Mississippi Project: Migration ecology of North American Turkey Vultures Cathartes aura wintering in the Neotropics: spatial and population dynamics

Mississippi Project

Migration ecology of North American Turkey Vultures Cathartes aura wintering in the Neotropics: spatial and population dynamics

January 2018 - December 2020

Personnel

Francisco Vilella, Principal Investigator

Participating Agencies

Hawk Mountain Sanctuary
Mississippi State University

We are using a database of > 60 vultures radiomarked with satellite transmitters during the last decade. Our objectives in this research is to fill knowledge gaps focusing on three North American Turkey Vulture populations: Cathartes aura aura, C. a. meridionalis, and C. a. septentrionalis across North America. Our research will test ecological hypotheses on migration strategies, migratory connectivity, space use, resource selection and survival of these vulture populations and the influence that multi-resolution landscape characteristics, anthropogenic disturbance and weather conditions play in the life cycle of this North American raptor.

Research Publications

Research Publications	Publication Date
Naveda-Rodriguez A., K.L. Bildstein, D.R. Barber, J.F. Therrien, M.L. Avery, B.M. Kluever, S.A. Rush, and F.J. Vilella. 2023. Turkey Vulture survival is reduced in areas of greater road density. Ornithological Applications 125:duad024. \| Abstract \| Download	July 2023	Annual survival of Turkey Vultures (<i>Cathartes aura</i>) may be influenced by landscape heterogeneity and anthropogenic disturbance. We quantified the effects of landscape composition (Shannon’s diversity index) and configuration (contagion, edge density and largest patch index), and human footprint (road density) on the survival probabilities of the three North American breeding populations (western, central and eastern) of Turkey Vultures wintering in the Neotropics during a 17-year period. We used Cox’s proportional hazards models with time-varying covariates to estimate spatial and temporal changes in survival rates of adult Turkey Vultures. Human footprint, but not landscape composition and configuration, influenced survival rates in space and time. Overall annual survival averaged 0.87 (95% CI = 0.74 – 0.98). Mortality risk was low in western and central populations (hazard ratio <1) but was 3.7 times greater for vultures in the eastern population. Risk of mortality for all vulture populations increased with road density, and this was greater during the non-breeding and return migration seasons. The spatial variation in road density across America may generate a network of ecological traps for Turkey Vultures induced to stop in areas of greater road-kill abundance. The negative impact of roads on Turkey Vultures goes beyond the ecological aspect. Roads acting as a magnet for vultures can increase the occurrence of vulture-vehicle collisions and potentially aggravate human-wildlife conflicts. Further analysis are needed to address survivorship and mortality factors of young birds. We emphasize the need for studies focusing on the impact of other linear infrastructures (<i>e.g.</i> railways and power lines) and the management of human-vulture conflicts (through vultures depredation permits) that may can compromise the long term survival of Turkey Vultures and other avian scavengers.

Cooperative Fish and Wildlife Research Units Program: Mississippi Education, Research and Technical Assistance for Managing Our Natural Resources