Population reinforcement of Eagle Owl Bubo bubo in Biscay (Spain)

Abstract

Aims: The main objective of our study was to valorise the population reinforcement methods as a way to recover endangered species, the case of Eagle Owl Bubo bubo. Location: Biscay (Bizkaia), North of Spain. Methods: During five years we released Eagle Owls that came from wildlife rehabilitation centres located in other sites of Spain (Madrid, Cádiz, Huelva). All of them were individuals that had been treated in wildlife rehabilitation centres. These Owls were maintained in the Centro de Recuperación de la Fauna Silvestre de Biscay during nearly 45 days, where they improved the hunting techniques and the fly muscles. At the beginning, nine owls were radio-tracked and monitored and we compared two release methods: from a cage located in the release place or directly, resulting better the second method. Results: We released 64 Owls. Nineteen released Owls were found dead after 101 days, on average. They dispersed an average of 9.55 km. There was not correlation between the travelled distance and the time. We also located 10 Owls that had settled in territories. The average distance between the release point and them was 8.07 km. There were not differences between the distance travelled by the recovered Owls and the territorial Owls. Finally, we recorded three cases of reproduction. Conclusions: Thus and even, considering that more time is needed to find new evidences, we can consider this reinforcement program has been a success.Peer reviewe