Megascops asio Eastern Screech Owl Class: Aves. Order: Strigiformes. Family: Strigidae. Other names: Common screech owl, gray owl, little cat owl, little gray owl, little horned owl, mottled owl, red owl, shivering owl, whickering owl, ghost owl, dusk owl, spirit owl, mouse owl.
Physical Description: Small, mottled owl with large, rounded head and almost no neck; prominent ear tufts; yellow eyes. Its wings are rounded; its tail is short and square. Two color phases occur: gray and rufous (reddish), as well as brown intermediates. Eastern Screech owls are usually 7-10” long, with a wingspan ranging from 18-24”. Like most raptors, male Eastern Screech-Owls are smaller than females (males 3-6 oz., females 3-8 oz), and are more agile fliers and hunters. The female doesn’t hunt while on the nest; she and the chicks depend on food brought them by the male. Though the male is smaller, his voice is deeper than the female’s. It is the smallest owl with ear tufts in the eastern United States.
Diet in the Wild: Largely mice, shrews, and all types of insects. It will take songbirds, other small mammals (including bats), amphibians, small fish (wading right into shallow water to capture them), other arthropods (spiders, scorpions, millipedes, and crayfish), snails, earthworms, and reptiles. In spite of their small size, screech owls are exceptional hunters. They occasionally take ruffed grouse and large rats. Insects are caught in the beak in midair; other prey items are captured with the talons. They have been known to fish through holes in ice that were left by other animals.
Diet at the Zoo: Mice
Habitat & Range: Open deciduous woods, wood lots, suburban areas, lakeshores, old orchards; southeastern Saskatchewan, east along the Canadian border to New England, along the east coast to Florida, along the eastern foothills of the Rocky Mountains to central Texas and eastern Mexico. They are never found far from trees.
Life Span: Average 8 – 10 years in the wild, captive owls have been known to live over 20 years.
Perils in the wild: Larger birds of prey (especially larger owls), mink, weasels, raccoons, skunks, snakes, crows; habitat loss; humans. Owlets parasitized by insects found in their nests.
Physical Adaptations: Eastern Screech Owl has keen eyesight, which is helpful because they are strictly nocturnal Cryptic coloration mimics tree bark perfectly, which helps to camouflage the bird, while it sits very quietly, pulling in feathers and stretching body to resemble tree branch. All owls posses a zygodactyl fourth digit (the ability to reverse the fourth digit on its foot so that the talon either points forward or backwards as needed). Facial disc collects sounds and concentrates the sounds to the ear, allowing the owl to gauge direction and distance of possible prey.
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Owls have broad wings with large surface areas that help them to float through the air without flapping too much. Less flapping makes less noise. Short, rounded wings give the Screech Owl great maneuverability in tight spaces among trees. On both the primary and secondary feathers, there are comb-like structures at the edge of the feather that are responsible for muffling the sound of the air going over the wing – this essentially makes an owl silent when they fly. Also, an owl’s feathers can separate from each other on the same wing; therefore, the air flows over each of the individual feathers and their comb-like structures, which maximizes how silently an owl flies. Almost-silent flight enables the birds to hear the tiny sounds produced by their small mammal prey and approach them undetected. An Owl cannot move its eyes; it can only look straight ahead. Owls make up for this by being able to turn its head 270˚around, and almost upside-down. It is able to achieve this by having a long and very flexible neck. An owl's neck has 14 vertebrae; twice as many as humans. To protect their eyes, Owls are equipped with 3 eyelids. They have a normal upper and lower eyelid, the upper closing when the owl blinks, and the lower closing up when the Owl is asleep. The third eyelid is called a nictitating membrane, and is a thin layer of tissue that closes diagonally across the eye, from the inside to the outside. This cleans, protects, and moistens the surface of the eye. Owls use of parallax is facilitated by eyes and ears that are widely separated and forward facing; one of the most distinctive features of this family of birds.
Behavioral Adaptations: Eastern Screech Owls are almost entirely nocturnal unlike other owls that are sometimes active during the day. They are of the most nocturnal of North American owls. Live solitarily or in mated pairs Roosting owls become motionless when disturbed; as if ‘playing possum’. The screech owl rarely screeches (except when it defends its young). It has an extraordinary variety of courtship, territorial, and defense calls that include a descending whinny, pleasant trills and purrs, and quavering or bark-like whistles. Screech owls, being a resident rather than migrant species, can put on large amounts of fat in autumn to prepare for winter and will even hide food in caches. They survive winters by remaining inactive during harsh weather, feeding primarily on stores of hidden prey.
Reproduction and Development: Three to seven white eggs, February-July (specific times vary within its range), laid in sawdust found in natural cavities, hollow stumps, abandoned nesting holes (mostly of flickers and other woodpeckers), nest boxes. Male provides food while female incubates the eggs and protects the young. The parents feed the chicks for four weeks in and nest and even for the fifth and sixth week after the young have fledged. Eastern Screech Owl pairs usually are monogamous and remain together for life. Some males, however, will mate with two different females. The second female may evict the first female, lay her own eggs in the nest, and incubate both clutches. Parents are fierce defenders of their young and will attack and kill intruders; even animals larger than themselves. Nestling Screech-owls fight fiercely among themselves for food, and sometimes even kill and eat their smallest sibling.
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Additional Information: Experiments have shown that red owls have a higher rate of metabolism than grey owls. Also, red birds are more likely to die during heavy snowfalls whereas grey birds seem to be better adapted to colder regions. Eastern Screech Owls’ ability to kill birds much larger than themselves has led to individuals being described as ‘a feathered wildcat, a savage little brute.’ Virtually every wild bird is parasitized by a variety of lice and ticks. However many birds have developed ways to protect themselves and their offspring. The screech owl’s nest is often a very unclean place with left over prey, pellets, and feces, which is an invitation to insect larvae. Screech owls in some parts of their range sometimes carry live blind snakes back to the nest. These reptiles tend to live under the debris, where they eat insect larvae. Studies have shown that owlets from nests containing snakes tend to grow faster and to have lower mortality rates. Superstitions and folklore associated with owls: Owl meat was once considered an aphrodisiac. Owl marrow was mixed with oil of violets to make nose drops which were supposed to cure migraines. Plumbago herb was mixed with “burnt owl’s feet” to treat snakebite. Soup made from owls’ eggs was used for a variety of ailments including head lice, insomnia, and whooping cough. Another belief that has recurred over time is that if you place an owl, or part of an owl, on top of a sleeping person, that individual will be compelled to answer whatever questions you ask.
Conservation Status: Least Concern
Conservation Efforts:
Sources: Cincinnati Zoo & Botanical Gardens http://mynaturewatch.com/data1/images/eastern_screech_owl.jpg National Geographic Animal Diversity (.com) http://www.chattanooganaturecenter.org/www/docs/110.223 http://www.allaboutbirds.org/guide/Eastern_Screech-Owl/id Owls of the World Rob Hume Owls of the World John Burton
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