Avian Scavengers Modify Vigilance Across Visits to Foraging Sites

ABSTRACT The ability of wildlife to perceive the riskiness of a foraging site accurately and modify their behavior accordingly is crucial to feeding safely. Especially for avian scavengers, carrion is a risky food source, as predators defend their kills and mesocarnivores are attracted to carcasses. Vigilance is one strategy to balance foraging and safety. However, spending time vigilant makes feeding less efficient and can increase the total amount of time required at a carcass. We recorded videos of California condors ( Gymnogyps californianus ), golden eagles ( Aquila chrysaetos ), and turkey vultures ( Cathartes aura ) at 61 naturally occurring and staged carcasses May–September 2022 and 2023 using trail cameras. We assessed variables that were hypothesized to impact the proportion of time spent vigilant by each species at both carcass and visit scales and compared these across species. Carcass‐level models did not improve upon the null models tested, perhaps because carcass‐level attributes determine attendance, rather than altering behavior. Visit‐level models performed better than null models for vultures and eagles. Both top models were based on current interactions at the carcass, suggesting similar perceptions of risk at foraging sites. Vulture and eagle vigilance were negatively correlated with the aggression displayed by that individual, and eagle vigilance was positively correlated with numbers of individuals simultaneously present.