Site‐specific space use and resource selection by Black Vultures (Coragyps atratus) in the southeastern USA

Abstract

North American populations of Black Vultures Coragyps atratus have increased and expanded their distribution in the southern and eastern USA. In conjunction with these patterns has been a rise in human–vulture conflicts. To improve our understanding of space use patterns and better inform management, we evaluated the movements of Black Vultures (n = 23) in the southeastern USA using a long‐term GPS tracking database. Our specific objectives were to: (1) quantify home‐range sizes in relation to season and geographical study location and (2) examine within‐home‐range resource selection to identify landscape and anthropogenic factors influencing roost and diurnal space use. Home‐range sizes did not significantly differ between breeding and non‐breeding seasons. However, there were differences across geographical study locations, with the largest home‐ranges located in Florida. Similarly, there was limited seasonal variation in resource selection; however, use of anthropogenic features did vary by geographical study location. Overall Black Vultures avoided homogeneous landscapes regardless of season or activity and exhibited a strong selection for areas with increased landscape richness. Increased landscape richness, unlike homogeneous habitat, provides a diversity of resources for Black Vultures in a localized area, such as food, water, roosting and perch sites, and the creation of energy‐efficient flight opportunities. Contrasting with natural landscape feature selection, selection of anthropogenic features, such as landfill proximity and road density, was highly variable across individuals and study location. The high level of variation in selection for anthropogenic features provides further evidence of the propensity of Black Vultures to be flexible and opportunistic. The findings of this study stress the importance of using site‐specific studies effectively to understand and manage local vulture populations and mitigate associated human–vulture conflicts. Wildlife managers should exercise caution when implementing vulture management actions based on inferences from telemetry studies conducted in other geographical areas.