Owl
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 Spotted
Owl
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Strigidae Tytonidae |
An owl is a member of any of some 220+ species of solitary, mainly nocturnal birds of prey in the order Strigiformes. Owls mostly hunt small mammals, insects, and other birds, though a few species specialize in hunting fish. They are found in all areas of the Earth except Antarctica, most of Greenland, and some remote islands.
External appearance
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, 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 incredibly good.
Many owls can also hunt by sound in total darkness. Different species of owls make different sounds, one of which is the widely recognizable, drawn-out "hoo" sound. The facial disc helps to funnel the sound of rodents to their ears, which are widely spaced. In some species, they are placed asymmetrically, for better directional location.
Despite their appearance, owls are more closely related to the nightjars (Caprimulgiformes) than to the diurnal predators in the order Falconiformes. Some taxonomists place the nightjars in the same order as owls, as in the Sibley-Ahlquist taxonomy.
Behavior
Owls' powerful clawed feet and sharp beak enable them to tear their prey to pieces before eating, although most items are swallowed whole. Their muffled wings and dull feathers allow them to fly practically silent and unseen.
Scientists studying the diets of owls are helped by their habit of disgorging 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 white and almost spherical, and range in number from a few to a dozen dependent on species. Their nests are crudely built and may be in trees, underground burrows or barns and caves.
Most owls are nocturnal, but several, including the pygmy owls (Glaucidium), are crepuscular, or twilight active, hunting mainly at dawn and dusk. A few owls, such as the Burrowing Owl (Speotyto cunicularia) and the Short-eared Owl (Asio flammeus), are also active during the day.
The smallest owls include the pygmy owls, some of which are only 13 cm (5.1 in) long, have a 32-cm (12.6-in) wingspan, and weigh only 50 g (1.76 oz). The largest owls are the eagle owls, the Eurasian Eagle Owl Bubo bubo and Verreaux's Eagle Owl B. lacteus, which may reach 71 cm (28 in) long, have a wingspan of just over 2 m (6.6 ft), and weigh about 4 kg (almost 9 lb).
Digestion
Like other birds, owls cannot chew their food - small prey items are swallowed whole, while larger prey are torn into smaller pieces before being swallowed. Some Owl species will partially pluck bird and larger mammal prey. Unlike other birds, Owls have no crop. A crop is a loose sac in the throat that serves as storage for food for later consumption. Since an Owl lacks this, food is passed directly into their digestive system.
A bird's stomach has two parts: The first part is the glandular stomach or proventriculus, which produces enzymes, acids, and mucus that begin the process of digestion. The second part is the muscular stomach, or gizzard. There are no digestive glands in the gizzard, and in birds of prey, it serves as a filter, holding back insoluble items such as bones, fur, teeth and feathers (more about this below).The soluble or soft parts of the food are ground by muscular contractions, and allowed to pass through to the rest of the digestive system, which includes the small and large intestine. The liver and pancreas secrete digestive enzymes into the small intestine where the food is absorbed into body. At the end of the digestive tract (after the large intestine) is the cloaca, a holding area for wastes and products from the digestive and urinary systems. The cloaca opens to the outside by means of the vent.
It is interesting to note that birds (apart from the Ostrich) do not have a bladder. The excretion from the vent is largely made up of an acid which is the white part of a healthy dropping. Several hours after eating, the indigestible parts (fur, bones, teeth & feathers that are still in the gizzard) are compressed into a pellet the same shape as the gizzard.
The pellet travels up from the gizzard back to the proventriculus. It will remain there for up to 10 hours before being regurgitated. Because the stored pellet partially blocks the Owl's digestive system, new prey cannot be swallowed until the pellet is ejected.
Regurgitation often signifies that an Owl is ready to eat again. When the Owl eats more than one prey item within several hours, the various remains are consolidated into one pellet. The pellet cycle is regular, regurgitating the remains when the digestive system has finished extracting the nutrition from the food. This is often done at a favorite roost. When an Owl is about to produce a pellet, it will take on a pained expression - the eyes are closed, the facial disc narrow, and the bird will be reluctant to fly. At the moment of expulsion, the neck is stretched up and forward, the beak is opened, and the pellet simply drops out without any retching or spitting movements.
Owl pellets differ from other birds of prey in that they contain a greater proportion of food residue. This is because an Owl's digestive juices are less acidic than in other birds of prey. Also, other raptors tend to pluck their prey to a much larger extent than owls.
Myth and lore
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 as a result of frequently being companion animals for goddesses.
Africa
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Ancient Egyptians used a representation of an owl for their hieroglyph for the sound m, although they would often draw this hieroglyph with its legs broken to keep this bird of prey from coming to life.[ citation needed]
The Americas
In the culture of the Native American Hopi nation, taboos surround owls, as they are closely associated with evil sorcery. The possession of owl feathers is considered an indication of witchcraft.
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 still exists today: cuando el tecolote canta, el indio se muere ("when the owl cries/sings, the indian dies").
Asia
In Japanese culture, the owl is a symbol of death, and seeing one is considered a bad omen, though in recent times, they have sometimes been considered a bird of luck instead. Likewise, in Romanian culture, the mournful call of an owl is thought to predict the death of somebody living in the neighbourhood.
In Indian culture, a white owl is considered a companion of the goddess of wealth, and therefore a harbinger of prosperity. The owl has been adapted as an emblem to reflect it's implications of wisdom (Wise old owl) by a revered military institution in India known as the Defence Service Staff College. In colloquia however it is commonly used to refer to stupidity.
The Akkadian goddess Lilitu is thought to have been associated with owls as well.
Europe
In Greek mythology, the owl, and specifically the Little Owl, was often associated with the Greek goddess Athena, a bird goddess who often assumed the form of an owl. Athena was also the goddess of wisdom, the Arts, and skills, and as a result, owls also became symbols of teaching and of institutions of learning, being included in the crest of arms of many universities. In the Western world, owls continue to be traditionally associated with wisdom.
The Romans, in addition to having borrowed the Greek associations of the owl, 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. In Romania this still exists, causing minor disturbance when an owl showed up at Cotroceni Palace.