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least bittern

least bittern (Ixobrychus exilis) [state threatened]
Photo ©

Features and Behaviors

The least bittern averages 11 to 14 inches in length (tail tip to bill tip in preserved specimen). Both male and female have a similar appearance. There is a light, tan patch on each wing, and a dark cap can be seen on the head. The back has dark feathers with two, white stripes while the lower side has tan feathers. The pointed bill is thick.

The least bittern is an uncommon migrant and summer resident in Illinois. It is seen mostly in Cook and Lake counties, in the Illinois River valley and at Mermet Lake. The least bittern thrives in cattail marshes. Spring migrants begin arriving in Illinois in April. Eggs are produced from May through July. The nest is built in cattails, usually over water. Both the male and the female work to construct the nest of dead plants interwoven with live plants. Two to seven, pale-blue or green eggs are deposited by the female. The male and the female alternate incubation duties over the 17- to 20-day incubation period. Two broods are raised each year. Fall migration into Illinois begins in September. The least bittern winters from Panama to Colombia. It feeds on fishes, crayfish, insects and other aquatic animals. Its song is “coo-coo-coo.”

Illinois Range


​Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Pelecaniformes
Family: Ardeidae

Illinois Status: state threatened, native

The least bittern is threatened in Illinois mainly due to wetland destruction and human disturbance. It was fairly common in the state in the late 1800s. It lives at the edge of shallow lakes and marshes that are surrounded by dense plant growth. Destruction of wetland habitat is the main threat to this species in Illinois. Preservation and protection of large wetland areas with shallow water are needed for this species' survival in the state.