Поту (Nyctibiidae): Ночные птицы Центральной и Южной Америки

Family of nocturnal birds of tropical Central and South America

Potoos (family Nyctibiidae) are a group of birds related to the nightjars and frogmouths. They are sometimes called poor me ones, after their haunting calls. The family Nyctibiidae was formerly included with the nightjars in the order Caprimulgiformes but is now placed in a separate order, Nyctibiiformes. There are seven species in two genera in tropical Central and South America. Fossil evidence indicates that they also inhabited Europe during the Paleogene. Potoos are nocturnal insectivores that 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 stump. In Argentina and Bolivia, they are known as kakuy or cacuy from Quechua meaning 'to remain'. In Brazil, they are called urutau from Guaraní guyra 'bird' and tau 'ghost'.

The potoos today are exclusively found in the Americas, but they apparently had a much more widespread distribution in the past. Fossil remains of potoos dating from the Eocene have been found in Germany. A complete skeleton of the genus Paraprefica has been found in Messel, Germany. It had skull and leg features similar to those of modern potoos, suggesting that it may be an early close relative of the modern potoos. Because the only fossils other than these ancient ones that have been found are recent ones of extinct species, it is unknown if the family once had a global distribution which has contracted, or if the distribution of the family was originally restricted to Europe and has shifted to the Americas. The study also found a great deal of genetic divergence between the species, suggesting that these species are themselves very old. The level of divergence is the highest of any genus of birds, being more typical of the divergence between genera or even families. This raises the possibility that there are several cryptic species to be discovered. The northern potoo was for a long time considered to be the same species as the common potoo, but the two species have now been separated on the basis of their calls. In spite of this there is no morphological way to separate the two species.

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. Potoos range from in length. They resemble upright sitting nightjars, a closely related family (Caprimulgidae). They also resemble the frogmouths of Australasia, which 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". 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.

The potoos have a Neotropical distribution. The transition between perching and the freeze position is gradual and hardly perceptible to the observer. The English zoologist Hugh Cott, describing Nyctibius griseus as "this wonderful bird", writes that it "habitually selects the top of an upright stump as a receptacle for its egg, which usually occupies a small hollow just, and only just, large enough to contain it the stump selected had thrown up a new leader just below the point of fracture and the birds sat facing this in such a way that when viewed from behind they came into line and blended with the grey stem."

Potoos feed at dusk and at night on flying insects.