Eastern Screech Owl

The eastern screech owl or eastern screech-owl (Megascops asio) is a small owl that is relatively common in Eastern North America, from Mexico to Canada. This species is native to most wooded environments of its distribution, and more so than any other owl in its range, has adapted well to manmade development, although it frequently avoids detection due to its strictly nocturnal habits.

Description[]

Adults range from 16 to 25 cm (6.3 to 9.8 in) in length and weigh 121–244 g (4.3–8.6 oz). Among the differently sized races, length can average from 19.5 to 23.8 cm (7.7 to 9.4 in). The wingspan can range from 46 to 61 cm (18 to 24 in). In Ohio, male owls average 166 g (5.9 oz) and females 194 g (6.8 oz) while in central Texas, they average 157 g (5.5 oz) and 185 g (6.5 oz), respectively. They have either rusty or dark gray intricately patterned plumage with streaking on the underparts. Midsized by screech-owl standards, these birds are stocky, short-tailed (tail averages from 6.6 to 8.6 cm (2.6 to 3.4 in) in length) and broad-winged (wing cord averages from 14.5 to 17 cm (5.7 to 6.7 in)) as is typical of the genus. They have a large, round head with prominent ear tufts, yellow eyes, and a yellowish beak, which measures on average 1.45 cm (0.57 in) in length. The feet are relatively large and powerful compared to more southern screech owls and are typically feathered down to the toes, although the southernmost populations only have remnant bristles rather than full feathering on the legs and feet. The eastern screech owl (and its western counterpart) are actually some of the heaviest screech owls, the largest tropical screech owls do not exceed them in average or maximal weight, but (due to the eastern screech owls' relatively short tails) they are surpassed in length by Balsas (M. seductus), long-tufted (M. sanctaecatarinae), white-throated (M. albogularis), and rufescent owls (M. seductus), in roughly increasing order.

Two color variations are referred to as "red or rufous morphs" and "gray morphs" by bird watchers and ornithologists. Rusty birds are more common in the southern parts of the range; pairings of the two color variants do occur. While the gray morph provides remarkably effective camouflage amongst the bark of hardwood trees, red morphs may find security in certain pine trees and the colorful leaves of changing deciduous trees. The highest percentage of red morphs is known from Tennessee (79% of population) and Illinois (78% of population). A rarer "brown morph" is known, recorded exclusively in the south (i.e. Florida), which may be the occasional product of hybridation between the morphs. In Florida, brown morphs are typically reported in the more humid portions of the state, whereas they appear to be generally absent in the northern and northwestern parts of the state. A paler gray variation (sometimes bordering on a washed-out, whitish look) also exists in western Canada and the north-central United States

In the closely related western screech owl (Megascops kennicottii), no "morphs" are seen, as all owls of the western species are gray. Besides coloration, the western screech owl is of almost exactly the same general appearance and size as the eastern. The only reliable distinguishing feature is the bill color, which is considerably darker (often a black-gray) in the western and olive-yellow in the eastern; their voices also differ. The eastern and western screech owls overlap in the range in the Rio Grande valley at the Texas–Mexico border and the riparian woods of the Cimarron tributary of the Arkansas River on the edge of southern Great Plains. Other somewhat similar species that may abut the eastern screech owl's range in its western and southernmost distribution, like the Middle American screech owl (Megascops guatemalae; formerly called "vermiculated screech owl"), whiskered screech owl(Megascops trichopsis), and the flammulated owl (Psiloscops flammeolus), are distinguished by their increasingly smaller body and foot size, different streaking pattern on breast (bolder on the whiskered, weaker on the others), different bare part coloration, and distinctive voices. Through much of the eastern United States, eastern screech owls are essentially physically unmistakable, because other owls with ear tufts are much larger and differently colored and the only other small owl, the northern saw-whet owl (Aegolius acadius) is even smaller, with no ear tufts, a more defined facial disc, and browner overall color.

