Song: High-pitched "tee-zee-tee-zee-tee-zee", sometimes rising then falling in volume, usually faster than the two-syllabled song of Cape May Warbler. Easily confused with the song of Black-and-White Warbler but less strongly rhythmic and never complex (two or three-parted). Weak song will not carry far. Compare American Redstart, Cape May, Black-and-white, and Blackburnian Warblers.