Meeting Abstract
Hummingbirds are stable fliers under a diversity of challenging environmental conditions. In turbulent flow, hummingbirds adjust their wing kinematics on a stroke-by-stroke basis and both incline and fan their tails to improve stability. To better understand how hummingbirds modify their wing and tail motions in response to individual gusts, we filmed Anna’s Hummingbirds as they negotiated an upwards jet of air moving at 10 m/s. As birds entered, flew within, and then exited the gust, they demonstrated a sequence of pitch-up, upwards, and pitch-down motions, respectively. Together, these perturbations frequently caused a dramatic decrease in body angle (i.e., a nose dive) as birds exited the gust. Birds exhibited large variation in average wing elevation, tail pitch, and tail fan angles among trials as they repeatedly negotiated the same gust. After extracting three-dimensional kinematic parameters, we identified those circumstances under which birds used different techniques to negotiate the gust, and determined the effect of each technique on the subsequent trajectory. Finally, we demonstrate that a hummingbird-sized glider with a bio-inspired and passively deflectable tail can successfully negotiate the same gust.
