Bird Dynamic Soaring

Quite different physical principles underlie the soaring flight of seabirds, such as albatrosses, large petrels, and shearwaters. There are no thermals or updrafts over large bodies of water, only horizontal gusts of wind. The air masses that these gusts drive before them are slowed by friction at the water surface, and their speed is consequently slower than in higher altitudes. These seabirds have developed a type of soaring and gliding that does not depend upon the presence of either thermal or obstruction currents.