Funded Research Projects: WILDLIFE SCIENCE

Do wolves indirectly affect mule deer fawn survival by modifying coyote predation?

Research Sponsored By: Mule Deer Foundation
Principal Investigator: Aaron Wirsing
Project Description
Our goal is to assess the effect of predators on mule deer fawn survival to inform mule deer management and conservation. Mule deer (Odocoileus hemionus) populations have been declining throughout the western United States since the 1980’s, putatively due to low fawn survival, and the major causes of fawn mortality are unknown in Washington state. At the same time, gray wolves (Canis lupus) are in the process of recolonizing many areas of the northwestern USA, including Washington. The return of wolves to the Pacific Northwest offers a unique opportunity to explore the impacts these top predators will have on native ungulate populations. One interesting possibility is that wolves might indirectly benefit ungulate populations by suppressing coyotes (C. latrans). Coyotes account for up to 80% of fawn mortality in some areas and wolf recolonization has been shown to reduce coyote abundance in other ecosystems (e.g., the Greater Yellowstone Ecosystem). However, the possible link between wolves, coyotes and mule deer has yet to be investigated. We will test whether wolves indirectly influence mule deer fawn survival by decreasing coyote abundance. The results of this study will be applicable across mule deer range in western North America and will inform mule deer management and conservation. Specifically, results from this study will inform managers of the primary causes of mule deer fawn mortality and thereby facilitate more reliable population projection. Our work will also help managers to understand how the return of the wolf, one of the biggest ecological changes currently occurring in the west, will affect mule deer populations.