'Owls' are a group of
birds of prey. Most are
solitary and
nocturnal, with some exceptions (e.g. the
Burrowing Owl). They are classified in the
order 'Strigiformes', in which there are over 200 extant
species. Owls mostly hunt small
mammals,
insects, and other
birds, though a few species specialize in hunting
fish. They are found in all regions of the Earth except
Antarctica, most of
Greenland, and some remote islands. Though owls are typically solitary, the literary
collective noun for a group of owls is a ''parliament''.
The living owls are divided into two families: the
typical owls, Strigidae, and the
barn-owls, Tytonidae.
Description
Owls have large forward-facing eyes and ears, a
hawk-like
beak, and usually a conspicuous circle of feathers around each eye called a ''facial disc''. Although owls have
binocular vision, their large eyes are fixed in their sockets, as with other birds, and they must turn their entire head to change views.
Owls are far-sighted, and are unable to clearly see anything within a few inches of their eyes. Their far vision, particularly in low light, is exceptionally good, and they can turn their head 135 degrees in either direction; they can thus look behind their own shoulders. It is not correct, however, that they can turn the head so far as to face completely backwards.
Different species of owls make different sounds; the wide range of calls aids owl species in finding mates or announcing their presence to potential competitors, and
ornithologists and
birders in locating these birds and recognizing species. The facial disc helps to funnel the sound of prey to their ears. In many species, these are placed asymmetrically, for better directional location (Norberg, 1977).
Behavior
Most owls are nocturnal, actively hunting for prey only under cover of darkness. Several types of owl, however, are crepuscular, or active during the twilight hours of
dawn and
dusk; one example is the
pygmy owl (''Glaucidium''). A few owls are also active during the day; examples are the
Burrowing Owl (''Speotyto cunicularia)'' and the
Short-eared Owl (''Asio flammeus'').
Much of the owl's hunting strategy depends on stealth and surprise. Owls have at least two adaptations that aid them in achieving stealth. First, the dull coloration of an owl's feathers can render them almost invisible under certain conditions. Secondly, the owl's
remiges, or flight feathers, have fluffy trailing edges, muffling the owl's wingbeats and allowing its flight to be practically silent. Some fish-eating owls, which have no need of silence, lack this adaptation. Elf owls also lack the feathers for silent flying.
Once prey has been captured, the owl's sharp beak and powerful
talons, or clawed feet allow it to tear the food to pieces before eating, even though most items are swallowed whole. Scientists studying the diets of owls are helped by their habit of
regurgitating the indigestible parts of their prey (bones, scales, fur, etc.) in the form of
pellets. These "owl pellets" are often sold by companies to schools to be dissected by students as a lesson in biology and ecology, because they are plentiful and easy to interpret.
Owl eggs are usually white and almost spherical, and range in number from a few to a dozen, depending on species. The eggs are laid in intervals of 1-3 days and do not hatch at the same time. This accounts for the wide variation in the size of sibling nestlings. Owls do not constuct nests but rather look for a sheltered nesting site, be it in trees, underground burrows, or in buildings, barns and caves.
The smallest owl is the
Elf Owl (''Micrathene whitneyi''), at as little as 31 g (1.1 oz) and 13.5 cm (5.3 inches). Some of the
pygmy owls are scarcely larger. The largest owls are the two of the
eagle owls, the
Eurasian Eagle Owl (''Bubo bubo'') and
Blakiston's Fish Owl (''Bubo blakistoni''), which may reach a size of 76.2 cm (30 in) long, have a wingspan of just over 2 m (6.6 ft), and weigh of nearly 4.5 kg (10 lb).
Evolution and systematics
The
systematic placement of owls is disputed. For example, the
Sibley-Ahlquist taxonomy 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 Strigidae and the owls in general become a
family 'Strigidae'. This is not supported by more recent research
[1].
In any case, the relationships of the Caprimulgiformes, the owls, the
falcons and the
accipitrid raptors are not resolved to satisfaction; currently there is an increasing trend to consider each group (with the possible exception of the accipitrids) a distinct order.
