Chlidonias niger
(Black Tern)

Physical Description:
9-10 1/4" (23-26 cm). A small, dark tern with black bill. Breeding adult: Head and underparts black; back, wings, and top of slightly forked tail dark gray. Wing linings and undertail coverts white. In fall and winter have gray back and wings, white underparts, and white head with dark hood.

Song:
Call a sharp kip, krik, or keek.

Distribution:
Breeds from British Columbia, across portions of Canada to Nova Scotia, and south locally to southern California, Colorado, portions of Midwest, and northern New England. Winters along both coasts, and from Panama to Peru and Surinam.

Habitat:
Prefers sheltered, offshore waters and bays; comes to shore chiefly during migrations or when breeding, when it is found along seacoasts, bays, estuaries, lagoons, lakes, and rivers.

Diet:
Eats insects and other invertebrates, including small fishes and crustaceans.

Ecology:
Gregarious. Forms loose nesting colonies, sometimes in association with Forster'sTern. Usually builds floating platform nest in vegetation. Feeds from surface of saltwater, forages on vegetation, or plucks food from air.

Reproduction
Both sexes incubate 3 eggs (usually), for 20-24 days. Both parents tend young, which first fly at about 3 wk, and become fully fledged at about 4 wk.

Conservation:

Element Code:	ABNNM10020
Status:	Protected nongame species
Global Rank:	G4
State Rank:	S2
National Rank:	N4B,NZN

Important State References:
Trost, C.H. 1994. The status and distribution of colonial waterbirds in northern Idaho and selected species in southern Idaho, 1994. Dept. Biol. Sciences, Idaho St. Univ., Pocatello. 31pp.