Greater Spotted Eagle

From Wikipedia, the free encyclopedia
Greater Spotted Eagle
Adult wintering at Bharatpur (Rajasthan, India).
Note the inconspicuous eye.
Conservation status
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Subclass: Neornithes
Infraclass: Neognathae
Superorder: Neoaves
Order: Falconiformes (but see there)
Family: Accipitridae
Subfamily: Buteoninae (disputed)
Genus: Aquila
Species: A. clanga
Binomial name
Aquila clanga
Pallas, 1811
Breeding (light green) and wintering (blue) ranges

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.

Description

Museum specimen of juvenile

The eagle is 59–71 cm (23–28 in) in length and has a wingspan of 157–179 cm (5.15–5.87 ft). Typical body mass is 1.6–2.5 kg (3.5–5.5 lb), with an occasional big female weighing up to 3.2 kg (7.1 lb).[2][3]

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.

Identification

This medium-sized 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.[4]

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 typical eagles are often united with the buteos (Buteo), sea eagles (Haliaetus) and other more heavy-set Accipitridae, but they may be less distinct than formerly believed from the more slender accipitrine hawks. The Lesser Spotted Eagle (A. pomarina) is the Greater Spotted Eagle's closest living relative; their common ancestor seems to have diverged around the middle Pliocene, perhaps some 3.6 million years ago (mya),[5] 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.[6]

The spotted eagles are quite distinct as a group 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 future.

Distribution and habitat

This is a species of wooded country. The population is entirely migratory. It breeds from northern Europe eastwards across Asia, and winters in south-eastern Europe, north-eastern Africa, the Middle East and southern Asia. Migration to the breeding grounds takes place fairly late; in Bhutan, for example, birds can be seen with some regularity until the end of March.[7]

Movements

This species is prone to vagrancy. Its regular breeding range no longer extends as far westwards as Germany but birds are still occasionally seen there with a few records per decade. Even young birds disperse widely; the Staatliches Museum für Tierkunde Dresden has a specimen (C 21845) shot in November 1914 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.[8]

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 mi) from its wintering grounds in Yemen to it breeding grounds in western Siberia. It moved 150 km (93 mi) on average each day, but this increased to 280 km (170 mi) per day as the bird flew through Mesopotamia.[9]

Behaviour

In its winter range, the species is more social than when breeding. 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 such as local and/or migrant Black Kites (Milvus migrans lineatus and govinda) or Steppe Eagles (A. nipalensis), distinctly smaller and larger raptors, respectively.[7]

Feeding

The eagele hunts small mammals and similar, mainly terrestrial, prey.

Breeding

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.

Status and conservation

It is classified as Vulnerable to extinction by the IUCN.[1] 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.[10]

Gallery

  • Underside of adult wintering at Bharatpur (Rajasthan, India)

  • Upperside of adult wintering in Bharatpur (Rajasthan, India)
    Note light wing stripes

  • Greater spotted eagle wintering in Israel

  • Greater spotted eagle in flight, wintering in Israel

References

Notes

  1. ↑ 1.0 1.1 BirdLife International (2013). "Aquila clanga". IUCN Red List of Threatened Species. Version 2013.2. International Union for Conservation of Nature. Retrieved 26 November 2013. 
  2. ↑ Raptors of the World by Ferguson-Lees, Christie, Franklin, Mead & Burton. Houghton Mifflin (2001), ISBN 0-618-12762-3.
  3. ↑ CRC Handbook of Avian Body Masses by John B. Dunning Jr. (Editor). CRC Press (1992), ISBN 978-0-8493-4258-5.
  4. ↑ See Väli & Lõhmus (2004) for details
  5. ↑ 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.
  6. ↑ Parry et al. (2002), Rasmussen & Anderton (2005), Väli (2006)
  7. ↑ 7.0 7.1 Bishop (1999)
  8. ↑ Töpfer (2007)
  9. ↑ Meyburg et al. (1995)
  10. ↑ Väli & Lõhmus (2000)

Sources

  • 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 - 8 November 1986 International Birdwatching Centre Eilat

External links

Wikimedia Commons has media related to Aquila clanga.

This article is issued from Wikipedia. The text is available under the Creative Commons Attribution/Share Alike; additional terms may apply for the media files.