[order] ACCIPITRIFORMES | [family] Accipitridae | [latin] Accipiter novaehollandiae | [authority] Gmelin, 1788 | [UK] Grey Goshawk | [FR] Autour blanc | [DE] Grauhabicht | [ES] Azor variable | [NL] Grijze Havik
Subspecies
| Genus | Species | subspecies | Region | Range |
| Accipiter | novaehollandiae | AU | Australia, Tasmania |
Genus
Members of the genus Accipiter are small and medium-sized hawks, often called Sparrow-hawks or Goshawks. The females are almost invariably much larger than the males – in some cases weighing twice as much – a level of size dimorphism only exceptionally reached in any other genus Falconiformes. Their wings are short and rounded; the tail usually quite long. They are well adapted for flying through dense bush. Bird-catching Sparrow-hawks generally have long and slender legs, with slender digits, the middle one being especially long. Goshawks are usually larger, with shorter, thicker tarsi and digits and a shorter middle digit. Some smaller species have goshawk-like feet and vice versa, making it difficult on a world-wide basis to subdivide the genus on this or any other broad basis. Although many accipiters feed upon birds moreso than do other hawks, some species take many mammals, especially squirrels; others take lizards, frogs, snakes, insects, even snails. In these species the legs and digits are sometimes slender, but short. Accipiters are rarely crested, but some have very attractive colour patterns. Black phases are present, especially in the tropical species. One in Australia has the only pure white phase. Accipiter is the largest genus in the family, having about fifty species. It is present worldwide, but is especially rich in Papua-New Guinea, where a small island like New Britain may have three to five endemic species or distinct sub-species.
Physical charateristics
The adult in Australia and Tasmania is variable. In its white phase it pure white throughout with reddish orange eyes, and yellow cere and feet. White birds predominate in the south-east and in the north-west. In Tasmania all birds are white. In its grey phase it is clear pale grey above, except for faint white barring on the rump, white edges to inner webs of tail quills, and about eleven dark grey bars on the tail quills. Below, the throat is white, the sides of the face and the neck pale grey. Its breast is barred grey and white; the rest of the under side, including under-wing is white with some faint grey barring on thighs. Tail quills below are silvery, faintly barred grey on inner webs. Primaries are grey and white; secondaries pale grey, barred basally on inner webs with grey and white. Eye red, cere and legs yellow. Grey phase birds predominate in the centre portion of the Australian range. Females are much larger than males and, in the grey phase, rather darker and more heavily barred; otherwise alike. Immature in grey phase differs from the adult in being greyer generally, more heavily barred be low, with a grey wash over much of the under side. In white phase pure white like the adult. Eye brown, becoming reddish at about two months old, cere and feet yellow in both phases.
Downy young white in all known races, or sometimes grey in Australia. Eye dark brown, cere and legs yellow. There is much racial variation in this species, both in size and colour. Weight variation is from 175 grams in small male to about 1,000 grams in female. The New Guinea races, with white phase, form intermediate links between the large Australian birds and the smaller, brightly coloured island races. Almost all the island races of this species differ from the nominate race in being grey above and chestnut, rufous, or vinous below, the under side being either plain or more or less barred, the grey upper side varying greatly in shade from pale slate to almost black, sometimes with a rufous collar. The general trend is for the races inhabiting tropical forests to be darker above and more richly rufous below.
In general the paler forms among the island races are from the western part of the range, and the darkest forms occur in the Solomons Islands. The adult in white phase is impossible to confuse with anything but a white cockatoo; the same applies to the white New Guinea forms. The pale grey Australian form is likewise much paler than, and easy to distinguish from, the slate-coloured and strongly barred Australian Goshawk (Accipiter fasciatus). The plain-breasted Island forms, with rufous or vinous under sides and grey or slaty upper sides, are also unmistakable in adult plumage. They appear bulkier in flight than other Accipiter species in the same area. The barred island forms are more difficult to distinguish from the forms of the Collared Sparrow-hawk (Accipiter cirrhocephalus) and Australian Goshawk with which they share a range, but are much more uniform and brighter rufous below, and less clearly barred.
Downy young white in all known races, or sometimes grey in Australia. Eye dark brown, cere and legs yellow. There is much racial variation in this species, both in size and colour. Weight variation is from 175 grams in small male to about 1,000 grams in female. The New Guinea races, with white phase, form intermediate links between the large Australian birds and the smaller, brightly coloured island races. Almost all the island races of this species differ from the nominate race in being grey above and chestnut, rufous, or vinous below, the under side being either plain or more or less barred, the grey upper side varying greatly in shade from pale slate to almost black, sometimes with a rufous collar. The general trend is for the races inhabiting tropical forests to be darker above and more richly rufous below.
