We examined the distribution and fates of natural nests of ornate box turtles (Terrapene ornata) in the Hawkeye Wildlife Area, Johnson County, Iowa. We fitted twenty female ornate box turtles with small radio transmitters in May of 2008 and tracked them using radio telemetry during June and early July; these females were located every night, when they typically produce their nests. We also weighed these females regularly so that we might observe the weight loss associated with the release of a clutch of eggs. Six of the females we studied (30%) produced nests that contained 1-6 eggs each. We located many other ornate box turtle nests during both our nightly searches and during daytime surveys of the sand prairie in which nesting is concentrated. We marked all nests with flags and determined the location of each nest using GPS technology. We then plotted the location of nests on a map of our study site and compared this distribution with a Poisson distribution, which established that turtle nests are clumped. Nests were concentrated in areas with sparse vegetation and sandy soil. We also monitored the fate of all nests we identified. Over 80% of natural nests were destroyed by predators within three weeks of their construction. Our findings are consistent with those we obtained in previous years and suggest that the depredation of nests may be a factor that limits the growth and long-term persistence of this population.
Brock Nelson, ’11 Blue Grass, IA
Amanda Brodin, ’09 Parker, CO
Majors: Biochemistry and Molecular Biology, History
Amanda Gilbert, ’10 Bettendorf, IA
Pierce Sweeney, ’09 Peoria, AZ
Sponsors: Robert Black and S. Andrew McCollum