Least Tern

Amazing Facts About the Least Tern

• The smallest of American Terns, the Least Tern is found nesting on sandy beaches along the southern coasts of the United States and up the major river systems far into the interior of the continent.
• The tapered, pointed wings, back, and forked tail are grayish in color. The slender body has a gray mantle and snowy white undersides.
• Least Terns can be distinguished from all other terns by their small size and combination of a black crown and eye stripe with a white forehead.
• The pointed bill is yellow with a black tip during the breeding season but changes to a dusky gray, blackish, or dull yellow-orange color outside of full Definitive Alternate (adult breeding) plumage.
• The yellow legs of mature birds are relatively short, with webbed to partially webbed feet.
• First-summer birds are distinguishable by their dark bills and legs, with a black line though the eye, and a dark shoulder bar.
• The Least Tern is migratory, wintering in Central America, the Caribbean and northern South America. Many spend their whole first year in their wintering area.
• Least Terns eat mainly fish, although invertebrates such as crustaceans and insects are also taken.
• They fish in shallow water, very close to shore, hovering longer than other terns and plunging to the surface, without submerging, to capture their prey.

• Nests are shallow ‘scrapes’ in the sand, soil or gravel, and sometimes under low bushes. Both males and females construct several scrapes, which are formed by sitting on the substrate and kicking their feet while rotating their bodies.
• Colonies of up to 500 seasonally monogamous pairs nest in open areas near fresh or salt water such as on exposed salt or mudflats, river sandbars, or sandy beaches. They have even been known to nest on graveled rooftops!
• Within two days of nest construction, two or three eggs colored similarly to the ground (beige to light olive-brown hues, with brown or black splotches) are laid.
• During excessively hot weather, parents may soak their bellies in water and drip it onto the eggs, or chicks, as a method of cooling them.
• At 2 days of age, the young are capable of leaving the nest.
• The young experience their first flight at about 20 days of age.
• The parents stay with the young until autumn migration. During the late summer, before migrating south, adults and young congregate at prime fishing sites along waterways, then move south in small, loose groups which follow major rivers and coasts, feeding along the way.
• Usually leaving breeding areas in late summer or early autumn, birds winter in Central and South America, though rarely, some birds may remain on the Pacific and Gulf shores.