Petrel (Procellaria), a genus of sea-birds of the family Procellariidæ, which includes the albatrosses, shearwaters, fulmars, and petrels proper, and is allied to the gulls (Laridæ). The true petrels, of which there are eighteen widely distributed species, are long-winged birds of powerful flight; the tail is broad and of medium length; the hind-toe is very small; the claws are narrow and pointed; the bill is short and slender, and the tube-like nostrils are set close together. They are strictly oceanic, and visit coasts and islands only for breeding purposes. The best-known species is the Stormy Petrel (P. pelagica) or Mother Carey's Chicken (q.v.), which is scarcely larger than a lark, and is the smallest web-footed bird known. The head and back are sooty-black, the wings black, with streaks of white, the under surface grayish black, the bill black, and the feet reddish brown. The name Petrel—a diminutive of Peter—refers to its apparent walking on the water, the lightness of its body enabling it to skim up and down the waves, even in a storm, with only enough motion of the wings to keep the feet from sinking under the surface. Because of its frequent occurrence before or during stormy weather, when the molluscs and other animals upon which it feeds are driven to the surface, and possibly also because of its blackness, it is regarded by sailors as a bird of evil omen.
Its flesh is so oily that the Faroe islanders, it is said, draw a wick through the body to make a lamp. See FULMAR.