Recolonizing carnivores: Is cougar predation behaviorally mediated by bears?

Area of Science:

• Ecology
• Wildlife Conservation
• Behavioral Ecology

Background:

• Apex predator populations are recovering, leading to altered ecological interactions.
• Recolonizing black bears (Ursus americanus) in Nevada scavenge cougar (Puma concolor) kills, creating a unique multi-carnivore system.

Purpose of the Study:

• To evaluate the impact of recolonizing black bears on cougar foraging behavior in the Great Basin.
• To model how bear density affects cougar feeding bout duration and diet composition.

Main Methods:

• Investigated 31 cougar kill sites over 8 years (2009-2017) across varying bear densities.
• Utilized mixed-effects models to analyze feeding bout duration and the proportion of mule deer (Odocoileus hemionus) in cougar diets.
• Assessed the influence of prey size, bear density, and cougar reproductive status (kittens) on foraging.

Main Results:

• Feeding bout duration depended on prey size, local bear density, and presence of cougar kittens.
• Mule deer proportion in cougar diets declined over time and was lower for males, but increased with kittens and higher bear densities.
• Cougar consumption of feral horses (Equus ferus) increased over time in areas where they were present.

Conclusions:

• Increased black bear densities may shorten cougar feeding bouts and shift prey selection towards potentially riskier alternatives.
• Foraging behavior shifts in multi-carnivore systems have cascading effects on prey selection and resource use.
• Understanding impacts of sympatric predators and scavengers is crucial for managing dynamic ecosystems.