After 90 Years, Wolverine Returns to Colorado
WCS tracks animal on 500-mile odyssey beginning near Wyoming’s Grand Teton National Park
NEW YORK (June 18, 2009)—The Wildlife Conservation Society (WCS), working with state and federal partners, announced today that a wolverine that WCS researchers have been tracking since early April has crossed into northern Colorado – the first known incidence of a wolverine in the state since 1919.
The wolverine, a young male labeled M56, was captured near Grand Teton National Park and traveled approximately 500 miles during April and May, successfully navigating significant human-made features including Interstate 80 – the heavily trafficked route across Wyoming that links Chicago, Salt Lake City and San Francisco.
WCS researchers affixed a radio-tracking collar to the wolverine as part of an ongoing study to understand these wide-ranging little-known animals. A growing body of research is showing that wolverines need large areas to survive and that the young often disperse long distances between mountain ranges to find a territory and mates.
The Greater Yellowstone Wolverine Program is a unique public-private partnership between the Wildlife Conservation Society, the state game departments in Wyoming, Idaho and Montana, Grand Teton National Park, and the Bridger-Teton, Caribou-Targhee, Beaverhead-Deerlodge, and Gallatin National Forests.
Even though adult wolverines average about 30 pounds, a home range is often as large as a grizzly bear’s. The size of a wolverine's territory, as much as 500 square miles for some adult males, limits the number of individuals that a given area can support. Adults tend to inhabit areas above timberline where there are snow-covered avalanche chutes and freezing temperatures much of the year.
“Wolverines are the real ‘iron men’ of the animal kingdom traveling seemingly non-stop in some of the most rugged country in North America,” said Robert Inman, director of WCS’s Yellowstone Wolverine Program. “It is great news that this animal has ventured into Colorado where it hasn’t been documented in 90 years, but it also underscores the need to manage this species at a multi-state, landscape scale.
This state, federal, and private partnership represents the longest ongoing study of wolverines in North America, and has focused its field-based research on documenting the species-specific biology necessary to develop successful management strategies here in the Lower 48.
“The partnership has been able to increase research capacity of the governing agencies by combining resources from private sources together with the limited public funding available to learn about wolverines,” said Mark Orme, Forest Biologist for the Caribou-Targhee.
Wolverines are the largest land-dwelling members of the weasel family. Resident adults occupy arctic habitats in Alaska and Canada, and range south into the lower 48 states only high in mountains where near-arctic conditions exist.
The wolverine was once native to the mountainous areas of Washington, Idaho, Montana, Wyoming, Utah, Colorado, and California. Records indicate that populations were nearly wiped out by about 1930. Recovery has occurred to some degree during the previous 80 years. However, vast areas of suitable habitat on public lands in California, Utah and Colorado do not appear to have breeding populations at present.
The Colorado Division of Wildlife is working with WCS to track the wolverine in order to monitor its movements and activities. At this time the CDOW has no plans for either wolverine reintroduction or surveys. Future considerations for wolverine management in Colorado would have to involve members of the public and would be guided by direction from the Colorado Wildlife Commission.
"This is certainly an interesting event and could give us some initial information on wolverines in Colorado," said Rick Kahn, Terrestrial Section Manager for the CDOW. “But the occurrence of a single animal needs to be treated as somewhat of an anomaly.”
In 2008 and again in 2009, a lone male wolverine thought to be from a Rocky Mountain population was photographed by a remote-controlled camera in Tahoe National Forest of northern California.
“The single instances of male wolverines being documented in California during 2008 and now Colorado are encouraging,” said Shawn Sartorius of the U.S. Fish and Wildlife Service. “But it remains to be seen if females can make similar movements that would be required to establish populations.”
One thing is clear, biologists say: the dispersal of young wolverines from one mountain range to another where there are unrelated individuals is essential. One of the reasons the researchers were tracking M56 was to understand which habitat features wolverines key-in on while dispersing across arid valley bottoms, many of which are under increasing pressure to be converted from ranchland to subdivision. Ultimately these data will help identify migration corridors and other habitats important for wolverine conservation.
“As a state with a source population of wolverine, Montana has adjusted wolverine management to be in-line with these landscape-scale, multi-state objectives.” said Brian Giddings with Montana Fish, Wildlife and Parks. “If we had the opportunity to make further progress toward collaborative wolverine management at this large scale, I could see using our sportsmen to help live-capture and restore the species to some of its former range. Then they could be part of a historical achievement for wildlife conservation in the U.S.”
As scientists gain insights to wolverine behavior here in the Lower 48, wildlife conservation groups are advocating for greater efforts to conserve this unique species that feeds on marmots and gives birth during mid-winter under the snow-covered debris pile of an avalanche chute.
“The great thing about wolverines is that almost everyone finds them interesting,” said Inman. “They live in such rugged terrain and are so elusive that even the most weathered outdoorsmen have rarely caught a glimpse of one. When they do, it becomes a moment that is not forgotten.”
The Wildlife Conservation Society saves wildlife and wild places worldwide. We do so through science, global conservation, education and the management of the world's largest system of urban wildlife parks, led by the flagship Bronx Zoo. Together these activities change attitudes towards nature and help people imagine wildlife and humans living in harmony. WCS is committed to this mission because it is essential to the integrity of life on Earth.
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