STATUS: Endangered in the U.S., including Texas, except within 50 miles (80 Km) of the Gulf Coast, without critical habitat.|
DESCRIPTION: Least Terns are small birds, about 21 cm long with a wingspan of about 51 cm. Sexes are alike; breeding plumage is characterized by a black crown, white forehead, grayish back and dorsal wing surfaces, jet black wing tips, snowy white underparts, orange legs, and a black-tipped yellow bill. The male's bill is orange to bright yellow and the female's is light or dull yellow or straw-colored.
HABITAT: Premier nesting sites are salt flats, broad sandbars, and barren shores along wide, shallow rivers. Important breeding habitat characteristics include: (1) presence of bare or nearly bare ground and alluvial islands or sandbars for nesting, (2) availability of food (primarily small fish), and (3) favorable water levels during the nesting season (so nests remain above water). They have been found on sites with an average of 11 to 30% vegetative cover, composed of grasses, shrubs, and trees and ranging from 39 to 95 cm in height. Vegetation, if present, is usually located will away from the colony, with the exception of bugseed, eastern cottonwood, and sandbar willow. As natural nesting sites have become sparse, birds have used dredge islands, dikefields, fly-ash lagoons, sandpits, and gravel levee roads as nesting sites.
Present: Occur as remnant colonies within their historic distribution. Winters along the Gulf Coast.
THREATS AND/OR REASONS FOR DECLINE: Permanent inundation or destruction of nesting areas by reservoirs and channelization projects; alteration of natural river or lake dynamics, causing unfavorable vegetational succession of remaining islands; recreational use of sandbars; nest inundation by reservoir water releases and annual spring floods; water pollution; and predation (25-39% of nest failures are due to coyote predation).
Historic: In Texas; bred on sandbars on the Canadian, Red, and Rio Grande river systems. Also along the Arkansas, Missouri, Ohio, and Mississippi River systems; braided rivers of northwest Oklahoma and southwest Kansas; salt flats of northwest Oklahoma; mud playa lakes in southeast New Mexico
OTHER INFORMATION: Least terns arrive from late April to early June and spend 4 to 5 months at their breeding grounds. Terns winter along the Central American and north South American coast to northeastern Brazil. Recovery plan published in 1990. Least terns eat fish, feeding in shallow waters of rivers, streams, and lakes. Fish prey for terns are small and primarily include members of the Fundulus, Notropis, Campostoma, Pimephales, Gambusia, Benosox, Morone, Dorosoma, Leporhis, and Carpiodes fish genera. The Fish & Wildlife Service is working with the Bureau of Reclamation and the states of NEw Mexico, TExas, and Oklahoma to monitor population levels. Population numbers have been increasing since a partial census in 1975. Breeding areas in Texas are located along the Canadian, Red, and Rio Grande river systems.
U.S. Fish and Wildlife Service. August 1992. Threatened and Endangered Species of Texas.
Endangered Species Office, Albuquerque, New Mexico