Populations of mule deer across much of the West have declined or remained relatively stagnant, while at the same time, populations of elk have increased. Several ideas have been brought to the table to explain why mule deer are doing poorly such as predation and drought, as well as disease. However, more recently, questions regarding what effects elk may have on mule deer have come to the surface. With the Deer-Elk Ecology Research (DEER) Project, we aim to identify the roles of predation, habitat conditions, and disease on survival and reproduction of mule deer in the Greater Little Mountain Area, a high-desert ecosystem of southwest Wyoming. Further, our goal is to understand if elk who occur in this same system compete with mule deer for food resources and space, and if so, how that effects population dynamics of mule deer.
We expect that predation, habitat quality, and disease all play a role in limiting mule deer in this system. However, we suspect that the presence of elk on the landscape effects how mule deer use space, which may also have implications for survival and reproduction. For instance, if elk occupy areas that are good quality habitat, and deer avoid these areas because of the presence of elk, mule deer may be forced to use low quality habitat resulting in poor nutritional condition that translates to poor survival.
Do elk and mule deer compete?
We are evaluating whether exposure to elk within areas where mule deer spend most of their time during the summer months affects summer and winter adult survival and neonate recruitment. Understanding how changes in behavior link to condition and subsequently to fitness of female deer will provide insight into management of elk and deer in high-desert systems and help untangle this complex knot of deer-elk interactions.
How do coyotes affect mule deer fawns?
In the Greater Little Mountain Area, encounters between coyotes and fawns are more likely to occur when fawns occupy rabbit habitat, better mule deer habitat, or during periods when coyotes and fawns are more active. Understanding encounters between predator and prey helps us to determine the actual risk that prey face when sharing habitat with predators.
How do mule deer balance multiple sources of risk?
Mule deer live in areas that overlap with elk, mountain lions, and coyotes. Instead of changing their behavior to reduce interacting with these other species, mule deer actually move in ways that put them at higher risk of running into elk and mountain lions, and even at higher risk of being killed by mountain lions.
“Risky business: How an herbivore navigates spatiotemporal aspects of risk from competitors and predators” by Katey S. Huggler, Joseph D. Holbrook, Matthew M. Hayes, Patrick W. Burke, Mark Zornes, Daniel J. Thompson, Justin G. Clapp, Patrick Lionberger, Miguel Valdez, Kevin L. Monteith. Published 2022 in Ecological Applications.
“Cats and dogs: a mesopredator navigating risk and reward provisioned by an apex predator” by Mitchell J. Brunet, Kevin L. Monteith, Katey S. Huggler, Justin G. Clapp, Daniel J. Thompson, Patrick W. Burke, Mark Zornes, Patrick Lionberger, Miguel Valdez, Joseph D. Holbrook. Published 2022 in Ecology and Evolution.
To see other scientific papers that have come from this research, visit our list of peer-reviewed publications.
Outreach and engagement
We frequently attend sportsmen’s banquets and events, such as Mule Deer Days, to share our findings about mule deer.
Collaborators, partners, and funders
This work would absolutely not be possible without the dedicated efforts of our collaborators, partners, and funders. We sincerely thank you all for your support of mule deer conservation. Supporters include Muley Fanatic Foundation and associated chapters (Southwest Wyoming, Central Wyoming, Upper Green Wyoming, Wyoming Range Wyoming, and Flaming Gorge Wyoming chapters), Wyoming Game and Fish Department, Bureau of Land Management, Rocky Mountain Elk Foundation, Wyoming Wildlife and Natural Resource Trust, Bowhunters of Wyoming, Safari Club International Foundation, Wyoming Governor’s Big Game License Coalition, National Science Foundation, and Wyoming Animal Damage Management Board.