Distribution and breeding performance of ahigh-density Eagle Owl Bubo bubo population in southeast Spain

Abstract

CapsuleDespite very high breeding density, no density-dependent effects on reproductive parameterswere detected.AimsTo describe the distribution, abundance and breeding performance of Eagle Owls and to analysedensity-dependent effects on breeding parameters.MethodsWe censused a high-density population of Eagle Owls in southeast Spain between 2003 and2010. To census the population we employed acoustic signals and searched for field signs. Breedingperformance was determined by nest monitoring.ResultsThe population’s density, productivity and fledgling rate were the highest recorded for this species.We detected a negative relationship between the laying date and productivity. Despite breeding pairs’ highdensity, no density-dependent effects on reproductive parameters were detected.ConclusionsOur results suggest that resources in the study area (mainly the availability of RabbitsOryc-tolagus cuniculus) and adult turnover might be responsible for this population’s high density and breedingsuccess.