Retention rate of hard-released translocated Egyptian tortoises Testudo kleinmanni

Abstract

We examined the suitability of using translocations as a method to create a new population of Egyptian tortoises Testudo kleinmanni in an area where the species historically occurred. We released 109 tortoises, comprising 57 males, 48 females and 4 juveniles. Dispersal from the release site influenced survival and retention rate, i.e. the proportion of individual tortoises found after the original release. The number of times a tortoise was recaptured decreased as the minimum distance at which it was found from the release site increased. In addition, live tortoises were significantly more likely to be found at shorter minimum distances from the release site than were dead tortoises. The sex ratio of pre-released tortoises tended to be different from the sex ratio of tortoises found during later surveys, with females proportionally more likely to be found than males. Prerelease mass was not a significant predictor of an individual tortoise being recaptured. Retention rates of future reintroductions may be improved by allowing tortoises to acclimatize and develop fidelity to the release site before they are translocated. © Inter-Research 2010.