The oilbird (Steatornis caripensis), locally known as the guácharo, is a bird species found in the northern areas of South America including the Caribbean island of Trinidad.

Nesting in colonies in caves, oilbirds are nocturnal feeders on the fruits of the oil palm and tropical laurels.

However, the nightjars and their relatives are insectivores while the oilbird is a specialist fructivore, and it is sufficiently distinctive to be placed in a family (Steatornithidae) and suborder (Steatornithes) of its own.

In Trinidad it was sometimes called diablotin (French for 'little devil'), presumably referring to its loud cries, which have been likened to those of tortured men.

The common name oilbird comes from the fact that in the past chicks were captured and boiled down in order to make oil.

Some of the same families and genera of plants the present day oilbird feeds on have been found in the Green River Formation, suggesting that prehistoric species may have eaten the same fruit and spread the same seeds.

The long wings have evolved to make it capable of hovering and twisting flight, which enables it to navigate through restricted areas of its caves.

The eyes are small, but the pupils are relatively large, allowing the highest light-gathering capacity of any bird (f-number of 1.07).

The oilbird ranges from Guyana and the island of Trinidad to Venezuela, Colombia, Ecuador, Peru, Bolivia and Brazil.

The species has highly specific habitat requirements, needing both caves to breed in and roost in frequently, and forest containing fruiting trees.

Colombia also has a national park named after its "Cueva de los Guácharos", near the southern border with Ecuador.

Oilbirds have been reported in various other places along the Andean mountain chain, including near Ecuador's Cueva de los Tayos and in Brazil: they are known to dwell as far south as the Carrasco National Park in Bolivia.