This is an excellent overall review of wolverine ecology by the co-author of the first and only field study of wolverines in Montana. It includes nice graphics: a wolverine drawing, and photos of a den site, live trap, etc. It is a chapter in a book published by Ontario Ministry of Natural Resources.

Notable excerpts:

Status and Distribution
Figure 1 shows the historical distribution of wolverines in the western U.S., "extended southward from Canada through the montane ecoregions to Arizona and New Mexico" (Banci 1994). Banci then qualifies this statement: "However, it is not known whether these southern occurrences represent reproducing populations or dispersers." Banci also relies on this figure to conclude: "The northward retreat of wolverine distribution in the United States began in the 1840's." The figure shows that wolverines are now believed to be extirpated from the entire northern tier of the contiguous United States except the northern Rocky Mountains and portions of the Northwest; and from the southern tier of Canada from the Atlantic west to the Canadian Rockies.
In his conclusions, Hash mentions some evidence of some gains in wolverine distribution since historic lows at the turn of the century: "There are many areas where the range is uncertain, but general reports (Hornocker 1974, Novak 1975, Johnson 1977, Kovach 1981, Hoak et al. 1982, Nead et al. 1984) have indicated reoccupancy of some parts of its historical range where suitable habitat occurs." (583)

Mortality
"Wild wolverines harvested in Montana rarely exceeded 8 years of age, with an average of 4-6 years (H.Hash, unpublished data). Well-cared-for captive wolverines often live longer than wild wolverines. Woods (1944) presented records that showed that the average longevity was about 5.5 years and that some animals could live for 15 years. Jackson (1961) believed that captive animals could reach 18 years of age." (577)

Habitat
"Hornocker and Hash (1981) reported that wolverines inhabiting forested areas in Montana appeared reluctant to cross large openings, often skirting the edges or or running and loping across in a straight line, in contrast to the meandering travel patterns commonly displayed within timbered areas." (578)

Population Density and Dynamics
"Reporte natural densities of wolverine populations are low compared with those of other carnivores or predators, even under optimal habitat conditions (Quick 1953a, Krott 1959, Van Zyll de Jong 1975). Quick (1953a) based his estimate of 1 wolverine/207 km2 (80 miles2) on returns from a registered Canadian trapline. Hornocker and Hash (1981) estimated that 20 wolverines inhabited a 1,300 km2 (500 miles2) study area in northwestern Montana (1 wolverine/65 km2 [25 miles2]). Many fringe areas adjacent to the core study area supported wolverines at a density of about 1 wolverine/150-200 km2 (58-77 miles2)." (578)

Home Ranges
"Home ranges of the wolverine are large, and reports of individual wolverines covering long distances within 1-3 days are common (Krott 1960, Hornocker and Hash 1981, Wilson 1982). Magoun (1985) reported an average yearly home range of 666 km2 (257 miles2) for adult males in Alaska, and resident females maintained average summer home ranges of 94 km2 (36 miles2)... Whitman et al. (1986) estimated a mean home range of 35 km2 (207 miles2) for males (N=4) and 105 km2 (41 miles2) for females (N=3) in south-central Alaska. Hornocker and Hash (1981) calculated average annual home ranges of 422 km2 (163 miles2) and 388 km2 ( 150 miles2) for males and females respectively." (578)

Trapping
"The primary impacts of exploitation in North America apparently occurred from about 1840 to 1925, as manifested by range reductions and extirpation from many areas (Newby and Wrigth 1955, Jackson 1961, Newby and McDougal 1964, Van Zyll de Jong 1975).

Conclusions
"Hunting and trapping appear to be the primary sources of mortality for adult wolverines, as the species has few natural enemies. Wolverines are vulnerable to bait trapping because their scavenging nature and long distance travel patterns increase the overall probability of their encountering traps, even in remote areas. In contrast, females with newborn young are limited in their ranging and foraging and as a result become expecially vulnerable to easily obtained trap baits (Hornocker and Hash 1981). Bait trapping for all species should be prohibited in areas where expansion of wolverine populations is desired. Harvest seasons should be closed during late winter and early spring (Feb-Apr) o protect females with kits. Wolverines are susceptible to traps intended for other species; any set made for a coyote, lynx, bobcat, or wolf can effectively take a wolverine." (583)
"Much of the general wolverine population decline and extirpation that occurred during the late 1800's and early 1900's on many ranges, particularly the conterminus United States, has been attributed to overtrapping and habitat degradation. It is essential that the harvest of a species with a naturally low density and relatively low reproductive potential be monitored closely. Any actual or contemplated harvest program should be directed only towards viable populations that are producing surplus animals. General populations or localized subpopulations that are expanding their ranges or that are in the process of reestablishment should be fully protected. Areas of the wolverine's historical range with suitable habitat which are currently vacant or only occasionally occupied would be ideally suited to reintroduction programs." (583)
"The future of the wolverine appears bright. The species has survived the pioneer periods of unregulated trapping, hunting, and predator control, accelerated and irresponsible natural resource development, and widespread habitat degradation. The designation of vast national park and wilderness areas has greatly benefited the wolverine. Our greater awareness and responsibility toward environmental issues and threatened species will favor the survival of the wolverine, as well as many other wildlife species. Carefully regulated harvest programs, the implementation of refined monitoring techniques, appropriate reintroduction programs, and the preservation of adequate suitable habitat should endure the survival of the wolverine for future generations." (584)

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