Chislers

A Uinta ground squirrel, known colloquially as a chisler, sounds an alarm whistle on the National Elk Refuge.

The alarm call rang out on an overcast afternoon nearing the end of March, a familiar sound on Refuge Road and a telltale sign of spring that had returned to the landscape.

It was the chirp of the Uinta ground squirrel, commonly referred to as a chisler. The ubiquitous small mammals were out of their burrows, after an eight-or-so-month stint below ground in hibernation.

The timing of emergence on the National Elk Refuge was of no surprise to Wyoming Game and Fish Department nongame biologist Susan Patla. The chislers near her west slope Tetons home usually show up right as April arrives, almost regardless of snow conditions.

The plump rodents might not look the part of an icon northwest Wyoming species like the elk, but they play just as integral a role in the healthy function of the ecological food web, she said.

“You can think of chislers as the salmon of the interior West,” Patla said. “Salmon on the West Coast are the main biomass for the ecosystem, and chislers here, especially for the raptor community, are enormously important.”

“What’s critical about them is they supply a food source for raptors in the pre-nesting and early nesting season,” she said. “Birds haven’t started to reproduce. And the grass is low, so they’re very easy to prey upon.”

Raptors like goshawks, she said, key in on chislers so much early in the year that they’ll constitute as much as 80 percent of their diet.

But then the taste apparently wears on them.

“Ground squirrels put on a lot of fat before they go back underground,” Patla said. “And they tend to be avoided later in the season, when they have those heavy fat layers. You’d think that might be attractive [to raptors], but I guess it’s not.”

Uintah ground squirrels tip the scale at 1/2 to 1.3 pounds, and pack it on over the course of a year. When Urocitellus armatus first emerges in the spring it forages primarily on fresh green grasses but will switch over to grass seeds once vegetation cures, according to the Smithsonian Natural Museum of Natural History.

Utah State University research has found that chislers are among the beneficiaries of climate change. The rodents’ average weight has increased over the last century, and scientists surmise that the fatter chislers of today have better survival and are therefore more numerous.

Naturalist Bert Raynes, who has chisler neighbors near his Mallard Road abode, is among those who await the tawny rodents’ emergence each spring.

“A lot of people look for the first ground squirrels,” Raynes said, “just because it’s the first sign of spring, and in a normal winter out here people want to see spring, even the skiers and snowboarders.”

When Raynes arrived in the valley full-time in 1972 he had never heard a chisler’s normal chirp or alarm call. For a moment the ruckus threw him for a loop.

“When I first heard them I thought, ‘Damn this bird I’ve never heard before,’” Raynes said. “I walked around and I kept hearing it, but I couldn’t see it. Then I realized it was terrestrial.”

No new bird to check off, but a decades-long interest in chislers was born.

Contact Mike Koshmrl at 732-7067, env@jhnewsandguide.com or @JHNGenviro.

Mike has reported on the Greater Yellowstone Ecosystem's wildlife, wildlands and the agencies that manage them since 2012. A native Minnesotan, he arrived in the West to study environmental journalism at the University of Colorado.

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