Tuesday, February 3, 2015
I'm back! Today we'll be continuing Learning about owls since I couldn't manage to get everything last time. so, we're continuing to learn from the same wiki from last time. Hearing.
Owls exhibit specialized hearing functions and ear shapes that also aid in hunting. They are noted for asymmetrical ear placements on the skull in some genera. Owls can have either internal or external ears, both of which are asymmetrical . Asymmetry has not been reported to extend to the middle or internal ear of the owl. Asymmetrical ear placement on the skull allows the owl to pinpoint the location of its prey. This is especially true for strictly nocturnal species such as the barn owls 'Tyto' or Tengmalm's owl. With ears set at different places on its skull, an owl is able to determine the direction from which the sound is coming by the minute difference in time that it takes for the sound waves to penetrate the left and right ears. The owl turns its head until the sound reaches both ears at the same time, at which point it is directly facing the source of the sound. This time difference between ears is a matter of about 0.00003 seconds, or 30 millionths of a second. Like the eyes, which utilize feather movements to focus light, the ears are surrounded by feathers to maximize hearing capabilities. Behind the ear openings there are modified, dense feathers, densely packed to form a facial ruff, which creates an anteriorly-facing concave wall that cups the sound into the ear structure. This facial ruff is poorly defined in some species and prominent, nearly encircling the face, in other species. The facial disk also acts to direct sound into the ears, and a downward-facing, sharply triangular beak minimizes sound reflection away from the face. The shape of the facial disk is adjustable at will to focus sounds more effectively
Talons.
While the auditory and visual capabilities of the owl allow it to locate and pursue its prey, the talons and beak of the owl do the final work. The owl kills its prey by using these talons to crush the skull and knead the body. The crushing power of an owl’s talons varies according to prey size and type, and by the size of the owl. The burrowing owl (Athene cunicularia), a small partly insectivorous owl, has a release force of only 5 N. The larger barn owl (Tyto alba) needs a force of 30 N to release its prey, and one of the largest owls, the great horned owl (Bubo virginianus) needs a force of over 130 N to release prey in its talons. An owl’s talons, like those of most birds of prey, can seem massive in comparison to the body size outside of flight. The masked owl has some of the proportionally longest talons of any bird of prey; they appear enormous in comparison to the body when fully extended to grasp prey. An owl’s claws are sharp and curved. The family Tytonidae have inner and central toes of about equal length, while the family Strigidae have an inner toe that is distinctly shorter than the central one. These different morphologies allow efficiency in capturing prey specific to the different environments they inhabit.
Beak.
The beak of the owl is short, curved and downward-facing, and typically hooked at the tip for gripping and tearing its prey. Once prey is captured, the scissor motion of the top and lower bill is used to tear the tissue and kill. The sharp lower edge of the upper bill works in coordination with the sharp upper edge of the lower bill to deliver this motion. The downward-facing beak allows the owl’s field of vision to be clear, as well as directing sound into the ears without deflecting sound waves away from the face.
Camouflage.
The coloration of the owl’s plumage plays a key role in its ability to sit still and blend into the environment, making it nearly invisible to prey. Owls tend to mimic the colorations and sometimes even the texture patterns of their surroundings, the common barn owl being an exception. Nyctea scandiaca, or the snowy owl, appears nearly bleach-white in color with a few flecks of black, mimicking their snowy surroundings perfectly. Likewise, the mottled wood-owl (Strix ocellata) displays shades of brown, tan and black, making the owl nearly invisible in the surrounding trees, especially from behind. Usually, the only tell-tale sign of a perched owl will be its vocalizations or its vividly colored eyes.
Evolution and systematics.
Great horned owl (Bubo virginianus) sleeping during daytime in a hollow tree
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 Strigiformes, and the owls in general become a family 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.[22] 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 some 220 to 225 extant species of owls, 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 Paleocene genera Berruornis and Ogygoptynx show that owls were already present as a distinct lineage some 60–57 mya (million years ago), and, hence, possibly also some 5 million years earlier, at the extinction of the non-avian dinosaurs. This makes them one of the oldest known groups of non-Galloanserae landbirds. The supposed "Cretaceous owls" Bradycneme and Heptasteornis are apparently non-avialan maniraptors.
During the Paleogene, the Strigiformes radiated into ecological niches now mostly filled by other groups of birds.[clarification needed] 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. 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[25] were formerly placed in part with the owls, specifically the Sophiornithidae; they appear to be Ameghinornithidae instead.
The ancient fossil owl Palaeoglaux artophoron
For fossil species and paleosubspecies of extant taxa, see the genus and species articles.
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)
Ogygoptyngidae[edit]
Ogygoptynx (Middle/Late Paleocene of Colorado, USA)
Protostrigidae[edit]
Eostrix (Early Eocene of WC USA and England – Middle Eocene of WC USA)
Minerva (Middle – Late Eocene of W USA) formerly Protostrix, includes "Aquila" ferox, "Aquila" lydekkeri, and "Bubo" leptosteus
Oligostrix (mid-Oligocene of Saxony, Germany)
Sophiornithidae
Sophiornis
Tytonidae: barn-owls
Barn owl (Tyto alba)
Genus Tyto – typical barn-owls, stand up to 500 millimetres (20 in) tall. Some 15 species and possibly one recently extinct
Genus Phodilus – bay-owls, 1–2 extant species and possibly one recently extinct
Fossil genera
Nocturnavis (Late Eocene/Early Oligocene) includes "Bubo" incertus
Selenornis (Late Eocene/Early Oligocene) – includes "Asio" henrici
Necrobyas (Late Eocene/Early Oligocene – Late Miocene) includes "Bubo" arvernensis and Paratyto
Prosybris (Early Oligocene? – Early Miocene)
Placement unresolved
Tytonidae gen. et sp. indet. "TMT 164" (Middle Miocene) – Prosybris?
