Bighorns Bear The Brunt Of Domestic Sheep On Public Lands

FORT COLLINS, CO – By Paige Blankenbuehler, High Country News. A frozen, severed head arrived at the lab.

The bighorn sheep’s horns, splattered with bright red blood, curled tightly around its face. Its open eyes seemed alive, and its cracked mouth revealed yellowed teeth. Karen Fox, the lead wildlife pathologist for Colorado Parks and Wildlife in Fort Collins, swabbed the animal’s nostrils. The ram had been shot by a state biologist because of potential exposure to a deadly bacteria called Mycoplasma ovipneumoniae, which Fox was now testing for.

Domestic sheep transmit the deadly virus to bighorns when the two species mingle on public lands. Wildlife officials are supposed to make sure that wild and domestic sheep don’t interact. But according to a trove of Colorado Parks and Wildlife documents recently obtained by High Country News, they mingle more frequently than previously known. And though failures on the part of ranchers, federal agencies and state wildlife managers are often to blame, it’s always the bighorns that pay the price.

See all of the documents obtained for this story here.

Ranchers who hold permits to graze sheep on public lands are responsible for keeping their sheep out of known bighorn range. But domestic sheep often stray from their flocks. And when gregarious bighorns get too close, the ranchers’ herd dogs and employees sometimes fail to haze them away. Yet the permit-holders are rarely penalized. Instead, whether or not disease transmission has been confirmed, any bighorns known to have interacted with domestic sheep — like the ram in Fox’s lab — are euthanized to prevent the possible spread of disease to their wild kin.

A domestic ewe trails a bighorn ram over rocky terrain near Gunnison in December 2015. Courtesy Colorado Parks and Wildlife

Though their current population numbers pale in comparison to the distant past, bighorn sheep appear to be expanding their range in southwest Colorado, a sign that the populations are healthy. Rocky Mountain bighorns are considered a species “of conservation concern” at the state level, but are not currently listed under the federal Endangered Species Act.

READ MORE in The Colorado Independent

Image: In April 2016, a bighorn ram jumped over fencing into a pen holding six domestic sheep on private property west of Durango. The bighorn was euthanized. Courtesy Colorado Parks and Wildlife