There are 222 extant species of owls, which are subdivided into two families;
typical owls (Strigidae) and
barn-owls (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 Early
Paleocene (c.58
mya) genus ''Ogygoptynx'' can be taken to indicate that owls were present as a distinct lineage already at the extinction of the non-avian
dinosaurs, making them one of the oldest known groups of non-
Galloanserae landbirds. The supposed "
Cretaceous owl" ''Bradycneme'' is a non-avian dinosaur however, possibly ''
Elopteryx''.
During the
Paleogene, the Strigiformes
radiated into
ecological niches now mostly filled by other groups of birds. The owls as we know them today, on the other hand, 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) owl 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, there was rather an expansion of immigrant lineages of ancestral typical owls.
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.(Olson 1985:131, 267) 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 united by Mayr (2005) under ''
Strigogyps'' were formerly placed in part with the owls, specifically the Sophiornithidae; they appear to be
Ameghinornithidae instead (Alvarenga & Höfling 2003, Peters 2007).
For fossil species and
paleosubspecies, see the genus and species articles.
'Unresolved and basal forms' (all fossil)
★ Genus ''
Berruornis'' (Late Paleocene of France) - basal? Sophornithidae?
★ Genus ''
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: Olson 1985:131)
★ ''
Mioglaux'' (Late Oligocene? - Early Miocene of WC Europe) - includes ''"Bubo" poirreiri''
★ ''
Intutula'' (Early/Middle -? Late Miocene of C Europe) - includes ''"Strix/Ninox" brevis''
★ ''
Alasio'' (Middle Miocene of Vieux-Collonges, France)
Ogygoptyngidae
★ Genus ''
Ogygoptynx'' (Middle/Late Paleocene of Colorado, USA)
Protostrigidae
★ Genus ''
Eostrix'' (Early Eocene of WC USA and England - Middle Eocene of WC USA)
★ Genus ''
Minerva'' (Middle - Late Eocene of W USA) - formerly ''Protostrix'', includes ''"Aquila" ferox'', ''"Aquila" lydekkeri'', and ''"Bubo" leptosteus''
Sophiornithidae
★ Genus ''
Sophiornis''
Typical owls
★ Genus ''
Otus'' - scops owls; includes ''Megascops'', some 65 species
★ Genus ''
Pyrroglaux'' - Palau Owl
★ Genus ''
Gymnoglaux'' - Cuban Screech Owl
★ Genus ''
Ptilopsis'' - white-faced owls, 2 species
★ Genus ''
Mimizuku'' - Mindanao Eagle Owl
★ Genus ''
Bubo'' - horned owls, eagle owls and fish owls; includes ''Nyctea'', ''Ketupa'' and ''Scotopelia'' but possibly
polyphyletic, some 25 species
★ Genus ''
Strix'' - earless owls, some 15 species
★ Genus ''
Ciccaba'' - 4 species
★ Genus ''
Lophostrix'' - Crested Owl
★ Genus ''
Jubula'' - Maned Owl
★ Genus ''
Pulsatrix'' - spectacled owls, 3 species
★ Genus ''
Surnia'' - Northern Hawk Owl
★ Genus ''
Glaucidium'' - pygmy owls, about 30-35 species
★ Genus ''
Xenoglaux'' - Long-whiskered Owlet
★ Genus ''
Micrathene'' - Elf Owl
★ Genus ''
Athene'' - 2-4 species (depending on whether ''Speotyto'' and ''Heteroglaux'' are included or not)
★ Genus ''
Aegolius'' - saw-whet owls, 4 species
★ Genus ''
Ninox'' - Australasian hawk-owls, some 20 species
★ Genus ''
Uroglaux'' - Papuan Hawk
★ Genus ''
Pseudoscops'' - Jamaican Owl and possibly
Striped Owl
★ Genus ''
Asio'' - eared owls, 6-7 species
★ Genus ''
Nesasio'' - Fearful Owl
★ Genus ''
Mascarenotus'' - Mascarene owls, 3 species;
extinct (c.
1850)
★ Genus ''
Sceloglaux'' - Laughing Owl;
extinct (
1914?)