Strigidae: typical owls[edit]
Long-eared owl (Asio otus) in erect pose
Laughing owl (Sceloglaux albifacies), last seen in 1914
Aegolius – saw-whet owls, four species
Asio – eared owls, 6–7 species
Athene – 2–4 species (depending on whether Speotyto and Heteroglaux are included or not)
Bubo – horned owls, eagle-owls and fish-owls; paraphyletic with Nyctea, Ketupa, and Scotopelia, some 25 species
Ciccaba – four species
Glaucidium – pygmy-owls, about 30–35 species
Grallistrix – stilt-owls, four species; prehistoric
Gymnoglaux – bare-legged owl or Cuban screech-owl
Jubula – maned owl
Lophostrix – crested owl
Mascarenotus – Mascarene owls, three species; extinct (c.1850)
Megascops – screech-owls, some 20 species
Micrathene – elf owl
Mimizuku – giant scops-owl or Mindanao Eagle-owl
Ninox – Australasian hawk-owls, some 20 species
Nesasio – fearful owl
Ornimegalonyx – Caribbean giant owls, 1–2 species; prehistoric
Otus – scops-owls; probably paraphyletic, about 45 species
Pseudoscops – Jamaican owl and possibly striped owl
Ptilopsis – white-faced owls, two species
Pulsatrix – spectacled owls, three species
Pyrroglaux – Palau owl
Sceloglaux – laughing owl; extinct (1914?)
Strix – earless owls, about 15 species
Surnia – northern hawk-owl
Uroglaux – Papuan hawk-owl
Xenoglaux – long-whiskered owlet
Fossil genera
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) – includes "Strix" collongensis
Oraristrix (Late Pleistocene)
Placement unresolved
"Otus/Strix" wintershofensis: fossil (Early/Middle Miocene of Wintershof West, Germany) – may be close to extant genus Ninox[24]
"Strix" edwardsi – fossil (Middle/Late? Miocene)
"Asio" pygmaeus – fossil (Early Pliocene of Odessa, Ukraine)
Strigidae gen. et sp. indet. UMMP V31030 (Late Pliocene) – Strix/Bubo?
Ibiza Owl, Strigidae gen. et sp. indet. – prehistoric
Symbolism and mythology.
Africa.
Among the Kikuyu 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.
The Americas.
In the culture of the Uto-Aztec tribe, the Hopi, taboos surround owls, which are associated with sorcery and other evils. The Aztecs and 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 Hočągara (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. An owl appeared to Glory of the Morning, the only female chief of the Hočąk nation, and uttered her name. Soon afterwards she died. People often allude to the reputation of owls as bearers of supernatural danger when they tell misbehaving children, "the owls will get you." Also, in the Cherokee culture, as well as many other Native American cultures, owls are a very bad omen. It is said that if you are outside in the broad day light and an owl flies over your head a family member or loved one would die within the coming week.
Middle East.
In Arab mythology, owls are seen as bad omens.
Hinduism.
In Hinduism, an owl is the vahana, mount, of the Goddess Lakshmi.
Western culture.
Owl-shaped protocorinthian aryballos, ca. 640 BC., from Greece
Roman owl mosaic from Italica, Spain
The modern West generally associates owls with wisdom. 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.[39] 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.
T. F. Thiselton-Dyer in his Folk-lore of Shakespeare says that "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 lustration, 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 human kind. 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."A list of "omens drear" in John Keats' Hyperion includes the "gloom-bird's hated screech." Pliny the Elder reports that owl's eggs were commonly used as a hangover cure.
The coat of arms of Leeds, seen here on Leeds Bridge, displays three owls.
In France, Belgium and the Netherlands, where owls are divided into eared owls (fr. hiboux / d. oehoes) and earless owls (fr. chouettes/ d. bosuilen), the former are seen as symbols of wisdom while the latter are assigned the grimmer meaning.
Three Canadian provinces have owls as provincial symbols: the great horned owl in Alberta, the great grey owl in Manitoba, and the snowy owl in Quebec.
Three owls appear on the coat of arms of the English city of Leeds, as the crest and the two supporters. They are derived from the arms of the city's first alderman, Sir John Saville.
In contrast, in Finnish culture, the owl has been considered a stupid animal, probably due to its wide-open eyes. The word pöllö means both "owl" and "idiot", and silmät pöllöllään "eyes owl-y" means "disoriented, dazed".
Use as 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
Attacks on humans.
Although humans and owls frequently live together in harmony, there have been incidents when owls have attacked humans. In January 2013, a man from Inverness, Scotland went into shock and suffered heavy bleeding after being attacked by an owl, which was likely a two-foot tall eagle owl. The photographer Eric Hosking lost his left eye after attempting to photograph a tawny owl, which inspired the title of his 1970 autobiography, An Eye for a Bird.
Conservation issues.
See also: List of Strigiformes by population
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). 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.
And that's it for Owls! Oops! I almost forgot to put in a pic. here you go!
Yes, I know, I like Barn Owls. Blame it on Legend of the Guardians: The Owls of Ga'hoole. Well, that's it for now! Seeya next time!
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Owls are awesome! Ive recently become a HUGE owl fan and have to buy everything owls now. Thanks for the info!
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