Urbanization influences spatiotemporal patterns of roost site selection by black vultures and turkey vultures

Authors

Jacob E. Hill, Savannah River Ecology Laboratory, University of GeorgiaFollow
Kenneth F. Kellner, Michigan State University
Amanda E. Holland, State University of New York
Bryan M. Kluever, USDA National Wildlife Research Center/Wildlife ServicesFollow
Morgan B. Pfeiffer, United States Department of Agriculture, Wildlife Services, National Wildlife Research Center, Ohio Field StationFollow
Travis L. DeVault, USDA National Wildlife Research CenterFollow
Jerrold L. Belant, Michigan State University

Date of this Version

2023

Citation

Urban Ecosystems (2023) 26:967–979

doi:10.1007/s11252-023-01328-w

Comments

U.S. government work

Abstract

Roost locations can be an important contributor to vulture conflicts with humans, but factors influencing roost-site selection at a landscape level remain largely unexplored. Further, there has been little research comparing how these factors vary between nocturnal and diurnal roosting sites. We used remote cameras to document daily variation in vulture use of 21 roosts (20 communication/water towers and 1 natural roost) near Beaufort, South Carolina, USA from October 2019–August 2020. Numbers of vultures on roosts increased with decreasing urban cover and with greater distance to water, but were not influenced by habitat fragmentation or elevation. Roosts surrounded by greater proportions of urban cover were used more often during the day, whereas roosts adjacent to less urban cover were more commonly used at night. We suggest that this relationship results from a greater daytime association with human development, areas that likely provide food and favorable soaring conditions for vultures. Vultures tended to depart nocturnal roosts before sunrise and return within two hours of sunset, indicating that aircraft collision risk resulting from movement around nocturnal roosts would be elevated during these times. Several communication towers routinely had > 100 vultures roosting on them at once, likely contributing to conflict with humans. Our findings reiterate the generalism of these species and their capacity to exploit novel structures for roosting, which has likely contributed to range expansions and resultant increases in human-vulture conflicts over the past several decades.