JACKSON, Wyo. — Biologists looking for the elusive fisher, a large cousin of the weasel, have come up empty-handed in the Wyoming neck of the Northern Rockies.
Habitat models predict that the fisher's range extends well into Teton and Park counties, and south to the very northwest tip of Fremont County. That caused the Wyoming Game and Fish Department to lead a search for the mustelid, which was recently, but is no longer, a candidate for protection under the Endangered Species Act.
"We didn't find any (fishers)," Game and Fish nongame biologist Bob Oakleaf said. "What we did find is (pine) marten everywhere."
Using a $23,000 state wildlife grant, Game and Fish personnel last year searched the Sunlight Basin, near the Beartooth Mountains, just to the east of Yellowstone National Park. In January 1995, a fisher was photographed by a remote camera near this area Remote cameras are the primary method used to find the critters.
Game and Fish isn't quite sure where it will spend a $31,500 wild life grant to try to find the fisher this year, Oakleaf said. The North Fork of the Shoshone River near Cody is a possibility, he said, but a search of Teton County isn't being considered.
Game and Fish's 2010 "Wyoming State Wildlife Action plan" suggests that Teton County south to about Jackson Lake and Buffalo Valley is fisher habitat. The state's plan states that "distribution is suspected to be restricted" and that the species has a spotty distribution in Wyoming.
"Although sightings of the fisher are reported in most mountain ranges," the Game and Fish document said, "few documented records exist for Wyoming and are limited to the extreme northwestern part of the state."
There have been only three or four reports of a fisher in Wyoming, and it's been about a decade since the last sighting, Oakleaf said.
"There was one individual animal collected," he said. "It was found in a trap in the Big Horns in the '60s."
Ranging in weight from about 4 to 13 pounds, fishers are light brown to blackish-brown with a long body, short legs and a long bushy tail.
They look much like a weasel, mink or pine marten and are inhabitants of old growth forests.
After reviewing its status across the Northern Rockies in 2010 and 2011, the U.S. Fish and Wildlife Service concluded fishers don't warrant Endangered Species Act protections in Idaho, Montana or Wyoming. A petition filed by four environmental groups, including the Center for Biological Diversity, seeking to list Northern Rockies fishers as a "distinct population segment," prompted the review.
Based on trapping data in Montana, fishers in the Northern Rockies are rarer than lynx and wolverine, both of which are afforded federal protections. They are considered the rarest mammalian carnivore in the ecosystem.
Unlike lynx and wolverines, however, in other parts of the country, including the Great Lakes Region and Northeast, fishers are common and trapped regularly.
It's not well understood why fishers don't appear to be inhabiting Wyoming, Oakleaf said.
"Sometimes we don't know what the factors are that are limiting the range of a species," he said. "Sometimes we can figure it out and sometimes not."
Factors such as over-trapping, timber harvesting and habitat fragmentation are considered the historic catalysts for the near elimination of fishers in the Northern Rockies.