SREL Reprint #3893

Use of scat DNA to estimate coyote abundance on a newly colonized barrier island

Sonia M. Hernandez1, Michael J. Yabsley1, Sarah C. Webster2, Elizabeth M. Kierepka3, Rochelle R. Beasley4, Carly L. Landa5, Heather W. Barron6, Kelly Sloan7, Holly Milbrandt8, and James C. Beasley2

1University of Georgia, Warnell School of Forestry and Natural Resources and Southeastern Cooperative Wildlife Disease Study, 180 East Green Street, Athens, GA 30602, USA
2University of Georgia, Savannah River Ecology Laboratory and Warnell School of Forestry and Natural Resources, P.O. Drawer E, Aiken, SC 29803, USA
3North Carolina Museum of Natural Sciences, North Carolina State University, Forestry and Environmental Resources Department, 2820 Faucette Dr., Raleigh, NC 27695, USA
4Savannah River Nuclear Solutions, Aiken, SC 29803, USA
5University of Georgia, Warnell School of Forestry and Natural Resources, 180 East Green Street, Athens, GA 30602, USA
6Clinic for the Rehabilitation of Wildlife, 3883 Sanibel Captiva Rd., Sanibel, FL 33957, USA
7Sanibel-Captiva Conservation Foundation, P.O. Box 839, Sanibel, FL 33597, USA
8City of Sanibel, Sanibel, FL 33957, USA

Abstract: Coyotes (Canis latrans) have expanded in mainland eastern North America and are known to have successfully colonized numerous islands. However, there are scarce data on the densities of coyotes in these ecosystems, in which coyotes can have substantive negative impacts. Coyotes first colonized Sanibel Island, a barrier island off the western coast of Florida, USA, in 2011, and their presence has been linked to declines in several sensitive species. However, the population size of coyotes has only been estimated from anecdotal reports and camera traps. Our goal was to estimate the size of the coyote population on Sanibel Island using genetic mark-recapture methods from fecal sampling. We used transect and opportunistic sampling in winter 2015–2016 to collect coyote scats across the main habitat types on Sanibel Island and determine genotypes for each sample. We then used open population POPAN capture-recapture models to estimate coyote population size. We collected 89 scat samples across Sanibel Island. Based on genotypes, these samples came from at least 25 different individual coyotes, with an estimated population size of 39 individuals (95% Cl = 30–67) based on our mark-recapture models. These results suggest the coyote population on Sanibel Island rapidly expanded throughout this island since presumed initial colonization in 2011 and that there are more than twice as many coyotes than previously estimated through observational and camera trap data. Further work should focus on better understanding coyote status, habitat use, and ecological impacts. Ultimately, understanding abundance and distribution of coyotes and other invasive species contributes toward developing appropriate management strategies to mitigate impacts to sensitive barrier island ecosystems.

Keywords: abundance, barrier island, Canis latrans, coyotes, genetic mark recapture, invasive species, nest predation, scat

SREL Reprint #3893

Hernandez, S. M., M. J. Yabsley, S. C. Webster, E. M. Kierepka, R. R. Beasley, C. L. Landa, H. W. Barron, K. Sloan, H. Milbrandt, and J. C. Beasley. 2025. Use of scat DNA to estimate coyote abundance on a newly colonized barrier island. Human–Wildlife Interactions 19(1).

This information was provided by the University of Georgia's Savannah River Ecology Laboratory (srel.uga.edu).