Comparing the effects of release methods on survival of the Eurasian black vulture Aegypius monachus reintroduced in France

The Near Threatened Eurasian black vulture Aegypius monachus is considered highly threatened in Europe, and the species was reintroduced in France between 1992 and 2004. A total of 53 individuals were released, using two methods: immatures were released from large aviaries at the reintroduction site after a stay of several months (the aviary method), whereas juveniles were placed on artificial nests until fledging (the hacking method). The survival rates of released birds were compared to the survival of wild-born offspring through a multi-event capture-recapture analysis accounting for tag loss. Survival rates were higher in adults than in juveniles and immatures (0.98 +/- SE 0.02 vs 0.85 +/- SE 0.03) and were constant over time. Overall there were no differences in post-release survival between the two release methods: immatures released by the aviary method had a similar survival to juveniles released by the hacking method or born in the wild. Immatures can breed before juveniles, so releasing immatures by the aviary method could accelerate reintroduction settlement and increase population viability. Accurate estimates of post-release survival are essential to improve the reliability of viability analysis of reintroduced populations and the management of such populations.