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Owls are from the order Strigiformes (), which includes over 200 species of mostly Solitary animal and Nocturnal animal birds of prey typified by an upright stance, a large, broad head, binocular vision, binaural hearing, sharp Claw, and feathers adapted for silent flight. Exceptions include the diurnal northern hawk-owl and the gregarious burrowing owl.
Owls are divided into two families: the true (or typical) owl family, Strigidae, and the barn owl and bay owl family, Tytonidae. Owls hunt mostly small , , and other birds, although a few species specialize in hunting fish. They are found in all regions of the Earth except the polar ice caps and some remote islands.
A group of owls is called a "parliament".
Owls can rotate their heads and necks as much as 270°. Owls have 14 neck vertebrae—humans have only seven—and their vertebral circulatory systems are adapted to allow them to rotate their heads without cutting off blood to the brain. Specifically, the foramina in their vertebrae through which the vertebral arteries pass are about ten times the diameter of the artery, instead of about the same size as the artery, as is the case in humans; the vertebral arteries enter the cervical vertebrae higher than in other birds, giving the vessels some slack, and the carotid artery unite in a very large anastomosis or junction, the largest of any bird's, preventing blood supply from being cut off while they rotate their necks. Other anastomoses between the carotid and vertebral arteries support this effect.
The smallest owl—weighing as little as and measuring some —is the elf owl ( Micrathene whitneyi).Konig, Claus; Welck, Friedhelm and Jan-Hendrik Becking (1999) Owls: A Guide to the Owls of the World, Yale University Press, . Around the same diminutive length, although slightly heavier, are the lesser known long-whiskered owlet ( Xenoglaux loweryi) and Tamaulipas pygmy owl ( Glaucidium sanchezi). The largest owls are two similarly sized species; the Eurasian eagle-owl ( Bubo bubo) and Blakiston's fish owl ( Ketupa blakistoni). The largest females of these species are long, have a wing span, and weigh . Eurasian Eagle Owl. Oiseaux-birds.com. Retrieved 2013-03-02. Eurasian Eagle Owl – Bubo bubo – Information, Pictures, Sounds. Owlpages.com (13 August 2012). Retrieved 2013-03-02. Take A Peek At Boo, The Eagle Owl – The Quillcards Blog . Quillcards.com (23 September 2009). Retrieved 2013-03-02. Blakiston's Fish Owl Project. Fishowls.com (26 February 2013). Retrieved 2013-03-02.
Different species of owls produce different sounds; this distribution of calls aids owls in finding mates or announcing their presence to potential competitors, and also aids and in locating these birds and distinguishing species. As noted above, their facial discs help owls to funnel the sound of prey to their ears. In many species, these discs are placed asymmetrically, for better directional location.
Owl plumage is generally crypsis, although several species have facial and head markings, including face masks, , and brightly colored irises. These markings are generally more common in species inhabiting open habitats, and are thought to be used in signaling with other owls in low-light conditions.
One theory suggests that selection has led males to be smaller because it allows them to be efficient Foraging. The ability to obtain more food is advantageous during breeding season. In some species, female owls stay at their nest with their eggs while it is the responsibility of the male to bring back food to the nest. If food is scarce, the male first feeds himself before feeding the female. Small birds, which are agile, are an important source of food for owls. Male burrowing owls have been observed to have longer wing chords than females, despite being smaller than females. Furthermore, owls have been observed to be roughly the same size as their prey. This has also been observed in other predatory birds, which suggests that owls with smaller bodies and long wing chords have been selected for because of the increased agility and speed that allows them to catch their prey.
Another popular theory suggests that females have not been selected to be smaller like male owls because of their sexual roles. In many species, female owls may not leave the nest. Therefore, females may have a larger mass to allow them to go for a longer period of time without starving. For example, one hypothesized sexual role is that larger females are more capable of dismembering prey and feeding it to their young, hence female owls are larger than their male counterparts.
A different theory suggests that the size difference between male and females is due to sexual selection: since large females can choose their mate and may violently reject a male's sexual advances, smaller male owls that have the ability to escape unreceptive females are more likely to have been selected.
If the character is stable, there can be different optimums for both sexes. Selection operates on both sexes at the same time; therefore it is necessary to explain not only why one of the sexes is relatively bigger, but also why the other sex is smaller.Székely T, Freckleton R. P., Reynolds J. D. (2004) Sexual selection explains Rensch's rule of size dimorphism in shorebirds. PNAS, 101, N. 33, p. 12224–12227. If owls are still evolving toward smaller bodies and longer wing chords, according to V. Geodakyan's Evolutionary Theory of Sex, males should be more advanced on these characters. Males are viewed as an evolutionary vanguard of a population, and sexual dimorphism on the character, as an evolutionary "distance" between the sexes. "Phylogenetic rule of sexual dimorphism" states that if there exists a sexual dimorphism on any character, then the evolution of this trait goes from the female form toward the male one.Geodakyan V. A. (1985) Sexual dimorphism. In: Evolution and morphogenesis. (Mlikovsky J., Novak V. J. A., eds.), Academia, Praha, p. 467–477.
