Meeting Abstract
The avian vocal organ, the syrinx, gives rise to highly diverse vocal behavior. While gross anatomy and syringeal muscles of the syrinx have been studied for centuries, relatively little is known of how syringeal morphology relates to function. Histological composition of the labia, the sound producing structures of the syrinx, plays an integral role in phonation. In addition to their size and muscular control, the composition and orientation of elastic proteins of the extracellular matrix significantly impacts acoustic features of the generated sound. Current histological data describing oscine syringes indicate a positive and nonlinear correlation between spectral range and histological complexity of the labia. Here we present data on the diversity of syringeal histological composition within suboscine families (22 species representing 5 families), and compare this diversity to that found in oscines (7 species). We then relate morphological characteristics to the acoustic features in the respective vocal repertoires and test the hypothesis that vocal learning and vocal motor control is associated with morphological complexity, which we assessed through tracheosyringeal nerve cuts. The range of acoustic features of specific vocal repertoires is bounded by morphological features, and characteristic acoustic features can arise from morphological specializations. Motor control enables regulation of spectral and other acoustic features within the morphologically determined boundaries.
