After dining on fish or other marine animals, cormorants spread their wings in the sun. I'd always thought it was to dry their wings, but there's some controversy. "Some sources state that cormorants have waterproof feathers, while others say that they have water-permeable feathers. Still others suggest that the outer plumage absorbs water but does not permit it to penetrate the layer of air next to the skin. The wing drying action is seen even in the flightless cormorant, but not in the Antarctic shags or red-legged cormorants. Alternate functions suggested for the spread-wing posture include that it aids thermoregulation or digestion, balances the bird, or indicates the presence of fish. A detailed study of the great cormorant concluded there is little doubt that it serves to dry the plumage." MORE PHOTOS