Petrel, any bird of the widely-distributed genus Procellaria, the number of species of which differs in various classifications. They are small oceanic birds of dusky plumage, rarely visiting land. except to breed, and seemingly delighting in storm, whence sailors consider them birds of ill omen. They have great powers of flight; the hind toe is rudimentary, and the nostrils, as in all the group (Tubinares), tubular. The best known species, the Stormy Petrel (P. pelagica), resembles a swift in general appearance, and is sooty-black in colour, with some white on the wings and tail. The name Petrel (= "little Peter") refers to the action of these birds, which often hover just above the surface, as if walking on the water.