期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2003
卷号：100
期号：12
页码：7372-7376
DOI：10.1073/pnas.1232227100
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Pure-tone song is a common and widespread phenomenon in birds. The mechanistic origin of this type of phonation has been the subject of long-standing discussion. Currently, there are three hypotheses. (i) A vibrating valve in the avian vocal organ, the syrinx, generates a multifrequency harmonic source sound, which is filtered to a pure tone by a vocal tract filter ("source-filter" model, analogous to human speech production). (ii) Vocal tract resonances couple with a vibrating valve source, suppressing the normal production of harmonic overtones at this source ("soprano" model, analogous to human soprano singing). (iii) Pure-tone sound is produced as such by a sound-generating mechanism that is fundamentally different from a vibrating valve. Here we present direct evidence of a source-filter mechanism in the production of pure-tone birdsong. Using tracheal thermistors and air sac pressure cannulae, we recorded sound signals close to the syringeal sound source during spontaneous, pure-tone vocalizations of two species of turtledove. The results show that pure-tone dove vocalizations originate through filtering of a multifrequency harmonic sound source.
