Bill long, straight, slender, rather soft and swollen at the tip : both mandibles grooved at the side; nostrils linear, basal, the gape in front of the base of the culmen. Wings long, 1st quill longest. Tail short, of 12 feathers. Legs short, feathered to the joint at the base of the tarsus.
Two or, including the North American form, sometimes separated generically, three species are known. Only the typical one is Indian.