Examining Turtle-Nest Predator Foraging Behaviors and Depredation Rates Using Simulated Turtle Nests
Katie Voegtlin ’18, Allegra Davis ’18, Marvin Corleto ’19, and Marshall Pregnall (Biology)
The Blanding’s turtle (Emydoidea blandingii) most commonly inhabits the Great Lakes region and surrounding areas. However, extant isolated populations occur in upstate New York, where they are classified as “Threatened” due to increasing levels of habitat destruction from anthropogenic activities and the unnaturally high abundance of nest predators that flourish in anthropogenically disturbed habitats. This study is part of an ongoing effort to conserve the Blanding’s turtle population in a complex of natural and constructed wetlands in Lagrangeville, New York through its assessment of turtle nest depredation rates during a fourteen-day simulated-nest experiment. We created simulated turtle nests with quail eggs, sham nests without eggs, and a control series with only marker stakes as experimental groups to measure predator foraging response to potential food resources from turtle nests. We found that predation rates were highest among the quail egg group, with all the nests in this group being depredated by the end of the two-week period. Sham nest depredation rates were comparatively lower, with only two fifths of the nests depredated and another two fifths partially disturbed. The control group had the lowest levels of depredation among the three experimental groups, with none of the controls being fully depredated and one half being partially disturbed. These data suggest that predators are capable of distinguishing simulated nests with eggs from sham nests without, and will forage in areas with known eggs more persistently. Motion-activated cameras used throughout the experiment also photographed the most common nest predators, including skunks, raccoons, ravens, crows, and minks. Results from this experiment could potentially be useful in future experiments to test methods for reducing nest depredation rates among Blanding’s or other turtle populations.