★ Genus ''
Grallistrix'' - stilt-owls, 4 species;
prehistoric
★ Genus ''
Ornimegalonyx'' - Caribbean giant owls, 1-2 species;
prehistoric
'Placement unresolved'
★ ''"Otus" wintershofensis'' -
fossil (Early/Middle Miocene of Wintershof West, Germany) - may be close to extant genus ''Ninox'' (Olson 1985:131)
★ ''"Strix" edwardsi'' -
fossil (Late Miocene)
★ ''"Asio" pygmaeus'' -
fossil (Early Pliocene of Odessa, Ukraine)
★ Ibiza Owl, Strigidae gen. et sp. indet. -
prehistoric (Sánchez Marco 2004)
Barn-owls
★ Genus ''
Tyto'' - typical barn-owls,stand up to 3 feet tall some 15 species and possibly 1 recently extinct
★ Genus ''
Phodilus'' - bay-owls, 1-2 extant species and possibly 1 recently extinct
Fossil genera
★ ''
Basityto'' (Early Eocene of Grafenmühle, Germany)
★ ''
Nocturnavis'' (Late Eocene/Early Oligocene) - includes ''"Bubo" incertus''
★ ''
Necrobyas'' (Late Eocene/Early Oligocene - Late Miocene) - includes ''"Bubo" arvernensis'' and ''Paratyto''
★ ''
Selenornis'' (Late Eocene/Early Oligocene) - includes ''"Asio" henrici''
★ ''
Prosybris'' (Early Oligocene? - Early Miocene)
Myth, lore, and popular culture
In many parts of the world, owls have been
associated with death and misfortune, likely due to their nocturnal activity and common screeching call. However, owls have also been associated with wisdom and prosperity, frequently being companion animals for goddesses.
Henry David Thoreau summarized one perception of owls, when he wrote in 1854's ''
Walden'', "I rejoice that there are owls. Let them do the idiotic and maniacal hooting for men. It is a sound admirably suited to swamps and twilight woods which no day illustrates, suggesting a vast and underdeveloped nature which men have not recognized. They represent the stark twilight and unsatisfied thoughts which all [men] have."
Africa
m Ancient Egyptians used a representation of an owl for their
hieroglyph for the sound ''m''. They would often draw this hieroglyph with its legs broken to keep this bird of prey from coming to life..
The Americas
In the culture of some Native Americans, (e.g. the
Native American Hopi nation), taboos often surround owls and they are often associated with evil or sorcery. Like
eagle feathers, the possession of owl feathers as
religious objects is regulated by federal law (e.g. The Migratory Bird Treaty Act of 1918 and Title 50 Part 22 Code of Federal Regulations).
The
Aztecs and
Mayans, along with other natives of
Mesoamerica, considered the Owl a symbol of death and destruction. In fact, the Aztec god of death,
Mictlantecuhtli, was often depicted with owls. There is a saying in Spanish that is still in use today: ''cuando el tecolote canta, el indio se muere'' ("when the owl cries/sings, the Indian dies"). The word "tecolote" means owl and is used in some parts of Mexico, although the proper Spanish word for "owl" is "buho".
Other Native American Tribes saw the owl as the carrier of the elders' spirits.
The
Moche people of ancient
Peru worshipped the animal and often depicted owls in their art.
[2]
Asia
In
Japanese culture, owls are seen as either negative or positive symbols depending on species. Sometimes owls are seen as divine messengers of the gods, while Barn or Horned owls are perceived as demonic figures.
In
Indian culture, a white owl is considered a companion of Lakshmi, the goddess of wealth, and therefore a harbinger of prosperity. The owl has been adapted as an emblem to reflect its implications of wisdom (''Wise old owl'') by a revered military institution in India known as the
Defence Service Staff College. In colloquial use, however, it is commonly used to refer to stupidity.
The
demoness Lilith is thought to have been associated with (screech) owls as well, by way of the
KJV translation of the passage in . Prior to the rise of
Islam, owls were considered bad
omens and associated with evil spirits in most
Middle Eastern
pagan traditions. In modern times, although such superstitions are less prevalent, owls are still popularly considered "evil" because of their fierce, horrific appearance.
Europe
In
Greek mythology, the owl, and specifically the
Little Owl, was often associated with the goddess
Athena, a
bird goddess who became associated with
wisdom,
the arts, and skills, and as a result, owls also became associated with wisdom. They are the unofficial mascot of the high-IQ society
Mensa.
The
Romans, in addition to having borrowed the Greek associations of the owl (see
Owl of Minerva), also considered owls to be funerary birds, due to their nocturnal activity and often having their nests in inaccessible places. As a result, seeing an owl in the daytime was considered a bad omen. The vampiric ''
strix'' of
Roman mythology was in part based on the owl.
