lesňáček modrohřbetý Setophaga caerulescens

Striking warbler with vastly different male and female plumages. Males are unique deep blue above with black face and sides and white belly. Females are plain brownish-olive with dingy buffy underparts and subtle face pattern. Always look for small white patch on the wing, lacking only on the dullest immature females. Breeds in the understory of mixed forests, favoring hills with dense vegetation. Found in nearly any wooded or shrubby habitat during migration. Winters primarily in the Caribbean. Listen for lazy buzzy song, usually a series of notes with a final long buzz.