Anthropogenic features influencing occurrence of Black Vultures (Coragyps atratus) and Turkey Vultures (Cathartes aura) in an urban area in central Amazonian Brazil

Abstract

Recent increases in Black Vulture (Coragyps atratus) and Turkey Vulture (Cathartes aura) numbers, particularly in urban-suburban settings, have led to more frequent human-vulture interactions, including vulture-aircraft strikes. This problem highlights the need for vulture management strategies, including determining habitat use by these species in urban settings. We investigated the effects of structures and landscape features on habitat use by Black and Turkey vultures in and around the city of Manaus in central Amazonian Brazil. We repeatedly surveyed 80 sites (3-9 visits per site in 2009-2010) and used detection histories to derive maximum-likelihood estimates of (1) vulture occurrence and detection probabilities and (2) environmental covariate effects on occupancy. Hierarchical logistic models showed that Black Vultures were associated with urban features such as open garbage containers and streams, but Turkey Vultures were associated with forest fragments. These results suggest that Black Vultures select environments where the food supply is abundant, whereas Turkey Vultures may avoid sites that attract Black Vultures in favor of forest remnants, a habitat for which they have specific foraging adaptations. Black Vulture management should focus on reducing the amount of food waste available to the birds in urban open garbage containers and streams, but Turkey Vulture management could be improved through removal of animal carcasses, and perhaps also removal of nests and roosts from forest remnants, especially near airfields. © 2014 Cooper Ornithological Society.