Adult breeding in flight. Note: white forehead, yellow bill with black tip and two black primaries.
  • Adult breeding in flight. Note: white forehead, yellow bill with black tip and two black primaries.
  • Adult breeding. Note: white forehead and yellow bill with black tip.
  • Juvenile

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Least Tern

Sternula antillarum
This is a large and highly varied group of birds that do not have many outward similarities. Most are water birds that feed on invertebrates or small aquatic creatures. The order is well represented in Washington, with seven families:
The family Laridae is made up of birds closely associated with water. Distributed throughout the world, representatives of this family nest on every continent, including Antarctica. Most are long-lived birds, many of which do not breed until they are three or four years old. Most are colony nesters and nest on the ground. Clutch size is generally small, varying from one to four eggs. Both parents incubate the eggs and help feed the young. The young typically hatch covered with down and stay in the nest for a few days, after which they leave the nest but stay nearby. Most, especially in Washington, raise a single brood a year. This group is known for its elaborate displays in the air and on the ground.

The Washington representatives of this family can be split into two groups, or subfamilies. The adaptable gulls are the most familiar. Sociable in all seasons, they are mainly coastal, but a number of species also nest inland. Many—but not all—are found around people. Gulls have highly variable foraging techniques and diets. Terns forage in flight, swooping to catch fish or insects. They dive headfirst into the water for fish. Although they are likely to be near water, they spend less time swimming than gulls.

    General Description

    This highly migratory New World tern frequents estuaries, coastal lagoons, river sandbars, and sandy beaches, where it attracts attention by its tiny size and buoyant flight. The adult has a black cap, white forehead, gray mantle, white underparts, yellow legs, and black on the outer primaries. The tail is short and forked. In breeding plumage, the black-tipped yellow bill is a diagnostic field mark. Identification of terns in other plumages is less straightforward: consult a good field guide.

    Least Tern has three breeding populations that have been described as distinct subspecies: along the Atlantic and Gulf Coasts from New England south through the Caribbean (S.a. antillarum); along rivers in the central United States (S.a. athalassos); and on the Pacific Coast from San Francisco Bay to western Mexico (S.a. browni). The first two populations winter from the Caribbean to Brazil, while the Pacific population winters along the coast in Mexico and Central America. The breeding populations of Least Tern in California and the interior U.S. are listed as Endangered under the federal Endangered Species Act. Least Tern nests on the ground, where it is vulnerable to predators and to human activity such as beach recreation. The California population had shrunk to 600 pairs by 1973. Protection of its nesting sites—thanks, especially, to an active management program on military installations—led to a population rebound, with 2,750 pairs recorded by 1994.

    Least Terns occur very rarely in the Pacific Northwest as spring migration “overshoots,” non-breeding vagrants, or post-breeding dispersants. Oregon has about 11 records, mostly coastal, between March and mid-August. Washington’s three records are all from coastal Grays Harbor County: Ocean Shores in August 1978 and May 2005 (two birds), and Westport in May 2004. Idaho’s one accepted record is from Sandpoint in March 1988. The single record from British Columbia came at Osoyoos in June 1998.

    Revised June 2007

    North American Range Map

    North America map legend

    Federal Endangered Species ListAudubon/American Bird Conservancy Watch ListState Endangered Species ListAudubon Washington Vulnerable Birds List

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