bittern, common name for migratory marsh birds of the family Ardeidae (heron family). The American bittern ( Botaurus lentiginosus ), often called "stake driver" because of a territorial male's booming call in the spring, is widely distributed in E North America. It is mostly nocturnal and feeds on frogs, fish, and insects. When pursued, the bittern escapes detection by standing motionless with its bill uplifted, its brown and yellow markings and striped foreneck blending with the marsh grasses. It is about 2 to 3 ft (61–91 cm) tall; the western and eastern least bitterns, genus Ixobrychus, are about half this size. Of the 12 species of bitterns, 8 constitute the smaller birds. The female bittern builds the nest, which consists of an unkempt arrangement of sedge grass and reeds. The nests are built on the ground along rivers or lakeshores and house the clutch of 3 to 6 eggs. Both male and female share the incubation duties. Bitterns are classified in the phylum Chordata, subphylum Vertebrata, class Aves, order Ciconiiformes, family Ardeidae.