The Body Size of Headstarted and Wild Juvenile European Pond Turtles ( Emys orbicularis )

Headstarting is a popular conservation technique in which animals are raised under artificial conditions, and then released into natural habitat. The objective of this procedure is to grow animals to a size at which they are less vulnerable to predators. However, there is still little empirical evidence for the long-term effectiveness of the technique. Therefore, we compared body size of juvenile «wild» (= not taken to artificial rearing) and headstarted European pond turtles ( Emys orbicularis ), from two populations (in central and western Poland). Immediately after hatching there were no differences in size of the turtles, but after seven-ten years headstarted turtles were smaller. This sound alarming, but our samples are small, and thus it is impossible to far-reaching conclusion; good comparative data on «wild» and headstarted animals are urgently needed.