Abstract
We used light-level geolocators to track the migratory journey of a globally near-threatened trans-Saharan migrant, the European roller Coracias garrulus, from its breeding grounds in Iberia to its wintering grounds in southern Africa. During autumn migration, birds followed the western African coast with lengthy stopovers within sub-Saharan countries before crossing the equatorial rainforests towards the wintering areas, mainly in Angola. Although based in only two tracked birds, comparison of our results with other studies suggests that western European rollers use distinct migration routes and stopover sites towards shared wintering grounds. Time spent in widely separated and ecologically disparate countries highlights the vulnerability of the species facing the cumulative risks of each area used along their journey.
Zusammenfassung
Aufklärung der Zugwege und Überwinterungsgebiete von Blauracken mittels Hell-Dunkel-Geolokatoren Mithilfe von Hell-Dunkel-Geolokatoren verfolgten wir die Zugroute eines weltweit potentiell gefährdeten Transsaharaziehers, der Blauracke Coracias garrulus, von ihren Brutgebieten auf der Iberischen Halbinsel zu ihren Winterquartieren im südlichen Afrika. Auf dem Herbstzug folgten die Vögel der westafrikanischen Küste, wobei sie längere Rastpausen in subsaharischen Ländern einlegten, um dann die äquatorialen Regenwälder zu überqueren und in die vor allem in Angola gelegenen Überwinterungsgebiete zu fliegen. Obwohl nur zwei Vögel verfolgt wurden, legen Vergleiche mit anderen Studien nahe, dass westeuropäische Blauracken auf dem Weg in die gemeinsamen Winterquartiere klar abgegrenzte Zugrouten und Rastgebiete nutzen. Es unterstreicht die Anfälligkeit dieser Vogelart, dass sie dabei Zeit in weit auseinander liegenden und ökologisch ganz verschiedenartigen Ländern verbringt und somit den geballten Risiken aller Gegenden ausgesetzt ist, die sie auf ihrer Reise aufsucht.
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Acknowledgments
We are grateful to Miguel Lecoq, Ricardo Correia, and João Paulo Silva for help capturing rollers and deploying geolocators. Two anonymous referees made useful comments on the manuscript. Special thanks to Ricardo Lourenço for the roller photo in Fig. 1. IC. TC benefited from post-doctoral grants from Fundação para a Ciência e Tecnologia (SFRH/BPD/76514/2011 and SFRH/BPD/46967/2008, respectively). This study was partly supported by Fundação para a Ciência e Tecnologia (FCT-http://www.fct.pt/index.phtml.en) through the Project “Invisible Links” (PTDC/MAR/119920/2010).
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Communicated by N. Chernetsov.
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Catry, I., Catry, T., Granadeiro, J.P. et al. Unravelling migration routes and wintering grounds of European rollers using light-level geolocators. J Ornithol 155, 1071–1075 (2014). https://doi.org/10.1007/s10336-014-1097-x
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DOI: https://doi.org/10.1007/s10336-014-1097-x