- 8.3–9.1 in
- 18.9–20.9 in
- 1.1–1.6 oz
- Petite Sterne (French)
- Charrán mínimo, Golondrinita marina, Gallito (Spanish)
- The Least Tern prefers sandy beaches for nesting, but it will use a flat gravel roof of a building. On sunny days the hot tar showing through the gravel can burn the feet of chicks or become stuck in their down.
- The oldest recorded Least Tern was at least 24 years, 1 month old when it was found in New Jersey in 1981. It had been banded in 1957 in Massachusetts.
Seacoasts, beaches, bays, estuaries, lagoons, lakes and rivers, breeding on sandy or gravelly beaches and banks of rivers or lakes, rarely on flat rooftops of buildings.
Small fish. Some invertebrates.
- Condition at Hatching
- Downy, eyes open, able to walk but stays in nest.
Shallow scrape in sand, soil, or pebbles.
Plunges into water from flight; may hover briefly before plunging.
Least Tern populations declined by about 88% between 1966 and 2015, according to the North American Breeding Bird Survey. The North American Waterbird Conservation Plan estimates a continental population of 60,000-100,000 breeding birds, and lists it as a Species of High Concern. Least Tern rates a 14 out of 20 on the Continental Concern Score. The species is on the 2016 State of North America's Birds' Watch List, which lists bird species that are most at risk of extinction without significant conservation actions to reverse declines and reduce threats. Least Tern are widespread and common in places, but its favored nesting habitat is prized for human recreation, residential development, and alteration by water diversion, which interfere with successful nesting in many areas. Least Tern is classified as threatened, endangered, or as a species of concern for most states because of loss of nesting habitat, and the interior population has been federally listed as endangered since 1985.
- Thompson, B. C., J. A. Jackson, J. Burger, L. A. Hill, E. M. Kirsch, and J. L. Atwood. 1997. Least Tern (Sterna antillarum). In The Birds of North America, No. 290 (A. Poole and F. Gill, eds.). The Academy of Natural Sciences, Philadelphia, PA, and The American Ornithologists' Union, Washington, D.C.
- Kushlan, J.A., et al. 2002. Waterbird conservation for the Americas: the North American Waterbird Conservation Plan, version 1. Waterbird Conservation for the Americas. Washington, DC.
- North American Bird Conservation Initiative. 2016. The State of North
America’s Birds 2016. Environment and Climate Change Canada: Ottawa, Ontario.
- U.S. Fish & Wildlife Service, ECOS-Environmental Conservation Online System, Least Tern (Sterna antillarum).
- USGS Patuxent Wildlife Research Center. 2016. Longevity records of North American Birds.
- USGS Patuxent Wildlife Research Center. 2015. North American Breeding Bird Survey 1966–2015 Analysis.