adult, breeding
Gulf Restoration

Least Tern

Photo: James M. Wedge/VIREO

Least Tern

Tiny, spunky denizens of beaches and barrier islands, Least Terns lay their eggs on bare sand. Because they nest in areas hardest hit by oil and where cleanup and response operations were most intense, they faced many challenges during the 2010 breeding season, and this year will be another tough one with lingering oil and cleanup crews walking and driving the beaches. Even before the spill, habitat loss and disturbance by humans had taken a toll on the Least Tern, which is classified Red on Audubon's WatchList.

Both sexes look alike, with a gray back and wings, white underparts, black cap, relatively long, narrow wings, yellow legs, a short, notched tail, and a yellow bill unique among North American terns.

Small fish, crustaceans, and insects are preferred foods; they eat small mollusks and marine worms as well. Least Terns forage over water, hovering briefly before plunging in to catch tiny prey just below the surface; they sometimes dip to pluck prey from the surface or to catch insects in flight.

Least Terns generally nest in colonies. In courtship, a male carrying fish will fly up, followed by the female; both then glide down together. Their nests are shallow scrapes on open sand, soil, or pebbles, occasionally lined with pebbles or grasses. Although they prefer sandy beaches for nesting, they occasionally use flat, gravel-covered rooftops instead. Least Terns lay one to three buff or pale green eggs with dark blotches. Both sexes build nests, incubate the eggs, and care for the young. Incubation lasts slightly over 3 weeks. The downy chicks are able to walk soon after hatching, with their eyes open. A few days after hatching, they move to short vegetation nearby. They begin to fly at just under 3 weeks of age, and may remain with their parents for up to 3 months.