The disadvantage of such feather adaptations for barn owls is that their feathers are not waterproof. The adaptations mean that barn owls do not use the uropygial gland, informally the "preen" or "oil" gland, as most birds do, to spread oils across their plumage through preening. This makes them highly vulnerable to heavy rain when they are unable to hunt. Historically, they would switch to hunting indoors in wet weather, using and other agricultural buildings, but the decline in the numbers of these structures in the 20th and 21st centuries has reduced such opportunities. The lack of waterproofing means that barn owls are also susceptible to drowning, in Manger and other structures with smooth sides. The Barn Owl Trust provides advice on how this can be mitigated, by the installation of floats.
The prominences above a great horned owl's head are commonly mistaken as its ears. This is not the case; they are merely feather tufts. The ears are on the sides of the head in the usual location (in two different locations as described above).
Much of the owls' hunting strategy depends on stealth and surprise. Owls have at least two adaptations that aid them in achieving stealth. First, the dull coloration of their feathers can render them almost invisible under certain conditions. Secondly, serrated edges on the leading edge of owls' remiges muffle an owl's wing beats, allowing an owl's flight to be practically silent. Some fish-eating owls, for which silence has no evolutionary advantage, lack this adaptation.
An owl's sharp beak and powerful talons allow it to kill its prey before swallowing it whole (if it is not too big). Scientists studying the diets of owls are helped by their habit of regurgitating the indigestible parts of their prey (such as bones, scales, and fur) in the form of pellets. These "owl pellets" are plentiful and easy to interpret, and are often sold by companies to schools for dissection by students as a lesson in biology and ecology. Owl Pellets in the Classroom: Safety Guidelines. Carolina.com
See below cladogram:
Cladogram of Telluraves relationships based on Braun & Kimball (2021)Braun, E.L. & Kimball, R.T. (2021) Data types and the phylogeny of Neoaves. Birds
Some 220 to 225 extant species of owls are known, subdivided into two families: 1. or typical owls 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 non-avian . This makes them one of the oldest known groups of non-Galloanserae landbirds. The supposed "Cretaceous owls" Bradycneme and Heptasteornis are apparently non-Avialae Maniraptora.
During the Paleogene, the Strigiformes radiated into now mostly filled by other groups of birds. The owls as known today, though, evolved their characteristic morphology and 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 was 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 true 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 "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 toward 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)
Fossil genera
Fossil genera
In Hinduism, an owl is the vahana (mount) of the goddess Lakshmi, especially in the eastern region of India. Owls are considered a symbol of wealth, prosperity, wisdom, good luck, and fortune. This is the reason why Owls are seen with Lakshmi, who is also the goddess of fortune, wealth, and prosperity. At the same time, owls are also associated with evil times in Hinduism. At times, Chamunda (fearsome form of Chandi) is depicted seated on an owl, her vahana (mount or vehicle). Hindus believe that owls are messengers of death. In China, owls were traditionally considered to be omens of evil or misfortune. In Japan, owls are regarded as lucky, although in ancient times they were associated with death.
In Sumerian, Akkadian, and Babylonian culture, the owl was associated with Lilith. Sex and gender in the ancient Near East: proceedings of the 47th Rencontre Assyriologique Internationale, Helsinki, July 2–6, 2001, Part 2 p. 481.
The Western culture generally associates owls with wisdom and Alertness. This link goes back at least as far as Ancient Greece, where Athens, noted for art and scholarship, and Athena, Athens' patron goddess and the goddess of wisdom, had the owl as a symbol.Deacy, Susan, and Villing, Alexandra (2001). Athena in the Classical World. Koninklijke Brill NV, Leiden, The Netherlands, . Marija Gimbutas traces veneration of the owl as a goddess, among other birds, to the culture of Old Europe, long pre-dating Indo-European cultures.Gimbutas, Marija (2001) The living goddesses, University of California Press, p. 158. .
In medieval Europe, the owl was often used with more negative symbolism. The bird was associated with darkness, uncleanliness, and mourning. The bird was linked to the bubonic plague. Owls were even used as anti-Semetic caricatures of Jews.
