UWEC CERCA 2025

Behavioral flexibility is an important mechanism by which animals may respond to changing environments. Within the context of foraging, dietary shifts allow animals to react to changes in foraging risks and opportunities. A large literature demonstrates that many prey species, including various squirrel species (family Sciuridae), adjust their foraging to predation risk. However, far fewer studies have systematically documented the behavioral shifts of squirrels to large pulses of food. Here we document the novel emergence of widespread hunting of California voles and carnivorous feeding behavior by California ground squirrels. Over two months in the twelfth year of a long-term study on the squirrel population, we document 74 events of juvenile and adult ground squirrels of both sexes depredating, consuming, and/or competing over vole prey. Our video footage, photographic evidence, and direct observations of marked individual squirrels provide insights into the ecological circumstances favoring behavioral flexibility associated with a decadal peak in vole abundance. Future studies are required to track the effects of innovative hunting behavior by the California ground squirrel on ecological processes.