The role of auditory feedback in the maintenance of song in adult male bengalese finches Lonchura striata var. domestica

Abstract

Young songbirds use auditory feedback to match their own vocalizations with a memorized tutor's song in order to develop their songs normally. After learning, songs of adult birds are stereotyped and remain stable. Recent studies showed that auditory feedback is necessary for maintaining the stability of adult bird song in some species including Bengalese finches. We deprived adult male Bengalese finches of auditory input by removing their cochleae and acoustically analyzed the songs of the deafened birds. After the operation, song patterns altered within a week and remained unstable for approximately a month. The post-operative songs were finally stabilized within 60 days after the operation, although their patterns were different from those of the pre-operative songs. Compared with the pre-operative songs, syllables with higher fundamental frequencies decreased and those with lower fundamental frequencies increased in the stabilized post-operative songs of all the birds examined. These results suggest that adult male Bengalese finches need auditory feedback in order to maintain their normal songs and that this feedback is involved in retaining the syllables of higher fundamental frequencies. They also suggest that the stabilized post-operative songs consisting of syllables with lower fundamental frequencies may be maintained by other sensory feedback systems.