''Strix'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

owl 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 a ...

s in the typical owl family (Strigidae), one of the two generally accepted living families of owls, with the other being the

barn-owl Barn-owls (family Tytonidae) are one of the two families of owls, the other being the true owls or typical owls, Strigidae. They are medium to large owls with large heads and characteristic heart-shaped faces. They have long, strong legs with po ...

(Tytonidae). Common names are earless owls or wood owls, though they are not the only owls without

ear tuft Ear tufts are a collection of fur or feathers found on animals which can resemble an animal's ear or is near the animal's ear. Cats Ear tufts are not found on all cat breeds. The ear tufts are located on the tips of cat ears and are also known ...

s, and " wood owl" is also used as a more generic name for forest-dwelling owls.

Neotropical The Neotropical realm is one of the eight biogeographic realms constituting Earth's land surface. Physically, it includes the tropical terrestrial ecoregions of the Americas and the entire South American temperate zone. Definition In bioge ...

birds in the genus '' Ciccaba'' are sometimes included in ''Strix''. These are medium-sized to large, robustly built, powerful owls. They do not have ear tufts and most are highly

nocturnal Nocturnality is an animal behavior characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnal meaning the opposite. Nocturnal creatures generally have highly developed sens ...

woodland birds. Most prey on small

mammal Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...

s, birds, and

reptiles Reptiles, as most commonly defined are the animals in the Class (biology), class Reptilia ( ), a paraphyletic grouping comprising all sauropsid, sauropsids except birds. Living reptiles comprise turtles, crocodilians, Squamata, squamates (lizar ...

. Most owls in the genus ''Strix'' can be distinguished from other

genera Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclat ...

of owls through their hooting vocalization and lack of visible ears. The

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

genus name ''Strix'' referred to a mythical vampiric owl-monster believed to suck the blood of infants. Although the genus ''Strix'' was established for the earless owls by

Linnaeus Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his ennoblement in 1761 as Carl von Linné Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalised binomial nomenclature, the ...

in 1758, many applied the term to other owls (namely the ''

Tyto ''Tyto'' is a genus of birds consisting of true barn owls, grass owls and masked owls that collectively make up all the species within the subfamily Tytoninae of the barn owl family, Tytonidae. Taxonomy The genus ''Tyto'' was introduced in 1828 ...

'') until the late 19th century.Mlíkovský, Jirí (2002)
''Cenozoic Birds of the World, Part 1: Europe''
. Ninox Press, Prague. p.217 This genus is closely related to the extinct Ornimegalonyx.

Taxonomy

The genus ''Strix'' was introduced by the Swedish naturalist

Carl Linnaeus Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his ennoblement in 1761 as Carl von Linné Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalised binomial nomenclature, the ...

in 1758 in the tenth edition of his ''

Systema Naturae ' (originally in Latin written ' with the ligature æ) is one of the major works of the Swedish botanist, zoologist and physician Carl Linnaeus (1707–1778) and introduced the Linnaean taxonomy. Although the system, now known as binomial nomen ...

''. The

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...

is the

tawny owl The tawny owl (''Strix aluco''), also called the brown owl, is commonly found in woodlands across Europe to western Siberia, and has seven recognized subspecies. It is a stocky, medium-sized owl, whose underparts are pale with dark streaks, an ...

. The genus name is a

word meaning "owl".

Species

The genus contains 22 species: *

Spotted wood owl The spotted wood owl (''Strix seloputo'') is an owl of the earless owl genus, ''Strix''. Its range is disjunct; it occurs in many regions surrounding Borneo, but not on that island itself. Description The spotted wood owl grows to a length of ...

, ''S. seloputo'' *

Mottled wood owl The mottled wood owl (''Strix ocellata'') is a species of large owl found in India. They are found in gardens and thin deciduous forests adjacent to dry thorn forests or farmland. They are easily detected by their distinctive tremulous eerie call ...

, ''S. ocellata'' *

Brown wood owl The brown wood owl (''Strix leptogrammica'') is found in India, Bangladesh, Sri Lanka, Indonesia, Taiwan, and south China. The brown wood owl is a resident breeder in south Asia. This species is a part of the family of owls known as typical owls ...

, ''S. leptogrammica'' *

Tawny owl The tawny owl (''Strix aluco''), also called the brown owl, is commonly found in woodlands across Europe to western Siberia, and has seven recognized subspecies. It is a stocky, medium-sized owl, whose underparts are pale with dark streaks, an ...

, ''S. aluco'' *

Maghreb owl The Maghreb owl (''Strix mauritanica'') is an owl of the earless owl genus, ''Strix''. It occurs in northwestern Africa from Morocco to Tunisia and Mauritania. It was previously considered a subspecies of the tawny owl. This species is a rathe ...

