Eastern Screech-Owl Life History

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.Back to top

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.Back to top

Nesting

Nest Placement

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.

Nest Description

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.

Nesting Facts

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. Back to top

Conservation

Eastern Screech-Owl numbers are difficult to determine owing to their nocturnal lifestyle. According to the North American Breeding Bird Survey, their numbers have decreased annually by close to 1% for a cumulative decline of about 37% between 1966 and 2019. Partners in Flight estimates a global breeding population of 560,000 and rates the species 10 out of 20 on the Continental Concern Score, indicating a species of low conservation concern. This little owl is a generalist, with unfussy eating and nesting habits, and 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.

Credits

Lutmerding, J. A. and A. S. Love. (2020). Longevity records of North American birds. Version 2020. Patuxent Wildlife Research Center, Bird Banding Laboratory 2020.

Partners in Flight. (2020). Avian Conservation Assessment Database, version 2020.

Ritchison, G., F. R. Gehlbach, P. Pyle, and M. A. Patten (2020). Eastern Screech-Owl (Megascops asio), version 1.0. In Birds of the World (P. G. Rodewald, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA.

Sauer, J. R., D. K. Niven, J. E. Hines, D. J. Ziolkowski Jr., K. L. Pardieck, J. E. Fallon, and W. A. Link (2019). The North American Breeding Bird Survey, Results and Analysis 1966–2019. Version 2.07.2019. USGS Patuxent Wildlife Research Center, Laurel, MD, USA.

Sibley, D. A. (2014). The Sibley Guide to Birds, second edition. Alfred A. Knopf, New York, NY, USA.

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