page_title: Owl
section_title: Evolution and systematics
hierarchical_section_title: Owl / Evolution and systematics
caption_attribution_description: English: fossil of palaeoglaux
context_page_description: Owls are birds from the order Strigiformes, which includes over 200 species of mostly solitary and nocturnal birds of prey typified by an upright stance, a large, broad head, binocular vision, binaural hearing, sharp talons, and feathers adapted for silent flight. Exceptions include the diurnal northern hawk-owl and the gregarious burrowing owl.
  Owls hunt mostly small mammals, insects, and other birds, although a few species specialize in hunting fish. They are found in all regions of the Earth except polar ice caps and some remote islands.
  Owls are divided into two families: the true owl family, Strigidae, and the barn-owl family, Tytonidae.
  A group of owls is called a "parliament".
context_section_description: The systematic placement of owls is disputed. For example, the Sibley–Ahlquist taxonomy of birds finds that, based on DNA-DNA hybridization, owls are more closely related to the nightjars and their allies (Caprimulgiformes) than to the diurnal predators in the order Falconiformes; consequently, the Caprimulgiformes are placed in the Strigiformes, and the owls in general become a family, the Strigidae. A recent study indicates that the drastic rearrangement of the genome of the accipitrids may have obscured any close relationship of theirs with groups such as the owls.
  In any case, the relationships of the Caprimulgiformes, the owls, the falcons, and the accipitrid raptors are not resolved to satisfaction; currently, a trend to consider each group (with the possible exception of the accipitrids) as a distinct order is increasing.
  Some 220 to 225 extant species of owls are known, subdivided into two families: 1. Typical owls or True owl family (Strigidae) and 2. barn-owls family (Tytonidae). Some entirely extinct families have also been erected based on fossil remains; these differ much from modern owls in being less specialized or specialized in a very different way (such as the terrestrial Sophiornithidae). The Paleocene genera Berruornis and Ogygoptynx show that owls were already present as a distinct lineage some 60–57 million years ago (Mya), hence, possibly also some 5 million years earlier, at the extinction of the nonavian dinosaurs. This makes them one of the oldest known groups of non-Galloanserae landbirds. The supposed "Cretaceous owls" Bradycneme and Heptasteornis are apparently nonavialan maniraptors.
  During the Paleogene, the Strigiformes radiated into ecological niches now mostly filled by other groups of birds. The owls as known today, though, evolved their characteristic morphology and adaptations during that time, too. By the early Neogene, the other lineages had been displaced by other bird orders, leaving only barn-owls and typical owls. The latter at that time were usually a fairly generic type of (probably earless) owls similar to today's North American spotted owl or the European tawny owl; the diversity in size and ecology found in typical owls today developed only subsequently.
  Around the Paleogene-Neogene boundary (some 25 Mya), barn-owls were the dominant group of owls in southern Europe and adjacent Asia at least; the distribution of fossil and present-day owl lineages indicates that their decline is contemporary with the evolution of the different major lineages of typical owls, which for the most part seems to have taken place in Eurasia. In the Americas,  rather an expansion of immigrant lineages of ancestral typical owls occurred.
  The supposed fossil herons "Ardea" perplexa (Middle Miocene of Sansan, France) and "Ardea" lignitum (Late Pliocene of Germany) were more probably owls; the latter was apparently close to the modern genus Bubo. Judging from this, the Late Miocene remains from France described as "Ardea" aureliensis should also be restudied. The Messelasturidae, some of which were initially believed to be basal Strigiformes, are now generally accepted to be diurnal birds of prey showing some convergent evolution towards owls. The taxa often united under Strigogyps were formerly placed in part with the owls, specifically the Sophiornithidae; they appear to be Ameghinornithidae instead.
  For fossil species and paleosubspecies of extant taxa, see the genus and species articles. For a full list of extant and recently extinct owls, see the article "List of owl species".
  Unresolved and basal forms (all fossil)
  Berruornis (Late Paleocene of France) basal? Sophornithidae?
  Strigiformes gen. et ap. indet. (Late Paleocene of Zhylga, Kazakhstan)
  Palaeoglaux (Middle – Late Eocene of WC Europe) own family Palaeoglaucidae or Strigidae?
  Palaeobyas (Late Eocene/Early Oligocene of Quercy, France) Tytonidae? Sophiornithidae?
  Palaeotyto (Late Eocene/Early Oligocene of Quercy, France) Tytonidae? Sophiornithidae?
  Strigiformes gen. et spp. indet. (Early Oligocene of Wyoming, USA)
caption: The ancient fossil owl Palaeoglaux artophoron
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