynx may concentrate in pockets of high hare density, leading to density estimates that are not representative for landscapes at a broad scale (Koehler and Aubrey 1994). POPULATION DYNAMICS Lynx generally occur at low density and are associated with boreal forest habitats. Their population dynamics are characterized by low reproductive rates and are strongly related to population dynamics of snowshoe hare, a keystone species that is the primary prey of lynx. In Canada, lynx populations fluctuate roughly on a ten-year cycle, lagging behind a similar cycle for snowshoe hares (Elton and Nicholson 1942, Keith 1963). While hare densities may change 200-fold, those of lynx change only up to 20-fold. One explanation is that lynx numbers are tied to a poorly understood interaction between hares and vegetation, with regional synchrony tied to weather effects. Cycles may be muted or absent near the southern limits of the lynx?s distribution (i.e., in the conterminous U.S.), where hare populations apparently are more stable than those in Canada (Dolbeer and Clark 1975), possibly owing to greater diversity and stability in hare predators and competitors and the absence of adequate habitat during periods of hare lows. Snow-tracking surveys for hares in Montana showed a three-fold change in numbers of hare tracks from 1990 to 1998; lynx tracks varied eight-fold (Giddings et al. 1998). Consequently, dramatic differences in reproduction, habitat use, prey selection, dispersal, and vulnerability may exist between lynx populations in Canada and the conterminous U.S. When hare populations crash, lynx may emigrate great distances, potentially making treks from Canada to the GYA. Dramatic increases in lynx numbers occurred in western Montana following peaks in the Canadian population during 1962?63 and 1971?72 (Hoffmann et al. 1969, Koehler and Aubrey 1994). Following the hare crash of the early 1970s, lynx populations apparently increased in Wyoming as suggested by the high trapper harvest in the Wyoming Range (Laurion and Oakleaf 1998). Immigrating lynx have large home ranges and little reproductive success. When hares are scarce, lynx may also concentrate in small areas making them vulnerable to human-caused mortality (Koehler and Aubrey 1994). Consequently, rapid declines in populations occur. For example, Minnesota trappers harvested 215 lynx in 1972, 691 in 1973, 88 in 1974, and 0 in 1975 (Mech 1980). Recovery from trapping exploitation may be slow when lynx are at low numbers (Laurion and Oakleaf 1998). Lynx are characterized by fluctuating reproductive rates that are driven by food limitation. Females may not reproduce at all during food shortages. In Montana, pregnancy rates of adult females reached 90 percent, but declined to 33 percent when food was scarce (Giddings 1994). Litters of adult females averaged 3.2 kittens and those of yearlings averaged 1.7 (Brainerd 1985) or 2.7 (Giddings 1994). In the GYA, one female had four kittens (Laurion and Oakleaf 1998). In general, population dynamics of lynx are affected more by failure to produce litters than the size of litters. Food availability directly correlates with the survival of young lynx. Few kittens survive when food is scarce, with the result that recruitment of offspring to the breeding population is low to non-existent (Koehler 1990a). In the Wyoming Range, Laurion and Oakleaf (1998) found that few kittens survived through the summer. Lynx may disperse long distances from their natal area. Dispersal distances for females range from 103?250 km and from 164? 1,100 km for males (Slough and Mowat 1996). One female from Montana moved 325 km to British Columbia (Brainerd 1985). Previously territorial adults may become transient if prey bases become reduced. Most dispersers are young animals in search of unoccupied territories. FOOD HABITS Snowshoe hares constitute the main portion of the lynx?s diet, about 60 percent in winter and 40 percent in summer. Other prey include squirrels (Tamiasciurus hudsonicus), voles (Clethrionomys spp. and Microtus spp.), mice (Peromyscus spp.), grouse (Bonasa spp. and Dendragapus spp.), ptarmigan (Lagopus spp.), and other birds. While not important predators of ungulates, lynx occasionally may kill adult deer (Odocoileus spp.) and moose (Alces alces) in poor physical condition or when snow conditions are favorable for predation or when ungulate offspring are available. Although chiefly an obligate predator, lynx will scavenge carcasses and eat vegetation. Lynx take a variety of mammals when hares are scarce, but only hares support high population densities of lynx (Koehler 