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The forest raven (''Corvus tasmanicus'', also commonly known as the Tasmanian raven) is a passerine bird in the family Corvidae native to Tasmania and parts of southern Victoria, such as Wilsons Promontory and Portland. Populations are also found in parts of New South Wales, including Dorrigo and Armidale. Measuring in length, it has all-black plumage, beak and legs. As with the other two species of raven in Australia, its black feathers have grey bases. Adults have white irises; younger birds have dark brown and then hazel irises with an inner blue rim. New South Wales populations are recognised as a separate subspecies ''C. tasmanicus boreus'', but appear to be nested within the Tasmanian subspecies genetically. The forest raven lives in a wide variety of habitats in Tasmania but is restricted to more closed forest on mainland Australia. Breeding takes place in spring and summer, occurring later in Tasmania than in New South Wales. The nest is a bowl-shaped structure of sticks sited high in a tree. An omnivorous and opportunistic feeder, it eats a wide variety of plant and animal material, as well as food waste from urban areas and roadkill. It has been blamed for killing lambs and poultry and raiding orchards in Tasmania, and is unprotected under Tasmanian legislation. The forest raven is sedentary, with pairs generally bonding for life and establishing permanent territories. ==Taxonomy and naming== John Latham described the "South-Seas raven" in 1781, with loose throat feathers and found in "the Friendly Isles" in the South Seas, but did not give a binomial name. Although "the Friendly Isles" refers to Tonga, the specimen resembles what is now known as the forest raven and was collected by ships' surgeon William Anderson on the third voyage of James Cook in January 1777. Tasked as the expedition's naturalist, Anderson collected many bird specimens but had died of tuberculosis in 1778 before the return home. Many collection localities were incorrect, and notes were lost or pieced together many years later. German naturalist Johann Friedrich Gmelin gave the species the name ''Corvus australis'' in the 13th edition of ''Systema naturae'' in 1788. Since Australia was settled by Europeans, all species of crows and ravens have been colloquially known as crows by the general population and are difficult to distinguish.〔 In his 1865 ''Handbook to the Birds of Australia'', John Gould noted a single species of corvid in Australia, ''Corvus australis'', which he called the white-eyed crow. He used Gmelin's 1788 name, which took precedence by virtue of its age over Vigors and Horsfield's description. In 1912 Scottish naturalist William Robert Ogilvie-Grant clarified the species as ''C. coronoides'' (raven, and incorporating little and Australian ravens) and ''C. cecilae'' (Torresian crow). Subsequently, French-American ornithologist Charles Vaurie acted as First Revisor 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. Gregory Mathews described the forest raven as a distinct subspecies—''Corvus marianae tasmanicus''—of the Australian raven in 1912, its species name derived from Tasmania, the type locality. Rowley raised the forest raven to species rank in 1970, noting there were no intermediate forms between it and the little raven (its closest relative) and that it was clearly larger with a much more massive bill. He described a second subspecies—''Corvus tasmanicus boreus''—the same year, observing that ''C. tasmanicus'' from Tasmania and southern Victoria has a very short tail compared with individuals from the northern New South Wales population.〔 Rowley gave the species name forest raven in 1970. The term "crow" is colloquially applied to any or all species of Australian corvid.〔 |label2= raven ancestor |2= }} }} }} Preliminary genetic analysis of the genus using mitochondrial DNA showed the three raven species to belong to one lineage and the two crows to another, and that the two lineages are not closely related. The genetic separation between species is small and there was a suggestion the forest raven may be conspecific with the Australian raven. Subsequent multigene analysis using nuclear DNA by Jønsson and colleagues in 2012 clarified that the forest and little raven are each other's closest relative. The northern subspecies ''boreus'' turned out to be nested in the Tasmanian ''tasmanicus'', indicating the populations separated very recently. It is still recognised as a distinct subspecies by the International Ornithological Committee. 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. The raven diverged into the ancestor of the forest and little ravens in the east and Australian raven in the west. As the climate was cooler and dryer, the aridity of central Australia split them entirely as the habitat between became inhospitable. Furthermore, the eastern diverged into nomadic little ravens and, in forested refuges, forest ravens. As the climate eventually became warmer, the western ravens spread eastwards and outcompeted forest ravens on mainland Australia, as evidenced by the forest raven being only found in closed forest refuges on the mainland but in a wider variety of habitats in Tasmania. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Forest raven」の詳細全文を読む スポンサード リンク
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