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The invisible rail, Wallace's rail, or drummer rail (''Habroptila wallacii'') is a large flightless rail that is endemic to the island of Halmahera in North Maluku, Indonesia, where it inhabits impenetrable sago swamps adjacent to forests. Its plumage is predominantly dark slate-grey, and the bare skin around its eyes, the long, thick bill, and the legs are all bright red. Its call is a low drumming sound which is accompanied by wing-beating. The difficulty of seeing this shy bird in its dense habitat means that information on its behaviour is limited. Recorded dietary items include sago shoots and insects, and it also swallows small stones to help break up its food. It is apparently monogamous, but little else is known of its courtship behaviour. The only known nest was a shallow bowl in the top of a rotting tree stump that was lined with wood chips and dry leaves. The two young chicks were entirely covered in black down typical of precocial newly hatched rails. The estimated population of 3,500–15,000 birds and the restricted range mean that the invisible rail is classified as vulnerable by the International Union for Conservation of Nature (IUCN). Habitat loss has occurred through the harvesting of sago and conversion of the wetlands to rice cultivation, and the rail is eaten by local people. The described nest was in an area frequented by local villagers, so the rail may be more adaptable to habitat changes than had been thought. ==Taxonomy== The rails are a large and very widespread family, with nearly 150 species. They are small to medium-sized, terrestrial or wetland birds, and their short bodies are often flattened laterally to help them move through dense vegetation. Island species readily become flightless; of 53 extant or recently extinct taxa restricted to islands, 32 have lost the ability to fly.〔 〕 The invisible rail, first classified by English zoologist George Robert Gray in 1860, is the only member of the monotypic genus ''Habroptila''.〔 The genus name ''Habroptila'' derives from the Greek ''habros'', "delicate, pretty, splendid" and ''ptilon'', "feather, wing";〔, .〕 '' wallacii '' commemorates British zoologist Alfred Russel Wallace. Local names include "soisa", "tibiales" and "rèie".〔 This rail is related to the New Guinea flightless rail, ''Megacrex inepta'', and the chestnut rail, ''Eulabeornis castaneoventris'', all three Australasian genera probably being derived from ''Amaurornis'' ancestors.〔 Storrs Olson argued that the genus ''Megacrex'' was so similar to ''Habroptila'' that ''Megacrex'' should be considered a junior synonym of ''Habroptila'', resulting in two species in the genus. This was further lumped in Sidney Dillon Ripley's 1977 monograph of the Rallidae; he included ''Habroptila'' within the large genus ''Rallus''. This suggestion was, however, not accepted by Gerlof Fokko Mees, who pointed out distinct differences in the shape and structure of the bill. A molecular phylogenetic analysis based on mitochondrial DNA sequence similarity found that ''Habroptila'' is part of evolutionary radiation within the broad genus ''Gallirallus'' that took place around 400,000 years ago in the region. 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「Invisible rail」の詳細全文を読む スポンサード リンク
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