Issues: Wildlife

Least Tern (Interior Population)

SCIENTIFIC NAME: Sterna antillarum

STATUS: Endangered

HABITAT: Sparsely vegetated sand and gravel bars within wide, unobstructed river channels; salt flats along lake shorelines

LIFE HISTORY: Seasonally monogamous; nest in colonies in mudflats and on sandbars and sandy beaches. Thrives in areas where natural fluctuation of water levels occurs.

THREATS: Loss of nesting habitat due to hydro-management projects; nesting disturbance due to human recreation

FORMER RANGE: Montana to Texas, eastern Colorado to southern Indiana along the Mississippi, Red and Rio Grande river systems and rivers of central Texas

CURRENT POPULATION: About 5,000

Explorer Meriwether Lewis collected two of these black-capped birds from the hundreds he spotted nesting in sandbars in the Missouri River in 1804, writing, "This bird is very noysey when flying which it dose exttreemly swift. It has two notes one like the squaking of a small pig only to reather a high kee, the other kit'-tee', -kit'tee' as near as letters can express the second."

Decades after Lewis and Clark's journey, American engineers began damming, deepening and diverting the Missouri and other Midwestern rivers, swallowing tern nesting sites in the process. As their sandbar habitat disappeared, the bird's population plummeted, not only in the Great Lakes but around the rivers of the mountain West and the Southeast as well.

The least tern was declared endangered in 1985. Endangered Species Act protections for the least tern have since helped preserve thousands of acres of riverine habitat from development.

Photos: Isle Royale National Park © William Walsh; Indiana bat © USFWS; Canadian lynx © Erwin and Peggy Bauer, USFWS; least tern © Ryan Hagerty, USFWS