During the winter they migrate to the west coast. They breed in large colonies, usually the nest is a large mound of soil or plant debris on an island or in a marsh. The eggs, one to six, are dull white. The males share the incubation period of four to five weeks. Chicks are altricial and are fed by regurgitation.
Sexual maturity is reached at three to four years.
Predators Gulls are chief predators of eggs or young birds.