1990b). Kill rates average about two hares per three days, but rates vary with prey density. Food consumption may be 37 percent lower when hares are scarce (Brand et al. 1976). Food caching has been reported, particularly when prey is scarce. HABITAT REQUIREMENTS In Wyoming, lynx occur primarily in spruce-fir and lodgepole pine forests that slope at 8?12? at elevations between 2,437 and 2,937 m. For denning, lynx often select mature stands (250 years or older) of Engelmann spruce (Picea engelmanni), subalpine fir (Abies bifolia), and lodgepole pine (Pinus contorta) on north or northeast slopes and prefer sites larger than 30 acres in size with more than 80 downed logs (>20 inches diam.) per acre on north or east aspects. Old-growth spruce forests that have escaped natural fires in landscapes that are otherwise dominated by lodgepole pine also provide ideal denning habitat. Denning habitat is enhanced if forest parcels contain numerous alternate den sites and/or they are connected to other denning habitats (Koehler and Aubrey 1994, Tanimoto 1998). Dens are often located in hollow logs or in brush piles, particularly where surrounded by dense thickets. Downed logs 40?50 m in length provide escape cover for young kittens (Koehler 1990a, Koehler and Brittell 1990). Security cover is also necessary for diurnal rest areas used by adults and kittens that no longer use dens. Diurnal bed sites frequently occur in thickets near game trails. Lynx are specialized predators that hunt in habitats preferred by snowshoe hares. Hares require densely stocked stands of deciduous shrubs or young conifers (e.g., lodgepole pine <2.5 cm dbh) (Koehler and Brittel 1990) for forage, escapes routes, and thermal cover. Hare abundance is positively correlated with the density of cover at 1?3 m above ground or snow. Hare food is typically woody browse smaller than 4 mm in diameter that is less than 60 cm above the ground or snow. Stands that reach densities of 16,000 stems per ha are ideal (Keith et al. 1984). The structural attributes of vegetation needed by hares can be achieved in less than 20 years of growth and serial succession in the moist forests of Oregon and Washington. However, these conditions may not be achieved for 80 years or longer in the GYA. Hares require a diversity of food items, foraging on birch (Betula sp.), poplar (Populus sp.), willow (Salix sp.), and conifers. Pines are preferred to spruce, and spruce is preferred to fir. Because the nutrient content and palatability of forage decreases with increasing stem diameter, hares must browse selectively, consuming about 300 g per day, and cannot compensate for low food quality by increasing their consumption. Aspen (P. tremuloides) stands and forest edges, as well as open grass meadows and edges with forests, may also support high numbers of hares and lynx. At the southern extent of lynx range, Colorado lynx were found near upper treeline in mature spruce-fir habitats where the forest and tundra edges provided food for hares (Halfpenny and Miller 1981; Halfpenny and Thompson 1987; Thompson and Halfpenny 1989, 1991). Hares feed on buds, young branches, and tips of older trees. Forage must be above the snow (hares do not excavate), but not out of reach. Heavy snowfall may bend small trees, increasing forage for hares (Koehler et al. 1979, Koehler 1990b, Koehler and Brittell 1990). Deer, elk, and moose often reduce browse available to hares at ground level, particularly where wintering ungulates concentrate in or near habitats used by hares (Olson 1957; Telfer 1972, 1974). Lynx denning and hunting habitat must be connected by corridors providing cover for travel. Corridors used by lynx include tops of ridges and riparian zones with more than 30 percent canopy cover provided by subalpine fir, spruce, and lodgepole pine. Corridors should be at least 100 m in width and contain at least 300 stems per acre (Ruediger 1994). Lynx will cross narrower openings but will rarely hunt in them. On a landscape scale, lynx habitat includes a mosaic of early seral stages that support snowshoe hare populations and late seral stages of dense old growth forest that is not heavily fragmented by logging, roads, reservoirs, train tracks, or other developments. Connectivity between lynx populations is critical. Dispersal corridors should be several miles wide with only narrow gaps. Large tracts of continuous coniferous forest are the most desirable for lynx travel and dispersal (Tanimoto 1998). INTERSPECIFIC INTERACTIONS Lynx may compete with canids, other felids, mustelids, and raptors for snowshoe hares and small mammals. Bobcat home ranges