State studying mountain goats near Aspen

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Catherine Cussaguet/Aspen Journalism

Mountain goats on a ridge between Geissler Mountain and the upper Marten Creek basin, on the Continental Divide not far from Independence Pass, and about 15 miles from the Maroon Bells - Snowmass Wilderness, in 2014.

Hikers in the high country near Aspen who catch a glimpse of shaggy, white mountain goats might notice this year that some are wearing collars.

That’s because researchers are trying to figure out why local populations of mountain goats are thriving while populations of another high-alpine animal — bighorn sheep — have been declining.

In December 2018, Colorado Parks and Wildlife began a two-year study in the Maroon Bells-Snowmass Wilderness that aims to determine the range and movement patterns of mountain goats and whether hunting can be better used to manage their populations for the benefit of bighorn sheep. This marks the first time that mountain goats have been studied in a Colorado wilderness area.

In the narrow window between hunting season and the onset of winter, Alaska-based Quicksilver Air used net gunning — a technique performed from a helicopter — to capture roughly 30 animals so researchers could affix collars around their necks.

Those collars beam location data to biologists’ computers every couple of days as the goats roam the rocky ridgetops and basins of the high country. Researchers hope the data will reveal how quickly the animals move around, where they spend the winters and what type of habitat they like best.

According to the research study plan, the mountain goat herd in game-management unit 12, which is in the Maroon Bells-Snowmass Wilderness, has grown from about 75 animals to 300 over the past two decades.

“I think people were surprised a little bit when they thought they were keeping that herd at a certain level and it turns out it was growing,” said Eric Bergman, a CPW researcher who is leading the study. “That emphasized we should actually try to learn more about what’s going on here.”

Bighorn sheep interactions

Brent Gardner-Smith/Aspen Journalism

A group of bighorn sheep in the lower Fryingpan River basin. Such sheep are common in the Maroon Bells – Snowmass Wilderness.

The two species are known to compete for some of the same food sources, but there is also evidence that the more-aggressive goats push bighorn sheep from their habitat.

“It’s more that they just don’t want to be around each other,” Bergman said. “There’s strong evidence that mountain goats are a bit more behaviorally aggressive. Bighorn sheep just aren’t going to go in there because goats chase them out.”

CPW issues 54 hunting permits for mountain goats in the G12 area, and according to Bergman, hunters have a 60 to 70% success rate. CPW has increased the number of tags in recent years to account for the uptick in goat populations.

Pitkin County contributed $26,000 toward the project as part of its biodiversity initiative, according to Open Space and Trails director Gary Tenenbaum.

“We are trying to get the science to make management decisions,” he said, “and CPW can do the science. Until we know where all the animals are going, we just don’t know how to manage for it.”

Native or not?

Catherine Cussaguet/Aspen Journalism

A mountain goat on a ledge between Geissler Mountain and the upper Marten Creek basin, on the Continental Divide not far from Independence Pass, and about 15 miles from the Maroon Bells – Snowmass Wilderness, in 2014.

Mountain goats occupy a unique and controversial position in the world of Colorado wildlife. According to the Colorado Bighorn Sheep Management Plan, mountain goats were first introduced into Colorado in 1948 by the then-Colorado Game, Fish and Parks Department, with the intent of creating a population for hunting. In the 1960s and ’70s, a handful of animals were released in Sawatch Range, Mount Evans, Needle Mountains, Gore Range and Ragged Mountains.

In 1993, the Colorado Wildlife Commission passed a resolution granting native status to mountain goats. The decision was based on historical accounts of their presence in the region in the 1880s and ’90s. But those reports were not verified, and in some cases people misidentified (or misnamed) other species. For example, pronghorn antelope were called “white goats.” Despite the 1993 native designation, wildlife authorities generally consider mountain goats an introduced species.

But whether mountain goats are truly native, they are here and are thriving, and it could be at the expense of the Colorado state animal, the bighorn sheep.

From those handfuls of goats released into Colorado’s high country, they slowly and opportunistically populated the mountains near Aspen. They can now be spotted clinging to the cliffs and rocky outcrops along Four Pass Loop, near Independence Pass and in other alpine areas.

“The rocky, steep, alpine habitats are a very good habitat for them,” said Julie Mao, a CPW biologist who is assisting with the study. “They have adapted well across North America, and introduced populations seem to be doing well.”

The collars will continue collecting information about the animals’ whereabouts for about another year. Then the collars will automatically drop off and be retrieved by researchers. Data from the collars have indicated that a few of the goats have died, probably perishing in last winter’s historic avalanches.

“If that collar hasn’t moved, we know they died,” Bergman said. “We have had a couple mortalities, and I think they were avalanche-related. It’s not too surprising, given where they live.”

Where the goats live — in some of the most rugged and remote mountains in the state — is one of reasons so little is known about their movement patterns. Bergman said he’s excited to see what this first-of-its-kind study turns up.

“Logistically, it’s just harder to work on goats in Colorado than any other species,” Bergman said. “This is our first chance to study goats and sheep in an area that’s wilderness, so I think anytime you get your first crack at learning something about the animals, you’re going to learn a lot.”

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