Meeting Abstract

72.5  Thursday, Jan. 6  Visual stabilization during hummingbird flight GOLLER, B.*; ALTSHULER, D.L.; Univ. of California, Riverside; Univ. of California, Riverside bgoll001@ucr.edu

Animal visual systems provide important feedback used for target localization, distance measurement, and the maintenance of stability during flight behavior. Both insect and avian flyers rely heavily on visual cues, but most of the studies of control circuits and visual control programs have concentrated on insect systems, leaving avian visual control of flight a largely unexplored field. We used the hummingbird as a study system to investigate the vertebrate response to several types of visual stimuli known to elicit robust responses in insects. By exposing hummingbirds to moving linear gratings, poles of expansion and contraction, and rotating patterns during hovering flight, we could assess the importance of these background motions on hovering and the maintenance of stability. Gratings and linear patterns did not produce a measureable response, however we found a strong response to rotating spirals, which create a constant-luminance expansion or contraction. Expansion elicited an increasing avoidance response up to 0.5 Hz rotational frequency, while the contraction response was strong but approach flight was physically limited by the feeder. In conclusion we have shown that one way hummingbirds stabilize hovering flight during short feeding bouts is to compensate for background visual expansion and contraction. Additional psychophysical studies will add to an understanding of avian visual-motor control pathways and will allow further, more robust, comparisons between insects and vertebrates.