Upper Powder River Mule Deer study

A Mule Deer herd in central Wyoming is the subject of a study to determine why its numbers aren’t reaching population objectives. In this week’s Game and Fish Report, Ray Hageman says as the study enters its second year, researchers have already learned some interesting findings.

The second year of a mule deer research project in northern Wyoming has already provided researchers with some interesting findings, as they look to understand why this herd’s numbers are stagnating. The Wyoming Game and Fish Department is maintaining a study of adult mule deer does in the Upper Powder River Mule Deer Herd using 70 radio collars to assess deer survival, their nutritional status, seasonal movement patterns, fawn recruitment and habitat use patterns. The deer are fitted with radio collars to track their movement, and biological samples are taken to assess nutritional condition, which is key to understanding why the herd’s numbers aren’t improving.

“We initially caught these deer last year in December—so exactly a year ago—and we measured their body condition with ultra sound. We want to re-measure that every year to see if it’s fluctuating annually or what kind of patterns that we’re seeing throughout the life of these radio collars, which is three years," said Wyoming Game and Fish Sheridan region Biologist Cheyenne Stewart.

Blood, hair, and fecal samples offer additional hints to the animals’ nutritional condition. The downloaded radio collar data provides deer locations to target the department’s habitat assessment and treatment efforts. In the first year of the study, 18 deer died; causes range from Chronic Wasting Disease, pneumonia, predation, one even falling from a cliff. Researchers also learned a few deer migrated over 30 miles. Nutritional condition of the deer has been less than expected, despite precipitation being above average over the last two years. This study received a boost from the Bureau of land management, who provided funding for some of the collars. Wildlife Biologist Christopher Sheets says the BLM shares the same concerns about the herd.

“Anything affecting wildlife has to do with habitat, so, being concerned with habitat and the multiple-use mission we have with the BLM, we allocated some funding to help purchase the collars for the study, and we’re going to help do some of the field data as well and follow up,” said Christopher Sheets, Wildlife Biologist.

This population has been below its objective of 18,000 animals since the early 2000's. Many mule deer herds across the west are in decline. This study is a response to public concerns voiced in 2014 as part of the agency’s Mule Deer Initiative, a plan that identifies the most pressing issues affecting mule deer in Wyoming, and establishes goals and objectives for management.