Northern Prairie Wildlife Research Center
BLACK TERN Chlidonias niger L10" (26cm)
The black tern, with its black head, black body, and gray wings is one of the easiest terns to identify. It inhabits inland marshes, sloughs, and small lakes that contain emergent vegetation. The black tern nests in small colonies and is gregarious year round. Its flight is buoyant and erratic and is often observed hovering above a marsh. The nest usually consists of a floating mass of dead plants but may also be built on top of a muskrat house. The average clutch size is three olive-brown colored eggs with an incubation period lasting 22 days. The chicks are able to leave the nest a few days after hatching and are vigorously guarded by both parents. The black tern feeds primarily on insects such as dragonflies, grasshoppers, and beetles. The black tern has lost much of its breeding habitat due to wetland drainage and is therefore listed as a candidate species by the US Fish and Wildlife Service. A candidate species is defined as a species that may warrant an official listing as endangered or threatened but there is not enough data at the present time to justify the action.