Likewise, in
Romanian culture, the mournful call of an owl is thought to predict the death of somebody living in the neighbourhood. Such superstitions caused a minor disturbance when an owl showed up at Romanian President's residence,
Cotroceni Palace.
In the Welsh Cycles of the
Mabinogion, the Owl is considered cursed - the first owl was
Blodeuedd, a woman born of flowers to be the wife of
Lleu Llaw Gyffes. Because she fell in love with another man and plotted to kill Lleu, Lleu's guardian
Gwydion turned her into the first owl, saying ''"You are never to show your face to the light of day, rather you shall fear other birds; they will be hostile to you, and it will be their nature to maul and molest you wherever they find you. You will not lose your name but always be called Blodeuwedd."'' The addition of the w in her name changed her from a woman of flowers to an owl.
In
Finland the owl is paradoxically viewed as both a symbol of wisdom, and as a symbol of imbecility (presumably because of its "dumb" stare).
See also
★
Guardians of Ga'Hoole
References
★ (2003): ''Systematic revision of the Phorusrhacidae (Aves: Ralliformes)''. ''
Papéis Avulsos de Zoologia'' '43'(4): 55-91
PDF fulltext
★ (1990): ''Owl in the House: A Naturalist's Diary''. Joy Street Books, Boston.
ISBN 0316354562
★ (1987): ''One Man's Owl''
★ (2002): ''North American Owls: Biology and Natural History'', 2nd ed.. Smithsonian Institution Press, Washington DC.
ISBN 1-56098-939-4
★ (2005): "Old World phorusrhacids" (Aves, Phorusrhacidae): a new look at ''Strigogyps'' ("''Aenigmavis''") ''sapea'' (Peters 1987). ''PaleoBios (Berkeley)'' '25'(1): 11-16
HTML abstract
★ (1977): Occurrence and independent evolution of bilateral ear asymmetry in owls and implications on owl taxonomy. ''Philosophical Transactions of the Royal Society of London, Series B, Biological Sciences'' '280': 375-408.
★ (1985): The fossil record of birds. ''In:'' Farner, D.S.; King, J.R. & Parkes, Kenneth C. (eds.): ''Avian Biology'' '8': 79-238. Academic Press, New York.
★ (2007): The fossil family Ameghinornithidae (Mourer-Chauviré 1981): a short synopsis. ''Journal of Ornithology'' '148'(1): 25-28.
PDF fulltext
★ (2004): Avian zoogeographical patterns during the Quaternary in the Mediterranean region and paleoclimatic interpretation. ''Ardeola'' '51'(1): 91-132.
PDF fulltext
★ (1990): ''Distribution and taxonomy of the birds of the world: A Study in Molecular Evolution''. Yale University Press, New Haven, CT.
ISBN 0-300-04969-2
Footnotes
1.
In reality, for the distant relationship of the accipitrids - namely, the "Accipitriformes" according to Sibley & Ahlquist (1990) - with owls (and most other bird lineages) is most likely due to systematic error. Accipitrids have undergone drastic chromosome rearrangement and thus appear in DNA-DNA hybridization generally unlike other living birds.
2. Berrin, Katherine & Larco Museum. ''The Spirit of Ancient Peru:Treasures from the Museo Arqueológico Rafael Larco Herrera.'' New York: Thames and Hudson, 1997.
External links
General
★
Owl species of the World
★
Animal Diversity Web Page: Owls
★
Owl Brain Atlas
★
Smithsonian Snowy Owl Info
★
Owls of the Harry Potter movies - learn about the owls featured in the films, threats to the species, and conservation activities
★
World Owl Trust
★
Owl Physiology, 'The Owl Pages' website.
★
Migratory Bird Treaty Act of 1918
★
Athenian Owl coins
Eurasia
★
World of OwlsNorthern Irelands only Owl, Bird of Prey and Exotic Animal Centre.
★
Current Blakiston's Fish Owl Research in Russia
North America
★
List of Owl Species Breeding In North American and Owl Photos
★
South Okanagan Rehabilitation Centre For Owls (
British Columbia)
Australia
★
Australian Owls and Frogmouths
.jpg)
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