[order] CHARADRIIFORMES | [family] Laridae | [latin] Sternula antillarum | [UK] Least Tern | [FR] Petite Sterne | [DE] | [ES] | [NL] Amerikaanse Dwergstern
Subspecies
| Genus | Species | subspecies | Breeding Range | Breeding Range 2 | Non Breeding Range |
| Sternula | antillarum | NA, MA | widespread | n SA coast | |
| Sternula | antillarum | antillarum | e and s USA to Honduras, Caribbean, n South America | to Brazil | |
| Sternula | antillarum | athalassos | c and sc North America | to n Brazil | |
| Sternula | antillarum | browni | c California (USA) to w Mexico | Central America |
Physical charateristics
The least tern is the smallest American tern, weighing about 1 ounce (28 gm) and measuring about 9 inches (23 cm) in length. It is identified in spring and summer by a white forehead contrasting with a black crown and nape. Its body is slate grey above and white below, with the pointed wings and forked tail characteristic of most terns. The bill and feet are yellow. Wingbeats are uniquely rapid and the black leading edge of the outer wing is conspicuous in flight. Immature least terns have upper parts which are mottled white and dark brown.
Listen to the sound of Least Tern
[audio:http://www.aviflevoland.nl/sounddb/L/Least Tern.mp3]
Copyright remark: Most sounds derived from xeno-canto
| wingspan min.: | 30 | cm | wingspan max.: | 31 | cm |
| size min.: | 28 | cm | size max.: | 29 | cm |
| incubation min.: | 20 | days | incubation max.: | 21 | days |
| fledging min.: | 19 | days | fledging max.: | 21 | days |
| broods: | 1 | eggs min.: | 2 | ||
| eggs max.: | 3 |
Range
North America, Middle America : widespread
Habitat
The least tern breeds on broad, level expanses of open sandy or gravelly beach, dredge spoil and other open shoreline areas, and more rarely, inland on broad river valley sandbars. In an unusual case, 20 pairs nested on the roof of a city auditorium in Pensacola, Florida in 1957, and have continued to do so annually.
Reproduction
Least Terns generally nest and breed 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 utilize flat, gravel-covered rooftops instead. Least Terns lay 1 to 3 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.
Feeding habits
Least terns feed mostly on small fish caught by skimming the surface of the water or by making dives from the air. Banding studies have shown individuals living up to 21 years.
Conservation
This species has a large range, with an estimated global Extent of Occurrence of 470,000 km2. It has a large global population estimated to be 65,000-70,000 individuals (Wetlands International 2002). Global population trends have not been quantified, but the species is not believed to approach the thresholds for the population decline criterion of the IUCN Red List (i.e. declining more than 30% in ten years or three generations). For these reasons, the species is evaluated as Least Concern.
Migration
Highly Migratory. Pacific breeders arrive late Apr, and return in Aug to coasts of W Mexico and Central America. Interior and E birds migrate to Caribbean and N South America, wintering mainly off Brazil. Substantial inter-colony exchange from year to year, even when original colony persists. Nominate race accidental inland.
Distribution map
