All species › Waders, gulls and terns › Skimmers, noddies, terns and gulls › Least Tern
Position in the tree Birds Aves › Birds with a flexible palate Neognathae › All other modern birds Neoaves › Birds of the elements Elementaves › Cranes and waders Gruimorphae
Least Tern | Sternula antillarum
Amerikaanse dwergstern | Charrán mínimo
The Least Tern is the smallest tern in the guide area, with a yellow bill and a white forehead triangle in the black cap. It breeds in small colonies on bare beaches, sandbars and salt pans and hunts with rapid, fluttering wingbeats and brief hovering over shallow water before diving steeply after small fish.
Voice
A high, sharp kreet and a rapid, chattering kidik-kidik; very noisy at the colony, diving at intruders.
Recording: Paul Driver — CC BY-NC-SA 4.0 · converted to mono · xeno-canto
Identification
22–24 cm, small, with narrow wings and a short, forked tail. In breeding plumage a black cap with a sharply defined white forehead triangle reaching above the eye, pale grey upperparts and white underparts. The bill is yellow with a black tip, the legs yellow to orange. The two or three outer primaries form a dark leading edge to the wingtip. In non-breeding plumage the bill is black, the forehead broadly white and the cap reduced to a black band across the hindcrown and nape. Juveniles have brown-scaled upperparts, a dark bar on the forewing and a dark bill.
Confusion species
Common Tern Sterna hirundo, Forster's Tern Sterna forsteri and Roseate Tern Sterna dougallii are much larger, with a longer tail and slower flight. Juvenile and non-breeding Black Terns Chlidonias niger are slightly larger, with a dark breast-side patch, a greyer rump and a darker grey back.
Habitat
Beaches, sandbars, lagoons, estuaries, salt pans and shallow coastal lakes, also shrimp farms and ponds near the coast. It breeds on bare, open ground with sand, shells or gravel, locally also on reclaimed land and bare ground around harbours.
Where the bird is most at home, classified by the vegetation units of Mexico and Central America.
Range and movements
Breeds along the Pacific coast of Mexico, from Baja California and Sonora southwards, and on the Gulf side from Tamaulipas to the Yucatán Peninsula; also in Belize. On migration along both coasts of all of Central America to Panama; a few birds winter in the guide area. Outside the guide area the species breeds along the coasts of the United States, along large rivers in its interior and in the Caribbean; birds winter mainly along the coasts of northern South America.
- Summer visitor (c. Apr–Sep)
- dark = core range, pale = thinly spread
How and when to look
In the breeding season at coastal lagoons and salt pans, where birds hover and dive over shallow water, calling loudly. Colonies are best watched from a distance; breeding birds react strongly to disturbance.
Conservation status
Not threatened. Beach nesting sites suffer from disturbance by recreation, free-roaming dogs and cats, vehicles and high water; development of coastal plains and salt pans also removes breeding habitat. Locally, reclaimed land and bare ground provide temporary new nesting sites.
Scientific name
Sternula antillarum | Lesson, 1847
Lesson described the species in 1847 and placed it straight away in the genus where it still stands. The genus Sternula was introduced in 1822 by Boie. Sternula is a Latin diminutive of Sterna and so means 'little tern'. antillarum means 'of the Antilles'; the species was described from Guadeloupe. The specimen the first description was based on came from Guadeloupe.