The grey currawong (Strepera versicolor) is a large passerine bird native to southern Australia, including Tasmania. One of three currawong species in the genus Strepera, it is closely related to the butcherbirds and Australian magpie of the family Artamidae. It is a large crow-like bird, around long on average; with yellow irises, a heavy bill, dark plumage with white undertail and wing patches. The male and female are similar in appearance. Six subspecies are recognised and are distinguished by overall plumage colour, which ranges from slate-grey for the nominate from New South Wales and eastern Victoria and subspecies plumbea from Western Australia, to sooty black for the clinking currawong of Tasmania and subspecies halmaturina from Kangaroo Island. All grey currawongs have a loud distinctive ringing or clinking call.

Within its range, the grey currawong is generally sedentary, although it is a winter visitor in the southeastern corner of Australia. Comparatively little studied, much of its behaviour and habits is poorly known. Omnivorous, it has a diet that includes a variety of berries, invertebrates, and small vertebrates. The habitat includes all kinds of forested areas as well as scrubland in drier parts of the country. It is less arboreal than the pied currawong, spending more time foraging on the ground. It builds nests high in trees, which has limited the study of its breeding habits. Unlike its more common relative, it has adapted poorly to human impact and has declined in much of its range, although not considered endangered.

Taxonomy and naming

The grey currawong was first described as Corvus versicolor by ornithologist John Latham in 1801, who gave it the common name of "variable crow". The specific name versicolor means 'of variable colours' in Latin. Other old common names include grey crow-shrike, leaden crow-shrike, mountain magpie, black-winged currawong (in western Victoria), clinking currawong (in Tasmania), and squeaker (in Western Australia). the word meaning "to sneak" or "to track". Kiling-kildi was a name derived from the call used by the people of the lower Murray River.<!-- refs both sentences previous -->

Together with the pied currawong (S.&nbsp;graculina) and black currawong (S.&nbsp;fuliginosa), the grey currawong forms the genus Strepera. Although crow-like in appearance and habits, currawongs are only distantly related to true crows, and are instead closely related to the Australian magpie and the butcherbirds. The affinities of all three genera were recognised early on and they were placed in the family Cracticidae in 1914 by ornithologist John Albert Leach after he had studied their musculature. Ornithologists Charles Sibley and Jon Ahlquist recognised the close relationship between the woodswallows and the butcherbirds and relatives in 1985, and combined them into a Cracticini clade, which later became the family Artamidae.

  • S. v. versicolor, the nominate race, is known as the grey currawong, and is found in New South Wales, the Australian Capital Territory, and eastern and central Victoria, west to Port Phillip on the coast, and to the Grampians inland.
  • S. v. intermedia, the grey-brown form of South Australia, is also known as the brown currawong. It is found in the Yorke and Eyre Peninsulas, the Gawler and Mount Lofty Ranges and the eastern areas of the Great Australian Bight. First described by Richard Bowdler Sharpe in 1877 from a specimen collected in Port Lincoln, its specific name is the Latin adjective intermedia "intermediate".

right|thumb|The clinking currawong of Tasmania has sooty black plumage.|alt=a sooty black crow-like bird stands on grass.

  • S. v. arguta, the darkest race, is from eastern Tasmania or locally as the black magpie. Sharpe called it the Tasmanian hill-crow. The specific name is the Latin adjective argūtus "shrill/piercing", "noisy" or "melodious". Larger and heavier than the nominate subspecies, it has longer wings, tail, bill, and tarsus.
  • S. v. melanoptera, known as the black-winged currawong, is from western Victoria's Mallee region and South Australia west to the Mount Lofty Ranges. It can be difficult to distinguish from the black and pied currawongs at any distance. American ornithologist Dean Amadon observed that birds from northwestern Victoria were lighter in plumage than those of South Australia, and tentatively classified them as a separate subspecies howei. However, he noted they warranted further investigation, and subsequent authorities have not recognised the populations as separate. The common name leaden crow-shrike refers to this group. Very similar in plumage to the nominate subspecies, it differs in its thicker, more downward curved bill. The base plumage is variable, but tends to be slightly darker and possibly more brown-tinged than the nominate subspecies. 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. 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. The clinking call resembles that of the superb lyrebird, which imitates the currawong call at times.<!-- cites previous four sentences --> In northwestern Victoria, the black-winged currawong (subspecies melanoptera) has a darker plumage than other grey subspecies, and is thus more similar in appearance to the pied currawong, but its wings lack the white primaries of the latter species. In Tasmania, the black currawong is similar but has a heavier bill and call similar to the pied and lacks the white rump.

