Hellenica World

Aquila clanga

Aquila clanga (*)

Cladus: Eukaryota
Supergroup: Opisthokonta
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Cladus: Deuterostomia
Phylum: Chordata
Subphylum: Vertebrata
Infraphylum: Gnathostomata
Superclassis: Tetrapoda
Classis: Aves
Subclassis: Carinatae
Infraclassis: Neornithes
Parvclassis: Neognathae
Ordo: Falconiformes
Familia: Accipitridae
Subfamilia: Aquilinae
Genus: Aquila
Species: Aquila clanga

Name

Aquila clanga Pallas, 1811

References

* Zoographia Rosso-Asiatica 1 p.351

Vernacular names
Internationalization
Български: Голям креслив орел
Česky: Orel volavý
Ελληνικά: Στικταετός
English: Greater Spotted Eagle
Español: Águila moteada
Français: Aigle criard
한국어: 항라머리검독수리
Lietuvių: Didysis erelis rėksnys
Polski: Orlik grubodzioby
Português: Águia-gritadeira
Slovenščina: Veliki klinkač
Svenska: Större skrikörn

The Greater Spotted Eagle (Aquila clanga), occasionally just called the spotted eagle, is a large bird of prey. Like all typical eagles, it belongs to the family Accipitridae. The typical eagles are often united with the buteos (Buteo), sea eagles (Haliaetus) and other more heaviset Accipitridae, but it appears as if they are less distinct from the more slender accipitrine hawks than believed.

Description

It is about 65 cm in length and has a wingspan of 160 cm. This medium-large eagle is very similar in general appearance to its closest relative the Lesser Spotted Eagle (A. pomarina), which shares part of its range. Head and wing coverts are very dark brown and contrast with the generally medium brown plumage; the Lesser Spotted Eagle has a paler head and wing coverts. The head is small for an eagle. The similarities of the Greater Spotted to the Lesser Spotted often results in misidentification as being that species. This is further complicated by occasional hybrids between the two species.[1]

There is often a less obvious white patch on the upperwings, but a light crescent on the primary remiges is a good field mark. The white V mark on the rump is less clear-cut in adults than in the Lesser Spotted Eagle. The juvenile has white spots all over its wings and lacks a lighter nape patch.

The call is a dog-like yip.

In winter, it occurs in the range of the Indian Spotted Eagle (A. hastata). From this recently-validated relative, it can be distinguished by the darker color and lighter eye (not darker than the body plumage at distance, lighter at close range), and in juveniles, the strong spotting. It is also a bit larger – though this cannot be reliably estimated in the field – and in the winter quarters prefers wetland habitat.

Systematics, taxonomy and evolution

The Lesser Spotted Eagle (A. pomarina) is this species' closest living relative; their common ancestor seems to have diverged around the middle Pliocene, perhaps some 3.6 million years ago (mya),[2] from the ancestors of the Indian Spotted Eagle (A. hastata) that lives across Iran, Pakistan and India. The "proto-Spotted Eagle" probably lived in the general region of Afghanistan, being split into a northern and a southern lineage when both glaciers and deserts advanced in Central Asia as the last ice age began. The northern lineage subsequently separated into the eastern (Greater) and western (Lesser) species of today, probably around the Pliocene-Pleistocene boundary not quite 2 mya.[3]

The spotted eagles as a group are quite distinct from the typical members of Aquila, the "true eagles". They will probably be included with their putative tropical relatives in Lophaetus or Ictinaetus, or moved to a genus of their own in the near future.

Distribution, ecology and status

This is a species of fairly wooded country, which hunts small mammals and similar, mainly terrestrial prey. It breeds from northern Europe across Asia, and winters in southeastern Europe, the Middle East and South Asia. Migration to breeding grounds takes place fairly late; in Bhutan for example birds can be seen with some regularity until the end of March[4]. This eagle lays 1-3 eggs in a tree nest.

