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The common grasshopper warbler (''Locustella naevia'') is a species of Old World warbler in the grass warbler genus ''Locustella''. It breeds across much of temperate Europe and western Asia. It is migratory, wintering in north and west Africa. This small passerine bird is found in short dense vegetation, often close to water. It is a medium-sized warbler about long. The adult has a streaked brown back and whitish grey underparts which are unstreaked except on the undertail coverts. The sexes are identical, as with most warblers, but young birds are yellower below. Like most warblers, it is insectivorous. Four to seven eggs are laid in a nest on or near the ground in thick vegetation or in a tussock of grass. This is a species which skulks in the undergrowth, creeping through bushes and low foliage, and which is very difficult to see except sometimes when singing from a prominent position. The song, which gives this species its name, is a monotonous mechanical insect-like reeling, often given at dawn or dusk. ==Description== The adult common grasshopper warbler (the name is the IOC recommended English name〔Gill, Frank, and Minturn Wright, ''Birds of the World: Recommended English Names''; Princeton University Press, 2006, p. 154.〕) has a length of about . It is a very secretive bird and seldom seen, but its presence is easily detected because of its characteristic song.〔 The upper-parts are pale olive-brown, each feather having a central darker brown streak. The cheeks are greyish, the irises are brown and there is a faint eye streak behind the eye. The upper mandible of the beak is dark brown and the lower mandible yellowish-brown. The underparts are cream-coloured or yellowish-buff with a few dark brown spots and streaks on the breast and flanks. The wings are brown with the outer edge of the feathers rimmed with paler brown. The tail feathers are reddish-brown with faint transverse bars being visible in some individuals and the under-tail coverts are streaked. The slender legs and the feet are pale yellowish-brown. The song is an unmusical long, high-pitched reeling trill performed with beak held wide open and the whole body vibrating. It lasts for from a few seconds to two or three minutes with hardly a pause for breath. It varies in volume from a faint hum to a sound resembling a distant mowing machine. It is performed at any time of day from early morning until after the sun has set and is constantly to be heard from the arrival of the bird in spring until late July. The alarm call is a repeated ticking noise that has been rendered as "twkit-twkit-twkit". 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「common grasshopper warbler」の詳細全文を読む スポンサード リンク
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