We report a male Cerulean Warbler (Dendroica cerulea) singing a highly accurate version of another species' song (Hooded Warbler; Wilsonia citrina), as well as a typical Cerulean Warbler song. We performed playback experiments to examine the manner in which this bird used, and responded to, the different songs. He responded aggressively (wing flicks and garbled song), and with his Cerulean Warbler song, to recorded versions of two different types of Cerulean Warbler songs, including a type that he was not observed singing. He did not respond in any manner to playback of Hooded Warbler song.