European Pond Turtle - Nesting

Nesting

Most freshwater turtles lay their eggs on land, typically near a water body, but some species of Emys have been found to lay their eggs distances less than 150 meters from water. The search of a nesting areas by adult females can last several hours to more than one day. Once the location of the nest is established, females spend time for the construction of the nest, laying of the eggs, and closing the nest which can take up to another 4 hours.

Nest fidelity is a characteristic that female European pond turtles carry out by selecting a nesting site based on its ecological characteristics and then return there for future expeditions so long as the site has not changed. Emys orbicularis females tend to change to another nesting site if there are visible changes to the present environment or because of dietary changes. If an Emys orbicularis female must change from nest to nest, it will typically select a site in close proximity. In addition, females can also lay eggs in an abandoned nesting site if the conditions change to become better suited for egg survival. If the ecological characteristics of the nesting site changes, this may influence the survival of the hatchlings and their sex ratio. Due to ecological changes such as trees growing to shade the nest, this can change the environment into an inadequate location for egg incubation. Females that do not exhibit nesting fidelity and lay eggs in the same area for long periods of time, even with the ecological changes, may produce large proportions of males as vegetation grows and nesting areas become more shaded. Since the sex of these turtles are temperature-dependent, a change in temperature may produce a larger number of males or females which may upset the sex ratio.