often exhibit elevational separation from those of lynx, which are better adapted to deep snow. Bobcats are thought to displace lynx where both felids are locally sympatric. However, lynx occasionally may kill bobcats (Giddings et al. 1998). EFFECTS OF WINTER RECREATION ON LYNX Winter recreation has cultural, economic, and social aspects that may affect lynx both directly and indirectly. With respect to winter recreation, direct effects are those that change the survival of individuals. Losses resulting from lynx trapping, non-target trapping, or accidental deaths (e.g., hit by cars) are examples of direct effects. Losses or degradation of habitat through habitat destruction or disturbance are examples of indirect effects. Because both direct and indirect effects influence vital rates (e.g., natality and survival), they may strongly influence the viability of lynx populations. Because of the secretive nature of lynx and their habit of using deep-forest habitats, few ecological studies of lynx exist, let alone research on the effects of winter recreation. However, the paucity of data should not be construed as evidence that winter recreation has no adverse effects on this species. DIRECT EFFECTS Trapping seasons may significantly reduce the viability of lynx populations, particularly if lynx are few and/or key breeding individuals are removed. Currently, Montana is the only state in which lynx may be legally trapped, but very few are taken in the Montana portion of the GYA. In all states of the Yellowstone ecosystem, lynx may also be killed incidentally by bobcat trappers and hunters that are unable to distinguish the two felids when observed directly (Todd 1985, Bailey et al. 1986, Koehler and Aubrey 1994, Giddings et al. 1998). In addition, houndsmen may chase lynx with their dogs after mistaking lynx tracks for those of bobcats or cougar. Roads and snowmobile trails are an important aspect of winter recreation because they provide people with their principal access to wildlands. The type, density, and distribution of roads and trails in lynx habitat affect the probability that trappers will locate lynx tracks and legally take them in traps. Roads also affect the rate at which lynx are killed, incidentally by trappers and/or illegally by hunters or houndsmen. Thompson (1987) noted that all known lynx sightings on Vail Mountain Ski Area, Colorado, were animals that were shot (n=1) or illegally trapped (n=2). Easy access to lynx habitat is particularly detrimental when pelt prices are high or recruitment of young lynx to the breeding population is low (Koehler and Aubrey 1994). No road-killed lynx have been documented in the GYA, but losses of coyotes, wolves, cougars, and black and grizzly bears are well documented (Caslick and Caslick 1997, Gunther et al. 1998). During an attempted restoration of lynx in New York, 22 percent of introduced animals were killed by automobiles (Brocke et al. 1992, Weaver 1993). Lynx behavior may predispose them to collisions with vehicles, especially when emigrating, hunting, or travelling (Weaver 1993). Road edges and train tracks support exposed forbs, grasses, and shrubs during winter; these locations are suited to foraging snowshoe hares, mice, voles, and other small mammals. Consequently, these sites are also excellent hunting areas for lynx (Koehler and Aubrey 1994). During winter, lynx frequently travel along roads where adequate cover is available on both shoulders (Koehler and Aubrey 1994). INDIRECT EFFECTS Humans alter the structure, biotic composition, and arrangement of habitat components that are essential to lynx. Winter recreation and its associated infrastructure reduces the amount of suitable habitat available to lynx and reduces the effectiveness of pristine habitat because human disturbance causes lynx to avoid habitats that are otherwise suitable. Habitat Destruction.?Development of resort and other destination infrastructure for winter recreationists destroys and fragments lynx habitat. Human populations in the ten counties comprising the GYE increased 7.4 percent from 1980 to 1990, while the number of households increased 8.4 percent (Feigley 1993). Although only a fraction of this development occurred in habitats potentially used by lynx, road and housing development in expanding recreation-based communities such as West Yellowstone and Big Sky, Montana, and Old Faithful, Wyoming, could represent a significant cumulative loss of lynx habitat. In addition, the highways and improved roads that connect these communities also represent habitat losses because the improved surface, particularly for wide