Generally territorial, juveniles spend some time with their parents after fledging, until they reach sexual maturity and seek out a territory and a mate of their own. In winter quarters, the species is more social. Small flocks of up to ten birds or so, of varying age, can be seen to patrol the land together. They also associate with other Accipitridae in winter quarters, like local and/or migrant Black Kites (Milvus migrans lineatus and govinda) or Steppe Eagles (A. nipalensis), distinctly smaller and larger raptors, respectively.[4]

This species is prone to vagrancy. Its regular breeding range does not reach to Germany anymore these days, but still they are not rarely met with in that country, with a few birds seen every decade. Even young birds disperse widely; the Staatliches Museum für Tierkunde Dresden has a specimen (C 21845) shot in November 1914 at Großgrabe near Bernsdorf in Saxony. It is a juvenile, and though its exact age cannot be determined it is heavily spotted and probably less than 20 months old.[5]

An adult Greater Spotted was tagged with a satellite transponder in 1993 in order to track migration. The tagged eagle migrated a total of 5,526 kilometers (3,434 miles) from its wintering grounds in Yemen to it breeding grounds in western Siberia. It moved 150 km (94 miles) on average each day, but this increased to 280 km (175 mi) per day as the bird flew through Mesopotamia.[6]

It is classified as Vulnerable to extinction by the IUCN. As of 2000, the world population of this eagle was estimated at less than 4,000 breeding pairs. The primary threats are habit degradation and habitat loss, as well as human disturbance during the mating season.[7]
Footnotes

1. ^ See Väli & Lõhmus (2004) for details
2. ^ The estimate in Väli (2006) is certainly incorrect; it uses a molecular clock that is appropriate for small passerines with half the generation times of eagles.
3. ^ Parry et al. (2002), Rasmussen & Anderton (2005), Väli (2006)
4. ^ a b Bishop (1999)
5. ^ Töpfer (2007)
6. ^ Meyburg et al. (1995)
7. ^ Väli & Lõhmus (2000)

References

* BirdLife International (2008). Aquila clanga. In: IUCN 2008. IUCN Red List of Threatened Species. Downloaded on 30 April 2009.
* Bishop, K. David (1999): Preliminary notes on some birds in Bhutan. Forktail 15: 87-91. PDF fulltext
* Meyburg, Bernd-U.; Eichaker, Xavier; Meyburg, Christiane & Paillat, Patrick (1995): Migrations of an adult Spotted Eagle tracked by satellite. Brit. Birds 88: 357-361. PDF fulltext
* Parry, S.J.; Clark, W.S. & Prakash, V. (2002): On the taxonomic status of the Indian Spotted Eagle Aquila hastata. Ibis 144(4): 665-675. doi:10.1046/j.1474-919X.2002.00109.x (HTML abstract)
* Rasmussen, Pamela C. & Anderton, John C. (2005): Birds of South Asia - The Ripley Guide. Lynx Edicions, Barcelona. ISBN 84-87334-67-9
* Töpfer, Till (2007): Nachweise seltener Vogeltaxa (Aves) in Sachsen aus der ornithologischen Sammlung des Museums für Tierkunde Dresden [Records of rare bird taxa (Aves) in Saxony from the ornithological collection of the Zoological Museum Dresden]. Faunistische Abhandlungen 26(3): 63-101 [German with English abstract]. PDF fulltext
* Väli, Ülo (2006): Mitochondrial DNA sequences support species status for the Indian Spotted Eagle Aquila hastata. Bull. B.O.C. 126(3): 238-242. PDF fulltext
* Väli, Ülo & Lõhmus, Asko (2000): The Greater Spotted Eagle and its conservation in Estonia. Hirundo Supplement 3: 1-50. HTML abstract
* Väli, Ülo & Lõhmus, Asko (2004): Nestling characteristics and identification of the lesser spotted eagle Aquila pomarina, greater spotted eagle A. clanga, and their hybrids. J. Ornithol. 145(3): 256-263. doi:10.1007/s10336-004-0028-7 PDF fulltext


Further reading

* Svensson, Lars (1987) Underwing pattern of Steppe, Spotted and Lesser Spotted Eagles, pp. 12-14 in International Bird Identification: Proceeedings of the 4th International Identification Meeting, Eilat, 1st - 8th November 1986 International Birdwatching Centre Eilat

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