BERG, A.M.*; BIEWENER, A.A.; Harvard University; Harvard University: Differences among Ascending, Level, and Descending Flapping Flight

Rock pigeons (Columba livia) flew along paths of varying angles of ascent and descent. Flights at angles of 60, 30, 0, -30, and -60 degrees were recorded with high-speed video. Kinematic marks were then digitized. During ascending flight, pigeons exhibited greater angles of excursion and greater wingbeat frequency relative to level flight. Flight velocity and angle of attack did not change with increasing ascent angle. When the birds descended, they showed lower angles of excursion and lower angles of attack during most of downstroke. Pigeons flew faster when descending, though wingbeat frequency did not differ from level flight. Kinematic patterns suggest that pigeons use wingbeats with tip reversal during ascending flight and wingbeats with feathered upstrokes during descending flight.