By Jessianne Castle EBS Contributor
LIVINGSTON – After a significant downtick in the number of bighorn sheep in Grand Teton National Park, officials are now accepting comments on a proposal to remove all mountain goats from the park, which are a non-native species that could be negatively affecting the sheep. The public comment period will run through Jan. 6.
Prior to 2015, researchers estimated the park’s bighorn herd was approximately 100 to 125 individuals. However, winter flight surveys between 2015 and 2017 indicate the population dropped to approximately 50 sheep. According to Grand Teton’s proposal, the herd is currently estimated at about 80, though at EBS press time on Dec. 19, representatives from the park’s public affairs office were unavailable to discuss this population increase from 2017, due to a potentially impending government shutdown.
Overall, officials believe the bighorn population has declined, though the exact cause isn’t apparent.
In the 59-page proposal, the authors discuss ongoing research that suggests mountain goats and bighorn sheep have the potential to transmit diseases and could compete for resources, the latter of which can be critical when the animals share winter range. This is of particular concern for the Teton Range bighorns, which are one of the smallest and most isolated Wyoming herds, and was never extirpated, nor improved with reintroduced sheep.
“Without active management, the mountain goat population is expected to continue to grow and expand its distribution within the park, threatening the existence of the native Teton Range bighorn sheep herd,” park officials wrote in a press release, adding that a rapidly growing breeding population of 100 mountain goats has become established since first coming to the Tetons in 1979.
These mountain goats likely came from a population that was introduced outside of the park, southwest of the Tetons in the late 1960s and early 1970s. Mountain goat native range, however, extends from southeastern Alaska, south to the Columbia River in Washington, east into Idaho and western Montana, and north to the southern Yukon.
Park officials are proposing two methods for managing the non-native mountain goats—either by lethally removing the entire population, or by combining a level of lethal removal with some live-capture. Animals that are captured would either be relocated to zoos or reintroduced to their native home ranges.
While it is possible that mountain goats could re-establish a population in Grand Teton after their removal, the proposal authors note that it took roughly 40 years for mountain goats to establish a breeding population in the park after first being spotted in 1979. They add that managers could remove individual goats that enter the park in order to prevent recolonization.
Representatives from the Wyoming Game and Fish Department have shown their support for the park’s plan. To assist the park with the removal, Wyoming will hold special-draw mountain goat hunts next fall in the Caribou-Targhee National Forest just beyond the park boundary. These licenses will not be once-in-a-lifetime like other goat hunting opportunities in Wyoming.
Wildlife management coordinator Doug McWhirter said these hunts should keep mountain goats to a very limited population and hunters will have the potential to draw every year. This new hunting opportunity is a management strategy authorized by the state legislature, over-riding a state statute that limited mountain goat hunting, he said.
Despite the hunting increase, McWhirter said the department does support the removal of goats in the park. “Most of the area’s goats and sheep reside in Grand Teton National Park,” he said. “We can’t manage the entire mountain goat population with hunting outside of the park.”
Though mountain goats in the Spanish Peaks near Big Sky are also non-native, conditions are allowing Montana managers to leave the population intact.
“Although the mountain goats are non-native, they are a numerous and healthy population in the Spanish Peaks. They overlap somewhat with bighorn sheep on summer range, but generally not on winter range,” wrote Montana Fish, Wildlife and Parks Bozeman area wildlife biologist Julie Cunningham in an email to EBS. “Meanwhile, the bighorn sheep population is also currently healthy and at the highest numbers in recent history.
“I currently see no reason to suspect deleterious competition between these two species in the Spanish Peaks,” she added. “My current management strategy is to maintain both populations at healthy levels.”
Visit parkplanning.nps.gov/mountaingoat to learn more, view Grand Teton’s proposal, or submit comments.