Potoo

Potoos (family Nyctibiidae) are a group of birds related to the oilbird, with which they share the Sedentaves subclade. 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, they are known as kakuy or cacuy from Quechua meaning 'to remain'. In Bolivia they are called guajojo, for the sound of their call. In Brazil and Paraguay, 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.

A 1996 study of the mitochondrial DNA of the potoos supported the monophyly of the family although it did not support the previous assumption that it was closely related to the oilbirds. 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. 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 family Nyctibiidae was introduced (as Nyctibie) in 1853 by the French naturalists Jean-Charles Chenu and Œillet des Murs. Prior to this, its species were classified in the Caprimulgidae.

The family Nyctibiidae contains seven species in two genera:

Prior to 2018, Nyctibius was considered the only extant genus within the Nyctibiidae; however, a study that year found a deep divergence between the rufous potoo and all other species in the genus, leading it to be described in the new genus Phyllaemulor and expanding the number of genera within the family. This was followed by the International Ornithological Congress in 2022.