Feeding Behavior

Forages while swimming underwater. Does most foraging within 50' of surface, but can dive to about 200'.

Eggs

One (rarely 2, probably laid by 2 females). White, sometimes faintly marked with brown, purple. Incubation is by both sexes (female may do more), 36-45 days, usually 39-42. Young: Both parents feed nestlings, carrying fish in bill; may feed fish directly to young at first, later drop them on floor of nest. Young leave nest usually 38-44 days after hatching; usually leave at night, flying directly out to sea.

Young

Both parents feed nestlings, carrying fish in bill; may feed fish directly to young at first, later drop them on floor of nest. Young leave nest usually 38-44 days after hatching; usually leave at night, flying directly out to sea.

Diet

Fish, crustaceans. Food brought to young in nest is mostly small fish, especially sand lance, herring, capelin, cod, many others. Diet of adults (especially in winter) poorly known; in addition to fish, may include many crustaceans (such as euphausiid shrimp, mysids, copepods) as well as mollusks and marine worms.

Nesting

Usually first breeds at about 5 years. Breeds in colonies. Birds often have same mates each year. In courtship, male repeatedly flicks head up and back so that bill points up; may continue for minutes. Members of pair swing bills sideways, clashing them together repeatedly. Nest site is in burrow 3-7' long, or in natural crevice or under rocks. Sometimes one entrance leads to side branches and multiple nests. Both sexes help excavate. Nest in chamber in burrow usually has sparse lining of grass, feathers.