Spanish imperial eagle
|Spanish imperial eagle|
C. L. Brehm, 1861
Aquila heliaca adalberti
The Spanish imperial eagle, Iberian imperial eagle or Adalbert's eagle (Aquila adalberti) is a threatened species of eagle native to the Iberian Peninsula. The binomial commemorates Prince Adalbert of Bavaria.
Formerly, the Spanish imperial eagle was considered to be a subspecies of the eastern imperial eagle, but is now widely recognised as a separate species due to differences in morphology, ecology, and molecular characteristics.
The Spanish imperial eagle averages 2.5–3.5 kilograms (5.5–7.7 lb), 78–82 centimetres (31–32 in) in length and 180–210 centimetres (71–83 in) in wingspan, and darker than its eastern cousin, and is a resident species (eastern imperial is partially migratory). It feeds mainly on rabbits, but can prey on many other animals, such as partridges, rodents, hares, pigeons, crows, ducks, foxes or -rarely, since they are not typically present in the eagle's habitat- small dogs.
The species occurs in central and south-west Spain and adjacent areas of Portugal, in the Iberian peninsula. Its stronghold is in the dehesa woodlands of central and south-west Spain, such as in Extremadura, Ciudad Real and areas in the north of Huelva and Seville's Sierra Norte.
Stable occurrence in Morocco is disputed but immature birds during the dispersion period regularly visit Morocco. Rising numbers of vagrant birds born in Spain and then electrocuted in Morocco have been noted; some areas used by the species in Morocco could be becoming sort of a 'drain' in terms of the species recovery and this is due to the fact that the country stands in a similar situation as Spain was in the early 1980s when it comes to insulation of transmission towers.
The species is classified as Vulnerable by IUCN. Threats include loss of habitat, human encroachment, collisions with pylons (at some point in the early 1980s, powerlines were responsible for 80% of deaths among birds in their first year of life) and illegal poisoning. There has also been a decline in the species' main prey: rabbits have been kept at bay or even declined in some of the areas where the eagle is or could be present as a result of myxomatosis and, most recently, rabbit haemorrhagic disease.
By the 1960s it had become a critically endangered species, with only 30 pairs remaining, all located in Spain. Following conservation efforts, recovery began in the 1980s at a rate of five new breeding pairs per year up to 1994. In 2011, the species's global population had increased to 324 pairs, with 318 pairs in Spain. The species recolonised Portugal in 2003, after an absence of breeding activity for over 20 years, and has been slowly increasing since, with six breeding pairs located in 2011 and nine located in 2012. The population in Spain showed an average annual increase of c.7% between 1990 and 2011. These positive trends are largely attributed to mitigation measures to reduce mortality associated with powerlines, supplementary feeding, reparation of nests, reintroductions and decreases in the disturbance of breeding birds, although some of the observed increases may be due to more thorough searches within its range.
- BirdLife International (2013). "Aquila adalberti". IUCN Red List of Threatened Species. Version 2013.2. International Union for Conservation of Nature. Retrieved 26 November 2013.
- Sangster et al. 2002
- Cramp & Simmons 1980
- Meyburg 1994
- Seibold et al. 1996
- Padilla et al. 1999
- European Raptor Conservation European This is a national bird of Spain Spanish Imperial Eagle, Aquila adalberti. Accessed 17 May 2011
- British Ornithologists' Club 1988, p. 89
- Amezian, M., Irizi, A., Errati, A., Loran, H., El Khamlichi, R., Morandini, V., González, D. G., Garrido, J. R. (2015). Spanish Imperial Eagles and other eagles found electrocuted in Morocco and proposition of correction measures. figshare. doi:10.6084/m9.figshare.1613292 Retrieved November 28, 2015.
- Las águilas imperiales vuelven a Marruecos y mueren electrocutadas|Ciencia|EL PAÍS
- González, L. M. & Oria, J. (2004). Águila Imperial Ibérica Aquila adalberti. In: Madroño, A., González C. & Atienza, J. C. (editors): Libro rojo de las aves de España: 145–152. Dirección General para la Biodiversidad & SEO/BirdLife, Madrid.
- Weenink, R.; van Duivendijk, N.; Ebels, E. B. (2011). "[Spanish Imperial Eagle at Loozerheide in May 2007]". Dutch Birding. 33: 94–102.
- Salvando al águila imperial ibérica|Ciencia|EL PAÍS
- Aquila adalberti (Adalbert's eagle, Spanish eagle, Spanish Imperial eagle IUCN factsheet
- British Ornithologists' Club (1988). Bulletin of the British Ornithologists' Club. 108-109. British Ornithologists' Club. ISSN 0007-1595.
- Cramp, S. & Simmons, K. E. L. (1980) Birds of the Western Palearctic, Vol. 2. Oxford University Press, Oxford.
- Ferguson-Lees, James & Christie, David A. (2001): Raptors of the World. Houghton Mifflin, Boston. ISBN 0-618-12762-3
- Ferrer, Miguel (2001): The Spanish Imperial Eagle. Lynx Edicions, Barcelona. ISBN 84-87334-34-2
- Meyburg, B. U. (1994): [210 & 211: Imperial Eagles]. In: del Hoyo, Josep; Elliott, Andrew & Sargatal, Jordi (editors): Handbook of Birds of the World, Volume 2: New World Vultures to Guineafowl: 194-195, plate 20. Lynx Edicions, Barcelona. ISBN 84-87334-15-6
- Padilla, J. A.; Martinez-Trancón, M.; Rabasco, A.; Fernández-García, J. L. (1999). "The karyotype of the Iberian imperial eagle (Aquila adalberti) analyzed by classical and DNA replication banding". Cytogenetics and Cell Genetics. 84: 61–66. doi:10.1159/000015216.
- Sangster, George; Knox, Alan G.; Helbig, Andreas J.; Parkin, David T. (2002). "Taxonomic recommendations for European birds". Ibis. 144 (1): 153–159. doi:10.1046/j.0019-1019.2001.00026.x.
- Schuhmacher, Eugen (1973): Europe's Paradises
- Seibold, I.; Helbig, A. J.; Meyburg, B. U.; Negro, J. J. & Wink, M. (1996): Genetic differentiation and molecular phylogeny of European Aquila eagles (Aves: Falconiformes) according to cytochrome-b nucleotide sequences. In: Meyburg, B. U. & Chancellor, R. D. (eds): Eagle Studies: 1–15. Berlin: World Working Group on Birds of Prey.