Spatial Ecology of Coyotes and Cougars: Understanding the Influence of Multiple Prey on the Spatial Interactions of Two Predators

Abstract

The coyote (Canis latrans) has expanded throughout much of North America over the past century following the regional extirpation of apex predators. These highly adaptable canids can occupy a variety of landscapes from the rainforests of Central America to the dense, human-dominated urban centers of the United States. As a generalist predator, coyotes can capitalize on a variety of food resources, including anthropogenic subsidies such as domestic livestock and food tailings at landfills. These tendencies often bring coyotes in direct conflict with humans, forcing managers to consider mitigation strategies ranging from the targeted removal of problem individuals to a broader reduction in population abundance. However, managing these wild canids is not without controversy. Thus, I take a science-based approach to understanding the nuances of coyote impacts on mule deer (Odocoileus hemionus). I present my findings from a 4-year study in southcentral Utah pertaining to the general ecology of coyotes and their primary competitor, the cougar (Puma concolor), as well as specific findings with regards to the efficacy of a predator control program used in mule deer management. My findings indicate coyotes generally favor areas with high lagomorph density over that of areas occupied by pregnant mule deer, suggesting deer fawn predation by coyotes may be opportunistic. Interestingly, coyotes strongly avoid areas utilized by cougars, which may indicate cougars can regulate coyote access to deer. Cougars, on the other hand, strongly select for areas utilized by mule deer, which make up almost two thirds of their diet. However, during the cougar harvest season and over the winter months, cougars appear to be more willing to consume elk (Cervus elaphus), likely because of increased access and spatial overlap with elk. Finally, my evaluation of aerial control of coyotes as a management strategy for deer indicates that outcomes are often highly variable across space and among individual coyotes removed. However, there is some indication control can be effective at local scales where there is strong overlap between coyote removal and areas favored by pregnant deer. My results suggest that predator-prey processes are multi-dimensional and dynamic through time, which likely contribute to the lack of resolution with regard to the efficacy of predator control and the regulatory potential of predators in general