Eastern Screech Owl - Megascops asio

Formerly Otus asio

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Calls - Megascops asio

A-song		© John Feith
B-song		© Unknown
A-song	Winnipeg, Manitoba, Canada	© Lucie Brisebois

The Eastern Screech Owl was first described by Carolus Linnaeus (the Swedish naturalist who developed binomial nomenclature to classify and organise plants and animals), who classified it in 1758. The origin of the word "Asio" is unknown, but it came to mean "Owl" in Latin. Eastern Screech Owls have also been called the common screech Owl, Ghost Owl, Dusk Owl, Little-eared Owl, Spirit Owl, Little Dukelet, Texas Screech-Owl, whickering Owl, little gray Owl, mottled Owl, the red Owl, the mouse Owl, the cat Owl, the shivering Owl, and the little horned Owl.

Description: The Eastern Screech Owl is a small, nocturnal, woodland Owl. There are two colour morphs, a gray phase and a reddish-brown phase.
Adult (gray phase) - facial disks dusky white with fine gray-brown mottling, bordered by black. The iris is bright yellow and the bill is gray-green, with tufts of bristly feathers around its base. Overall gray-brown, with gray narrow vertical stripes, bars, and spots on underparts, and barred wings and tail - legs light cinnamon buff, and toes are yellow.
Adult (red phase) - similar pattern to gray phase except cinnamon instead of gray - face plain light cinnamon - whitish superciliary and loral plumage.
Juvenile (gray phase) - similar to adults but indistinct stripes and bars more patterned - many feathers tipped with white Juvenile (red phase) - grayish brown, but distinctly rufescent colour overall - bars and stripes less distinct than adults.
Eastern Screech-Owls can be confused with Western Screech-Owls. One way to tell the difference is the bill colour - Eastern Screech Owls have gray-green bills while Western Screech Owls have gray to black bills. They can also be distinguished by their different calls, and only occur together locally in eastern Colorado and southern Texas.

The Eastern Screech-Owl flies fairly rapidly with a steady wingbeat (about 5 strokes/second). They rarely glide or hover, but may fly with erratic movements, when manoeuvring through wooded areas. Their wings are broad and the head is held tucked in giving the bird a stubby appearance when flying.

When threatened, an Eastern Screech Owl will stretch its body and tighten its feathers in order to look like a branch stub to avoid detection, but will take flight when it knows it has been detected. In open roosts, gray-phase birds tend to roost next to a tree trunk, whereas red-phase birds tend to roost in outer foliage, possibly because of thermal requirements.

Size: Female average Length:23cm (9.2")  Wingspan:56cm (22")  Weight:208g (7.3oz)
Male average Length:21cm (8.2")   Wingspan:54 cm (21")  Weight:200 g (7oz)

Habits: A nocturnal bird, with activity begining after sunset. Similar to the Western Screech Owl.

Voice: Males have a lower-pitched voice than females. The male's most common call (A-song) is a mellow, muted trill - each call lasts 2 to 3 seconds with about 35 notes given, and repeated at various intervals. The B-song is a descending whinny call, often given during courtship. Duets may consist of borh A and B songs. Females tend to bark or hoot when defending the nest. Young "peep" for food during their first three weeks, then chatter or hum later. Fledglings demand food with a harsh "keeeerr-r-r-r". They do not call while in flight, except when alarmed.

Hunting & Food: Eastern Screech Owls hunt from dusk to dawn, with most hunting being done during the first four hours of darkness. They hunt mainly from perches, occasionally hovering to catch prey. This Owl mainly hunts in open woodlands, along the edges of open fields or wetlands, or makes short forays into open fields. When prey is spotted, the Owl dives quickly and seizes it in its talons. They will also capture flying insects on the wing. Small prey will usually be swallowed whole on the spot, while larger prey is carried in the bill to a perch and then torn into pieces. An Eastern Screech Owl will tend to frequent areas in its home range where it hunted successfully on previous nights. They are opportunistic hunters and will switch to almost any suitably-sized prey when abundant. An extremely wide range of prey species is captured, the most favoured being small microtine rodents and deer mice. Other mammals taken include wood and Norway rats, chipmunks, cotton rats, squirrels, shrews, bats, and moles. Large flying insects are also taken. Birds, including many species of small songbirds, and larger birds such as Northern Bobwhite, Rock Dove, and Ruffed Grouse comprise about 7% of an Eastern Screech Owl's diet. They may be captured more often during periods of heavy songbird migration. Other prey include small fish, small snakes, lizards, and soft-shelled turtles, small frogs, toads, and salamanders, and invertebrates such as crayfish, snails, spiders, earthworms, scorpions, and centipedes. They have been observed fishing at holes in lake ice left by fishers, or at open pockets of water.
Pellets are medium-sized, averaging about 3.8 by 1.9 cm (1.5 by 0.75" inches). They are compact, dark gray, ovals that are composed of fur, feathers, bones, teeth, and chitin. Two to four pellets are expelled per day.

