Chapter 9 - Locomotion

Abstract

The chapter describes some locomotory patterns in petrels. There are many references scattered in literature, little on movements on land or under water, and much remains unclear. Klemm (1969) analyzed the hind-limb musculature and its function in standing, walking, running and burrowing, Pennycuick in the 1980s looked at petrel flight dynamics. Standing, walking, running, burrowing, and swimming on the surface and beneath have been observed. The petrels that are best able to stand erect for quite long periods are the albatrosses, the giant petrels and Pagodroma nivea. Their center of gravity lies over their large webbed feet with the lower parts of the legs forming straight lines below them. Albatrosses and giant petrels have a pigeon-toed digitigrade gait, shifting their weight at each step like a goose, to keep a leg below the body. On unimpeded flat ground giant petrels can sprint, wings flailing, about as fast as a man can run. The section on flying includes information on flight around the breeding colonies, alighting and taking off. Flight mechanics are analyzed focusing on dynamic and slope soaring, flap-gliding, flapping, hovering, glide-running, flight direction, and wind conditions. Petrel aerodynamics are discussed, providing information on wing areas and loadings, wing shapes and aspect ratios, flight speeds, disc loadings, flight ranges, glide ratios, and power requirements for flights.