copyright: Curt Kessler
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.
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).
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.
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 Hawks 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.
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. [conservation status from birdlife.org]
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.
Sedentary but females tend to be somewhat nomadic during the non-breeding season, more so than males do.
- spanwidth min.: 0 cm
- spanwidth 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
- Conservation Status