Journal of Ornithology

, Volume 153, Issue 3, pp 663–675 | Cite as

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

  • Christina KassaraEmail author
  • Anastasios Dimalexis
  • Jakob Fric
  • Georgios Karris
  • Christos Barboutis
  • Spyros Sfenthourakis
Original Article


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.


Geographic information system (GIS) Nest habitat Spatial models Autocorrelation Logistic regression Maximum entropy 


Untersuchungen zu Neststandort-Präferenzen von Eleonorenfalken (Falco eleonorae) auf unbewohnten kleinen Inseln der Ägäis unter Zuhilfenahme von GIS und Artverteilungsmodellen

Eleonorenfalken sind Koloniebrüter kleiner Inseln des Mittelmeers und Makaronesiens. Trotz der Vielzahl an Veröffentlichungen, die die Bedeutung der Nist-Charakteristika für den Bruterfolg dieser Art hervorheben, haben nur wenige versucht, explizit die Frage nach der Nistplatzwahl zu beantworten. In der vorliegenden Arbeit haben wir Anwesenheits-Abwesenheits- und Nur-Anwesenheits-Modelle entwickelt um das Nestvorkommen als eine Funktion der Topographie des Brutreviers vorherzusagen. Von neun unbewohnten kleinen Inseln der Ägäis, dem Hauptverbreitungsgebiet der Weltpopulation, lagen uns Daten zu den Nestvorkommen vor. Unsere Resultate legen nahe, dass die Anwesenheit von Artgenossen zusammen mit bestimmten topographischen Oberflächencharakteristika verwendet werden kann, um die Nestvorkommen auf den untersuchten unbewohnten Inselchen der Ägäis vorherzusagen. Daraus schlussfolgern wir, dass flexible und/oder Abwesenheits-Daten beinhaltende Vorhersagemodelle, die außerdem ein mögliches Clustern von Nestern berücksichtigen, robuste Prognosen zu Nestvorkommen des Eleonorenfalkens in griechischen Brutkolonien zulassen. Darüber hinaus könnten sie zukünftige Monitoringpläne erleichtern. Da hiermit zum ersten Mal die Neststandort-Präferenz von Eleonorenfalken mit Hilfe von Artverteilungsmodellen analysiert wurde, rufen wir dazu auf, eine ähnliche Methodologie in anderen Bereichen im Brutverbreitungsgebiet der Art anzuwenden, nicht zuletzt um unsere Resultate weiter zu untermauern.



Data were collected in the framework of and funded by the LIFE-Nature Project “Conservation measures for Falco eleonorae in Greece” (LIFE 03NAT/GR/000091) coordinated by the Hellenic Ornithological Society (HOS-Birdlife-Greece) and the Leventis Foundation. We would like to thank Portolou Danae, Latsoudis Panagiotis, Bourdakis Stratis, Xirouchakis Stavros, Georgiakakis Panagiotis and all field ornithologists, volunteers and boat captains for their assistance in fieldwork. We also thank Thomas Gottschalk and two anonymous referees for their fruitful comments on a previous version of this manuscript. Special thanks are extended to Sinos Giokas (University of Patras) for his advice on several statistical issues, Olga Tzortzakaki for contributing the German translation of the abstract and to Costas Lagouvardos (National Observatory of Athens) for the provision of meteorological data for the study areas.


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Copyright information

© Dt. Ornithologen-Gesellschaft e.V. 2011

Authors and Affiliations

  • Christina Kassara
    • 1
    Email author
  • Anastasios Dimalexis
    • 2
  • Jakob Fric
    • 2
  • Georgios Karris
    • 3
  • Christos Barboutis
    • 4
  • Spyros Sfenthourakis
    • 1
  1. 1.Section of Animal Biology, Department of BiologyUniversity of PatrasPatrasGreece
  2. 2.Hellenic Ornithological SocietyAthensGreece
  3. 3.Department of Environmental Technology and EcologyTechnological Educational Institution (TEI) of the Ionian IslandsZakynthosGreece
  4. 4.Department of Biology and Natural History Museum of CreteUniversity of CreteHerakleionGreece

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