Pennington County, South Dakota
Note: This information is provided for reference purposes only. Although the information provided here was accurate and current when first created, it is now outdated.
Pesticide Table | About the Least Tern
South Dakota Map | ESPP Home
Table of Pesticide Active Ingredients
|3s||Within the shaded area shown on the map and 2 miles up all streams that join the shaded area, do not apply this pesticide within 100 yards from the edge of water for ground applications, nor within 1/4 mile for aerial applications.|
Least tern [Sterna antillarum antillarum] (interior population)
Least terns are among the smallest of the terns, measuring 8 to 9 inches in length. Both sexes have a black cap and nape, white forehead, grayish back and wings, white belly, orange legs, and a black-tipped yellow bill. Immature birds have darker plumage, a dark bill, dark eye stripes, and white heads. A special characteristic of the least tern is the "fish flight" the male performs during courtship. This high-flying aerial display with one or two other terns is done while carrying a fish in his bill that the female takes and eats. Female terns usually lay one to four eggs around late May to early August in colonies of about 20 small ground nests.
Least terns occur along coastal areas and along rivers with sufficient breeding sites; only the "interior" populations (more than 50 miles from coasts) are considered endangered. Preferred river systems for the interior least tern are those with bare or nearly bare alluvial islands or sandbars, favorable water levels during the nesting season, and food availability. Historically, interior Least terns bred along the Colorado, Red, Rio Grande, Arkansas, Missouri, Ohio, and Mississippi Rivers. Current studies indicate that this tern is extremely limited in both numbers and distribution. It is now considered rare throughout most of its interior range but recent studies have documented significant increases along the Mississippi River. The exact wintering area for the tern is unknown; however populations have been known to winter along the Central American coast and the northern coast of South America from Venezuala to northeastern Brazil.
The main reason for this species' decline is the reduction in suitable nesting habitat throughout the central and western United States. This is largely due to increased vegetation brought by man-made changes in river flow. Other disturbances, such as recreational activities that disturb nest sites, housing construction and development, continue to threaten tern populations.
The U.S. Fish and Wildlife Service has developed a recovery plan that describes the actions considered necessary to conserve this species. Research is being conducted into the tern's habitat requirements, breeding patterns, lifespan, and winter residence. Increased public awareness and habitat protection are also projects that are currently being undertaken to help prevent this species from becoming extinct.
Matthews, J.R (ed.), The Official World Wildlife Fund Guide to Endangered Species Vol. II, Beacham Publishing Inc, Washington, DC. pp. 697-697.