Mechanisms of Coexistence in Vultures: Understanding the Patterns of Vulture Abundance at Carcasses in Masai Mara National Reserve, Kenya

Abstract

Abstract. Because of the high, albeit seasonal, availability of carcasses, the Mara-Serengeti ecosystem, Kenya, has a high diversity of scavengers, leading to considerable competition between species. From patterns of occurrence of vultures at 163 carcasses over an 8-year period in the Masai Mara National Reserve, we were able to identify some mechanisms that may reduce competition. Species are associated on the basis of similar dietary needs and beak morphology, and they are highly interdependent, showing little evidence of disassociation. Social vultures (genus Gyps) dominated the vulture scene at the reserve; they were more abundant at carcasses when migratory ungulates were present in the dry season, when more carcasses are likely to be available, than when migratory ungulates were absent. In addition, regardless of the predator's identity, presence of a predator reduced the number of vultures, suggesting that vultures prefer carrion not killed by predators where available. Comparisons between past an...