Grey Hawk

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Grey Hawk/Grey-lined Hawk

Kingdom:	Animalia
Phylum:	Chordata
Class:	Aves
Order:	Falconiformes
Family:	Accipitridae
Genus:	Asturina
Species:	A. nitidus

Binomial name

Asturina nitidus
(Latham, 1790)

Synonyms

Asturina nitida
Asturina plagiata
Buteo plagiatus

The Grey Hawk or Grey-lined Hawk (Buteo nitidus) is a smallish raptor found in open country and forest edges. It is sometimes placed in the genus Asturina as Asturina nitida.

It breeds from the southwestern USA and Mexico south to Bolivia, Brazil and central Argentina. It is fairly common on Trinidad, and there have been recent sightings on Tobago.

The Grey Hawk is 46-61 cm in length and weighs 475 g on average. The adult has a pale grey body, the tail is black with three white bands and the legs are orange. The population from southeastern Pacific Costa Rica to Brazil and Argentina has fine white barring on the upper parts; the northern population is darker overall and uniformly grey above. It is sometimes split as the separate species Buteo plagiatus (or Asturina plagiata; the Grey Hawk proper), but the vocalisations of the "grey" and the "grey-lined" populations are identical.

Immature birds have dark brown upperparts, a pale-banded brown tail, brown-spotted white underparts and a brown streaked buff head and neck. This species is quite short-winged, and has a fast agile flight for a Buteo. The call is a shrill whistled kleee-ooo.

Buteo nitidus feeds mainly on lizards and snakes, but will also take small mammals, birds and frogs. It usually sits on an open high perch from which it swoops on its prey, but will also hunt from a low glide. The nest is of sticks and built high in a tree. The usual clutch is one to three, usually two white^{[verification needed]} eggs, pale blue^{[verification needed]} with red markings. The young take about 6 weeks to fledging.

When Buteo plagiatus was still considered a good species, it was allso listed as Least Concern by the IUCN^[1]. In the 2007 Red List, it is united with B. nitidus.

[edit] Footnotes

^ E.g. Baillie et al. (2004), BirdLife International (2004b).

[edit] References

Baillie, J.E.M.; Hilton-Taylor, C. & Stuart, S.N. (eds.) (2004): 2004 IUCN Red List of Threatened Species. A Global Species Assessment. IUCN, Gland, Switzerland and Cambridge, UK. ISBN 2-8317-0826-5
BirdLife International (2004a). Asturina nitida. 2006 IUCN Red List of Threatened Species. IUCN 2006. Retrieved on 05 December 2006.
BirdLife International (2004b). Asturina plagiata. 2006 IUCN Red List of Threatened Species. IUCN 2006. Retrieved on 05 December 2006.
ffrench, Richard; O'Neill, John Patton & Eckelberry, Don R. (1991): A guide to the birds of Trinidad and Tobago (2nd edition). Comstock Publishing, Ithaca, N.Y.. ISBN 0-8014-9792-2
Hilty, Steven L. (2003): Birds of Venezuela. Christopher Helm, London. ISBN 0-7136-6418-5
Stiles, F. Gary & Skutch, Alexander Frank (1989): A guide to the birds of Costa Rica. Comistock, Ithaca. ISBN 0-8014-9600-4