Wyoming has seen a significant increase in winter die-offs from big game due to prolonged and harsher winter conditions. This winter has been one of the worst winters for big game in the western part of the state in many decades.
Many things influence whether an animal lives or dies during winter .The severity of winter conditions can be a huge factor, but, the extent that winter conditions matter for survival often depends on the condition an animal is in when they start the winter.
“For big game species, especially those that live in areas that experience deep snow and cold temperatures for many months, the amount of body fat that they have at the beginning of winter can be one of the biggest, and sometimes, most important things that determine if an animal lives or dies,” Tayler LaSharr, Ph.D. Candidate and Muley Fanatic Foundation Fellow for UW, said.
“If animals are not starting winter with enough fat and then are exposed to very harsh conditions, they will almost definitely die before the snow melts and the landscape greens up in the spring.”
LaSharr is a Wildlife Scientist that researches the factors that influence big game populations. The majority of her work is focused on mule deer in the Wyoming Range and how these animals respond to winters.
LaSharr is also a Fellow of the Muley Fanatic Foundation (MFF). The MFF is a Wyoming-based nonprofit that is focused on supporting the conservation of mule deer through science-based management.
“For mule deer and other populations of big game, the habitat and the places they live in the summertime are what matter for them. Animals that live in areas with good food are able to put on more fat, and it gives them a better buffer during these harsh winters,” LaSharr said.
“During a pretty typical winter, a mule deer in the Wyoming Range that starts winter with around 8% body fat may be able to survive; this winter with very deep snow and consistently cold temperatures, animals exposed with under 8% body fat was not nearly enough for animals to survive.”
Big game populations across the West face many obstacles that influence survival and their ability to reproduce, from disease to human development.
Wildlife-vehicle collisions often can have devastating effects on big game, which may be especially true in winter when animals are searching for areas with not a lot of snow and might be drawn to roadways.
“In Wyoming, there have been incredible efforts to mitigate risk to big game populations from vehicle collisions from a huge number of stakeholders, including the Wyoming Game and Fish, the Wyoming Department of Transportation and the MFF,” LaSharr said.
Wyoming Game and Fish are adjusting their hunting tags to help the big game animals that survive the winter because of the significant loss impact big game face and to help conserve wildlife.
“In the western part of the state, the population has been severely reduced, and the animals that are alive are barely scraping by,” LaSharr said.
“Female deer who are pregnant right now are trying their best to make it to spring, but that probably means that the energy and nutrients they are investing in the fawns growing inside them are limited.”
The condition of a mother doe during this very critical period can have a lifetime effect on how big her fawn grows. Some research shows that the stress a mother doe is experiencing now might stunt the growth of her fawns for their entire lives, and in the coming years, Wyoming might see deer that are less impressive than we are used to in the western part of the state.
“Despite the bleak and harsh conditions deer are facing now, the high snowpack might help promote really good food on the landscape this summer, which can help animals put on the fat that they need to survive harsh winters,” LaSharr said.
“If conditions continue to stay as harsh and cold as they are now, identifying and conserving summer ranges might be one of the most important tools we have to help big game populations.”