Habitat[]

Almost any habitat with sufficient tree cover will do for this cosmopolitan owl. Tree cavities or nest boxes are essential, and fairly open understories are preferred, but Eastern Screech-Owls live and breed successfully in farmland, suburban landscapes, and city parks. On the Great Plains, at the westernmost edge of its range, Eastern Screech-Owls occur in the uneven traces of wooded land along streams and rivers. Screech-owls cannot survive if all trees are removed, but the species readily recolonizes once trees are replanted, especially if nest boxes are also provided.

Food[]

Eastern Screech-Owls eat most kinds of small animals, including birds and mammals as well as surprisingly large numbers of earthworms, insects, crayfish, tadpoles, frogs, and lizards. They eat many kinds of mammals, including rats, mice, squirrels, moles, and rabbits. Small birds taken as prey include flycatchers, swallows, thrushes, waxwings, and finches, as well as larger species such as jays, grouse, doves, shorebirds, and woodpeckers. This owl is agile enough to occasionally prey on bats, and can rarely even be cannibalistic. When prey is plentiful, Eastern Screech-Owls cache extra food in tree holes for as long as four days.

Nesting[]

Eastern Screech-Owls nest in holes and cavities, but never dig a cavity themselves. Thus, they depend on tree holes opened or enlarged by woodpeckers, fungus, rot, or squirrels. They often occupy abandoned woodpecker nest holes. Eastern Screech-Owls readily accept nest boxes, including those built for Wood Ducks or Purple Martins, and sometimes nest in wood piles, mailboxes, or crates left on the ground. Eastern Screech-Owls build no nest. The female lays her eggs on whatever debris is at the bottom of her nesting cavity, be it wood-chips, twigs, or the cast-off feathers and droppings from a previous year’s nest. Settling in, she makes a body-shaped depression where her eggs lie. Eastern screech owls lay between 2-6 eggs, that hatch after 4 weeks of incubation and both parents will take care of the chicks for about one month.

Behavior[]

Eastern Screech-Owls are chiefly active at night, though they often hunt at dawn or dusk, and occasionally in daylight. These versatile hunters sit and wait in the trees for prey to pass below. They tend to pounce from perches six to ten feet off the ground, occasionally snatching an insect or bat on the wing or hitting shallow water talons-first to snag fish or tadpoles. Most flights are short (less than 75 feet or so). When traveling between perches, these owls often drop, fly straight, then rise again, in a characteristic U-shaped pattern. Eastern Screech-Owls form stable matches, usually one male with one female but occasionally one male with two females. Males defend small territories containing several cavity roost spots. When nesting, the female stays in the nest hole except for brief dawn and dusk excursions. She and the nestlings are fed by her mate, though it is the female who tears the prey into small bits for the babies. At fledging, the young first hop to the ground or nearby branches, using feet and fluttering wings to climb laboriously back to safety. Young gain flight and hunting skills slowly; they depend on their parents for food for 8–10 weeks after fledging. Both parents feed the youngsters at this stage, and adults, especially the females, shelter together with the young in communal tree roosts. Gradually, as the young gain skill, they begin to roost and hunt apart from their parents and siblings.

Conservation[]

Eastern Screech-Owl numbers are difficult to determine owing to their nocturnal lifestyle. The North American Breeding Bird Survey estimate that between 1966 and 2015, numbers increased in Canada, but declined in the U.S. Partners in Flight estimates a global breeding population of 900,000 with 95% living in the U.S., 4% in Mexico, and 1% in Canada. The species rates a 10 out of 20 on the Continental Concern Score. Eastern Screech-Owl is not on the 2016 State of North America's Birds' Watch List. This little owl is a generalist, with unfussy eating and nesting habits, and it adjusts well to the presence of humans. In fact, suburban birds often survive better than their rural kin, as suburbs provide more prey, milder climates, and fewer predators. Eastern Screech-Owls need trees to nest in, or, at least, nest boxes and brushy cover, but their small size, territorial tolerance, and broadly varied diet make this owl a successful survivor.