US-IALE 2018

AUTHORS: Anjelika D. Kidd*, Warnell School of Forestry and Natural Resources, University of Georgia, Southeastern Cooperative Wildlife Disease Study, College of Veterinary Medicine, University of Georgia; Jeffrey Hepinstall Cymerman, Warnell School of Forestry and Natural Resources, University of Georgia; Maureen H. Murray, Sonia M. Hernandez – Warnell School of Forestry and Natural Resources, University of Georgia, Southeastern Cooperative Wildlife Disease Study, College of Veterinary Medicine, University of Georgia

ABSTRACT: When animals adapt to urbanized landscapes, they often exhibit altered behaviors, such as reduced home range sizes, increased site fidelity, and resource switching from natural to urban resources. The American White Ibis (Eudocimus albus) is a nomadic wading bird that typically moves unpredictably between wetlands of the Everglades and throughout the Southeastern U.S. searching for ephemeral wetland foraging conditions. Within the last two decades, ibis in south Florida are increasingly found foraging in urban areas and relying on artificial wetland-like habitats (e.g., urban ponds, water reclamation sites). As part of a larger effort investigating avian health and ecology in wildland versus urban habitats, we characterize movement behaviors of ibis across an urbanization gradient to understand the relationship between anthropogenic resource availability and changes in ibis ecology. Ibises (n = 48) were captured in urban parks and wetlands in south Florida and outfitted with GPS transmitters recording up to 12 locations per day. We based ibis degree of urbanization on non-breeding habitat use, when their resource selection is least constrained. Ibis range sizes, site fidelity, and use of urban and other habitats were compared to urbanization scores for non-breeding, breeding, and transitional seasons. As ibis degree of urbanization increased, range size decreased and site fidelity increased. During the breeding season, range size and location changed for both urban and wildland ibis, likely to accommodate nesting requirements. Ibises were more likely to use urban areas during the non-breeding season than while breeding, presumably because urban habitats are associated with lower quality resources such as inadequate rookery sites and human-provided food. In contrast to previous VHF-telemetry studies, GPS data provides a fine-scale picture of movements along an urbanization gradient and into remote areas; information instrumental in understanding how species change their movement ecology when adapting to urbanized landscapes.