Nyctibiidae – Potoos

The Nyctibiidae or Potoos are a group of near passerine birds related to the nightjars and frogmouths in their own order, the Nyctibiiformes. They are sometimes called poor-me-ones, after their haunting calls. There are seven species in two genera, all found in tropical Central and South America. The genus Nyctibius, is drawn from Greek to indicate night-feeding, literally being nux for night and bios for life. The Rufous Potoo was shown (2018) through study, to be in its own genus, as it diverges deeply from the other potoos.

They are nocturnal insectivores which lack the bristles around the mouth found in the true nightjars. They hunt from a perch like a shrike or flycatcher. During the day they perch upright on tree stumps, camouflaged to look like part of the stump. The single spotted egg is laid directly on the top of a broken branch stump.

The potoos are a highly conservative family in appearance, with all the species closely resembling one another; species accounts in ornithological literature remark on their unusual appearance. They range from 21cm to 58cm in length. They resemble upright sitting nightjars, a closely related order – Caprimulgiformes. They also resemble the frogmouths of Australasia, that are stockier and have much heavier bills. They have proportionally large heads for their body size and long wings and tails. The large head is dominated by a massive broad bill and enormous eyes. In the treatment of the family in the Handbook of the Birds of the World, Cohn-Haft describes the potoos as little more than a flying mouth and eyes. The bill, while large and broad, is also short, barely projecting past the face. It is delicate, but has a unique ‘tooth’ on the cutting edge of the upper mandible that may assist in foraging. Unlike the closely related nightjars, the potoos lack rictal bristles around the mouth. The legs and feet are weak and used only for perching.

Common Potoo Nyctibius griseus – ©Dubi Shapiro

Their eyes are large, even larger than those of nightjars. As in many species of nocturnal birds, they reflect the light of flashlights. Their eyes, which could be conspicuous to potential predators during the day, have unusual slits in the lids, which allow potoos to sense movement even when their eyes are closed. Their plumage is cryptic, helping them blend into the branches on which they spend their days.

 At night, they emit distinctive songs, from the plaintive whistles of the Common Potoo Nyctibius griseus to the percussive guttural roar of the Great Potoo Nyctibius grandis. They respond well to tape playback of their songs, often approaching closely and replying repeatedly, and their highly reflective eyes make them relatively easy to find at night.

They have a Neotropical distribution. They range from Mexico to Argentina, with the greatest diversity occurring in the Amazon Basin, which holds five species. They are found in every Central and South American country except Chile. They also occur on three Caribbean islands: Jamaica, Hispaniola and Tobago.

Northern Potoo Nyctibius jamaicensis – ©Dubi Shapiro

They are generally highly sedentary, although there are occasional reports of vagrants, particularly species that have travelled on ships. All species occur in humid forests, although a few species also occur in drier forests.

They are highly nocturnal and generally do not fly during the day. They spend the day perched on exposed branches with the eyes half closed. With their extraordinarily cryptic plumage they resemble stumps, and should they detect potential danger they adopt a ‘freeze’ position which even more closely resembles a broken branch. The transition between perching and the freeze position is gradual and hardly perceptible to the observer.