Cooperative Fish and Wildlife Research Units Program: Wyoming
Education, Research and Technical Assistance for Managing Our Natural Resources

Wyoming Project

Deer-Elk Ecology Project (DEER PRoject)

July 2015 - July 2020


Participating Agencies

  • Muley Fanatics Foundation
  • Bowhunters of Wyoming
  • BLM
  • Wyoming Wildlife and Natural Resource Trust
  • Wyoming Community Foundation
  • Wyoming Game and Fish Department
  • Rocky Mountain Elk Foundation
Little Mountain Fawn

Mule deer are an integral part of the outdoor heritage of western North America, a relished species of pursuit among big-game hunters throughout the country, and a key component of the landscape of the West. Nevertheless, mule deer populations have declined across much of their range during the last 2 decades, with a number of factors potentially contributing to those declines. Coincident with waning populations of mule deer, populations of elk have burgeoned throughout much of their range through growth in abundance and range expansion. The opposite trajectories of these two species that overlap throughout much of their range have spawned the hypothesis that competition between elk and mule deer may contribute to declining mule deer populations. Quantifying the net effects of competition on nutritional condition, survival, productivity, and ultimately population growth is a difficult endeavor and one that has not been adequately addressed. To better understand factors regulating growth of struggling mule deer populations, and identifying what, if any, effect elk have on mule deer is key to knowing what management and conservation actions will enhance mule deer populations, while maintaining robust elk populations in the future. In few places are these questions more prevalent than for the south Rock Springs mule deer and elk herds in southwest Wyoming. This region harbors some of the most sought mule deer and elk hunting in the state of Wyoming. While elk have been above desired levels during most of the last 2 decades, the mule deer population remains about half of the desired population level. In an effort to address the underlying reasons for failed growth of this and other mule deer populations in the West, a non-profit organization, a management agency, and a research entity have formed a key partnership to conceive and execute the Deer-Elk Ecology Research (DEER) Project.