A statewide project to learn more about respiratory disease pathogens in bighorn sheep has moved into southeast Wyoming. In mid-January, 34 bighorn sheep were captured in herds near Encampment, Laramie Peak and the Douglas Creek area of the Snowy Range. They join more than 840 sheep captured and sampled across the state since the study began in 2012.
Very little is known about the Encampment and Douglas Creek bighorn sheep herds, but neither herd has grown to the size that biologists had hoped since the sheep were introduced many years ago. “The populations have stayed fairly small without much growth,” said Hank Edwards, disease specialist for the Game and Fish Department. Meanwhile, the Laramie Peak herd is doing well and has shown some expansion. Edwards said the study hopes to identify some of the respiratory pathogens that are known to affect bighorn sheep populations, as well as other factors, such as trace minerals or nutrition, which may influence how one herd may do better than others when infected with the same pathogens.
Capturing an animal as fleet and agile as a bighorn sheep takes a bit of resourcefulness, and wildlife managers looked the skies for help. Native Range Capture Services uses a helicopter to locate the sheep in their rugged and remote habitat. The pilot moves the craft close to the herd, and a net gunner shoots a 6-foot square net over one of the animals.
The pilot lands the helicopter, and the gunner now becomes a “mugger,” jumping out of the helicopter, untangling the sheep from the net and fitting it with a blindfold and leg hobbles. The mugger then puts the sheep into a safety sling and it is flown back to a group of biologists for processing. While bighorn sheep flying through the air sounds like something out of a science fiction novel, the study should help biologists learn more about the issues affecting sheep populations.
Once the sheep are safely on the ground again, they undergo a series of tests: A tube of blood is drawn and will be used to determine whether the animal is getting enough minerals in its diet, and to serve as a serum bank for future disease investigations. Nasal and tonsil swabs are collected to determine if a sheep caries respiratory pathogens that can cause pneumonia. An ear swab looks for mites that can cause scabies, and a fecal sample can show the presence of lung and intestinal parasites. Ewes then have a quick ultrasound to determine whether they are pregnant. The temperature of the sheep is constantly monitored throughout the entire process to ensure the animals are not overheating or exhibiting too much stress.
Thirty of the captured sheep were fitted with GPS tracking collars that will provide biologists with eight location points a day for the next two years. This information will help biologists estimate the number of sheep that use critical winter ranges, and learn more about their movement patterns to help determine future habitat improvement projects.
Monitoring collared animals is a lot of work, but students from Encampment K-12 School are on hand to help. The sixth- and eighth-grade students in Jordan Seitz’s Earth Science class have been studying bighorn sheep, and they braved the cold January wind to help with the project. The students will help monitor the collared sheep and assist with lamb surveys later this spring.
When a sheep has completed the processing and sports a new GPS collar, it is carried away from the processing area, and the hobbles and blindfold are removed. Realizing it is free, the sheep races to the safety of its herd, taking with it the hopes of a brighter future for the species. “Our end goal is to see a more robust sheep population overall,” said Teal Cufaude, Game and Fish Department wildlife biologist in Saratoga.