Meeting Abstract
54.1 Sunday, Jan. 5 13:30 Mechanics of Escape Maneuvers in Hummingbirds CHENG, B*; TOBALSKE, BW; HEDRICK, TL; POWERS, DR; WETHINGTON, SM; DENG, X; Purdue Univ.; Univ. of Montana; Univ. of N. Carolina; George Fox Univ.; Hummingbird Monitoring Network; Purdue Univ. chengbograd@gmail.com
We undertook the present study to begin to compare control strategies for flight maneuvers in small vertebrates and insects. Escape maneuvers of four species of hummingbirds that vary in body mass and wing and tail morphology (Blue-throated, 8 g; Magnificent, 8 g; Black-chinned, 3 g; Broad-billed, 3 g) were recorded and analyzed. The maneuvers were initiated by startling the hovering hummingbirds during feeding. Despite the differences in body morphology and wingbeat frequency, for all the species, the maneuvers consist of rapid pitch-roll body rotations, accompanied by minor yaw rotation. Specifically, hummingbirds start with major nose-up pitching and yawing to the direction of turn, which is followed by rolling and pitching back to the normal flight posture (hover or forward flight). The pitching direction maintained nose-up throughout the maneuver despite the changes in rolling and yawing. Such a rotation sequence results in a global yaw turn and body translation away from the feeder. Average yaw rate reaches about 1500 degs/s for blue-throated hummingbirds, while the peak pitch and roll rates reach 2000 degs/s and 3000 degs/s, respectively, substantially higher than those observed in escape maneuvers in hawkmoths. Blue-throated and Magnificent hummingbirds show conspicuous wing kinematic changes during the maneuver, including wingbeat frequency and asymmetry in the left and right wing deviation angles. Average wing kinematics during up and down strokes correlate strongly and linearly with the body angular velocities during maneuvers. For example, roll rate correlates with the difference in left and right wing deviation during downstrokes (p<=0.006); and pitch rate correlates with the magnitude of downstroke wing velocity (p<= 0.0009). NSF CMMI-1234737.
