The storm petrel nests in crevices and burrows, sometimes shared with other seabirds or rabbits, and lays a single white egg, usually on bare soil. The adults share the lengthy incubation and both feed the chick, which is not normally brooded after the first week. This bird is strongly migratory, spending the Northern Hemisphere winter mainly off the coasts of South Africa and Namibia, with some birds stopping in the seas adjoining West Africa, and a few remaining near their Mediterranean breeding islands. This petrel is strictly oceanic outside the breeding season. It feeds on small fish, squid, and zooplankton, while pattering on the sea's surface, and can find oily edible items by smell. The food is converted in the bird's stomach to an oily orange liquid, which is regurgitated when the chick is fed. Although usually silent at sea, the storm petrel has a chattering call given by both members of a pair in their courtship flight, and the male has a purring song given from the breeding chamber.