Aegothelidae – Owlet-nightjars

The Aegothelidae or Owlet-nightjars are small crepuscular birds related to the nightjars and frogmouths; they are an exclusively Australasian group. Most are native to New Guinea, but some species extend to Australia, the Moluccas, and New Caledonia. The monotypic family has one genus Aegotheles.

Owlet-nightjars are insectivores that hunt mostly in the air but sometimes on the ground; their soft plumage is a cryptic mixture of browns and paler shades, they have fairly small, weak feet (but larger and stronger than those of frogmouths or nightjars) and a tiny bill that opens extraordinarily wide, surrounded by prominent whiskers. Their wings are short, with 10 primaries and about 11 secondaries; their tails are long and rounded.

The relationship between the owlet-nightjars and the (traditional) Caprimulgiformes has long been controversial and obscure and remains so today: in the 19th century they were regarded as a subfamily of the frogmouths, and they are still generally considered to be related to the frogmouths and/or the nightjars. It appears though that that they are not so closely related to either as previously thought, and that the owlet-nightjars share a more recent common ancestor with the Apodiformes. It has been suggested that they should be considered a distinct order, Aegotheliformes. This, the caprimulgiform lineage(s), and the Apodiformes, are postulated to form a clade called Cypselomorphae, with the owlet-nightjars and the Apodiformes forming the clade Daedalornithes.

However, a comprehensive 2003 study incorporating DNA sequencing suggests that there are just 9 species of owlet-nightjar; they are set out below.