BOSTWICK, Kimberly; Cornell University: How do the feathers of the Club-winged Manakin (Aves: Pipridae) produce a sustained note composed of integer-related harmonics?

In 1871 Darwin noted that in the context of intense sexual selection during courtship displays the anatomy of male birds was occasionally modified to enable the production of non-vocally produced acoustic signals, or sonations. He used as an example Machaerotperus deliciosus (Pipridae), the Club-winged Manakin, knowing only of the most superficial of its morphological modifications� wing-feather rachi that were thickened and club-shaped. Recent research has shown that the Club-winged Manakin produces a sustained (.3 s) note composed of the integer harmonics of a fundamental frequency. In this talk I describe the sound, and report the results of digital high-speed video recordings made in remote field settings which has allowed the discovery of a unique mechanism of sound production in vertebrates; the Club-winged Manakin has evolved a suite of traits more typical of insects to enable the production of an acoustically unique, feather-produced sound. I use computer- and field-generated video to describe the morphology and the kinematics of sound production, and discuss the likelihood of stridulation as the physical mechanism of sound production in this species.