In general the paler forms among the island races are from the western part of the range, and the darkest forms occur in the Solomons Islands. The adult in white phase is impossible to confuse with anything but a white cockatoo; the same applies to the white New Guinea forms. The pale grey Australian form is likewise much paler than, and easy to distinguish from, the slate-coloured and strongly barred Australian Goshawk (Accipiter fasciatus). The plain-breasted Island forms, with rufous or vinous under sides and grey or slaty upper sides, are also unmistakable in adult plumage. They appear bulkier in flight than other Accipiter species in the same area. The barred island forms are more difficult to distinguish from the forms of the Collared Sparrow-hawk (Accipiter cirrhocephalus) and Australian Goshawk with which they share a range, but are much more uniform and brighter rufous below, and less clearly barred.
Listen to the sound of Grey Goshawk
[audio:http://www.planetofbirds.com/MASTER/ACCIPITRIFORMES/Accipitridae/sounds/Grey Goshawk.mp3]
Copyright remark: Most sounds derived from xeno-canto
| wingspan min.: | 71 | cm | wingspan max.: | 110 | cm |
| size min.: | 38 | cm | size max.: | 55 | cm |
| incubation min.: | 31 | days | incubation max.: | 34 | days |
| fledging min.: | 30 | days | fledging max.: | 42 | days |
| broods: | 1 | eggs min.: | 2 | ||
| eggs max.: | 4 |
Range
Australasia : Australia, Tasmania. It can be found in Tasmania, the Australian Continent, New Guinea, and islands west as far as Sumbawa and Ceram, east to the Solomons.
Habitat
It is most commonly to be found throughout its range in forests or woodland. In Australia and Tasmania it is a bird of wooded country, extending round the continent to the north-west (Kimberley Mts) and avoiding the desert regions of the interior. It is resident where it occurs and does not migrate. The New Guinea and Island races can be found in dense jungle, both in mountains and near the coast. In heavily forested areas it favours secondary growth or open clearings, villages, native gardens, etc.
Reproduction
In Australia the nest is usually placed in large Eucalyptus, often well out on a horizontal limb, at an average of about 60 feet above the ground. It is a flat structure made of fine sticks and lined with green leaves, built by the birds themselves. Both sexes build, breaking off the twigs from dead branches. Nest repair or the construction of a new nest may occupy from six weeks to two months. The breeding season is from August to December, with most eggs in clutches of three, during September and October. Both sexes are known to incubate, but the female usually incubates alone and the male seldom visits the nest except to bring prey; when females have been shot the male does not necessarily incubate the eggs, but obtains another mate. When the young hatch they are brooded closely by the female; the male then spends little time near the nest, but brings all the prey which is received by the female and fed by her to the young. From egg-laying to fledging young takes a little over two months
Feeding habits
The diet varies according to the size of the race. The large Australian form takes birds up to the size of a fruit pigeon, small megapodes, mammals up to the size of a rabbit, reptiles, including snakes, and some insects. The smaller island forms eat small birds, small ground mammals, lizards, and large insects, with probably a larger proportion of insects and lizards than the continental race. Avian prey is taken either on the wing or on the ground; mammalian, reptile and insect prey on the ground or from the branches of trees. In its general behaviour it is similar to many other goshawks and sparrow-hawks. It hides in the cover of woodlands or forest, and attacks birds and other prey either in the open or inside the cover. It will plunge into dense vegetation in pursuit of prey on occasion. Sometimes it soars almost with the ease of a buzzard. The larger Australian forms are less agile than some of the small island forms and hunt either from perches within woodland, or by flying low through the trees in the hope of surprising prey. It is possible that the white phase birds benefit from their similarity to the cockatoo when approaching other birds. In all races the males are smaller than the females to such a degree that they tend to take more birds while the females take more mammals and reptiles on the ground.
Video Grey Goshawk
httpv://www.youtube.com/watch?v=ckbKszTMeo0
copyright: Nick Talbot
Conservation
This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size may be moderately small to large, but it is not believed to approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
The population is suspected to be in decline owing to ongoing habitat destruction and human persecution.
The population is suspected to be in decline owing to ongoing habitat destruction and human persecution.
Migration
Resident and once a territory has been estahblishes also sedentary. YOung might disperse post-fledging
Distribution map
