 A fibrous layer deep in the breast muscles can hold the wings rigidly horizontal for gliding and soaring . Thus they use thermals for soaring to heights of 3000 m ( 10 @,@ 000 ft ) or more , combined both with gliding and with flapping flight in V formation , to commute distances of up to 150 km ( 93 mi ) to feeding areas . Pelicans also fly low ( or " skim " ) over stretches of water , using a phenomenon known as ground effect to reduce drag and increase lift . As the air flows between the wings and the water surface it is compressed to a higher density and exerts a stronger upward force against the bird above . Hence substantial energy is saved while flying . 
