DNA study tallies Glacier wolverines

Results from a multiyear DNA study of Glacier National Park’s wolverines show a relatively high density compared to other places where the rare carnivores are known to exist.

Park biologist John Waller, along with about 50 volunteers, set up “hair traps” for wolverines from 2009 to 2012.

The traps consisted of a deer leg from roadkill bolted to a pole. Wire brushes were attached to snag hair from any animal that tried to climb the pole to gnaw on the leg.

Waller said a litany of scavengers came to the traps, which were set only in winter to avoid bears. An occasional bear still showed up — some grizzlies in Glacier Park never completely hibernate.

The traps snagged hair from lynx, foxes, bobcats, pine martens, wolverines and even curious moose.

The study was designed to follow up on work conducted by biologist Jeff Copeland from 2003 to 2008. Copeland’s groundbreaking study tracked wolverines on a day-to-day basis using radio transmitters.

Waller’s study was noninvasive. Wolverines that sniffed around a trap got a free venison meal and left behind some valuable hair.

The study grew from 12 traps in 2009 to 18 in 2010 and then ramped up with a 10-kilometer grid sampling across the Park using 39 traps in 2011 and 37 traps in 2012.

Volunteers spent long hours skiing in the backcountry, rebaiting traps and gathering hair samples. The samples were then analyzed at the Forest Service’s Rocky Mountain Research Laboratory, and Waller ran the results through five different population monitoring models.

The end result was a population estimate of about 36 wolverines in the Park, averaging about 13 animals per 386 square miles. Waller cautioned that his results have a fairly wide confidence level.

That might not sound like many animals, but Glacier Park has the third-highest density of regions in the West and Alaska that have undergone a population study.

The highest known population is in the Northwest Territories of Canada, about 17 wolverines per 386 square miles.

The second highest is in the South Fork of the Flathead River drainage, about 15 per 386 square miles. By comparison, Yellowstone has about 3.5 per 386 square miles.

“It’s interesting that our density came up that high,” Waller said.

Glacier Park has become known as one of the best places for average people to see a wolverine. The largest land member of the weasel family, wolverines are renowned for their toughness.

A male called M3 that Copeland tracked spent just 90 minutes climbing up and over Mount Cleveland, the park’s highest peak — in winter. M3 could still be alive, Waller said. The male was first trapped by Copeland in 2003, and his hair was snagged in 2012. M3 was at least 10 years old at the time.

“That’s really old for a wolverine,” Waller said.

Waller snagged hair from six of the 17 wolverines Copeland trapped.

“It appears we have a pretty good survival rate,” Waller said.

Waller’s study also snagged hair from 11 new animals. He’s looking at using traps for a greater study of the entire Northern Continental Divide Ecosystem, much like an earlier grizzly bear study

Covering that big an area could be expensive and difficult, Waller said. The ecosystem covers about 8 million acres, and the terrain, particularly in the Bob Marshall Wilderness Complex, is tough to access in winter.

The Glacier Park study was relatively inexpensive, about $1,200 a year, because it used volunteer labor and the Forest Service did the DNA analysis.