Song ranging by the dusky antbird,Cercomacra tyrannina: ranging without song learning

In a population of dusky antbirds (Cercomacra tyrannina), less aggressive responses to distance-degraded playbacks than to undegraded playbacks of pair duets show that this tropical suboscine passerine uses sound degradation to range distance from singing conspecifics. This is the first example of song-ranging in a species that does not learn songs, supporting the hypothesis that ranging preceded the song learning that occurs in more recently evolved passerine birds (oscines). Both sexes sing and are able to use song degradation to range distance from singers when their sex-specific song is played back. Received: 27 May 1994/Accepted after revision: 24 March 1996