Song complexity and auditory feedback in birds: a comparison between two strains of Bengalese finches with different degrees of song complexity.

In adult songbirds, the degree of dependency on audition for maintenance of stable song structure varies from species to species. To date, studies suggest that song deterioration after deafening may be related to the song complexity of the species. Bengalese finches sing songs that are composed of complex note-to-note transitions, and their songs are critically dependent on auditory feedback. Song deterioration occurs within five days of auditory deprivation surgery, much faster than in other species. In contrast, white-rumped munias, a wild strain of Bengalese finches, sing simple songs. To test the hypothesis that the degree of dependency on auditory feedback for the maintenance of song structure is related to song complexity, we deafened two adult white-rumped munias by cochlear removal. Songs of white-rumped munias changed in syntax within five days of surgery, a similar trend observed in Bengalese finches. We suggest that real-time auditory feedback is important in white-rumped munias, despite the simplicity of their song structure. The time course of song alteration by deafened adult birds not determined solely by song complexity.