Wednesday, September 9, 2015 by Mike Koshmrl, Jackson Hole News and Guide
An effort to determine where wolverines roam in the American West has confirmed the presence of the scarce mustelid in the Gros Ventre Range for the first time.
A wolverine was also potentially documented outside the species’ known turf in the northern Wyoming Range, but a nighttime photo snapped of the specimen was too dark to make an identification with certainty. The wolverine detection in the Gros Ventre was in the far east edge of the mountain range in the Tosi Creek area.
“They could have been there before, but at least now we have proof that they’re there right now,” said Zack Walker, the Wyoming Game and Fish Department’s nongame bird and mammal supervisor.
“We now know they’re in the Wind River Range, the Gros Ventre and the Absarokas and there was a possible wolverine sighting in the Wyoming Range,” Walker said. “They’re at least in the core western mountains.
“I don’t know if they’re going to be in the southern Wyoming Range, and we certainly don’t know if they’re going to be in the Bighorns,” he said.
Last year was first step of a multi-year research initiative in Wyoming, Idaho, Montana and Washington to map the distribution of wolverines south of the Canadian border. Generally, the Northern Rockies in Idaho and Montana and the North Cascades in Washington are considered to be occupied wolverine range. Much of the Greater Yellowstone Ecosystem, however, shows up on the maps as “unknown status.”
In the Equality State, Gulu gulo is managed as a species of “greatest conservation need.” The 20- to 50-pound cousin of the weasel was once extirpated from the Lower 48.
Two years ago the U.S. Fish and Wildlife Service proposed protecting wolverines through the Endangered Species Act, but the next year the federal agency abandoned plans to pursue listing. Wolverines had been a candidate for protection because scientists expect that their breeding grounds — which depend on deep spring snows — will retract significantly as the world warms during this century.
The first year the wolverine distribution research in Wyoming was contracted out to the Wolverine Initiative, but Game and Fish will handle the study internally going forward. The change occurred because Bob Inman, who headed the initiative, took a job at Montana State University.
In the pilot season, the nonprofit research group set out 18 infrared cameras in high-elevation areas throughout the Wyoming portion of the Greater Yellowstone. Baited with deer remains hung in trees and fitted with hair snares, the stations were located in the Absaroksa, Wind, Gros Ventre, Salt and Wyoming ranges between 7,000 and 10,500 feet in elevation.
Collectively, the wolverine detection stations ran for nearly 2,000 “trap nights,” according to an August progress report completed by the Wolverine Initiative. Some 8,200 photos of wolverines were acquired and 65 genetic samples gathered between February and June.
Five of the 18 stations turned up evidence of wolverines. Three stations in the Winds — at Burro Flat, Clear Creek and Moon Lake — documented wolverines, as did the Gros Ventre station and another located near Bonneville Pass in the southern Absarokas.
Before the study, there had been only a dozen “verifiable wolverine occurrence records” in Wyoming, the progress report says.
“Of the 12 current records, nine occurred in the Teton Range and were made via capture during a radio-telemetry study,” the report says. “Of the four remaining records in Wyoming over that 44-year period, one was a roadkill of a young female near Kemmerer in 2004 and one was an incidental capture of a male by a fur-trapper near Cheyenne in 1996. Both individuals could have been dispersers traveling long distances. The other two records appear to have come from near the northern border of Yellowstone National Park and near Jackson Hole.”
While the research didn’t extend into the Tetons this spring, Walker said Game and Fish will survey the range this winter. The Wind River, Gros Ventre and Wyoming ranges will also be searched, he said.
Next winter, if funds are secured, the distribution research will extend to another 20 to 25 sites in the Bighorn Mountains and Absaroka Range.
When wolverine researchers headed by Inman studied the Tetons between 2001 and 2008, they discovered four adults regularly inhabiting the range. Young wolverines, in years that kits were reared, boosted the population up to about seven animals in the 40-mile-long range, biologists found.
But wildlife researchers trying to determine the effects of winter recreation on Teton Range wolverines more recently had trouble finding the far-ranging species.
Kim Heinemeyer, of Round River Conservation Studies, spoke about the study at Teton County Library in late August.
“In the Tetons, historically, there was a nice population and it was kind of considered a cornerstone of wolverine presence and occupation for the Yellowstone region,” Heinemeyer said. “But we only found one male.”
The Tetons’ lone Gulo gulo, nicknamed Jed for “Jedediah Smith,” is 14 years old — ancient by wild wolverine standards. Jed had been a research subject in the earlier Inman study.
“We would have expected him to be replaced by now with a young, more vigorous animal,” Heinemeyer said. “But he seems to be the only one home that we could find in the Tetons, and we looked pretty hard for two years. We didn’t find any females.”
A focal point of last winter’s Wolverine Initiative survey was to determine the distribution of female wolverines — it’s in the title of the progress report. Determining the gender or reproductive statuses, however, proved problematic, and no new animals were sexed the first go-around.
Going forward, Wyoming, Montana, Idaho and Washington are going with field-research techniques that will not distinguish between males and females, Walker said.
“The future work will not be using run poles and looking for signs of female reproduction,” Walker wrote in an email. “However, when we submit hair to the genetics lab we will have the option of determining gender. I am not sure on the cost of this, and how far we will proceed down that path.”
If enough funding is secured, Game and Fish will “try to get as much information out of the hair samples as possible,” Walker said. Genetic data acquired could verify that an animal is a wolverine and confirm its sex and individual identity, he said.
The Wolverine Initiative progress report called the pursuit of information on the whereabouts of females “important.”
“In areas on the periphery of the currently documented wolverine range, determining whether wolverines are reproducing would benefit wildlife managers,” the report says.
At her Teton County Library talk, Heinemeyer also stressed the importance of knowing where wolverines are breeding versus being seen. Her study struggled to find females in historically occupied areas such as the Tetons and mountain ranges in Idaho.
“It seems we can easily make assumptions on where there’s reproducing populations of wolverines based on historic evidence,” Heinemeyer said. “But we’re not finding those animals now, and we should just be cautious about the assumptions we make about how the species is doing.
“If you hear rhetoric currently, it’s often that wolverines are doing fine or expanding because you get these males that disperse long distances and end up in Colorado, or the Uintas or California,” she said. “But those are just single male animals of a species that do big dispersals.”