The White Tern, also known as the Common Fairy-Tern or White Noddy, nests on islands throughout tropical and subtropical oceans of the world. In the Hawaiian Archipelago, it is a common breeder in northwestern refuge islands, with a small population also on O'ahu Island.
This striking all-white tern constructs no nest. Instead, it lays its single egg, often delicately balanced, on a branch, building, or rock. Newly hatched chicks have well-developed feet and claws with which they cling to their perilous nest sites. Adults carry to their chick small fish and squid-often several at a time-in their bills. Adults seem tolerant of disturbance, often rearing their young near human activity.
The White Tern is well suited for life in an oceanic environment of changeable resources and weather. A short relay period after loss of an egg or chick moderates the impacts of storms on population recruitment. Simultaneous waves of feather replacement shorten the time needed to molt, allowing a protracted breeding season that enables pairs to renest several times after nest failures. Some breeding pairs successfully raise 2 broods within a nesting season.
The remoteness of most White Tern nesting islands has limited study of this species, and little is known about the time it spends at sea. Most information on its breeding biology is available from studies at Christmas Island (Pacific), Midway Atoll, and Tern Island, French Frigate Shoals, Hawaiian Archipelago (Ashmole 1968b, Howell 1978, KRN). Studies of diet at Christmas Island and in the Northwestern Hawaiian Islands indicate that prey of appropriate size in surface waters are taken opportunistically (Ashmole and Ashmole 1967b, Harrison 1983b). Information on molt is available from studies at Ascension and Christmas Islands (Dorward 1963, Ashmole 1968b), and hostile and sexual behavior have been studied at Easter Island and at Midway and Johnston Atolls (Moynihan 1962a).