Scientific Name: Sterna dougallii Common Name: Roseate tern Class, Order, and Family: Class Aves, Order Charadriiformes, Family Laridae, Subfamily Sterninae.

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Description: The roseate tern is a seabird of the tern family, and has deeply forked tail feathers that appear like long streamers when the bird is flying. Its head is white on top, black elsewhere, and it has white wings and black legs. The colour of its bill changes during the year: for northeast populations in May, the bill is black, but as the summer progresses during June and July, the bill becomes redder, but turns black again in August. In Caribbean populations, the bill is less than one-half red in May, and becomes mostly red during June and July. The roseate tern is 33-41 cm long, has a wingspan of 72-80 cm, and weighs 90-140 g. The call is a sharp, high-pitched “kir-rick”.

Habitat: This tern breeds on coasts and islands in the tropics, along the Indian, Pacific, and Atlantic Oceans.

Summer Range: The roseate tern breeds from May to late July along the Atlantic Coast from Nova Scotia to New York, the Florida Keys, the Caribbean, Europe, the Indian Ocean, Australia, and western Pacific Ocean. In late July, they move to staging areas for migration to non-breeding grounds in South America.

Winter Range: The winter range of the roseate tern is not well known, as it is unknown where they are from January to April. It is believed to be coastal South America and at sea. They are also around Africa, the Indian Ocean, and the western Pacific Ocean.

Food: The roseate tern eats small fish and some invertebrates. In salt water, they eat sand lance, white hake, juvenile herring, mackerel, gadid, cod, pollock, and haddock.

The roseate tern plunges into water from flight and can even “fly” short distances under water. They prefer to fish in rips, where currents meet, and other turbulent waters. They will steal fish from other terns, but gulls, crows and ravens may also steal fish from them.

Breeding Behaviour: The male roseate tern flies in high circles, carrying a fish, followed closely by one or more females. The male and lead female descend together in a zig-zag glide as part of an elaborate courtship ritual.

It breeds around the globe in tropical oceans and in the temperate zone of the northern Atlantic. The plumage also changes when breeding. The breeding plumage has a solid black cap, light gray back, white tail and rump, white to pale pink underside, red-orange legs, and the all-black bill turns red (from base) during nesting. Most young roseate terns wait until they are three or four to breed, but may breed at only two years of age.

Nest Type and Egg Description The roseate tern nest is a scrape in the ground, hidden under dense grasses and other plants, boulders, or washed-up debris. The eggs are brown with dark speckles and streaks and the clutch size is one to five eggs.

The parents take turns incubating the eggs for 23-24 days. At hatching, the young are downy, have open eyes, and are able to walk but stay in the nest. Because of limited food availability, having two chicks survive to fledging is not typical. Chicks generally fledge when 25-28 days old, leave the colony, but stay with their parents for at least six more weeks while learning to fish on their own.

Conservation Status: The roseate tern is listed as “threatened” by the Canadian Wildlife Service. The northeastern population in the United States is “endangered,” the Caribbean population is also “threatened” and the global status is “near threatened”.

Only three per cent of the population breeds in Canada (the northern limit of the breeding range) and is estimated at fewer than 140 pairs, concentrated on a few islands off the Atlantic Coast of Nova Scotia.

The roseate tern is not abundant anywhere globally and it has suffered major population declines in all parts of the world. Roseate terns have been negatively affected by the explosion of gull populations both from predation by gulls and because gulls occupy their prime nesting areas.

Information on this page compiled by Colleen Sutton.

Sources
BirdLife International. http://www.birdlife.org
Committee on the Status of Endangered Wildlife in Canada. http://www.cosewic.gc.ca/eng/sct5/index_e.cfm
Cornell Lab of Ornithology. All About Birds. http://www.birds.cornell.edu/AllAboutBirds/.
Ehrlich, Paul R. 1988. The Birder’s Handbook. Simon and Schuster, New York.
Godfrey, Earl W. 1986. Birds of Canada. National Museums of Canada, Ottawa.
Hinterland Who’s Who. http://www.hww.ca
Leslie, Scott. 2006. Wetland Birds of North America. Key Porter Books, Toronto. NatureServe. InfoNatura. http://www.natureserve.org/infonatura/

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