Wolverine continues to wander, but not leaving the state

NEW YORK (April 29, 2010)
—Eleven months after biologists radio-tracked a wolverine into Colorado, marking the first confirmed sighting in the state in 90 years, the Colorado Division of Wildlife reports that the animal was missing for about two months, but has resurfaced – this time south of I-70.  The wolverine was first radio-collared by the Wildlife Conservation Society, as part of a long-term study of the species.

Colorado Division of Wildlife biologists have been tracking the young male wolverine, labeled M56, since it first entered the state.  It spent last summer and fall in the vicinity of Rocky Mountain National Park, then vanished for about two months (the same period of time that it took him to travel over 500 miles from Grand Teton to Rocky Mountain National Parks).

Following its hiatus, it re-emerged near Leadville, Colorado.  The radio-location was made by a CDOW airplane and pilot after a wolverine track was reported by the general public. In March, the Colorado Division of Wildlife found M56 near Mount Evans, and subsequently tracked him north to Larimer County near the Wyoming border. It has recently headed back south along the Continental Divide.

“This is a young male probably trying to establish his own territory and find mates,” said Bob Inman of the Wildlife Conservation Society’s North America Program “During the two months he was missing, it is possible that he toured most of southern Colorado.”

Colorado Division of Wildlife biologists attribute M56's extended stay as an indicator that Colorado might be able to support a breeding population of wolverines.

“The fact that M56 has remained in the state for nearly a year, reaffirms our belief that Colorado still has suitable wolverine habitat,” said Shane Briggs, DOW wildlife conservation programs supervisor.

The wolverine was originally captured near Grand Teton National Park by WCS biologists and traveled approximately 500 miles between April and May of 2009 before eventually crossing into Colorado last June. A growing body of research is showing that these wide-ranging, little-known animals need large areas to survive and that the young often disperse long distances between mountain ranges to find a territory and mates.

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 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.

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.

“We think Colorado could have 20 percent of suitable wolverine habitat in the lower 48 states,” said Jodi Hilty, director of the Wildlife Conservation Society’s North America Program. “Establishing a population in Colorado would be significant for the species.”


Stephen Sautner: (1-718-220-3682; ssautner@wcs.org)
John Delaney: (1-718-220-3275; jdelaney@wcs.org)

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