Introduction
The Eastern Screech Owl is a small, nocturnal woodland Owl with short ear-tufts and yellow eyes. There is a greyish-brown, red and grey morph, with intermediates also occuring. The species name asio is Latin for "Horned Owl".
Photo Gallery (17 pictures)
Sound Gallery
Information
Description: Greyish-brown morph: The facial disc is pale greyish-brown, finely motled or vermiculated darker, and having a
blackish rim. The eyebrows are paler than the surrounding plumage. Eyes are bright yellow. Ear-tufts are short, and prominent when erected. The bill and
cere are greenish-olive, and the whiskers at the base of the bill are pale greyish-brown. Upperparts are greyish-brown, with blackish shaft-streaks and
fine transverse bars or vermimculations. The crown is like the back, with blackish shaft-streaks and fine, dark vermiculations. The scapulars have
blackish-edged whitish outer webs, forming a line of white spots across the shoulder. Flight feathers are barred light and dark. The tail is
greyish-brown, mottled and vermiculated dark, with several thin pale bars.
The underparts have blackish shaft-streaks and irregular cross-barring. The upper breast has some broad shaft-streaks the resemble dark spots.
Tarsi are feathered to the base of the greyish-brown toes, which are partly feathered and bristled. Claws are dark horn.
Grey and red morphs: Similar in pattern, but general colouration is grey or fox-red respectively.
Eastern Screech-Owls can be confused with Western Screech-Owls. One way to tell the difference is the bill colour: Eastern Screech Owls have grey-green bills while Western Screech Owls have grey to black bills. They can also be distinguished by their different calls, and only occur together locally in eastern Colorado and southern Texas.
Size: Length 18-23cm. Wing length 145-175mm. Tail length 62-100mm. Weight 125-250g.
Habits: A nocturnal bird, with activity begining after sunset. 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.
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 both 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 x 1.9 cm. 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. Grey 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 larger 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.
Range of the Eastern Screech Owl Megascops asio
Status: Widespread and locally common.
Original Description: Linnaeus, Carolis. 1758. Systema Naturae ed. 10, p. 92.