Breeding: Breeding season for Eastern Screech Owls is generally around mid April, but may range from mid March to mid May. They have an elaborate courtship ritual. Males approach females, calling from different branches until they are close. The male then bobs and swivels his head, bobs his entire body, and even slowly winks one eye at the female. If she ignores him, bobbing and swivelling motions intensify. If she accepts him, she moves close and they touch bills and preen each other. Pairs mate for life but will accept a new mate if the previous mate disappears. Gray and red colour phases will mate together.
They nest almost exclusively in tree cavities, with enlarged natural cavities being preferred, but they will also use old Pileated Woodpecker and Northern Flicker cavities. Nest cavities are usually 2 to 6 meters (6.5 to 20 feet) above the ground, but may be up to 15 meters (50 feet). They will readily nest in suitable nest boxes and occasionally behind loose boards on abandoned buildings or barns. Nests are almost always in deciduous trees such as oaks, elms, maples, sycamores, willows, and apples; occasionally in pines. Pairs will often reuse nest sites in consecutive years. No nest material is added, and the 2 to 8 (average 3-5) eggs are laid on natural sawdust on floor of cavity. Eggs are laid every two days and incubation begins after laying of the first egg. The incubation period is about 26 days and the fledging period about 31 days. Females do most of the incubating but males will assist. The male provides most of the food while the female broods the young, and will stockpile food during early stages. Eastern Screech Owls are single brooded, but may re-nest if the first clutch is lost. When the young are small the female tears the food up for them.
Adults tend to remain near their breeding areas year-round while juveniles disperse in the autumn. Siblings tend to disperse together. Small territories around nest sites are vigorously defended by males, but pairs may nest within 50 meters (164 feet) of another pair. Breeding territories range from 4 to 6 hectares (10 to 15 acres) in wooded suburban areas to 30 hectares (75 acres) in more open rural areas. Home ranges are much larger, up to 80 hectares (200 acres), but these are not defended and there is much overlap between pairs.

Mortality: While captive Eastern Screech Owls have lived for over 20 years, wild birds would be unlikely to reach this age. Juvenile and adult mortality may be as high as 70% and 30% respectively. Predators of these Owls include Great Horned Owls, Barred Owls, Long-eared Owls, Great gray Owls, Short-eared Owls, Snowy Owls, mink, weasels, raccoons, skunks, snakes, crows, and Blue Jays.

Habitat: Eastern Screech Owls inhabit open mixed woodlands, deciduous forests, parklands, wooded suburban areas, riparian woods along streams and wetlands (especially in drier areas), mature orchards, and woodlands near marshes, meadows, and fields. They will avoid dense forests because Great Horned Owls use that habitat. They will also avoid high elevation forests. Eastern Screech Owls roost mainly in natural cavities in large trees, including cavities open to the sky during dry weather. In suburban and rural areas they may roost behind loose boards on buildings, boxcars, or water tanks. They will also roost in dense foliage of trees, usually on a branch next to the trunk, or in dense scrubby brush.

Distribution: East North America from East Montana and the Great Lakes to the Gulf of Mexico, South to Tamaulipas in Northeast Mexico. Also South Ontario to Florida.

Distribution of Megascops asio

Status: Widespread and locally common.

Original Description: Linnaeus, Carolis. 1758. Systema Naturae ed. 10, p. 92.

Subspecies: M. a. asio, M. a. naevius, M. a. floridanus, M. a. hasbroucki, M. a. maxwelliae, M. a. mccallii

References:

Page Information:

Page compiled by Deane P. Lewis.

OwlPages.com Owl Species ID: 040.040.000 - Page last updated 2007-04-11

External Links:

Iris' Baby Owl Page - 8 pictures of a baby Eastern Screech owl with one short mpg movie. A brief description of the owl family.