Birds Guide

Barn-owls
Barn Owl, Tyto alba
Scientific classification
Kingdom: Animalia   Phylum: Chordata   Class: Aves   Order: Strigiformes   Family: Tytonidae Ridgway, 1914
Genera
Tyto Phodilus For fossil genera, see article.

Barn-owls (family Tytonidae) are one of the two generally accepted families of owls, the other being the typical owls, Strigidae. They are medium to large sized owls with large heads and characteristic heart-shaped faces. They have long strong legs with powerful talons. The barn owls comprise two extant sub-families: the Tytoninae or Tyto owls (including the Common Barn Owl) and the Phodilinae or bay-owls.

The barn owls are a wide ranging family, absent only from northern North America, Saharan Africa and large areas of Asia. They live in a wide range of habitats from deserts to forests, and from temperate latitudes to the tropics. The majority of the 16 living species of barn owls are poorly known, some, like the Madagascar Red Owl, have barely been seen or studied since their discovery, in contrast to the Common Barn Owl, which is one of the best known owl species in the world. However, some sub-species of the Common Barn Owl possible deserve to be a species, and are very poorly known.

5 species of barn-owl are threatened, and some island species have gone extinct during the Holocene or earlier (e.g. Tyto pollens, known from the fossil record of Andros Island, and possibly the basis for the Chickcharnie). The barn-owls are mostly nocturnal, and generally non-migratory, living in pairs or singly.

Description

The barn-owls main characteristic is the heart-shaped facial disc, formed by stiff feathers which serve to amplify and locate the source of sounds when hunting. Further adaptations in the wing feathers eliminate sound caused by flying, aiding both the hearing of the owl listening for hidden prey and keeping the prey unaware of the owl. Barn-owls overall are darker on the back than the front, usually an orange-brown colour, the front being a paler version of the back or mottled, although there is considerable variation even amongst species. The bay-owls closely resemble the Tyto owls but have a divided facial disc, ear tufts, and tend to be smaller.

Species

The fossil record of the barn-owls goes back to the Eocene, with the family eventually losing ground to the true owls after the radiation of rodents and owls during the Neogene epoch . Two subfamilies are only known from the fossil record, the Necrobyinae and the Selenornithinae. Numerous extinct species of Tyto have been described; see the genus page for more information.

Genus Tyto

• Greater Sooty-owl, T. tenebricosa
  Lesser Sooty-owl, T. multipunctata
  Australian Masked-owl, T. novaehollandiae
  Golden Masked-owl, T. aurantia
• Lesser Masked-owl, T. sororcula
  • Buru Masked-owl, T. (sororcula) cayelii (possibly extinct)
• Manus Masked-owl, T. manusi
  Taliabu Masked-owl, T. nigrobrunnea
  Minahassa Masked-owl, T. inexspectata
  Sulawesi Owl, T. rosenbergii
• Barn Owl, T. alba
  • Eastern Barn Owl, T. (alba) delicatula
• Ashy-faced Owl, T. glaucops
  Madagascar Red Owl T. soumagnei
  African Grass-owl T. capensis
  Australasian Grass-owl T. longimembris

Genus Phodilus

• Oriental Bay-owl P. badius
  • Samar Bay-owl P. (badius) riverae (probably extinct)
• Congo Bay-owl, P. prigoginei - sometimes placed in Tyto

Fossil genera

• Necrobyas (Late Eocene/Early Oligocene - Early Miocene of France)
  Prosybris (Early Miocene of France)
  Nocturnavis
  Palaeobyas
  Palaeotyto
  Selenornis

The presumed "Easter Island Barn-owl", based on subfossil bones found on Rapa Nui, has turned out to be some procellarid (Steadman, 2006).

References

• Bruce, M. D. (1999): Family Tytonidae (Barn-owls). In: del Hoyo, J.; Elliott, A. & Sargatal, J. (eds): Handbook of Birds of the World, Volume 5: Barn-owls to Hummingbirds: 34-75, plates 1-3. Lynx Edicions, Barcelona. ISBN 84-87334-25-3

• Steadman, David William (2006): Extinction and Biogeography of Tropical Pacific Islands Birds. University of Chicago Press. ISBN 0226771423.

External links

• Barn-Owls on the Internet Bird Collection