Wolverine Ecology and Habitat Use
in the
Teton Range of Western Wyoming

1998 REPORT

Project Cooperators:

• Hornocker Wildlife Research Institute/Wildlife Conservation Society
• Alta, Wyoming 4H Natural Resource Club
• Grand Targhee Ski Resort
• Wyoming Game and Fish Department
• Idaho Department of Fish and Game
• USDA Forest Service
• Mountain Air Research
• Teton National Park
• The Wolverine Foundation

The wolverine's presence in the Teton Range bordering western Wyoming and eastern Idaho, has long been recognized, but its status as a resident species had not been confirmed. Teton Park rangers and hikers occasionally sight the animal and an individual was even photographed eating suet from a bird feeder on the back porch of a home near Moran, Wyoming. During the winter of 1997-98, a wolverine was photographed by remote camera in the Leigh Creek drainage on the Idaho side of the Tetons, in conjunction with a marten research project. Still, the wolverine's presence as a resident, reproducing species, or simply as an occasional transient individual wandering from some northern population, has yet to be established.

In 1997 a cooperative effort was developed to address the current status of the wolverine in the Tetons. The effort would combine the knowledge and cooperation of the public agencies charged with managing wildlife, with the resources, skills and labor of private individuals and organizations. The cooperators would develop a study plan, formulate objectives, and conduct the field work necessary to live-trap and radio instrument Teton wolverines.

Click here if you would like to see the project's original study plan.

The folks from Grand Targhee were enthusiastic about the project, providing help in checking traps and the use of snowcats. As such, it was decided to locate the traps within the administrative boundaries of the resort. This would provide a level of security for trap sites as well. During the fall of 1997, the 4H Club built 3 log live-traps. One of the traps was built on site, the other two were built in the parking lot of Grand Targhee and then transported to the trap sites. Both Idaho Fish and Game and Wyoming Game and Fish helped in the collection of road-killed deer and elk that would provide bait for the traps. The 4H group began efforts to raise money that would be needed for trap supplies and tracking flights should they capture and radio-mark a wolverine. Trapping began in early January, 1998, with traps operational until early May.

The first winter's trapping efforts were eventful. The 4H kids and their parents enthusiastically accepted the responsibility of operating the traps and collecting data. Traps were fitted with radio transmitters that could be monitored from the homes of the 4H'ers. If an animal entered the trap and pulled on the bait, the lid of the trap would be released trapping the animal inside and activating the transmitter. Each day, a receiver was tuned in to check if the trap transmitters had been activated. Any such signal would mobilize the group into action -- a snowmachine trip to the trap site to check on the contents of the trap. At times when trap action was slow, the traps were visited every 4 days to check bait condition and the film in remote camera systems installed at each trap site to monitor wildlife visits.

Trap checkers found the baited trap sites attractive to many wildlife species including the gray jay, magpie, and raven, the long-tailed weasel, American marten, and coyote, and, fortunately, the wolverine. Traps were pre-baited in December. With the first visit to re-bait and set traps in early January, the trappers had their first encounter with wolverine sign. A fresh set of wolverine tracks were discovered at one of the Leigh Creek traps. While this was cause for optimism, it would be over 3 months until evidence of Gulo was again detected. On April 17, a wolverine was captured in the same trap.

The animal was an adult female. She appeared in good health weighing nearly 22 pounds, which is large for a female wolverine. We had hoped to find evidence of lactation which would confirm the presence of kits. Unfortunately, she had not produced a litter of kits. Wolverine give birth from mid-February to mid-March. It is not uncommon for a female to not produce a litter in any given year. She was given the official label "F468." The "F" for female, the "46" for her ear tag number, and the "8" indicating she was captured in 1998. In feeling she needed a more personal handle, the 4H kids provided our first study animal with the name "Wolver-ann."

The delay in visitation from December to April, assuming this was the same individual, may be explained somewhat by data provided from other studies. There is evidence to suggest that the wolverine may be very traditional in its movements to foraging sites. Testimony of timely revisits to food sources is common to the legend associated with the wolverine in the trapper's tale of the beast's annual raid on his trap line. In this instance, myth may have a basis in truth. Winter food for a scavenging predator such as the wolverine will often be widely scattered, and commonly predictable. Traditional hunting camps and trap lines provide a consistent source of carcass remains. Wintering areas for deer and elk are generally used every year and are common sites of mortality. Marmots and squirrels generally hibernate in the same sites and consistently emerge from these sites at the same time each spring. Deer and elk generally use the same birthing sites. All of these situations provide a consistent food source for a predator that has developed an extremely sensitive sense of smell. Seasonal foraging routes develop within the home ranges of resident individuals, the knowledge of which may be passed on from generation to generation.

"Wolver-ann" has spent the past 6 months moving about the country from the south border of Yellowstone National Park to the north side of the Grand Teton. Her movements will tell us a great deal about how much space an adult wolverine requires. Hopefully, during this coming winter she will provide us with the data we hope for -- the site she will chose to have her kits. Only 2 completed studies in North America have provided information on the reproductive den of the wolverine -- within these the birthing dens of only 5 female wolverines have ever been found! Data from both North America and Scandinavia tell us that it is during this denning period, and until the kits are weaned at 9 to 10 weeks of age, the female may be extremely sensitive to disturbance -- abandoning the den with any level of disturbance, and abandoning the area with continued disturbance. If the wolverine is to remain in the western U.S., we need to understand if and how our presence might impact the animal's ability to live and reproduce. Human activities in areas important to denning females may force these individuals to leave and seek out den sites secure from human presence.

By developing an understanding of what this animal needs to live a secure and healthy life, we can make intelligent choices about using the land to meet our needs, while providing security necessary for the wolverine to exist.

Over the following 2 winters, 2 additional wolverine were captured and instrumented. This past fall (2000), primary responsibility for the study was handed over to the Hornocker Wildlife Institute . While the 4H group and local folks will still be involved in the effort, this will provide additional resources and guidance to insure that the project will continue to produce valuable information for the benefit of the wolverine.

The Wolverine Foundation will also continue its involvement and support of the project, but only with your continued support. Over the past 2 years, your donations have helped purchase 4 implant transmitters for the project. Field work continues to be supported by volunteer efforts of the Alta 4H Natural Resource Club. The kids have raised money primarily through local fund raising efforts and donations. If you would like to provide some generous help for this project, you can make a tax deductible contribution through The Wolverine Foundation, Inc. at the address listed below. Just let us know that you would like your contribution directed to the Teton Wolverine Project in your correspondence.