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African crake
The African crake (''Crex egregia'') is a bird in the rail family that breeds in most of sub-Saharan Africa away from the arid south and southwest. It is seasonally common in most of its range other than the rainforests and areas that have low annual rainfall. This crake is a partial migrant, moving away from the equator as soon as the rains provide sufficient grass cover to allow it to breed elsewhere. There have been a few records of vagrant birds reaching Atlantic islands. This species nests in a wide variety of grassland types, and agricultural land with tall crops may also be used.
A smallish crake, the African crake has brown-streaked blackish upperparts, bluish-grey underparts and black-and-white barring on the flanks and belly. It has a stubby red bill, red eyes, and a white line from the bill to above the eye. It is smaller than its closest relative, the corn crake; that species is also lighter-plumaged, and has an eye stripe. The African crake has a range of calls, the most characteristic being a series of rapid grating ''krrr'' notes. It is active during the day, and is territorial on both the breeding and non-breeding grounds; the male has a threat display, and may fight at territory boundaries. The nest is a shallow cup of grass leaves built in a depression under a grass tussock or small bush. The 3–11 eggs start hatching after about 14 days, and the black, downy precocial chicks fledge after four to five weeks. The African crake feeds on a wide range of invertebrates, along with some small frogs and fish, and plant material, especially grass seeds. It may itself be eaten by large birds of prey; snakes; or mammals, including humans, and can host parasites. Although it may be displaced temporarily by the burning of grassland, or permanently by agriculture, wetland drainage or urbanisation, its large range and population mean that it is not considered to be threatened.
== Taxonomy ==
The rails are a bird family comprising nearly 150 species. Although the origins of the group are lost in antiquity, the largest number of species and the most primitive forms are found in the Old World, suggesting that this family originated there. The taxonomy of the small crakes is complicated, but the closest relative of the African crake is the corn crake, ''C. crex'', which breeds in Europe and Asia, but winters in Africa. The African crake was first described as ''Ortygometra egregia'' by Wilhelm Peters in 1854 from a specimen collected in Mozambique,〔 but the genus name failed to become established. For some time it was placed as the sole member of the genus ''Crecopsis'' but subsequently moved to ''Crex'', created for this species by German naturalist and ornithologist Johann Matthäus Bechstein in 1803. Richard Bowdler Sharpe considered that the African bird differed sufficiently from the corn crake to have its own genus ''Crecopsis'', and later authors sometimes placed it in ''Porzana'', based on a resemblance to the ash-throated crake, ''P. albicollis''. Structural differences rule out ''Porzana'', and the placement in ''Crex'' is now the most common and best-supported treatment.〔Taylor & van Perlo (2000) p. 30〕〔Livezey (1998) p. 2098〕 Phylogeny and morphology confirm that the ''Porzana'' crakes are the closest relatives of the ''Crex'' genus.〔Livezey (1998) p. 2134〕 The genus name is onomatopoeic, referring to the repetitive grating call of the corn crake, and the species name ''egregia'' derives from Latin ''egregius'', "outstanding, prominent".
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
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