YANEGA, G; RUBEGA, M; University of Connecticut, Storrs, CT: The hummingbird bill as a utensil for insectivory: prey-capture and transport in the Ruby-throated Hummingbird

While it is generally recognized that hummingbirds require protein derived from animal (arthropod) sources, there have been no prior attempts to quantify the mechanics of insectivory in hummingbirds. The stereotypical bill morphology of hummingbirds is widely thought to be the product of a coevolutionary relationship with plants bearing tubular flowers. To what extent does morphological specialization for nectarivory influence insectivorous performance? We analyzed the feeding mechanics of ten Ruby-throated Hummingbirds offered insect prey in captivity. Kinematics of prey capture and handling were elucidated by frame-by-frame analysis of high-speed video footage. Hummingbirds feeding on fruit flies in captivity frequently failed to capture prey; when they caught them, they frequently failed to transport them along the bill successfully. We found evidence of tongue-based transport of prey, and, surprisingly, flexion in the lower jaw during capture. Our results highlight the trade-offs in prey capture performance in a bird specialized for nectar feeding, and the importance of constraints on the evolution of bill shape in nectivores.