Is individual prey selection driven by chance or choice? A case study in cougars (Puma concolor)

Many species have been increasingly recognized as an aggregate of individual dietary specialists. Previous work has emphasized the importance of individual dietary specialization in driving many ecological processes, but less is known about the relationship between individual diet and habitat use. We used data from 7 cougars and 331 predation events collected in western Colorado from 2010 to 2013 to test whether intraspecific variation in cougar (Puma concolor) diet resulted from chance encounters or from targeting particular prey species. One cougar within our study population (P06) selected for American beaver (Castor canadensis) more than expected based on availability, spent a disproportionate amount of time within beaver habitat, and exhibited reduced travel speeds when near waterways. Our results present evidence that specialist diets in predators are likely reflective of additional differences in foraging behaviors rather than random encounters with prey species (e.g., prey availability).