Journal of Ornithology

, Volume 149, Issue 2, pp 151–159 | Cite as

Origin and formation of the Spanish Imperial Eagle (Aquila adalberti)

  • Luis Mariano GonzálezEmail author
Original Article


A review of the paleontological records of the Eastern Imperial Eagle (Aquila heliaca) and the Spanish Imperial Eagle (Aquila adalberti) in the context of the paleoecological environment in Eurasia during the Pleistocene and Holocene epochs is presented. The Eastern Imperial Eagle expanded its range in Eurasia during the last Pleistocenic glaciation favoured by the expansion of the steppes. The first records of Spanish Imperial Eagles are from the Late Pleistocene and Early Holocene in the eastern Iberian Peninsula, and their distribution seems to have been limited to the distribution areas of Mediterranean vegetation and the European rabbit. Individuals of migrant A. heliaca could have reached the Iberian Peninsula at the end of the Pleistocene–beginning of the Holocene. These individuals could have adapted to the Mediterranean ecosystem, subsequently specializing in a diet of rabbit, a prey which is in abundance all year round. Due to the availability of such prey, A. heliaca would become more sedentary. These individuals may have overcome their breeding phenology and paired up assortatively, becoming genetically separate from the migrant populations and initiating the speciation mechanisms for sympatry or parapatry that resulted in A. adalberti. This is one possible mechanism. These findings reported here support the recent age of divergence between both taxons, and the incipient speciation supports its taxonomical considerations as a semi-species.


Aquila heliaca Aquila adalberti Fossil records Origin Speciation 



I am indebted to Roberto Sánchez, Javier Oria and Antoni Margalida for their help and assistance. I would particularly like to thank to Oscar Arribas for his comments and suggestions to the manuscript and to Tom Tyberg for providing me with useful information. This work is dedicated to the memory of Francisco Hernández Carrasquilla.


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Copyright information

© Dt. Ornithologen-Gesellschaft e.V. 2007

Authors and Affiliations

  1. 1.Dirección General para la BiodiversidadMinisterio de Medio AmbienteMadridSpain

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