MORGAN, S. M. *; ASHLEY-ROSS, M. A.; ANDERSON, D. J.: Foot Morphology and Water-bounding in the Nazca Booby

Nazca Boobies (Sula granti) have totipalmate feet, meaning they have webbing between all four of their toes. These birds use their unique feet in several aspects of their biology, including aiding them in taking off from the water after feeding. Birds in the study colony on Isla Espanola, Galapagos, Ecuador suffer naturally occurring damage to the webs of their feet. Birds with varying amounts of damage to their feet were caught and filmed with a video camera taking off from water. We discovered from the film that these birds actually bound across the water, stepping with both feet simultaneously, instead of running, stepping with one foot and then the other. From the video we measured time to take-off, bounds per minute, velocity, and air speed of each of the birds. Across all birds, mean time to take-off was 2:12 s, mean bounds per minute was 4.4 bounds, mean velocity was 0.15 m/s, and mean airspeed was 2 m/s. Birds with more foot web damage averaged a lower airspeed.