Land cover changes that result from increasing urbanization alter habitat types, structures, and resource availability on local and global scales. For vultures, urbanization may have both positive and negative impacts, with roadkill offering increased foraging opportunities and habitat loss and disturbance reducing roosting and nesting success. Vultures provide important ecosystem services including carcass consumption and disease management, making them an important feature of urban areas. We examined how landscape and local features affect roosting and nesting success of black vultures (Coragyps atratus) and turkey vultures (Cathartes aura) in the Charlotte Metropolitan Area, USA. Vultures appear to select roosting and nesting sites dependent upon foraging opportunities. We predict that roosting and nesting success will be greater at sites surrounded by higher road densities and more urban land use. We quantified the number of vultures at fifteen permanent roosting sites using monthly early-morning visual counts between November 2019 and March 2020 and measured nesting success at fifteen nests as clutch size, predated young, and the number of fledglings using biweekly visual checks between March and August 2020. At each roosting or nesting site, we quantified ground cover, surrounding vegetation, and canopy cover and measured land use and road density in surrounding landscapes.
Results/Conclusions
We tested for the effects of weather patterns and local and landscape features on roosting and nesting success using generalized linear models and multi-model inference. To date, an average of 37 +/- 46 vultures have been observed at roosts showing a great deal of variability within vulture roosting systems in the Charlotte Metropolitan Area that requires additional investigation. Roosting locations are often associated with little canopy cover (26.6% +/- 38.2%) and high shrub presence (76.3% +/- 38.9%) at the base of the roost, perhaps to discourage disturbances such as human and predator activity. Consistently occupied roosts appear to be associated with low disturbance areas or hard to access structures while unstable roosts exhibit more disturbance potential. Final results of models examining the effects of local and landscape features on roosting and nesting success will be presented in order to better understand the associations of vultures within urban areas and to promote healthy relationships between humans and vultures.