Activity and overlap among birds and mammals scavenging a bison carcass in shortgrass prairie

Abstract Bison serve as keystone species in prairie ecosystems of North America, yet few studies have evaluated the effects of bison carcasses on other animals. To determine which species forage on bison carcasses and whether such carcasses catalyze intraspecific and interspecific interactions, we used wildlife cameras to observe scavenger visits and activity over a 6-wk period following the death of an adult female bison from a conservation herd in northern Colorado. We captured more than 45 000 photos of avian and mammalian scavengers. Photos most often included coyote (51% of photos) and common raven (50%), followed by black-billed magpie (14%) and golden eagle (0.11%). Most photos (86%) captured individuals of the same species (intraspecific activity) visiting the carcass, while 14% had two or more different species (interspecific activity) at the carcass simultaneously. The species most often photographed together included the common raven and black-billed magpie (64%), followed by coyote and black-billed magpie (25%) and coyote and common raven (7%). Less than 1% of photos captured dominance behaviors among individuals. Our study demonstrates that bison carcasses have the potential to provide key food resources in the winter for shortgrass prairie animals. The role of bison carcasses in supporting grassland animal communities is likely to become increasingly important as efforts gain momentum to restore bison across their historic range in North America.