With more than 80% of the species global population breeding in Greece, Eleonora's Falcon (Falco eleonorae) is reported to be the most important bird species in the country. A national population survey was conducted during the breeding seasons 2004-2006 in order to assess the species' breeding distribution and population size. This census was the first of its kind and was part of a global population survey, involving more than 80 field workers. Standard field protocols, described in the International Species Action Plan, and a GIS interactive database were developed. Data were stored and spatially explored in conjunction to historical information and past records. A total of about 17,660 falcons were counted or an estimated 12,300 breeding pairs, which were concentrated in six major regions, i.e., northeast Aegean, Sporades, east Cyclades, Antikythira, southwest Dodecanese and the satellite islets of eastern Crete. Compared to previous descriptions of breeding colonies and population status, spatial variation in site occupancy was detected with a population decline in one of the aforementioned regions and an apparent increase in all the rest. The results of this national survey, expected to be repeated every 10 years, provided guidance for reviewing the conservation status of Eleonora's Falcon in Greece and baseline information for future monitoring of its population.

We gathered data for a four‐year period (2004–2007) on the nesting ecology and reproductive performance of Eleonora's falcon in the Aegean Sea. We investigated in an indirect way the relation between clutch size and pre‐laying food availability, the significance of site and pair quality on productivity, and the effects of habitat and intraspecific competition on breeding success. Overall, the species selected nest sites sheltered from sun exposure but not from the prevailing wind. Hatching, fledging, and breeding success rates were estimated at 64, 72%, and 60%, respectively. Fledglings per breeding pair ranged from 1.19 to 1.75, and fledglings per successful pair from 1.84 to 2.0, between the years. Productivity depended on parental care rather than nest‐site quality. Breeding parameters varied significantly between the years, exhibiting a strong spatial yet local effect. Low success rates were recorded in specific colonies, which were attributed to adverse weather conditions and habitat degradation. Insect food availability prior to egg‐laying, estimated via plant biomass, was positively correlated to clutch size. Meanwhile, low wind strengths in August, large distances from the mainland, and population size in the vicinity of the colonies had negative effects on breeding success. Considering data at the Mediterranean scale, a longitudinal trend is observed across the breeding range of this species, with breeding parameters slightly decreasing from west to east.

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.

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