Eastern Screech-Owl

About the eastern screech-owl

The eastern screech-owl is a stocky, short-tailed owl that's relatively common across eastern North America, from Mexico to Canada. It occupies most types of woodland within its range and adapts to urban and developed areas better than most owls, though its strictly nocturnal habits mean it often goes undetected even when living close to people. It was formally described by Carl Linnaeus in 1758, based on an illustration by English naturalist Mark Catesby, and originally placed in the genus Strix; it's now one of 22 screech owls in the genus Megascops, established in 1848. Taxonomists recognize five subspecies, though the boundaries between them are considered "muddled," with size decreasing from north to south and much of the color variation tied to local habitat.

Adults range from 16 to 25 cm (6.5 to 10 in) long and weigh 121 to 244 g (4.25 to 8.6 oz), with a wingspan of 46 to 61 cm (18 to 24 in); in Ohio, males average 166 g (5.9 oz) and females 194 g (6.8 oz). They're stocky and short-tailed, with broad wings, a large round head topped with prominent ear tufts, yellow eyes, and a yellowish beak about 1.45 cm (0.57 in) long. Plumage comes in two main color morphs, rusty ("red" or "rufous") and gray, with a rarer brown morph known only from Florida; red morphs are more common in the south, reaching 79% of the population in Tennessee and 78% in Illinois, while gray morphs dominate farther north. The gray morph camouflages well against hardwood bark, while red morphs may hide more effectively among pines and colorful autumn leaves. The eastern screech-owl closely resembles the western screech-owl in size and shape, but the two can be told apart by bill color — dark gray-black in the western bird, olive-yellow in the eastern — and by their calls; the two species' ranges overlap only narrowly, along the Texas-Mexico border and a stretch of the southern Great Plains.

Behavior and diet

Eastern screech-owls are strictly nocturnal, roosting by day in tree cavities or pressed against a trunk, and are heard far more often than seen thanks to their small size and camouflage. Their signature call is a descending, tremulous whinny, likened to a miniature horse, along with a separate monotone purring trill lasting three to five seconds — despite the name, they don't actually screech. They're most vocal at night, especially during the spring breeding season, and their calls follow a distinctly different pattern than the western screech-owl's.

Their diet in urban and suburban settings often centers on species that thrive near people, particularly introduced house sparrows and house mice, along with anole lizards and large insects such as cicadas. The species' ability to live in heavily developed areas exceeds that of the great horned owl and the barred owl, and it has proven considerably more resilient to urbanization than the American barn owl following the conversion of farmland to development. Eastern screech-owls generally avoid areas with regular activity from great horned owls, a much larger predator.

Breeding pairs are usually solitary and nest in a tree cavity, either a natural hollow or one excavated by a woodpecker — typically one made by a northern flicker or pileated woodpecker, since holes made by the mid-sized red-bellied woodpecker tend to be too small. The entrance needs to measure 7 to 20 cm (3 to 8 in) across. Owls also readily use nest boxes put up by people, and sometimes take over boxes intended for wood ducks, purple martins, or rock doves, occasionally killing and eating the box's original occupants in the process. A nine-year study comparing natural cavities and nest boxes found nearly identical fledging success between the two, with natural cavities holding a slight edge — up to 10% higher success — in some years. Nests have been recorded anywhere from 1.5 to 25 m (5 to 80 ft) off the ground. As with other owls, no actual nest is built; eggs are laid directly on the bare cavity floor or on a layer of fur and feathers left from earlier meals. Egg-laying typically begins in April, about two months after great horned owls start and roughly two weeks before American kestrels; eggs are laid at two-day intervals, with incubation beginning after the first egg is laid. Breeding pairs often return to the same nest site year after year.

Range and habitat

Eastern screech-owls occupy open mixed woodlands, deciduous forests, parklands, wooded suburban neighborhoods, riparian woods along streams and wetlands, mature orchards, and woodlands near marshes, meadows, and fields, occupying the widest range of habitats of any owl found east of the Rocky Mountains. Their range roughly tracks the distribution of eastern deciduous woodland, ending near the Rockies in the west and in northern Mexico in the south, where other screech owl species take over similar niches, and giving way to boreal owls farther north where true boreal forest begins. The introduction of scattered woodlots and cultivated land in the Great Plains has actually expanded the species' range there. Birds have been recorded nesting in unlikely urban spots, including along a busy highway border and atop a street light in a town square, and they may be found from sea level up to 1,400 m (4,600 ft) in the eastern Rockies and up to 1,500 m (4,900 ft) in the eastern Sierra Madre Oriental.

Roosting sites are typically natural tree cavities, sometimes ones open to the sky in dry weather, but in suburban and rural areas the owls also roost behind loose boards on buildings, in boxcars, on water tanks, or in dense foliage, usually on a branch near the trunk.

Conservation status

The eastern screech-owl carries an IUCN status of Least Concern (LC). Its ability to adapt to suburban and urban habitats, and to feed on introduced species like house sparrows and house mice, appears to have helped it persist even as farmland has given way to development across much of its eastern North American range.