Owlet-nightjar
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 Australian Owlet-nightjar, Aegotheles cristatus
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Owlet-nightjars are small nocturnal birds related to the nightjars and frogmouths. Most are native to New Guinea, but some species extend to Australia, the Moluccas, and New Caledonia. There is a single monotypic family Aegothelidae with the genus Aegotheles.
Owlet-nightjars are insectivores which hunt mostly in the air but sometimes on the ground; their soft plumage is a crypic mixture of browns and paler shades, they have fairly small, weak feet (but larger and stronger than those of a frogmouth or a nightjar), a tiny bill that opens extraordinarily wide, surrounded by prominent whiskers. The wings are short, with 10 primaries and about 11 secondaries; the tail long and rounded.
[edit] Systematics
The comprehensive 2003 study by Dumbacher et al. analyzing mtDNA sequences Cytochrome b and ATPase subunit 8 suggests that 11 species of owlet-nightjar should be recognized, plus one that went extinct early in the second millennium AD.
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 (Mayr 2002). As has been suggested on occasion since morphological studies of the cranium in the 1960 (Simonetta 1967), they are thus considered a distinct order, Aegotheliformes. This, the caprimulgiform lineage(s), and the Apodiformes, are postulated to form a clade called Cypselomorphae.
In form and habits, however, they are very similar to both caprimulgiform group - or, at first glance, to small owls with huge eyes. Interestingly, the ancestors of the swifts and hummingbirds, two groups of birds which are morphologically very specialized, seem to have looked very similar to a small owlet-nightjar, possessing strong legs and a wide gape, while the legs and feet are very reduced in today's swifts and hummingbirds, and the bill is narrow in the latter.
They are an exclusively Australasian group, but close relatives apparently occurred all over Eurasia in the late Paleogene.
- Genus Quipollornis (fossil; Early/Middle Miocene of New South Wales)
- Genus Aegotheles
- New Zealand Owlet-nightjar, Aegotheles novaezealandiae (prehistoric; formerly Megaegotheles)
- New Caledonian Owlet-nightjar, Aegotheles savesi
- Feline Owlet-nightjar, Aegotheles insignis
- Starry or Spangled Owlet-nightjar, Aegotheles tatei
- Moluccan or Long-whiskered Owlet-nightjar, Aegotheles crinifrons
- Australian Owlet-nightjar, Aegotheles cristatus
- Barred Owlet-nightjar, Aegotheles bennettii
- Upland Barred Owlet-nightjar, Aegotheles affinis (formerly A. bennettii affinis
- Salvadori's Owlet-nightjar, Aegotheles salvadorii (formerly A. albertisi salvadorii)
- Wallace's Owlet-nightjar, Aegotheles wallacii
- Archbold's Owlet-nightjar, Aegotheles archboldi
- Mountain Owlet-nightjar, Aegotheles albertisi
[edit] References
- Dumbacher, John P. ; Pratt, Thane K. & Fleischer, Robert C. (2003): Phylogeny of the owlet-nightjars (Aves: Aegothelidae) based on mitochondrial DNA sequence. Molecular Phylogenetics and Evolution 29(3): 540–549. DOI:10.1016/S1055-7903(03)00135-0 PDF fulltext
- Mayr, Gerald (2002): Osteological evidence for paraphyly of the avian order Caprimulgiformes (nightjars and allies). Journal für Ornithologie 143: 82–97. PDF fulltext
- Simonetta, A. M. (1967): Cinesi e morfologia del cranio negli Ucelli non passeriformi. Studio su varie tendenze evolative. Part II – Striges, Caprimulgiformes ed Apodiformes. Archive Zoologico Italiano 52: 1–35.
