PLASTIC INGESTION IN BLACK VULTURES AND TURKEY VULTURES ALONG AN URBAN-TO-RURAL GRADIENT IN THE CHARLOTTE METROPOLITAN AREA, NC

Plastics are pervasive pollutants found in ecosystems worldwide and can cause harmful effects to organisms and environments when accumulated. Previous research shows that black and turkey vultures within the Charlotte Metropolitan Area are roosting in larger numbers in areas with high urban landcover and low deer carcass densities, suggesting an adoption of alternative food sources. If urban vultures are adjusting their roosting sites in accordance with higher urban landcover and lower deer carcass densities, then it is likely that they are ingesting more anthropogenic materials than rural counterparts. To measure this, eight roosting sites were selected across an urban-to-rural gradient. Regurgitated vulture pellets were collected biweekly from roosting sites for 15 total collections between January 2021 and July 2022. Pellets were weighed and dissected to evaluate the proportion composed of natural, plastic, and other anthropogenic materials. We used Fourier Transform Infrared spectroscopy to identify types of plastics most commonly ingested across landscapes. We evaluated the effect of commercial food establishment density, landfill density, and livestock production site density at 10 different spatial scales (0.4, 0.5, 1, 2, 3, 4, 5, 10, 15, 20km) on the amount of plastic in vulture pellets using repeated measures linear mixed models. Preliminary results of 1,003 pellets suggest that density of livestock production sites within 2km landscapes surrounding roosting sites are associated with higher amounts of plastic in regurgitated pellets. Additionally, preliminary results reveal that vultures in landscapes with higher commercial food establishment density are ingesting more plastic material, along with a significant positive association between study site and plastic amount. A change in vulture diets and the consumption of anthropogenic materials may have unknown implications for the population and the functioning of the urban ecosystem of which they are a part.