Winter takes toll on pronghorn population

Several pronghorn carcasses line a wall of the Uinta BOCES No. 1 building on Evanston’s Cheyenne Drive. Game and Fish performed a battery of tests on the dead animals to try to determine a cause of death. Roughly 30 pronghorn have died in the area this winter. (HERALD PHOTO/Hayden Godfrey)

EVANSTON — In the course of a particularly harsh winter, roughly 30 pronghorn have died outside of the Uinta BOCES No. 1 building on Cheyenne Drive, but Wyoming Game and Fish have yet to discover why. Samples from the carcasses were screened for a bovine disease comparable to viral pneumonia last week.

A Wyoming Game and Fish employee in the office of Wildlife Health Laboratory Supervisor Hank Edwards said the samples had been tested and the suspected disease, Mycoplasma bovis, was not present. M. bovis is a small bacterium most commonly seen in cows, according to a CDC report. It affects mucous membranes and has been observed near Pinedale since 2019, beginning in February and ending around the beginning of April the past few years. This year, Game and Fish estimates more than 200 animals have died from it so far.

While the disease can be severe, it has not been significantly fatal in most Wyoming animal populations. It has not affected domestic animals and is not a risk to humans.

Game and Fish performed a battery of tests on the subjects, none of which were positive for M. bovis. Regina Dixon, an information and education specialist in Green River, said no information is yet available, and Edwards’ office said more analysis is required to identify a definitive cause of death.

BOCES facilities specialist Trudy Biorn said Evanston Public Works has collected carcasses from the premises since Monday, March 6.

On that day, approximately 15 animals were removed. Later, eight more were taken.

“Now there are another six that haven’t been collected,” Biorn told the Herald.

Biorn mentioned pronghorn deaths are unusual. Most winter casualties are deer, and they typically die in lower numbers.

“In really bad winters, we’ve had about three deer die,” she said.

This year, she is giving the animals food.

“We don’t feed them unless they’re starving to death,” she said.

This year’s feeding began the same day Public Works hauled away the first round of carcasses.

Biorn said deaths have decelerated since feeding began, indicating the issue was simply caused by a scarcity of food. Game and Fish expects their tests will conclusively determine the animals’ cause of death in the coming weeks.

Video News