The Wyoming Game and Fish Department captured and collared 34 bighorn sheep in January as part of an ongoing project to learn about disease pathogens in the species, as well as learn more about the herds in southeast Wyoming.
Sheep from herds near Encampment, Douglas Creek and Laramie Peak were included in the effort. More than 840 sheep across the state have been captured and sampled since 2012.
Native Range Capture Services, based in Elko, Nevada, was enlisted to fly its helicopter close enough to a herd that a gunner could shoot a square net over an animal. After landing in the rugged alpine terrain that bighorn sheep prefer, the crew untangled, hobbled and blindfolded the sheep before transporting it to a staging area where Game and Fish biologists waited.
Biologist Teal Cufaude, who is based in Saratoga, said the work-up included a blood draw to check for minerals in the diet, nasal and tonsil swabs to check for pathogens that can cause pneumonia, an ear swab to look for mites that cause scabies and a fecal sample to look for lung and intestinal parasites. Scientists also used ultrasound to check ewes for pregnancy.
“Quite a few of the Encampment River sheep did look like they were pregnant, so that was really good to see,” she said.
Once the sheep was fitted with a GPS tracking collar, its hobbles and blindfold were removed and it was taken away from the processing area for release.
Cufaude said biologists have a lot to learn about the southeast Wyoming herds, and GPS collars will provide a lot of useful information. The collars will transmit several signals a day for the next two years.
For example, scientists will use that location information to monitor lambing grounds this spring, learn where sheep spend the winter and see what habitat they use most frequently. That knowledge can in turn influence where Game and Fish uses its resources.
“If we decide to do a habitat treatment, it’s going to be in a particular location that’s going to benefit sheep,” she said.
She said decadent habitat, meaning habitat that is in decline, is one of the challenges facing herds in the Platte River Valley.
One herd unit occupies the area south of Encampment along the Encampment River. Another herd stays near Douglas Creek in the Snowy Range, while a third group lives near the Colorado border.
Bighorn sheep were transplanted to the area, which is part of their historic range, from near Dubois in the late 1970s.
“It’s thought that their population peaked probably quickly after they were transplanted, like the early- or mid-1980s,” Cufaude said.
Since then, the population has either declined or remained stagnant. Meanwhile, the Laramie Peak herd has expanded over the years.
“We’re really trying to get a handle on what the reason for that might be,” she said.
Hank Edwards, wildlife disease specialist for Game and Fish, said an ongoing study of bighorn sheep hasn’t yet turned up a direct link between herd health and any specific pathogen. The southeast Wyoming herds were the last to be sampled in the state.
“We’ve collected a lot of really important and really valuable data, but it just goes to show us that the health of the herd is complex,” he said.
Edwards said factors such as the presences of trace minerals and the quality of a herd’s diet can also influence why one herd does better than another, and scientists are hoping continued research will shed light on the issue.
“It’s more than just pathogens,” he said. “They’re a part of that, but it’s more than that.”
The Encampment and Douglas Creek herds are open for hunting every other, and two licenses are issued. Game and Fish manages the herds so the average ram is 6-8 years old.