Physiological and biomechanical mechanisms of animal maneuverability

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The goals of my NSERC-funded program are to determine the mechanisms of complex locomotion, and to train HQP from diverse backgrounds in integrative biology. Maneuverability is defined as the capacity to make changes in speed and direction, and is an essential activity that can define the margin between life and death. Whereas most studies on this topic are conducted in steady-state conditions, e.g., treadmills, my work focuses on small birds because they are adept at complex flight within laboratory settings. To date, my Discovery Grant program has focused on biomechanics and has produced a series of high-profile papers. We identified three major aspects of maneuvering that are common to all animals, determined distinct biomechanical associations with each aspect, and developed an experimental approach that can now be applied to studying maneuverability in any animal. My most recent work pointed to a new and critical role for visual signals: self-motion generates a global visual signal termed optic flow, whereas the movements of another individual produces a local signal termed object motion. New techniques are now available that will allow me to ask questions about how these signals influence maneuverability, which was not previously possible. There are three major objectives for the next five years of my Discovery Grant program. The research will focus on solitary Anna's hummingbirds (Calypte anna) and social zebra finches (Taenopygia guttata). Objective 1 is to determine how the natural statistics of optic flow and object motion differ by mode of locomotion, habitat, and the presence of conspecifics. Two MSc students will develop and use head-mounted cameras to record the visual signals reaching the eye of hummingbirds during solitary and competitive flight, and on zebra finches flying solitary and in flocks. Objective 2 is to determine if the responses of visual motion neurons are tuned to species-specific environmental and social signals. A PhD student will use visual signals determined from objective 1 to measure electrophysiological responses of neurons. Objective 3 is to determine if during maneuvering flight, solitary hummingbirds register conspecific birds as "objects" and social zebra finches register a group of conspecifics as "optic flow". One PhD and two MSc students will combine behavioral and neuroscience approaches through virtual reality, gene expression and in vivo electrophysiology. This research will address fundamental questions at the interface of locomotor biomechanics and visual neuroscience. The results of the proposed experiments will also reveal algorithms for encoding specific features of habitats and of other animals in flight. Because these guidance algorithms will have high resolution with respect to both behavior and signal processing, the work will have significant potential to advance robot and drone design for the tasks of navigating complex habitats and collective movement of groups.