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The American gray flycatcher, or just gray flycatcher (''Empidonax wrightii'') as it is known in North America, is a small, insectivorous passerine in the tyrant flycatcher family. It is common in the arid regions of western North America, especially the Great Basin. From sagebrush steppes to pinyon-juniper woodlands and ponderosa pine forests, this flycatcher forages for insects from shrubs or low tree branches. The gray flycatcher is one of the many species in the genus ''Empidonax''. These species are very similar in appearance and behavior, and they are notoriously difficult to differentiate. The best characteristics for distinguishing these species are voice, breeding habitat, and range. The gray flycatcher, however, can be identified by a unique behavior, its downward tail wag. Other ''Empidonax'' species typically exhibit a rapid upward tail flick. ==Description== Gray flycatchers are small birds, but larger than most ''Empidonax'' flycatchers. A typical adult measures in length, in wingspan, and in mass. Adults have pale gray upperparts, darker on the wings and tail, with a faint olive tinge after molting in fall. Underparts are whitish, but washed slightly with yellow in fresh plumage. They have white wing bars and an inconspicuous white eye ring. There is a pale supraloral band stretching above the base of the bill. Relative to other North American ''Empidonax'' flycatchers, the gray flycatcher has a long, narrow bill, a long tail, and the mandible tends to be paler for more of its length.〔 Juveniles are similar in appearance to adults, but with stronger olive and yellow tones. Also, young birds have buffy wing bars and brownish breasts.〔 Only the male sings. The song is a strong, two syllable note described as ''chuwip'' or ''wilip''. A weaker, higher-pitched ''teeap'' or ''seep'' is often inserted into the song. Both sexes give a dry ''pit'' or ''wit'' call. Females call often when foraging or collecting nest materials.〔Sterling, John C. 1999. Gray flycatcher (''Empidonax wrightii''), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology 〕 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「American gray flycatcher」の詳細全文を読む スポンサード リンク
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