HUBER, S.K.; University of Massachusetts, Amherst: Coordination of vocal production and flight in the cockatiel Nymphaticus hollandicus.

The evolution of communication signals in animals may be limited by the proximate mechanisms which underlie signal production, such as energetic constraints on physiological function or evolutionary constraints on morphology. The evolution of flight songs in birds may be constrained by morphological adaptations of the respiratory system that are specific for flight. Therefore, a dynamic relationship between flight and vocal production may exist because of overlapping morphological features that are used in both behaviors. I looked at the relationship between flight vocalizations and wing beat cycles in cockatiels. I flew cockatiels in a wind tunnel and recorded their vocalizations with an audio recorded, and recorded wing movements with a high speed video camera. I found that the cockatiels frequently vocalized while gliding and during flapping flight. Preliminary analyses of high speed video show that beak movements that correspond to a vocalization are coordinated with wing beats (n = 6 observations). The beak opens at the end of the down-stroke, and closes at the end of the up-stroke in a 1:1.5 ratio of beak to wing beat cycles. Because vocalizations are produced during exhalations, this suggests that respiration might be coordinated with wing beats, and that the timing of vocalizations may be constrained by flight.