Meeting Abstract
Hummingbirds are capable of extreme maneuverability and use this maneuverability to defend food resources from encroachment by conspecifics and other potential resource consumers. These competitive intraspecific interactions provide an opportunity to quantify the biomechanical aspects of hummingbird flight performance during ecologically relevant natural behavior. Here we used multi-camera videography to determine the three-dimensional flight trajectories of Ruby-throated Hummingbirds (Archilochus colubris) defending, being chased from and freely departing from a feeder and use these trajectories to compare natural flight performance to earlier laboratory measurements of maximum flight speed, flight force and power requirements. We found that the hummingbirds only rarely approached their maximum flight speeds from previously reported from wind tunnel tests and they never did so in level flight conditions, but rather used gravitational acceleration to boost flight speed. However, measures of acceleration and rates of change in kinetic and potential energy indicate that these hummingbirds likely operated near the maximum of their flight force and aerobic power capabilities. Finally, we found that although birds departing from the feeder while chased did so faster than freely-departing birds, they accomplished this by modulating their kinetic and potential energy gains (or losses) rather than increasing overall power output, trading altitude for speed during escape.
