Grey currawong

Appearance

A larger and more slender bird than its more common relative the pied currawong, the adult grey currawong ranges from 44 to 57 cm in length, with an average of around 52 cm; the wingspan varies from 72 to 85 cm, averaging around 78 cm, with an average weight of around 350 g.

Adults of the Tasmanian subspecies average around 440 g. The male is on average slightly larger than the female, but the size and weight ranges mostly overlap. It is generally a dark grey bird with white in the wing, undertail coverts, the base of the tail and most visibly, the tip of the tail. It has yellow eyes. The orbital, legs and feet are black, whereas the bill and gape range from greyish black to black.

The overall plumage varies according to subspecies. The nominate race "versicolor" and "plumbea" are slate-grey in colour, while "melanoptera" and "intermedia" are blackish-brown, and "arguta" of Tasmania and "halmaturina" a sooty black. The size of the white patch on the wing also varies, being large and easily spotted in "versicolor", "plumbea", "intermedia" and "arguta", but non-existent or indistinct in "melanoptera" and "halmaturina".

More specifically, the nominate subspecies has a grey forehead, crown, nape, ear-coverts and throat with the face a darker grey-black. The feathers of the throat are longer, giving rise to hackles there. The upperparts and underparts are a brownish-grey and become more brown with age. Towards the belly, the feathers are a paler grey. The wings are grey-brown, and the blackish primaries have white edges which merge to form the prominent white wing markings.

Birds appear to moult once a year in spring or summer, although observations have been limited. Young birds spend about a year in juvenile plumage before moulting into adult plumage at around a year old. Juvenile birds have more brown-tinged and uniform plumage; the darker colour around the lores and eyes are less distinct. Their blackish bill is yellow-tipped, and the gape is yellow. Their eyes are brownish, but turn yellow early. The exact timing is unknown but likely to be around four months of age.

Distribution

Grey currawongs are found right across the southern part of Australia from the Central Coast region of New South Wales, occurring south of latitude 32°S southwards and westwards, from the vicinity of Mudgee in the north and southwest to Temora and Albury onto the Riverina and across most of Victoria and southern South Australia to the fertile south-west corner of Western Australia and the semi-arid country surrounding it.

Behavior

Overall, data on the social behaviour of the grey currawong is lacking, and roosting habits are unknown. It is generally shyer and more wary than its pied relative, but has become more accustomed to people in areas of high human activity in southwest Western Australia. Its undulating flight is rapid and silent. It hops or runs when on the ground. Birds are generally encountered singly or in pairs, but may forage in groups of three to eleven birds. Up to forty birds may gather to harvest a fruit tree if one is found. The black-winged subspecies is seldom seen in groups larger than four or five, while the clinking currawong may form groups of up to forty birds over the non-breeding season.

There is some evidence of territoriality, as birds in the Wheatbelt maintain territories year-round there. The grey currawong has been recorded harassing larger birds such as the wedge-tailed eagle, square-tailed kite and Australian hobby. The species has been observed bathing by shaking its wings in water at ponds, as well as applying clay to its plumage after washing.

Habitat

The grey currawong is found in wet and dry sclerophyll forests across its range, as well as mallee scrubland, and open areas such as parks or farmland near forested areas. It also inhabits pine plantations.

Reproduction

The breeding habits of the grey currawong are not well known, and the inaccessibility of its nests makes study difficult. The breeding season lasts from August to December. The grey currawong builds a large shallow nest of thin sticks lined with grass and bark high in trees; generally eucalypts are chosen.

It produces a clutch of one to five rounded or tapered oval eggs, which vary in size and colour according to subspecies. Those of subspecies "versicolor" average 30 mm × 43 mm in size and are a pale brown or buff with shades of pink or wine tones, and are marked with streaks or splotches of darker brown, purple-brown, slate-grey or even blue-tinged.

Food

The grey currawong is an omnivorous and opportunistic feeder. It preys on many invertebrates, such as snails, spiders and woodlice, and a wide variety of insects including beetles, earwigs, cockroaches, wasps, ants and grasshoppers, and smaller vertebrates, including frogs, lizards such as the bearded dragon as well as skinks, rats, mice, and nestlings or young of Tasmanian nativehen, red wattlebird, eastern spinebill, house sparrow, and splendid fairywren.