Steppe eagle

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Steppe eagle
Steppe Eagle Portrait.jpg
Individual at Jorbeer, Bikaner, Rajasthan
Conservation status
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Accipitriformes
Family: Accipitridae
Genus: Aquila
Species: A. nipalensis
Binomial name
Aquila nipalensis
(Hodgson, 1833)
Aquila nipalensis dis.PNG
Light Green - nesting area, Blue - wintering area, Dark Green - resident all year
Synonyms

Aquila rapax nipalensis

The steppe eagle (Aquila nipalensis) is a bird of prey. It is about 62–81 cm (24–32 in) in length and has a wingspan of 1.65–2.15 m (5.4–7.1 ft). Females, weighing 2.3–4.9 kg (5–10.8 lbs), are slightly larger than males, at 2–3.5 kg (4.4–7.7 lbs). Like all eagles, it belongs to the family Accipitridae.[2] It was once considered to be closely related to the non-migratory tawny eagle (Aquila rapax) and the two forms have previously been treated as conspecific. They were split based on pronounced differences in morphology and anatomy (Clark, 1992; Olson, 1994; Sangsteret al., 2002); two molecular studies, each based on a very small number of genes, indicate that the species are distinct but disagree over how closely related they are.[3]

The steppe eagle breeds from Romania east through the south Russian and Central Asian steppes to Mongolia. The European and Central Asian birds winter in Africa, and the eastern birds in India. It lays 1–3 eggs in a stick nest in a tree. Throughout its range it favours open dry habitats, such as desert, semi-desert, steppes, or savannah.

The gape of the steppe eagle is an easy way to distinguish it from the tawny eagle. The gape extends beyond the centre of the eye as against the tawny. The oval nostril sets it apart from the spotted eagles.

This is a large eagle with brown upperparts and blackish flight feathers and tail. This species is larger and darker than the tawny eagle, and it has a pale throat which is lacking in that species.

Immature birds are less contrasted than adults, but both show a range of variation in plumage colour. The eastern subspecies A. n. nipalensis is larger and darker than the European and Central Asian A. n. orientalis.

Large numbers are seen at certain places such as Khare in Nepal during migration. As many as 15.3 birds per hour during October and November have been noted.[4]

The steppe eagle's diet is largely fresh carrion of all kinds, but it will kill rodents and other small mammals up to the size of a hare, and birds up to the size of partridges. It will also steal food from other raptors. Like other species the steppe eagle has a crop in its throat allowing it to store food for several hours before being moved to the stomach.

The call of the steppe eagle sounds like a crow barking, but it is rather a silent bird.

Concerns[edit]

The paper based on joint research conducted by the Bombay Natural History Society, Royal Society for the Protection of Birds and Indian Veterinary Research Institute, published in May 2014 in the journal of the Cambridge University Press, highlighted that steppe eagles are adversely affected by veterinary use of diclofenac and may fall prey to it. The research found the same signs of kidney failure as seen in the Gyps vulture killed due to diclofenac. They found extensive visceral gout, lesions and uric acid deposits in the liver, kidney and spleen, as well as deposits of diclofenac residue in tissues. Steppe eagles are opportunistic scavengers, which may expose them to the risk of diclofenac poisoning.[5]

References[edit]

  1. ^ BirdLife International (2013). "Aquila nipalensis". 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. ^ http://www.globalraptors.org/grin/SpeciesResults.asp?specID=8167
  4. ^ DeCandido, R., Allen, D., Bildstein, K.L. (2001) The migration of Steppe Eagles (Aquila nipalensis) and other raptors in central Nepal, autumn 1999. Journal of Raptor Research. 35(1):35-39
  5. ^ Phadnis, Mayuri (May 28, 2014). "Eagles fall prey to vulture-killing chemical". Pune Mirror. Retrieved May 28, 2014. 
  • Clark, W. S. (1992): The taxonomy of Steppe and Tawny Eagles, with criteria for separation of museum specimens and live eagles. 'Bull. B.O.C. 112: 150–157.
  • Olson, Storrs L. (1994): Cranial osteology of Tawny and Steppe Eagles Aquila rapax and A. nipalensis. Bull. B.O.C. 114: 264–267.

Further reading[edit]

  • 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[edit]

Thumamah, KSA 1993
At Wildpark Tripsdrill, Germany