Least Tern (Sterna antillarum)

Special Segments Butterflies of North America Conifers of North America Eastern Birds List of N.A. Insects Home Eastern Wildflowers General Topics Natural History Ecology Family Environment Evolution Home Education Home Conservation Geophysics Paleontology Commercial Organizations

Purchase

A Field Guide to Eastern Birds. by Roger Tory Peterson.

Return to Eastern Gulls and Terns

Color Photograph: © by and courtesy of John Cassady

Color Photograph: U.S. Army Corps of Engineers

Least Tern (Sterna antillarum)

Identification: Length from tip of bill to tip of tail 8 to 10 inches.

Adult: A small tern with a white head, black crown, and a distinctive black line running from the back of the crown to the base of the bill. Bill dark yellow with a black tip. Undersides white. Back and wings gray with the leading edge of the outer half of the wing black. Tail shallowly forked. Legs yellow-orange.

Immature: Similar in size to the adult, but back and wings gray-brown, heavily mottled. Head without a black crown and with only an indistinct gray line running through the eye. Bill dark.

Similar Species:  The combination the Least Tern's small size, the black line through the eye, and the black leading edge of the wing will easily separate this species from other North American terns.

Breeding Range (see map below): The Least Tern has a spotty and rare distribution in North America. It breeds along the Atlantic and Gulf Coasts as well as the California coastline. The species also breeds in colonies in the Mississippi River Basin.

Overwintering Range:  This species overwinters along the Pacific Coasts of Mexico, Central, and South America.

Habitat: The Least Tern breeds on sandy and rocky beaches along the coastlines and on sandbars in the interior. Least Terns are sometimes seen in landfills and garbage dumps.

Food: Mostly small fish, but aquatic invertebrates and refuse sometimes also eaten.

Behavior: The Least Tern is a rare species and is on the U.S. Endangered Species List. Its habit of breeding on sandbars makes it vulnerable to the loss of whole colonies during flooding. The voice is a sharp series of paired notes.

Reproduction:  The clutch consists of 2 to 3 brown-spotted tan eggs. The eggs are laid in a depression in the sand. Nests in colonies.