T. F. Thiselton-Dyer, in his 1883 Folk-lore of Shakespeare, says that
According to the Apache and Seminole tribes, hearing owls hooting is considered the subject of numerous "bogeyman" stories told to warn children to remain indoors at night or not to cry too much, otherwise the owl may carry them away. In some tribal legends, owls are associated with Ghost, and the bony circles around an owl's eyes are said to comprise the fingernails of apparitional humans. Sometimes owls are said to carry messages from beyond the grave or deliver supernatural warnings to people who have broken tribal taboos.
The and the Maya, 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 an old saying in Mexico that is still in use: Cuando el tecolote canta, el indio muere ("When the owl cries/sings, the Indian dies"). The Popol Vuh, a Mayan religious text, describes owls as messengers of Xibalba (the Mayan "Place of Fright").
The belief that owls are messengers and harbingers of the dark powers is also found among the Ho-Chunk (Winnebago) of Wisconsin. When in earlier days the Hočągara committed the sin of killing enemies while they were within the sanctuary of the chief's lodge, an owl appeared and spoke to them in the voice of a human, saying, "From now on, the Hočągara will have no luck." This marked the beginning of the decline of their tribe.Radin, Paul (1990 1923) The Winnebago Tribe, Lincoln: University of Nebraska Press, pp. 7–9 . An owl appeared to Glory of the Morning, the only female chief of the Hočąk nation, and uttered her name. Soon after, she died.Smith, David Lee (1997) Folklore of the Winnebago Tribe, Norman: University of Oklahoma Press, p. 160 "Glory of the Morning", Hočąk Encyclopedia.
According to the culture of the Hopi, a Uto-Aztec tribe, taboos surround owls, which are associated with sorcery and other evils.
The Ojibwe tribes, as well as their Aboriginal Canadian counterparts, used an owl as a symbol for both evil and death. In addition, they used owls as a symbol of very high status of spiritual leaders of their spirituality.
The Pawnee people tribes viewed owls as the symbol of protection from any danger within their realms.
The Puebloan peoples associated owls with Skeleton Man, the god of death and the spirit of fertility.
The Yakama tribes use an owl as a totem, to guide where and how forests and natural resources are useful with management.
In addition to hunting, other threats to owl populations are habitat loss, pesticides, viruses, and vehicle collisions.
Eurasia:
North America:
Oceania:
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Ogygoptyngidae
Protostrigidae
Sophiornithidae
Tytonidae
Placement unresolved
Strigidae
Extinct genera
Placement unresolved
Symbolism and mythology
Among the Kikuyu people of Kenya, it was believed that owls were harbingers of death. If one saw an owl or heard its hoot, someone was going to die. In general, owls are viewed as harbingers of bad luck, ill health, or death. The belief is widespread even today.
from the earliest period it has been considered a bird of ill-omen," and Pliny tells us how, on one occasion, even Rome itself underwent a , because one of them strayed into the Capitol. He represents it also as a funereal bird, a monster of the night, the very abomination of humankind. Virgil describes its death howl from the top of the temple by night, a circumstance introduced as a precursor of Dido's death. Ovid, too, constantly speaks of this bird's presence as an evil omen; and indeed the same notions respecting it may be found among the writings of most of the ancient poets.
Native American cultures
People often allude to the reputation of owls as bearers of supernatural danger when they tell misbehaving children, "the owls will get you", and in most Native American folklore, owls are a symbol of death.
Rodent control
Encouraging natural predators to control rodent population is a natural form of pest control, along with excluding food sources for rodents. Placing a nest box for owls on a property can help control rodent populations (one family of hungry barn owls can consume more than 3,000 rodents in a nesting season) while maintaining the naturally balanced food chain.
Conservation issues
Almost all owls are listed in Appendix II of the international CITES treaty (the Convention on Illegal Trade in Endangered Species of Wild Fauna and Flora) with four species listed in Appendix I. Although owls have long been hunted, a 2008 news story from Malaysia indicates that the magnitude of owl poaching may be on the rise. In November 2008, TRAFFIC reported the seizure of 900 plucked and "oven-ready" owls in Peninsular Malaysia. Said Chris Shepherd, Senior Programme Officer for TRAFFIC's Southeast Asia office, "This is the first time we know of where 'ready-prepared' owls have been seized in Malaysia, and it may mark the start of a new trend in wild meat from the region. We will be monitoring developments closely." TRAFFIC commended the Department of Wildlife and National Parks in Malaysia for the raid that exposed the huge haul of owls. Included in the seizure were dead and plucked barn owls, spotted wood owls, crested serpent eagles, barred eagles, and brown wood owls, as well as 7,000 live lizards.
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