State tracking wolverine, pika populations

BUFFALO — The Wyoming Game and Fish Department is ramping up its surveys of wildlife in the state’s most remote reaches, including in the Bighorn Mountains.

Surveys targeted two species, specifically, in nearby alpine habitats, the results of which were published in the department’s recently released annual job completion report for nongame mammals.

Both wolverines and pikas are species monitored periodically by the department, as they have each been petitioned for Endangered Species Act listing. Neither is listed currently.

These two separate studies are an attempt to gather data on these species, whose well-being is largely dependent on available habitat.

Andrew Gygli, a small carnivore biologist based at the Game and Fish office in Lander, was involved in the study of wolverines. The 2021-22 study was a follow-up to one completed five years earlier. Dana Nelson, nongame mammal biologist based in Lander, was part of the first of its kind statewide pika surveys.

In the Bighorns, researchers recorded sightings of pikas at certain sites, but wolverines were not captured on camera. Both surveys were challenging due to the remote terrain. Still, Nelson and Gygli said they look forward to repeating the surveys in the Bighorns and other mountain ranges in the coming years to build a comprehensive database.

“The motivation is that we would get baseline information so we can compare future trends, with the idea that we’d repeat these surveys every six years or so,” Nelson said of the pika survey.

Counting pikas

Pika occupancy surveys targeted alpine habitats in the Bighorns and other mountain ranges around the state, including the central Rocky Mountains and the Snowies.

Pikas are small mammals with a body and coat resembling a rabbit and rounded ears. The species was petitioned for ESA listing in 2007 and 2016, and the U.S. Fish and Wildlife Service ultimately determined listing wasn’t warranted due, in part, to a lack of rangewide data on population trends and the species’ response to climate change, according to the Game and Fish report.

The statewide study conducted in 2020 and 2021 aims to address gaps in knowledge and start a long-term data collection. Previous studies focused just on populations in the Greater Yellowstone Ecosystem in western Wyoming.

Researchers sought pikas in the late summer months of 2020 and 2021, which is when pikas are collecting vegetation for hay piles, a winter food source.

Pikas are considered an indicator species, meaning their population trends can point to ecological effects of climate change and other factors that impact habitat, according to the Game and Fish report. Because of their high metabolic rate, they are vulnerable to high temperatures. For refuge during both summer and winter months, pikas live in gaps of rock structures to thermoregulate.

“Pikas are sensitive to both heat and intense cold, or some of those temperature patterns and snowpack patterns that would change with climate change,” Nelson said. “It’s important for us to monitor them and have a good understanding of their distribution within the state and their general population trends.”

Nelson said researchers visited three different sites in the Bighorns, including one at the northern edge of the Cloud Peak Wilderness and two others south of U.S. Highway 14A. Statewide results showed a roughly 57% occupancy, she said, which is about the same rate as sightings in the Bighorn Mountains. Researchers on scene determined their presence either by sight of pikas or their fresh haypiles, and by sound.

“We have known they are in the Bighorns for quite a long time,” Nelson said. A previous study of pikas in western Wyoming in 2010 and 2012 showed a 58% occupancy rate, she said. “We’re not comparing apples to apples, but it was reassuring to see that occupancy rates were similar,” she said. Game and Fish will continue monitoring the Bighorn Mountains and other ranges, though exactly when it can undertake another study depends on funding sources, Nelson said.

Watching for wolverines

Wolverines have made headlines over the past year after the Fish and Wildlife Service listed the alpine forest- dweller as threatened. Whether they still occupy the Bighorn Mountains is uncertain, as trail cameras in the area did not capture any.

Gygli cautioned against assigning too much meaning to those results, considering wolverines are elusive, solitary creatures, which makes observations rare. He said that the department has received word of confirmed observations on both the east and west slopes of the Bighorns.

“It’s more a place that juveniles, when they’re looking for habitat, might pass through,” he said. “But, who knows? Wolverines require really large territories, so there might be enough space for a couple. If they’re there now, we just don’t know about them.”

Five base stations across the mountain range detected zero wolverines throughout the study’s four-month duration, from December 2021 through March 2022. These cells were 15 kilometers by 15 kilometers within suitable habitat, which includes proximity to alpine tree lines and natural travel corridors.

Gygli said that wolverines can quickly cover a lot of ground. One was spotted in North Dakota, for example, and it could have come from southern Canada or moved eastward from this area or Montana.

“They can pick a direction and just go,” he said. “I don’t know if they see mountains on the horizon or what triggers this. That’s part of their strategy, is to be able to cover these distances. A juvenile will need to find a place that is not already claimed by a large male or female.”

Like pikas, wolverine observations are more common in the Greater Yellowstone Ecosystem. Statewide results suggest an increase in wolverine occupancy from the latest survey in 2016-17. The report said that this could be explained by improvements in equipment and technology, but that it likely means more wolverines are present.

During the summer months, wolverines occupy higher elevations and later travel to lower elevations in the winter in search of food. Wolverine occupancy is highest in the Wind River and Absaroka mountain ranges, Gygli said.

The department plans to repeat its statewide occupancy survey for wolverines every five years to provide trend data, which may also illuminate the influences of climate change on wolverine presence and distribution.

“As managers learn more about wolverine populations in Wyoming, knowledge gaps can be identified and research targeted to address specific conservation and management needs,” the report says.

Gygli said that Game and Fish depends not just on these surveys but also on public wildlife sightings, especially of tough-to-track animals like wolverines or pikas. Though he tracks the animal for a living, Gygli said he’s never seen a wolverine outside of a trap in the wild. An observation reporting form is available at tinyurl.com/ wygfd.

“Being able to keep track of these animals is really important, and what we’re trying to do now is get a little finer detail on where these animals actually are located and what they need to continue to survive and thrive on the landscape,” Gygli said. “The world is changing and, ideally, I would hope that wolverines can change with it.”

This story was published on March 13, 2025.