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The tropical gnatcatcher (''Polioptila plumbea'') is a small active insectivorous songbird, which is a resident species throughout a large part of the Neotropics. There are large geographical variations in its voice and plumage, resulting in some populations sometimes being considered separate species, notably the ''bilineata'' group as the white-browed gnatcatcher, and the taxon ''maior'' as the Marañón gnatcatcher.〔 ==Description== The adult tropical gnatcatcher is long, and weighs .〔 Its "jizz" is similar to that of other gnatcatchers; a small bird with a relatively long thin bill, a long frequently cocked tail, grey upperparts and whitish underparts. The central rectrices are black, while the outer are white (consequently, the tail appears primarily black from above, white from below), and there is a white patch in the wing (caused by broad white edging to the tertials). Males of the nominate group have a contrasting black cap that reaches just below the eye, while this is lacking in females, which instead have a grey cap (same colour as back). Some females have an irregular black post-ocular patch. This is especially prominent in female of the subspecies ''atricapilla'' from north-eastern Brazil.〔 Males of the white-browed gnatcatcher (''bilineata'' group) resemble males of the nominate group, but the white of their underparts extends clearly above the eye, resulting in a more restricted black cap, which, however, often is connected with a fine black line from the nape to the rear of the eye. Females resemble males, but with the black of the cap replaced by grey, except for an irregular black patch in the post-ocular region (lacking in some females). As the white in both sexes extends above the eye, they appear rather "white-browed" (unlike the nominate group), resulting in the common name proposed for this group if considered a separate species.〔 The final group, which only includes the taxon ''maior'' (the so-called Marañón gnatcatcher), is distinctive. Males resemble males of the nominate group, but, except for their white forecrown, females resemble males of the ''bilineata'' group. Juveniles of all groups resemble females.〔 The tropical gnatcatcher has a thin buzzy ''gezzz'' call and a trilled ''swee see see si si si su su'' song. However, exact structure and tone of the voice varies greatly over its range.〔 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「Tropical gnatcatcher」の詳細全文を読む スポンサード リンク
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