BACKGROUND: The low prevalence of blood parasites in some bird species may be related to the habitats they frequent, the inexistence of the right host-parasite assemblage or the immunological ...capacity of the host. Here, we assess the parasite load of breeding populations of Eleonora’s falcon (Falco eleonorae), a medium-sized long-distance migratory raptor that breeds on small isolated islets throughout the Mediterranean basin and overwinters in inland Madagascar. METHODS: We examined the prevalence and genetic diversity of the blood parasites belonging to the genera Plasmodium, Haemoproteus and Leucocytozoon in Eleonora’s falcon nestlings from five colonies and in adults from two colonies from nesting sites distributed throughout most of the species’ breeding range. RESULTS: None of the 282 nestlings analysed were infected by blood parasites; on the other hand, the lineages of Plasmodium, Haemoproteus and Leucocytozoon were all found to infect adults. Our results support the idea of no local transmission of vector-borne parasites in marine habitats. Adult Eleonora’s falcons thus may be infected by parasites when on migration or in their wintering areas. CONCLUSION: The characteristics of marine environments with a lack of appropriate vectors may thus be the key factor determining the absence of local transmission of blood parasites. By comparing the parasite lineages isolated in this species with those previously found in other birds we were able to infer the most likely areas for the transmission of the various parasite lineages.
Eleonora’s Falcon (
Falco eleonorae
) is an endemic breeder of the Mediterranean Sea and the Canary Islands that overwinters in Madagascar and surrounding areas. Recent telemetry studies have ...revealed the migratory journey of falcons from the western and central Mediterranean breeding colonies. Our study complements the puzzle of the species’ migration providing data from an eastern Mediterranean breeding colony. In this paper, we describe for the first time the migratory routes of four falcons originating from the Aegean Sea, the core of the species’ breeding range. We tracked two adults and two immature siblings to their wintering grounds in Madagascar. According to our results, the timing of migration was consistent with previous studies. Our findings also suggest that the falcons adjust their flight speed according to the environmental conditions encountered en route, by accelerating during open-sea and desert crossings and by slowing down in potential foraging areas. Moreover, the selection of common staging areas, both among the two siblings and among the two adults, highlights the role of these areas in the migratory cycle of the species. Finally, according to the home-range analysis on the wintering grounds, space use was rather variable across the four tracked falcons. Still, the falcons were more frequently observed within the submontane forest, one of the last patches of primary rainforest in Madagascar. Thus, future studies aiming at unveiling the ecological requirements of the species in its wintering quarters are considered as top priority.
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 presence-pseudoabsence 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.
During the breeding seasons of 2004-2006, the population of Eleonora's falcon Falco eleonorae was censused on > 900 islands in the Ionian and the Aegean Seas, Greece. However, only one third of the ...islands hosted breeding pairs. With our study, we aim at understanding the factors that influence the occurrence of the species' breeding colonies on Greek islands. Thus, we developed generalised linear models for all candidate explanatory variables that according to previous studies are believed to influence the occurrence of the species. We identified the best set of models based on differences in the Akaike Information Criterion, and subsequently, we applied model averaging to estimate model average coefficients for those explanatory variables included in the best set of models. According to our results based on presence-absence data from approximately 370 islands, the presence of breeding colonies is related to the coastline geomorphology, where steep cliffs with ledges are preferred. These geomorphologic characteristics are considered to offer protection from wave action and terrestrial intruders, as well as visual privacy to breeding pairs, and they have previously been associated with nest-site selection. In addition, breeding colonies are more likely to be found on islands close to freshwater bodies and to other neighbouring colonies. Freshwater bodies constitute important foraging areas and provide a means to maintain the falcons' plumage in good condition. The clustered distribution pattern of the breeding colonies is probably due to the process of first-time breeders' settlement and/or colony connectivity. Finally, in view of these preliminary results, we recommend actions to be taken in future studies in order to better understand the role of these factors during the species' breeding period.
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