The Oilbird or Guacharo is the only representative of the family Steatornithidae. The Guacharo is a nocturnal bird of medium-sized and slim body, with a flattened hooked bill surrounded by long rictal bristles up to 5 centimetres (2.0 in) long. Chicks can weigh considerably more than adult birds as their parents feed them a good deal of fruit before they fly. Guacharos have stiff tail feathers and small and almost useless feet, other than for clinging to vertical surfaces. The long wings make them capable of hovering and twisting
flight, which enables them to navigate through restricted areas in the caves. Oilbirds are seasonally migrants moving from its breeding caves in search of fruit trees. During the day the birds rest on cave ledges and leave to find their food at night. Although it forages by sight, the oilbird is one of only a few birds, and the only nocturnal one, known to navigate by echolocation in sufficiently poor light conditions. They use a series of sharp audible clicks for this purpose. It also produces a variety of harsh screams while in its caves. Photo: Oillbird ©David Moran.