Adult male and female zebra finches (Taeniopygia guttata), previously trained with operant conditioning to discriminate between conspecific songs, were tested to determine their dependence on 2 properties of songs, the presence of song syllables and the temporal order of songs. The removal of song syllables disrupted discrimination performance but usually only if the stimulus was the bird's own song. All birds initially failed to identify reversed songs correctly, but males relearned discriminations with reversed songs in fewer trials than did females. The results suggest that there are 3 levels of song perception: a bird's own song, other males' songs as processed by males, and songs as processed by females. Each of these levels correlates with the known electrophysiological and neuroanatomical properties of the song system and with the natural history of song.