Methow wolverine project expands, is model for Canadian, west side studies

By Joyce Campbell
    Extreme avalanche conditions and slides at Harts Pass have slowed the start of the North American wolverine study season, but research teams are back on the trail this week riding snowmobiles to remote live-trap sites within the Methow Valley Ranger District and beyond.
    The wildlife researchers are baiting live traps on the district this week in hopes of re-capturing the bear-like predators that were trapped and radio-collared during the last three years. They also hope to capture new animals, and possibly the offspring of animals previously captured.
    The Forest Service has built an additional six traps and is going into its third year with a total of 12 traps located in the Twisp River Valley, Harts Pass, the upper Chewuch, Cutthroat Creek, Baldy Pass, the West Fork of the Methow trailhead and Sweetgrass Butte, according to district biologist John Rohrer.
    Four of the new wolverine traps were built of dimensional four-by-fours, a style developed in British Columbia. The rest of the traps were constructed using six-by-six logs. The durable traps are meant to withstand the powerful jaws of the bear-like mammal.
    The traps are baited with road-killed deer and beaver carcasses from western Washington provided by the U.S. Department of Agriculture Wildlife Services.
    Last year the team successfully trapped one male two times at the Harts Pass site. Estimated to be three to four years old, he was fitted with a VHF radio collar in January. When he was recaptured near the end of March, they replaced the satellite collar with a GPS-VHF combination collar.
    The VHS collar is programmed to send signals every other day and last for 400 days, said Rohrer. The GPS is programmed to fix once a day and has a 45-day life. Data is stored on board the unit, and the team hopes to recapture Rocky this year and retrieve the stored data.
    The six or seven people on the research team inspect traps daily by radio and weekly on site to monitor for captured animals. When a radio signal indicates that a trap has been tripped, the team rides to the trap to inspect it. Bobcats and martens have been lured into the traps and been released by the team members.
    Nine successful captures have been made of five individual animals during the past three years. Rohrer and Washington state Department of Fish and Wildlife biologist Scott Fitkin are trained to immobilize the animals with a medicated jab stick and fit them with collars. The team quickly takes tissue samples for genetic profiling and gathers data on their sex, age and condition. Small, brightly colored plastic tags are attached to each ear, which helps identify them later in remote camera photos.
    The first wolverine ever live-trapped in the state was captured during the pilot year. Named Melanie, she was recaptured during the second year and biologists determined that she was pregnant. During the third year a remote camera captured her image, without a collar and with one ear tag intact. Fly-overs of the area did not reveal any kits.
    This is the first field study of the rare mammal in the Pacific Northwest, due in part to low population densities and the limited access into their habitat – unroaded wilderness areas. Recent studies in the Rocky Mountains indicate that wolverines are wide-ranging, live near timberline and are sensitive to human disturbance at denning sites.
    Joining the study this year is the Canadian Ministry of the Environment, the University of Washington and Conservation Northwest. 
    “It’s a collaborative effort in every sense of the word,” said Keith Aubry, project leader and research wildlife biologist at the Forest Service Pacific Northwest Research Station in Olympia. All the data collected will be centrally collected and added to the USDA Forest Service study, he said.
    Canadian fur-bearer specialist Eric Lofroth will use 10 traps following the same protocols used in the Methow Valley. The project has expanded geographically this year to include the Skagit Valley and Manning Provincial Parks in British Columbia. Lofroth secured funding on his own for the study in Canada. Several wolverines in the study have been tracked by satellite radio telemetry on both sides of the border.
    Aubry helped Conservation Northwest obtain permits to set up remote cameras in the North Cascades National Park, hoping to increase the geographic scope of the study to the west of the Cascade crest.
    “If we get a picture, we will initiate the process of trapping on the west side,” said Aubry.
    Aubry plans to extend the season of the study by involving graduate students from the University of Washington. The winter months are well-covered, but summer research could provide valuable data from telemetry on the ground, remote cameras and DNA profiles from hair snag stations.
    “A wealth of opportunities arise if someone can spend three months in the wilderness,” said Aubry.
    The wolverine is considered a sensitive species in the Pacific Northwest by the Forest Service and a candidate species for listing as threatened or endangered by the state of Washington. However, the wolverine has been repeatedly denied listing and protection under the national Endangered Species Act. A lawsuit filed by nine conservation groups is currently challenging the U.S. Fish and Wildlife Service determination that listing the North American wolverine as a threatened or endangered species is not warranted.
    In a news release announcing its decision in March 2008, the USFWS stated that the wolverine population in the contiguous United States is not a geographically distinct population, but is connected to populations in Canada and “likely dependent on them to some degree for maintaining genetic diversity.”
    The agency determined that the population in the contiguous United States does not constitute a significant portion of the range of the North American wolverine subspecies, did not significantly contribute to the Canadian and Alaskan wolverine populations’ ability to maintain their genetic diversity and viability and therefore did not warrant further listing consideration.
    A comprehensive guide to worldwide scientific research studies on the wolverine is available on the website www.wolverinefoundation.org.

Photo courtesy of US Forest Service
This wolverine, a bear-like carnivore, was released after his second capture during the 2008 study. The team of Forest Service and WDFW researchers named the 31-pound male Rocky. They hope to re-capture him this season and retrieve data from the combination VHF-GPS radio collar.