Meeting Abstract
Birds frequently fly short distances as they forage among and within trees. Many small birds also exhibit bounding behavior during these low speed flights. While it is generally accepted that bounding at high speeds is used to save energy, it is still unclear why bounding is also observed at slower speeds. Takeoff and landing are particularly critical for foraging flights, but very few studies have quantitatively studied the transition of force generation from the legs to the wings. No studies have done so through the direct measurement of the aerodynamic forces produced in flight. By utilizing a new aerodynamic force platform (AFP), we can now directly quantify all of these forces for freely flying birds. We used this novel setup to study the perch-to-perch flight of a generalist bird, the Pacific parrotlet, over various distances and inclinations characteristic of foraging flight. Our time-resolved force measurements show how weight support generated by their legs and wings vary during these flights. When perches were set further apart, the parrotlets exhibited a brief bounding phase in flight. Aerodynamic weight support from the wings was predominately generated during each downstroke, with little to no weight support generated during upstrokes and bounds. Combining these in vivo force measurements with kinematic analysis provides further insight into how birds use their legs and wings to generate weight support, and when and why they may use bounding flight.
