Autour blanc

Identification

The grey morph has a pale grey head and back, dark wingtips, barred grey breast and tail, and white underparts. The white morph is the only bird of prey in the world to be entirely white.[citation needed]<p>Grey goshawks are the largest Accipiter on mainland Australia, at about 40 to 55 cm (16 to 22 in) long, with wingspans of 70 to 110 cm (28 to 43 in). Females are much larger than males, weighing about 720 g (1.59 lb) on average (and sometimes scaling up to 990 g (2.18 lb)) while males average 355 g (12.5 oz). The population on the Solomon Islands is much smaller however, with a female found to have weighed 245 g (8.6 oz) and two males averaging 180 g (6.3 oz).

Taxonomie

The grey goshawk was formally described in 1788 by the German naturalist Johann Friedrich Gmelin in his revised and expanded edition of Carl Linnaeus's Systema Naturae. He placed it with the eagles, hawks and relatives in the genus Falco and coined the binomial name Falco novaehollandiae. Gmelin based his description on the "New Holland white eagle" that had been described in 1781 by the English ornithologist John Latham. Latham in turn had based his short description on information provided by Johann Forster who had accompanied James Cook on his second voyage to the Pacific Ocean. Two specimens had been collected in March 1773 at Adventure Bay in Tasmania. The grey goshawk is now one of 49 species placed in the genus Accipiter that was introduced in 1760 by the French zoologist Mathurin Jacques Brisson. The genus name is Latin for "hawk", from accipere, "to grasp". The specific epithet novaehollandiae is Modern Latin for "New Holland", the name given to western Australia by early Dutch explorers. In ornithology the name is used for eastern Australia, especially New South Wales. The grey goshawk has no recognised subspecies.

Nom scientifique

Tachyspiza novaehollandiae

Autorité

(Gmelin, JF, 1788)

Ordre

Accipitriformes

Famille

Accipitridés

Genre

Tachyspiza

Répartition et habitat

The grey goshawk is found along the coasts of northern, eastern and south-eastern Australia, Tasmania and rarely Western Australia. The variable goshawk was previously considered a subspecies.<p>Their preferred habitats are forests, tall woodlands, and timbered watercourses.

Migration

Resident species

Comportement

Grey goshawks often seem to vary their prey selection opportunistically. For an Accipiter, they relatively often select mammals such as rabbits, possums, and bats. Other prey can include small reptiles, and insects. However, the most frequent prey type are most often birds. Evidence from different parts of the range shows females select larger prey than males, with males largely keeping to small to mid-sized passerines while females often prey on larger prey such as currawongs, gamebirds (including megapodes) and even herons. Pigeons and parrots are a popular prey item for grey goshawks. Evidence indicates that this species is less agile in the air and less skilled at twisting pursuits over the ground than co-occurring brown goshawks but, on the other hand, the grey species is more powerful and so select typically larger prey. <p>Hunting is often done by stealth, but grey goshawks are willing to pursue their prey before catching it with their talons.<p>Grey and white goshawks interbreed freely. They partner for life, breeding from July to December. They nest in tall trees on a platform of sticks and twigs with a central depression lined with green leaves. The female lays a clutch containing 2 or 3 eggs, which are incubated for about 35 days. Chicks fledge 35–40 days after hatching.<p>The female is usually responsible for incubating the eggs and feeding the young. The male does most of the hunting.

Conservation

State of Tasmania<p>State of Victoria (Australia)<p>State of Queensland

Tendance de la population

declining