Distribution and habitat

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. The clinking subspecies is endemic to Tasmania, where it is more common in the eastern parts, but is absent from King and Flinders Islands in Bass Strait. There is an outlying population in the arid area where the Northern Territory meets South Australia and Western Australia. In general, the grey currawong is sedentary throughout its range, although it appears to be resident in the cooler months only in south Gippsland in eastern Victoria and the far south coast of New South Wales.

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. Preferences vary between regions; subspecies versicolor is more common in wetter forests in southeastern mainland Australia, while the Tasmanian subspecies arguta is found most commonly in lowland dry sclerophyll forest. The subspecies melanoptera and intermedia are found mainly in mallee scrublands and woodlands, while in Western Australia, subspecies plumbea is found in various forests and woodlands, such as jarrah (Eucalyptus marginata), karri (E.&nbsp;diversicolor), tuart (E.&nbsp;gomphocephala) and wandoo (E.&nbsp;wandoo), as well as paperbark woodlands around swampy areas, and acacia shrublands dominated by summer-scented wattle (Acacia rostellifera) and mulga (Acacia aneura) with Eremophila understory.

Formerly common, the grey currawong appears to have declined across its distribution; it became scarce in northern Victoria in the 1930s, and in northeastern Victoria in the 1960s. Habitat destruction has seen it decline in southeastern South Australia around Naracoorte and from many areas in the Western Australian Wheatbelt. It also became rare in the Margaret River and Cape Naturaliste regions after 1920, and vanished from much of the Swan Coastal Plain by the 1940s. One place which has seen an increase in numbers is the Mount Lofty Ranges in the 1960s. The status of the species is uncertain in the Northern Territory, where it may be extinct. It has been classified as critically endangered there pending further information.

Behaviour

Overall, data on the social behaviour of the grey currawong is lacking, and roosting habits are unknown. Its undulating flight is rapid and silent. It hops or runs when on the ground. 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.

Two species of chewing louse have been isolated and described from grey currawongs: (Menacanthus dennisi) from subspecies halmaturina on Kangaroo Island in South Australia, and Australophilopterus strepericus from subspecies arguta near Launceston in Tasmania. A new species of spirurian nematode, Microtetrameres streperae isolated from a grey currawong at Waikerie was described in 1977. The parasitic alveolate Isospora streperae was described from a grey currawong (subspecies plumbea) from Western Australia.

Breeding

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.<!-- cites para -->

Data on nesting success rates is limited; one study of 35 nests found that 28 (80%) resulted in the fledging of at least one young currawong. Causes of failure included nest collapse by gale-force winds and rain, and harassment and nest raiding by pied currawongs. The incidence of brood parasitism is uncertain. A pair of grey currawongs have been observed feeding a channel-billed cuckoo (Scythrops novaehollandiae) chick on one occasion. and splendid fairywren (M. splendens), It has been recorded hunting at the nests of the superb fairywren (Malurus cyaneus), and the bell miner (Manorina melanophrys).

A wide variety of plant material is also consumed, including the fruit or berries of Ficus species, Leucopogon species, Exocarpos species, a cycad Macrozamia riedlei, a mistletoe Lysiana exocarpi, Astroloma humifusum, A.&nbsp;pinifolium, Myoporum insulare, Enchylaena tomentosa and Coprosma quadrifida. The grey currawong also eats berries of introduced plants such as Pyracantha angustifolia and P.&nbsp;fortuneana, and Cotoneaster species, and crops such as maize, apples, pears, quince, various stone fruit of the genus Prunus, grapes, tomato, passion flowers, and the nectar of gymea lily (Doryanthes excelsa). Boneseed (Chrysanthemoides monilifera subspecies monilifera), another invasive species readily dispersed in bird droppings, is also consumed by grey currawongs.

Foraging takes place on the ground, or less commonly in trees or shrubs. Most commonly the grey currawong probes the ground for prey, but sometimes chases more mobile animals. as well as employing the zirkeln method, where it inserts its bill in a crack or under a rock and uses it to lever open a wider space to hunt prey. The grey currawong usually swallows prey whole, A field study on road ecology in southwestern Australia revealed that the grey currawong is unusual in inhabiting cleared areas adjacent to roads. However, it was not recorded feeding on roadkill, and moves away from the area in breeding season. It was also commonly hit and killed by vehicles.

Conservation status

The grey currawong has a very large range and thus does not meet the range size criteria for vulnerable. The population trend appears to be stable, although the population size has not been quantified, it is unlikely to approach the susceptible thresholds under the population size criterion (10,000 mature individuals with a continuing decline estimated to be >10 percent in ten years or three generations, or with a specified population structure), and the International Union for Conservation of Nature evaluated it as least concern.

References

; Notes

; Cited texts

  • 'Nest of the squeaker bird', drawing by A. J. Campbell, now in NLA catalogue