Notes on the Nest Predation Dynamics of Graptemys at Two Wisconsin Sites Using Trail Camera Monitoring

Abstract

Abstract Incidental observations on nest predation dynamics at 2 map turtle (Graptemys spp.) nesting sites along the Wisconsin River, Iowa County, Wisconsin, were obtained during primary research on the use of electric fencing to decrease turtle nest predation. Sites were continuously monitored by digital trail cameras during the 2008–2011 reproductive seasons. Raccoons (Procyon lotor) displayed temporally focused turtle nest foraging efforts across both sites and years and were the only confirmed nest predators. Striped skunks (Mephitis mephitis), Virginia opossums (Didelphis virginiana), coyotes (Canis latrans), and American crows (Corvus brachyrhynchos) were less frequent on site but also displayed recurring seasonal chronologies. Nest predation levels exceeded 90%, with short nest survival timelines suggesting relatively high predation pressures on these sites. Available data provided only limited evidence that post–nest construction rainfall reduced nest predation rates.