The Osprey reintroduction in Central Italy: dispersal, survival and first breeding data

Abstract

Capsule Sex-biased dispersal and an age-dependent effect in survival rate accounted for the pattern of first settlement and reproduction in a newly reintroduced Osprey population.

Aims We estimate the survival of translocated individuals, describe juvenile movements and evaluate the success of first breeding events to document the re-establishment of an Osprey breeding population.

Methods Between 2006 and 2010, 32 fledgling Ospreys were reintroduced via hacking techniques in Maremma Regional Park, Italy. We evaluated the effects of age on survival through multistate capture-mark-recapture analyses. Movements were investigated by radiotracking and using records of resightings.

Results Survival was high for juveniles after the release (0.87), markedly decreased during the first winter (0.26), and improved again in subsequent years (annual apparent survival of 0.69 for immatures and 0.93 for adults). Mean distance covered in initial dispersal was greater for females (246.2 km) than for males (38.7 km).

Conclusion Our results provided information on dispersal and survival rate of reintroduced Ospreys in a Mediterranean area. Despite low apparent survival in the first year, the high survival rates found in immatures and adults suggested favourable conditions for this new population. The study of demographic parameters is important for calibrating management actions aimed at the establishment of a self-sustaining Osprey population.

ACKNOWLEDGEMENTS

We would like to thank the Corsica Regional Park for the constant support and for providing the Osprey nestlings. Thanks also to Roberto Muriel and Pertti Saurola for their important advice during the initial phases of the project. For the precious support in fieldwork during the release days we are grateful to Tim Mackrill and John Wright (from Rutland Water, UK). For their contribution in the resightings of ringed birds we are in debt with Beppe Anselmi, Gianfranco Martini, Francesco Pezzo, Fabio Cianchi, Pietro Giovacchini, Paolo Fastelli, Luca Becherucci, Paolo Maria Politi, Nicola Maggi, Sandro Canci and Alessandro Troisi. Vincenzo Rizzo Pinna, Alessia Martelli and Elena Germondari provide field support and data recording for the monitoring of the breeding pairs. We want to thank also Dr Ettore Randi, head of the genetic laboratory of the ISPRA who performed the genetic determination of sex from feather samples. We are indebted to the park wardens and the administrative personnel of the Maremma Regional Park for the logistic support provided.

Funding

Funding was provided by the Maremma Regional Park Agency and the Tuscany Region Administration. FM benefits from a grant from the Maremma Regional Park, from the Foundation Prince Albert II de Monaco and the Associazone Italiana della Fondation Prince Albert II de Monaco ONLUS and from a mobility grant from the Università Italo Francese/Université Franco Italienne.