, ''S. mauritanica'' *

Himalayan owl The Himalayan owl (''Strix nivicolum''), also known as the Himalayan wood owl, is an owl of the forests of the Asia, from the Himalayas to Korea and Taiwan. It is sometimes considered a subspecies of the tawny owl, but is separated from that spec ...

, ''S. nivicolum'' *

Desert owl The desert owl or desert tawny owl (''Strix hadorami''), formerly known as Hume's owl, is a species of owl. It is closely related to the more widespread tawny owl and to the range-restricted Omani owl. This species is a part of the family Strigi ...

, ''S. hadorami'' *

Omani owl The Omani owl (''Strix butleri'') is an owl of the genus '' Strix'' found in shrubland and rocky areas of Oman, Iran and the United Arab Emirates. It was discovered in 2013. After the distinctive Omani owl was discovered, a similar-looking owl ...

, ''S. butleri'' *

Spotted owl The spotted owl (''Strix occidentalis'') is a species of true owl. It is a resident species of old-growth forests in western North America, where it nests in tree hollows, old bird of prey nests, or rock crevices. Nests can be between high and u ...

, ''S. occidentalis'' *

Barred owl The barred owl (''Strix varia''), also known as the northern barred owl, striped owl or, more informally, hoot owl, is a North American large species of owl. A member of the true owl family, Strigidae, they belong to the genus '' Strix'', whic ...

, ''S. varia'' * Cinereous owl, ''S. sartorii'' *

Fulvous owl The fulvous owl (''Strix fulvescens''), or Guatemala barred owl, is a resident of the cloud forests of Central America. A medium-sized true owl, it has a round head, lacking ear tufts. Typical coloration is warm dark brown or reddish brown on th ...

, ''S. fulvescens'' *

Rusty-barred owl The rusty-barred owl (''Strix hylophila'') is a medium-sized "typical owl" in subfamily Striginae. It is found in Argentina, Brazil (where it is known as the Brazilian owl), and Paraguay.HBW and BirdLife International (2020) ''Handbook of the B ...

, ''S. hylophila'' *

Chaco owl The Chaco owl (''Strix chacoensis'') is an owl found in Argentina, Bolivia, and Paraguay. Taxonomy and systematics The Chaco owl was originally described as a species, then quickly reclassified as a subspecies of rufous-legged owl (''Strix r ...

, ''S. chacoensis'' *

Rufous-legged owl The rufous-legged owl (''Strix rufipes'') is a medium-sized owl. It is found in Argentina and Chile. Taxonomy and systematics The rufous-legged owl has two subspecies, the nominate ''Strix rufipes rufipes'' and ''S. r. sanborni''. The latter ...

, ''S. rufipes'' * Ural owl, ''S. uralensis'' *

Great grey owl The great grey owl (''Strix nebulosa'') (also great gray owl in American English) is a very large owl, documented as the world's largest species of owl by length. It is distributed across the Northern Hemisphere, and it is the only species in the ...

, ''S. nebulosa'' *

African wood owl The African wood owl (''Strix woodfordii'') or Woodford's owl, is a typical owl from the genus '' Strix'' in the family Strigidae which is widespread in sub-Saharan Africa. Description The African wood owl is a medium-sized owl which has the typ ...

, ''S. woodfordii'' *

Mottled owl The mottled owl (''Strix virgata'') is a medium-sized owl found in Central and South America from Mexico to Brazil and Argentina. The head and back are mottled brown and the underparts whitish, with vertical bars on the chest and throat. The eyes ...

, ''Strix virgata'' *

Black-and-white owl The black-and-white owl (''Strix nigrolineata'') is a species of owl in the family Strigidae.Compare with ITIS: Description The black-and-white owl is a medium-sized owl with a round head and no ear tufts. It is between 35 and 40 cm in le ...

, ''Strix nigrolineata'' *

Black-banded owl The black-banded owl (''Strix huhula'') is a species of owl in the family Strigidae. Entirely nocturnal, this midsized black and white neotropical bird is a resident species, therefore never migrates out of its native South America. Its natural ...

, ''Strix huhula'' * Rufous-banded owl, ''Strix albitarsis''

Fossil species

The genus ''Strix'' is well represented in the

fossil record A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in ...

