Harsh winter taking toll in Yellowstone

BILLINGS – This winter has been tough on some bison and elk in the higher elevations of Yellowstone National Park, researchers say.

Slabs of hardened snow and ice have kept food out of reach, leaving the animals to starve to death or become easy pickings for wolves, said Doug Smith, head of the National Park Service’s Yellowstone Wolf Project.

Smith said he hasn’t seen so many winter-killed elk and bison since the 1996-97 season, when severe weather killed 300 to 400 bison and, in the northern part of Yellowstone, more than 500 elk.

Swings in winter conditions are driving this year’s situation, he said. Cold snaps and snowstorms followed by warm periods have crystallized snow, making it more difficult for bison and elk to penetrate as they forage for food.

“It basically turned to concrete,” Smith said.

In those areas, weakened elk and bison have become easy meals for wolves, according to researchers conducting their annual survey of Yellowstone’s packs. Two wolf packs have been eating nothing but bison for the last two and a half months in the park’s interior, Smith said, which is rare because bison tend to be tough and dangerous prey.

P.J. White, a biologist for Yellowstone, said elk in lower elevations have fared better. And while the number of elk killed during the winter is up over previous years, “it’s nothing close to 1997,” he said.

Tom Lemke, a biologist for Montana Fish, Wildlife and Parks, flew over some of the elk herds on Wednesday. While numbers haven’t been tallied yet, he said he wasn’t alarmed by what he saw.

“I would say there may be a few more (winter-killed carcasses) but I don’t think it’s anything significant,” Lemke said.