Nest-site preferences of Eleonora's Falcon (Falco eleonorae) on uninhabited islets of the Aegean Sea using GIS and species distribution models

Abstract

Eleonora's Falcon breeds colonially on small islands of the Mediterranean Sea and Macaronesia. Despite the wealth of papers highlighting the importance of nesting characteristics on this species' breeding performance, few have addressed the issue of nest-site selection explicitly. In this paper, we develop presence-absence and presencepseudoabsence models to predict nest occurrence as a function of the topography of the nesting territory. Nest occurrence data were available for nine uninhabited islets of the Aegean Sea, within which the majority of the global population of Eleanora's Falcon is encountered. Our findings suggest that the presence of conspecifics together with certain topographic features according to the surface area of the islet being studied can be used to predict nest occurrence on uninhabited islets of the Aegean Sea. We conclude that predictive models characterized by flexibility and/or the use of absence data that also consider nest clustering can result in robust predictions of the nest occurrence of Eleonora's Falcons in Greek breeding colonies and eventually facilitate future monitoring schemes. Since this is the first time nest-site preferences of Eleonora's Falcon have been analyzed using species distribution models, we encourage the application of similar methodologies to other areas within the species' breeding range to further validate our findings. © Dt. Ornithologen-Gesellschaft e.V. 2011.