Grey Hawk or Grey-lined Hawk

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.

Distribution / Range

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

Description

The Grey Hawk is 46–61 cm (18–24 in) in length and weighs 475 g (16.8 oz) on average.

The adult has a pale grey body, the tail is black with three white bands and the legs are orange. The population of 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 upper parts, 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.

Calls / Vocalizations

The call is a shrill whistled kleee-ooo.

Diet / Feeding

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.

Nesting / Breeding

The nest is of sticks and is built high in a tree. The usual clutch is one to three, usually two white to pale blue eggs.

The young take about 6 weeks to fledge.

Status

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

Footnotes

1. BirdLife International (2008). Buteonitidus. In: IUCN 2008. IUCN Red List of Threatened Species. Downloaded on 01 August 2009.
2. Animal Diversity (Asturina nitida)”. http://animaldiversity.ummz.umich.edu. Retrieved 2008-06-26
3. E.g. Baillie et al. (2004), BirdLife International (2004b).

References

• Baillie, J.E.M.; Hilton-Taylor, C. and 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 and 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 and Skutch, Alexander Frank (1989): A guide to the birds of Costa Rica. Comistock, Ithaca. ISBN 0-8014-9600-4