Hawaiian Hawk (Buteo solitarius)

Hawaiian Hawk

[order] ACCIPITRIFORMES | [family] Accipitridae | [latin] Buteo solitarius | [authority] Peale, 1848 | [UK] Hawaiian Hawk | [FR] Buse d’Hawai | [DE] Hawaiibussard | [ES] Busardo Hawaiano | [NL] Hawaii-buizerd

Subspecies

Genus Species subspecies Region Range
Buteo solitarius PO Hawaiian Islands

Genus

Members of the genus Buteo are broad-winged, broad-tailed hawks, Well adapted for soaring. The bill, legs and talons are of average proportions. There is much colour variation both within the species, and, by way of phases, within individual species. In all cases the young are quite different from adults in that they are all well camouflaged with an overall brown appearance with varying amounts of striping below and paler mottling above.
The 25 species are spread worldwide with the exception of Australasia and much of the Indian sub-continent.

Physical charateristics

The Hawaiian Hawk measures approximately 40 to 46 centimetres (16 to 18 in) in length. The female is larger than the male. Two color phases exist: a dark phase (dark brown head, breast, and underwings), and a light color phase (dark head, light breast and light underwings). Feet and legs are yellowish in adults and greenish in juveniles.

Listen to the sound of Hawaiian Hawk

[audio:http://www.planetofbirds.com/MASTER/ACCIPITRIFORMES/Accipitridae/sounds/Hawaiian Hawk.mp3]

Copyright remark: Most sounds derived from xeno-canto


wingspan min.: 0 cm wingspan max.: 0 cm
size min.: 41 cm size max.: 46 cm
incubation min.: 36 days incubation max.: 40 days
fledging min.: 59 days fledging max.: 63 days
broods: 1   eggs min.: 1  
      eggs max.: 2  

Range

Pacific Ocean : Hawaiian Islands. Buteo solitarius breeds on Hawai`i in the Hawaiian Islands (USA), with vagrants recorded on Maui, O’ahu and Kaua’i. The population is thought to be fairly stable, and estimates range from 1,457 and 1,600 (1,120 adults) to 2,700 birds.

Habitat

This is a typical member of the Buteo genus – a bird that soars a great deal but can also often be seen resting on a dead tree or exposed snag. It is most prevalent at moderate elevations, between 2,000 and 5,000 feet and, with the possible exception of heavy forest, has adapted to most habitat types on the island. Its favoured location appears to be parkland, fields or clearings with nearby large trees for perching and roosting. It occurs in a broad range of habitats up to 2,700 m, from lowland agricultural areas to all types of forest. However, most successful nesting is restricted to native `ohi`a trees Metrosideros polymorpha (which are slow growing and generally in decline).

Reproduction

In the early part of the breeding season the pair soar together, high above the nest area. One, probably the male, soars higher, and there is much calling. The nest is in a large tree and is a large, circular structure built of dead branches and twigs. The species reproduces at a slow rate, and there are observations that incubation lasts for 38 days, nestlings fledge after 59-63 days, and parents care for fledglings for an average of 30.2 weeks. Parents feed nestlings with mostly mammalian and avian prey.

Feeding habits

Until the arrival of man, there were, with the exception of one species of bat, no land mammals or reptiles on the islands. The original food for these birds must then have been large insects and maybe small birds anf their eggs. This sparsity of food supply would seem to be in line with the fact that it is only on the largest island of the group that this species exists. The arrival of man has, of course, meant that the rats and mice that travelled on his ships had virgin territory into which to expand, and it is these species that now form the main part of the Hawaiian Hawk’s diet. They also eat the larvae of large moths, and spiders; and have been known to raid nests for eggs. It benefits from some anthropogenic changes, for example, it feeds on introduced game-birds, passerines and rodents, and uses edge habitat around sugar-cane fields and orchards for hunting.

Video Hawaiian Hawk

httpv://www.youtube.com/watch?v=TAzgOM-8vAY

copyright: Curt Kessler


Conservation

This species is classified as Near Threatened because it has a very small population and a small range, for which there is currently no evidence of a decline. If the population was found to be declining, it would warrant uplisting to a higher threat category.
Continuing threats include forest clearance for agricultural and other developments, logging, the actions of introduced ungulates that degrade native forests and inhibit their regeneration, repeated nest disturbance, and perhaps road-kills. Nesting habitat in particular has been reduced, with recruitment of M. polymorpha restricted by competition from exotic plants in some areas. The species is threatened by the conversion of land used for pasture and sugar-cane to eucalyptus plantations, and residential development in extensive areas of subdivided land, mainly in Puna District. It formerly suffered extensively from shooting and may come into conflict with future efforts to reintroduce the Critically Endangered Hawaiian Crow Corvus hawaiiensis, which it preys upon.
Hawaiian Hawk status Near Threatened

Migration

Sedentary but females tend to be somewhat nomadic during the non-breeding season, more so than males do.

Distribution map

Hawaiian Hawk distribution range map

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