Authors: Efrat, Ron; Mueller, Thomas;Sapir, Nir;Berger-Tal, Oded;

Reintroducing species to their historic range is a popular conservation effort aiming to maintain long-term viable populations of animals. This effort requires proper monitoring of the fate of the animals that are released to the wild to assess their success. Nevertheless, effective monitoring is often missing in conservation translocations. We assessed the efficiency of different monitoring methods and estimated survival of captive-bred Egyptian vultures Neophron percnopterus that were released to the wild during the first 15 years of a reintroduction project. First, we compared observations to location data from GPS transmitters. Then, we used GPS data to estimate survival of vultures that were released to the wild at different ages and different seasons. Finally, we compared the survival of captive-bred and wild-hatched Egyptian vultures. We show that GPS data was significantly better than observation data. We also show that release protocol and origin (captive-bred or wild-hatched) did not alter survival during the vultures’ first migration or during their first two years post release or post fledging. Our results show the importance of continuous and effective monitoring and confirm the efficacy of captive-breeding and release of Egyptian vultures as a conservation tool.