. Being a fairly generic type of strigid owl, they were probably the first truly modern Strigidae to evolve. However, whether several of the species usually placed in this genus indeed belong here is uncertain. Generally accepted in ''Strix'' are: *''S. dakota'' (Early Miocene of South Dakota, USA) – tentatively placed here *''Strix'' sp. (Late Miocene of Nebraska, USA) *''Strix'' sp. (Late Pliocene of Rębielice Królewski, Poland) apparently similar to the

great grey owl The great grey owl (''Strix nebulosa'') (also great gray owl in American English) is a very large owl, documented as the world's largest species of owl by length. It is distributed across the Northern Hemisphere, and it is the only species in the ...

*''Strix intermedia'' (Early - Middle Pleistocene of EC Europe) – may be paleosubspecies of ''S. aluco'' *''Strix brea'' (Late Pleistocene of SW North America) Now placed in its own genus. (See below) * *''Strix'' sp. (Late Pleistocene of Ladds, USA) ''"Strix" wintershofensis'' (Early/Middle Miocene of Wintershof West, Germany) and ''"Strix" edwardsi'' (Middle Miocene of Grive-Saint-Alban, France), while being strigid owls, have not at present been reliably identified to genus; they might also belong into the European ''Ninox''-like group. ''"Strix" ignota'' (Middle Miocene of Sansan, France) is sometimes erroneously considered a ''

nomen nudum In taxonomy, a ''nomen nudum'' ('naked name'; plural ''nomina nuda'') is a designation which looks exactly like a scientific name of an organism, and may have originally been intended to be one, but it has not been published with an adequate descr ...

'', but this assumption is based on what appears to be a ''

lapsus In philology, a lapsus (Latin for "lapse, slip, error") is an involuntary mistake made while writing or speaking. Investigations In 1895 an investigation into verbal slips was undertaken by a philologist and a psychologist, Rudolf Meringer and K ...

'' or misprint in a 1912 source. It may well belong into the present genus, but this requires confirmation. ''"Strix" perpasta'' (Late Miocene – Early Pliocene of Gargano Peninsula, Italy) does not appear to belong into this genus either. It is sometimes considered a

junior synonym The Botanical and Zoological Codes of nomenclature treat the concept of synonymy differently. * In botanical nomenclature, a synonym is a scientific name that applies to a taxon that (now) goes by a different scientific name. For example, Linna ...

of a brown fish-owl

paleosubspecies A chronospecies is a species derived from a sequential development pattern that involves continual and uniform changes from an extinct ancestral form on an evolutionary scale. The sequence of alterations eventually produces a population that is p ...

UMMP The University of Michigan in Ann Arbor is home to a number of museums. Located on the university's Central Campus are University of Michigan Museum of Natural History; the University of Michigan Museum of Art; the Kelsey Museum of Archaeology; Si ...

V31030, a

coracoid A coracoid (from Greek κόραξ, ''koraks'', raven) is a paired bone which is part of the shoulder assembly in all vertebrates except therian mammals (marsupials and placentals). In therian mammals (including humans), a coracoid process is prese ...

from Late Pliocene

Rexroad Formation The Rexroad Formation is a geologic formation in Kansas. It preserves fossils dating back to the Neogene period. These fossils include two types of skunk (''Spilogale rexroadi'' and '' Brachyprotoma breviramus''), a tree bat (''Lasiurus fossil ...

deposits of Kansas (USA), cannot be conclusively assigned to either the present genus or ''

Bubo A bubo (Greek βουβών, ''boubṓn'', 'groin') is adenitis or inflammation of the lymph nodes and is an example of reactive lymphadenopathy. Classification Buboes are a symptom of bubonic plague and occur as painful swellings in the thigh ...

''. Extinct forms formerly in ''Strix'': * ''"Strix" antiqua'' – now in '' Prosybris'' * ''"Strix" brea'' - now ''

Oraristrix The La Brea owl (''Oraristix brea'') is an extinct owl reported from the upper Pleistocene asphalt deposits of the La Brea Tar Pits in Los Angeles, California. It was first described in 1933 by Hildegarde Howard as ''Strix brea'', but this extinc ...

brea'' * ''"Strix" brevis'' – now in '' Intutula'' * ''"Strix" collongensis'' – now in '' Alasio'' * ''"Strix" melitensis'' and ''"Strix" sanctialbani'' – now in ''

'' * ''"Strix" murivora'' – male of the

Rodrigues scops owl The Rodrigues scops owl (''Otus murivorus''), also known as Rodrigues owl, Rodrigues lizard owl, Leguat's owl, or (somewhat misleadingly) Rodrigues little owl, was a small owl. It lived on the Mascarene island of Rodrigues, but it is nowadays e ...

* ''"Strix" newtoni'' and ''"Strix" sauzieri'' – male and female of the Mauritius scops owl

Taxonomy

Species

Fossil species

References

Further reading