Australian Raven

Australian Raven
Australian Raven
Australian National Botanic Gardens, Canberra, ACT
Conservation status
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Passeriformes
Family: Corvidae
Genus: Corvus
Species: C. coronoides
Binomial name
Corvus coronoides
Vigors & Horsfield, 1827
Subspecies
C. c. coronoides
C. c. perplexus

The Australian Raven (Corvus coronoides) is the largest Australian member of the genus Corvus and one of three Australian species commonly known as ravens. It is a more slender bird than the Common Raven of the Northern Hemisphere but is otherwise similar. It has all-black plumage, beak and legs with a white iris, as do the other Corvus members in Australia and some species from the islands to the north. It is distinguished by its prominent throat hackles and grey bases of its black feathers. It is omnivorous, has adapted well to urban environments and is a common city bird in Sydney and Canberra.

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Taxonomy and naming

The Australian Raven was first described by Nicholas Aylward Vigors and Thomas Horsfield in 1827;[1] its specific epithet coronoides "crow-shaped" is derived from the Greek corone/κορονη "crow" and eidos/ειδος "shape" or "form".[2] The two naturalists regarded the Australian Raven as very similar in appearance to the Carrion Crow (C. corone) of Europe.[3]

Although called a raven, its closest affinities lie with the other four species of Australian corvid, which include the Torresian Crow and Little Crow as well as the Forest Raven and Little Raven.[4]

Alternate names sometimes seen include Southern Raven, Southern Crow, and Kelly.[3] It was called wugan by the local Eora and Darug inhabitants of the Sydney basin.[5]

Nowra, NSW

Two subspecies are recognised:

  • C. c. coronoides, the nominate subspecies, is found across most of eastern Australia
  • C. c. perplexus occurs from the head of the Great Australian Bight in South Australia westwards into Western Australia where its northern limits are Shark Bay and the mulga-eucalypt boundary line

Intermediate birds are found in the Eyre Peninsula, Gawler Ranges and vicinity of Lake Eyre in South Australia.[3]

Description

juvenile with dark eyes

Measuring 46–53 cm (18–21 in) in length with a 100 cm (40 in) wingspan and weighing around 650 g,[3] the adult Australian Raven is an all black bird with black feet and beak and a white iris. The plumage is glossy with a blue-purple to blue-green sheen, greenish over the ear coverts, depending on light. The underparts are not glossy. Its throat feathers (hackles) are longer than those of other species.[6] It can be distinguished from the two species of crow occurring in Australia by the grey base of the feathers, which is white in the latter species. Juveniles resemble adults, but have dark eyes, shorter throat hackles, and sometimes have a pink fleshy gape.[7]

The territorial call of the Australian Raven is a slow, high ah-ah-aaaah with the last note drawn out. It will use this call to communicate with other Australian Ravens in the area.[4] The five Australian species are very difficult to tell apart, with the call being the easiest way to do so.[3]

Distribution and habitat

The Australian Raven is common throughout south-eastern Australia [8] and southern Western Australia (the populations being connected by a narrow strip across the Nullarbor Plain), but it is not found in the far north. It has adapted very well to human habitation in some cities and is a common bird in Melbourne, Sydney, and Rottnest Island.

Behaviour

In rural areas a single breeding pair and their brood will occupy about a square kilometre territory, whilst in urban areas over ten times as many ravens can search for food in the same square kilometre.[citation needed]

Diet

Food consists of carrion, insects, seeds, fruit, small reptiles, nestlings and eggs. The preference ratio is 34% carrion, 42% invertebrates and 24% plant material. Food is taken mainly from the ground but will occasionally feed in trees. Ravens have adapted well to eating rubbish and scraps in urban areas, such as school playgrounds. In one isolated study they were observed feeding on nectar from eucalypt flowers.[9]

Reproduction

Breeding season is from July to September.[10] Ravens always nest in tall trees, never near to the ground as some species do. Nests are generally large and untidy, consisting of a bowl or platform of sticks lined with grasses, barks, and feathers.[11] A clutch can comprise 3–6 eggs, though usually 4 or 5 are laid. Measuring 45x30 mm (1¾x1¼ in), eggs are pale green or bluish-green splotched with darker olive, brown and blackish markings.[10] Incubation of the eggs is done solely by the female over roughly 20 days. Only one brood is raised per year. Fledged by 45 days and staying with parents for about four months after that.

Rush Creek, SE Queensland, Australia

Relationship with Humans

The Australian Raven is frequently blamed for the loss of young lambs or kids.[12] Scientific observation in the country's southeast showed that the killing of healthy lambs was rare but that sick animals were predisposed to being attacked.[13]

References

  1. ^ Vigors, N.A. & Horsfield, T. (1827). "A description of the Australian birds in the collection of the Linnean Society; with an attempt at arranging them according to their natural affinities.". Trans. Linn. Soc. Lond. 15: 170–331. doi:10.1111/j.1095-8339.1826.tb00115.x. 
  2. ^ Liddell, Henry George and Robert Scott (1980). A Greek-English Lexicon (Abridged Edition). United Kingdom: Oxford University Press. ISBN 0-19-910207-4. 
  3. ^ a b c d e Higgins et al., p. 690
  4. ^ a b Australian Museum Online. "Crows and Ravens". http://www.amonline.net.au/factSheets/crows_ravens.htm. Retrieved 2007-08-12. 
  5. ^ Troy, Jakelin (1993). The Sydney language. Canberra: Jakelin Troy. p. 53. ISBN 0-646-11015-2. 
  6. ^ Higgins et al., p. 691
  7. ^ Birds in Backyards. "Australian Raven". http://birdsinbackyards.net/finder/display.cfm?id=26. Retrieved 2007-08-12. 
  8. ^ http://www.birdsinbackyards.net/species/Corvus-coronoides
  9. ^ Richardson, KC (1988). (abstract) "Are Australian corvids nectarivorous?.". Emu 88 (2): 122–23. doi:10.1071/MU9880122. http://md1.csa.com/partners/viewrecord.php?requester=gs&collection=ENV&recid=1855171&q=Corvus+coronoides&uid=1196122&setcookie=yes (abstract). Retrieved 2007-08-14. 
  10. ^ a b Beruldsen, Gordon (2003). Australian Birds: Their Nests and Eggs. Kenmore Hills, Qld: self. pp. 384. ISBN 0-646-42798-9. 
  11. ^ "Birds in Backyards". http://birdsinbackyards.net/finder/display.cfm?id=26. 
  12. ^ Temby, Ian. "Predatory Birds". http://www.dpi.vic.gov.au/dpi/nreninf.nsf/childdocs/-C3270146B772814F4A2568B30006FFEE-7A5820241AEA1564CA256BC800078098-7B785784C934E20E4A256DEA00292002-75C7A9C8E202D918CA256BCF000B4D7C?open. Retrieved 12 August 2007. [dead link]
  13. ^ Rowley, I (1969). (abstract) "An evaluation of predation by 'crows' on young lambs". CSIRO Wildlife Research 14 (2): 153–179. doi:10.1071/CWR9690153. http://www.publish.csiro.au/?paper=CWR9690153 (abstract). Retrieved 2007-08-14. 

Cited text

External links