Interior Least Tern (Sterna antillarum)

(Federally listed as Endangered)


Interior Least Tern
Description: The Least Tern is the smallest North American member of the gull and tern family. The Least Tern it is a slender, streamlined bird with a white breast and belly, a gray back and long, narrow, pointed wings. It has a forked tail and a straight, pointed beak that is usually a deep yellow color. Least Terns feed on small fish that they catch near the surface of the water.

Habitat: Terns live along large rivers and may sometimes be found hunting fish in shallow wetlands and the margins of ponds and lakes. Least Terns require bare sand and gravel for nesting and typically nest in small colonies consisting of two to 20 pairs along large rivers on sand bars and scoured bends. Colonies also occur on salt flats such as the large one at Salt Plains National Wildlife Refuge.

Current and Historic Distribution: The Least Tern is a rare species and is found in Oklahoma during the late spring and summer breeding season (mid-May through late August). In Oklahoma, Least Terns may be found on portions of the Arkansas, Cimarron, Canadian and Red rivers. Outside of Oklahoma, Least Terns occur along the Atlantic and Gulf coasts of the U.S., as well as on several wide, sandy rivers in Great Plains such as the Missouri, Platte and Yellowstone. In the fall, all Least Terns migrate south to spend the winter in the Caribbean and the northern coast of South America.

Reasons for Decline: Widespread loss and alteration of its riverine nesting habitat has eliminated the Least Tern from many locations within its former breeding range in the interior U.S. The construction of large reservoirs has permanently submerged some nesting areas and has altered the season flooding dynamics that are required to build and sustain the sandbars that the terns need for nesting. Additionally, recreational vehicle use and other disturbances around nesting colonies has reduced nesting success and reproduction.


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