Eastern Screech-Owl Life History

Habitat

Habitat ForestsAlmost 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

Food Small AnimalsEastern 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

Nest CavityEastern 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
Clutch Size:2-6 eggs
Number of Broods:1 brood
Egg Length:1.3-1.4 in (3.4-3.6 cm)
Egg Width:1.1-1.2 in (2.9-3 cm)
Incubation Period:27-34 days
Nestling Period:26-30 days
Egg Description:White.
Condition at Hatching:covered in white down; eyes closed.
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Behavior

Behavior Aerial Dive (ground/talons)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

Conservation Low ConcernEastern 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.Back to top

Backyard Tips

Eastern Screech-Owls readily accept nest boxes; consider putting one up to attract a breeding pair. Make sure you put it up well before breeding season. Attach a guard to keep predators from raiding eggs and young. Find out more about nest boxes on our Attract Birds pages. You'll find plans for building a nest box of the appropriate size on our All About Birdhouses site. These owls also use birdbaths and will visit them to drink and bathe.

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Credits

Lutmerding, J. A. and A. S. Love. Longevity records of North American birds. Version 2015.2. Patuxent Wildlife Research Center, Bird Banding Laboratory 2015.

Partners in Flight (2017). Avian Conservation Assessment Database. 2017.

Ritchison, Gary, Frederick R. Gehlbach, Peter Pyle and Michael A. Patten. 2017. Eastern Screech-Owl (Megascops asio), version 3.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA.

Sauer, J. R., D. K. Niven, J. E. Hines, D. J. Ziolkowski, Jr., K. L. Pardieck, J. E. Fallon, and W. A. Link (2017). The North American Breeding Bird Survey, Results and Analysis 1966–2015. Version 2.07.2017. USGS Patuxent Wildlife Research Center, Laurel, MD, USA.

Sibley, D. A. (2014). The Sibley guide to birds, second edition. Alfred A. Knopf, New York, USA.

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