roads (>15 m), is essentially unusable by lynx except for aforementioned opportunities to travel or hunt along the road shoulder. Loss of Habitat Effectiveness Resulting From Disturbance.?Human disturbance associated with recreational infrastructure and roads can reduce the effectiveness of habitat in supporting lynx, even if habitat is otherwise of high quality. Losses of habitat effectiveness can be adverse because disturbances preclude lynx from using habitat in an optimal manner. Lynx and other wildlife may avoid developments and roads because of the association with humans, particularly if they are unfamiliar with the sights, sounds, and smells that accompany human activity (Gutzwiller 1995). The paucity of studies makes it difficult to assess the magnitude of disturbance and displacement associated with winter recreation. Year-round, ungulates that are not habituated to humans adjust their distribution and activity patterns to avoid human activity (Lyon 1979, Aune 1981, Rost and Bailey 1979, Edge et al. 1985, Kufeld et al. 1988, Cassirer et al. 1992, Caslick and Caslick 1997). Displacement, including den abandonment, is documented for black bears (Ursus americanus) and grizzly bears (U. arctos) (Jonkel 1980, Goodrich and Berger 1994). The search for cross-country and downhill skiing opportunities leads recreational skiers to prime lynx habitat. Downhill and crosscountry ski development destroys and fragments lynx habitat and increases disturbance associated with human traffic, thereby reducing habitat security for lynx (Halfpenny and Miller 1981; Thompson 1987; Halfpenny and Thompson 1987; Thompson and Halfpenny 1989, 1991; Halfpenny 1991). Development of winter ski areas may also increase disturbance of lynx in the off-season, as recreational use and maintenance activity will occur year round. Snowmobiling may be particularly adverse to lynx because: (1) this activity occurs when animals are frequently in poor condition due to the stresses of winter (Anderson 1995); (2) this activity may be dispersed on the landscape (i.e., not confined to roads) on national forest lands outside of wilderness areas; (3) it may occur at night when lynx are usually active; (4) it is frequently accompanied by human disturbance and habitat loss associated with recreational infrastructure; and (5) this activity may alter the density and distribution of snowshoe hares, a favored prey item. In Ontario, Canada, snowmobile activity altered the mobility, distribution, and movements of hares (Neuman and Merriam 1972). Road plowing, grooming, and construction activities that support snowmobilers may also significantly reduce the effectiveness of winter lynx habitats. In this regard, road density and the level of automobile use are important considerations because they affect the frequency and intensity of disturbance. Disturbance, however, does not necessarily lead to a continued reduction in habitat effectiveness for lynx. With repeated exposure to human activity that is predictable in time and space, lynx may adapt behaviorally or physiologically (Bowles 1995). Lynx visited Geneva Basin and Vail Ski areas in Colorado at night to scavenge at garbage dumps (Halfpenny et al. 1982; Thompson 1987; Thompson and Halfpenny 1989, 1991). Lynx also used ski runs at Vail from adjacent nondeveloped habitat, despite night grooming operations (Thompson and Halfpenny 1989, 1991). Lynx also visited a night-active winter construction camp on the Frying Pan River in Colorado, presumably scrounging for garbage (J. Halfpenny, unpublished data). (Text continued on website)

Keywords: bibliography, Animal, Mammal, Felidae, Feline, Lynx, Lynx canadensis, Habitat, Human activity, Population, Mortality, Hunting, Trapping, Hare, Rodent, Predation, Food, lagomorph, Snowshoe hare, Lepus americanus, Wildlife, Management, Distribution, Migration, Yellowstone National Park, Greater Yellowstone Ecosystem, Bobcat, Lynx rufus, Carnivore, Grand Teton National Park, Gros Ventre Range, Bridger-Teton National Forest, Wind River Range, Teton Mountain Range, Wyoming Mountain Range, Idaho, Kemmerer, Big Piney, Greys River, Radio collar, Breeding, Canidae, Coyote, Canis latrans, Wolf, Canis lupus, Cougar, Felis concolor, Wolverine, Gulo gulo, Mustelidae, Disease, squirrel , Tamiasciurus hudsonicus, vole, Cricetidae, Clethrionomys spp, Microtus spp, Muridae, mouse , Peromyscus spp, Bird, Aves, grouse , Bonasa spp. , Dendragapus spp., ptarmigan , Lagopus spp., Deer, Odocoileus spp, Moose, Alces alces, breeding, den, denning, Raptor, Ursidae, Bear, Black bear, Grizzly bear, Ursus arctos horribilis, Ursus americanus