Common Tern (Sterna hirundo) | South Dakota Birds

The Common Tern are so-named because they are the most common tern in much of the Northeastern U.S. In much of the inland portion of the continent, they are outnumbered by the very similar Forster's Tern. They were hunted to near extinction in the 1800s for their "fashionable" feathers, but rebounded in the 1900s. As larger predatory gulls have learned to co-exist with human populations and thrive on their refuse, the Common Tern has once again suffered population declines from predation in the latter half of the twentieth century.

Habitat

Can be found in a wide range of aquatic habitats during the summer breeding months, including coastal and inland waters. Primarily winters along coastlines in tropical regions of South America.

Diet

Primarily feeds on small fish. Also will eat shrimp and other crustaceans, small mollusks, insects, marine worms, squid, and leeches.

Behavior

Primarily feeds by hovering over water to spot prey, and then plunging below the surface to catch it. They are also accomplished thieves and will sometimes steal fish and other prey from other Common Terns or other gull and tern species.

Nesting

June in South Dakota. Common Terns are colonial nesters, using areas near water with a surface of sand, gravel or small pebbles. The nest is a simple scrape on the ground, lined with vegetation, bits of shell or stone, or other material. The female lays between 1 and 3 eggs, and both she and the male help to incubate them. The young hatch from the nest after 21-25 days.

Song

Vocal birds with a variety of calls. Click here to listen to the flight call of a Common Tern (audio courtesy of Jerome Fischer). They also have a harsh descending alarm call (click here to hear it, audio courtesy of Annette Hamann).

Migration

Breeds in much of southern Canada and the northern tier of U.S. states. Most overwinter along the coast of South America, with only small numbers overwintering on the coasts of Central and North America.

Similar Species

Forster's Tern, Arctic Tern

Conservation Status

Numbers are much lower than historical levels due to hunting in the 1800s. Numbers rebounded in the first part of the 1900s, but the expansion in range and numbers of the large predatory gulls in the latter half of the century again caused reductions in their numbers. However, they are still found over a very broad geographic area, and they are common in parts of their range. The IUCN considers the Common Tern to be a species of "least concern".

Common Tern