PAITZ, R.T.; HARMS, H.K.; BOWDEN, R.M.; JANZEN, F.J.; Iowa State University; Iowa State University; Iowa State University; Iowa State University: The effect of nest site selection and hatchling size on post-emergent migration patterns and survivability in painted turtles

Two key characteristics of turtle life histories are high offspring mortality and low adult mortality. Offspring mortality can be influenced by several factors that appear to be under maternal control, including propagule size and nest site selection. We have previously found that younger female painted turtles select nesting sites closer to the water than do older females. Younger females also typically lay smaller eggs, which result in smaller hatchlings. The goal of this experiment was to determine if younger females could offset a potential hatchling size disadvantage by placing their nests closer to the water, thereby decreasing both the distance traveled to water and the time spent on land by hatchlings. We released 317 painted turtle (Chrysemys picta) hatchlings into a semicircular enclosure (radius = 40m) containing 26 pit fall traps along the fence. Hatchlings were released in two replicates 4 days apart. Each replicate contained two groups of hatchlings, one released at 25m and the other released at 40m from the edge of the enclosure. Overall, 65.3% of the hatchlings were recovered over the next 30 days of trap monitoring. Neither recapture time nor survivorship differed significantly between the two release points or between the two replicates. However, both survivorship and recapture time were size-dependent, with larger hatchlings having higher survivorship and reduced recapture time. These findings suggest that younger females are not able to compensate for reduced hatchling size by locating their nests closer to the water. They also support a key role for hatchling size in post-emergent migration patterns and survivorship.