LEAVENWORTH — Biologist Don Youkey picked his way along a log nailed to a tree trunk nearly five feet above the ground and reached overhead to hang a cow knuckle bone and chunk of raw rib meat.
He hopes the tasty new bait will lure one of the newest carnivores cruising these snowy woods to trigger a remote camera that will snap its photo: Gulo gulo, the wiley wolverine.
Once shot on sight, trapped and poisoned as vermin, wolverines were extinct in Washington by the 1930s. But they are making a comeback, repopulating portions of their historic home range for the first time in decades. On Friday, they were proposed for listing as a threatened species under the Endangered Species Act.
Wolverines used to range along the Cascade Crest from the Canadian border all the way to Mount Rainier, but now remain exceedingly rare, with perhaps just 25 animals in Washington, and only about 250 to 300 in the Lower 48.
The wolverine’s return to Washington is amazing scientists. “We are witnessing what we think is the expansion of wolverine into their former range,” said Keith Aubry, research wildlife biologist with the U.S. Forest Service, Pacific Northwest Research Station in Olympia. Aubry for eight winters had led the first-ever radio-tracking study of wolverines in Washington.
Genetic testing shows the animals they are finding can be traced to populations in Canada that recolonized here once the persecution stopped. Now, those animals, once just visitors, have established resident populations — and they are spreading. “We have growing evidence of them using larger and larger areas over time,” Aubry said.
So far, scientists have confirmed resident wolverine populations from the North Cascades to as far south as this bait lure south of Highway 2 west of Leavenworth.
“When you see a species like wolverine that needs openness and connected habitat coming here all on its own, this is the celebration moment. It’s the success, the reward,” said Jen Watkins of Conservation Northwest, a Seattle nonprofit, as she dunked pine-branch tips into a bottle of foul-smelling scent lure. So foul, she packed it on snowshoes up the Icicle Creek drainage in a double plastic bag, sealed in a kayaker’s dry bag, and handled it only with rubber gloves. “There!” she said, hastily screwing the top on the bottle, “Now all we need is a visitor!”
Even as wolverines rebound, threats loom in their future, with climate change over the next 100 years expected to melt out 63 percent of the landscapes where deep snow that wolverine need to survive persists into May. The U.S. Fish and Wildlife Service on Friday proposed listing wolverine for protection as a threatened species under the Endangered Species Act in at least six Western states, including Washington. Any decision to list would be at least a year away, after an extensive public comment period.
Smaller than a Labrador retriever, Gulo gulo, or “the gluttonous glutton,” is pound-for-pound among the most ferocious carnivores in Washington, capable of sniffing out frozen carcasses and tunneling through five feet of snow to crack open bones and tear apart even frozen carrion. Their powerful jaws and molars are specially adapted to shear off chunks of rock-hard flesh and bone.
Wolverines roam Washington’s wildest country in its most punishing weather, devouring miles with a loping stride and cruising over even deep powdery snow with oversized, snowshoe-like feet.
Their long, thick, brown-and-gold coat sheds frost and is underlaid with a soft insulating layer of fur that defeats the most brutal cold. Semi-retractable claws enable them to climb trees and scrabble up and down rocky slopes.
“They are the superheroes of the animal world,” said Shawn Sartorius, a wildlife biologist based in Helena, Montana, for the U.S. Fish and Wildlife Service. “When you follow the tracks of these things, you see they are not taking the easy way around; they will go straight over mountaintops, craggy peaks, the rockiest, steepest, cliffiest place; they will go right over that in the middle of winter, at night.”
John Rohrer, supervisory wildlife biologist with the U.S. Forest Service, Okanogan-Wenatchee National Forest based in Winthrop, has been astounded to learn in his work on Aubry’s research team just how much territory wolverines cover, even in winter.
“They live in places that are frozen in suspended animation more than six months a year and one of the few animals that is not is the wolverine,” Rohrer said. “The North Cascades in winter are pretty hostile to life. Most animals will avoid it in winter or hibernate. It’s amazing to see how they move in rugged, remote terrain in 10 to 12 feet of snow. In summer there are cougar and black bear and bobcat and coyotes and great horned owls. In winter time, it is only the wolverines.”
A wolverine trapped and radio-collared by Aubry’s team covered more than 14 air miles over the peaks of the North Cascades from a recent Saturday afternoon to Monday, “and if you were to lay it flat it covered double the distance,” Rohrer marveled.
The dominant radio-collared wolverine in that drainage — dubbed Rocky by the researchers — has been known to cover the home ranges of two or three females, or about 700 square miles. “And that’s a 30-pound animal,” Rohrer said. “Most dogs are bigger than that.”
And wolverine are ferocious. “When you see one in a live trap you never forget it,” Rohrer said. “They are growling, trying to bluff you, they are not cowering in the corner, if you crack open the lid they are charging and coming up to the front, snapping their jaws and drooling. They put on quite a show.”
But hikers have nothing to worry about: Wolverines are primarily carnivorous scavengers, feasting on a wide variety of foods, including carrion of every type, usually elk and deer. But they will also take live small mammals, including pikas, marmots, ground squirrels, porcupines and snowshoe hares. They will sometimes devour bugs, berries, eggs and roots.
For now, ensuring wolverine survival is about planning for the future, Watkins said, by preserving and providing safe access to the strongholds the wide-ranging wolverine are returning to now. Highway 2, for instance, is a travel corridor wolverines will need to cross if they are to make it as far south as Mount Rainier. They haven’t been seen there yet, but one lone wolverine already has been documented on Mount Adams.
“For these animals to come back to these places on their own, and take up residence there again, sticking around, and calling it home,” Watkins said, “That is thrilling.”