Australian Raven

The Australian raven (''Corvus coronoides'') is a passerine corvid bird native to Australia. Measuring in length, it has an all-black plumage, beak and mouth, as well as strong, greyish-black legs and feet. The upperparts of its body are glossy, with a purple-blue, greenish sheen; its black feathers have grey bases. The Australian raven is distinguished from the Australian crow, and other related corvids, by its long chest feathers, or throat hackles, which are prominent in mature birds. Older individuals and subadults have white irises, while the younger birds' eyes display blue inner rims; hatchlings and young birds have brown, dark irises until about fifteen months of age, at which point their irises become hazel-coloured, with an inner blue rim around each pupil, this lasting until they are roughly 2.5 to 3 years of age. Nicholas Aylward Vigors and Thomas Horsfield described the Australian raven in 1827, its species name ''coronoides'' highlighting its similarity with the carrion crow (''C. corone''). Two subspecies are recognised, which differ slightly in their vocalisations, and are quite divergent, genetically.

The preferred habitat of the Australian raven includes open woodlands and transitional zones, in addition to cities and towns; it has adapted well to human settlements and other urban environments, and is a commonly sighted bird in several major cities, including Sydney, Canberra, Perth, Adelaide and Brisbane. The Australian raven is territorial, with pairs generally bonding for life. Breeding takes place between July and September, with almost no variation across its range. The nest is a bowl-shaped structure of sticks sited high in a tree, or occasionally in a man-made structure such as a windmill or other building.

An omnivorous and opportunistic feeder, the Australian raven eats a wide variety of plant and animal material, from fruits and seeds to lizards, chicks of other bird species, and small mammals; they will also scour waste bins and disposal sites for human food waste, such as various produce, meats, seafood, eggs, etc. The ravens living in eastern Australia are often associated with sheep farms, and have been blamed for the killing of lambs; however, this is an exceedingly rare occurrence, as the ravens are likely seeking the afterbirth from ewes that may have recently given birth. Additionally, ravens aid in environmental "cleanup"—much like vultures on other continents—by helping rid the area of potentially dangerous pathogens which could deploy on carrion, stillborn farm animals (or other deceased mammals and birds), even scavenging newborn mammalian faeces.

Taxonomy and naming

The Australian raven was first described by Nicholas Aylward Vigors and Thomas Horsfield in 1827, when they reported George Caley's early notes on the species from the Sydney district. Its specific epithet ''coronoides'' "crow-shaped" is derived from the Greek ''corone''/κορόνη "crow" and ''eidos''/είδος "shape" or "form". The two naturalists regarded the Australian raven as very similar in appearance to the carrion crow (''C. corone'') of Europe, though they noted it was larger with a longer bill. They did not give it a common name. The location where the type specimen was collected is not recorded, but thought to be in the Parramatta district. Christian Ludwig Brehm described ''Corvus affinis'' in 1845, later determined to be this species. In his 1865 '' Handbook to the Birds of Australia'', John Gould recognised only one species of corvid in Australia, ''Corvus australis'', which he called the white-eyed crow. He used Johann Friedrich Gmelin's 1788 name, which predated Vigors and Horsfield's description. In 1877 Richard Bowdler Sharpe recognised two species, but recorded that the feather bases of the type specimen of ''C. coronoides'' were white. He named ''C. coronoides'' as the "crow" and ''C. australis'' (as ''Corone australis'') the "raven". Scottish naturalist William Robert Ogilvie-Grant corrected this in 1912 after re-examining the type specimen, clarifying the species as ''C. coronoides'' (raven, and incorporating little and forest ravens) and ''C. cecilae'' ( Torresian crow).

Gregory Mathews described the western subspecies ''perplexus'' in 1912, naming it the southwestern crow and noting that it was smaller than the nominate subspecies. He called ''C. coronoides coronoides'' the eastern crow, listing its range as New South Wales, and described what is now the Australian crow as another subspecies, ''C. coronoides cecilae'', calling it the north-western crow and recording its range as northwestern Australia. In the same work he listed the raven as ''Corvus marianae'', with a type specimen from Gosford and listing its range as New South Wales. He listed the little raven and forest raven as subspecies. Mathews had erected ''C. marianae'' in 1911 as the name after declaring ''Corvus australis'' Gould to be preoccupied; French-American ornithologist Charles Vaurie acted as first reviser under Article 24 of the International Code of Zoological Nomenclature (ICZN) Code and discarded ''C. australis'' as a junior homonym—in 1788, Gmelin had used the same binomial name to describe the black nunbird—to preserve the stability of the name. This has been followed by later authors.

German ornithologist Erwin Stresemann lumped all Australian corvids plus other species as far as India into a single species, ''C. coronoides'', as he believed there was intergradation between all characteristics such as iris colour, colour of feather bases and plumage. This was hotly disputed by Mathews. The official RAOU checklist listed three species (Australian raven, Torresian crow and little crow), with the little raven recognised as a fourth species in 1967 and forest raven in 1970. Stresemann described ''C. difficilis'' in 1943 from a single specimen, now thought to have been an unusual Australian raven or an Australian raven/Torresian crow hybrid.

"Australian raven" has been designated the official name by the International Ornithologists' Union (IOC). Alternative names sometimes seen include southern raven, southern crow and Kelly, the last thought to have alluded to the Kelly Gang, though did not appear until the 1920s. Southern crow was considered by the RAOU before Australian raven was adopted as the official name for the species in 1926. The term "crow" is colloquially applied to any or all species of Australian corvid. The Australian raven was called ''wugan'' by the local Eora and Darug inhabitants of the Sydney Basin.

Evolution and systematics

The Australian raven's closest relatives are the other two species of raven occurring in Australia: the little raven and forest raven. The Australian raven is also somewhat closely related to the Torresian and little crow, although not as closely related as it is to the other raven species. Initial single gene genetic analysis of the genus using mitochondrial DNA showed the three raven species to belong to one lineage and the two crows to another. The genetic separation between species is small and there was a suggestion the little raven may be nested within the Australian raven, though the authors conceded more genetic work was needed. Subsequent multigene analysis using nuclear DNA by Jønsson and colleagues in 2012 showed the eastern and western subspecies of the Australian raven to form two clades, almost as genetically distinct as the forest and little raven are to each other. This led the authors to propose that the subspecies be recognised as separate species.

Ian Rowley proposed that the common ancestor of the five species diverged into a tropical crow and temperate raven sometime after entering Australia from the north, which molecular evidence indicates occurred in the early Pliocene

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