Our group works on the biomechanics, energetics, and evolution of animal flight. Flight performance is investigated in the laboratory using high-speed three-dimensional videography, metabolic measurements, particle-imaging velocimetry, and physically variable gas mixtures.  We are particularly interested in hummingbird biomechanical and metabolic responses to various forms of aerodynamic challenge (e.g., flight in rain and turbulence, flight through vegetation), and in the use of robotic models to investigate the gliding origins of flight in birds and insects.  Laboratory studies of flight biomechanics are complemented by fieldwork to evaluate high-altitude adaptations of volant taxa (e.g., Andean hummingbirds, bumblebees in the mountains of western Sichuan), the ecophysiology of long-distance flight (migrant butterflies in Panama), and controlled aerial behaviors in wingless hexapods of the tropical rainforest canopy.