Eastern Screech-Owl

Description

Adults range from 16 to 25 cm (6+1⁄2 to 10 in) in length and weigh 121–244 g (4+1⁄4–8+5⁄8 oz). Among the differently sized races, length can average from 19.5 to 23.8 cm (7+11⁄16 to 9+3⁄8 in). The wingspan can range from 46 to 61 cm (18 to 24 in). In Ohio, male owls average 166 g (5+7⁄8 oz) and females 194 g (6+7⁄8 oz) while in central Texas, they average 157 g (5+1⁄2 oz) and 185 g (6+1⁄2 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+5⁄8 to 3+3⁄8 in) in length) and broad-winged (wing chord averages from 14.5 to 17 cm (5+3⁄4 to 6+3⁄4 in) in length) 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 (9⁄16 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. ingens), 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 against 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.

Range & 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 try to avoid areas known to have regular activity of larger owls, especially great horned owls (Bubo virginianus). Their ability to live in heavily developed areas outranks even the great horned and certainly the barred owl (Strix varia); screech owls also are considerably more successful in the face of urbanization than American barn owls (Tyto furcata) following the conversion of what was once farmland. Due to the introduction of open woodland and cultivated strips in the Great Plains, the range of eastern screech owls there has expanded. Eastern screech owls have been reported living and nesting in spots such as along the border of a busy highway and on the top of a street light in the middle of a busy town square. They often nest in trees in neighborhoods and urban yards inhabited by humans. In such urban environments, they often meet their dietary needs via introduced species that live close to humans such as house sparrows (Passer domesticus) and house mice (Mus musculus). They also consume anole lizards and large insects such as cicadas. They occupy the greatest range of habitats of any owl east of the Rockies. 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 in manmade locations such as behind loose boards on buildings, in boxcars, or on water tanks. They also roost in dense foliage of trees, usually on a branch next to the trunk, or in dense, scrubby brush. The distribution of the species is largely concurrent with the distribution of eastern deciduous woodlands, probably discontinuing at the Rocky Mountains in the west and in northern Mexico in the south due to the occupation of similar niches by other screech owls and discontinuing at the start of true boreal forest because of the occupation of a similar niche by other small owls (especially boreal owls (Aegolius funereus). Eastern screech owls may be found from sea level up to 1,400 m (4,600 ft) in elevation in the eastern Rocky Mountains and up to 1,500 m (4,900 ft) in the eastern Sierra Madre Oriental Mountains, although their altitudinal limits in the Appalachian Mountains, near the heart of their distribution, is not currently known.

Behaviour

Eastern screech owls are strictly nocturnal, roosting during the day in cavities or next to tree trunks. They are quite common and can often be found in residential areas. Due to their small size and camouflage, though, they are much more frequently heard than actually seen. These owls are frequently heard calling at night, especially during their spring breeding season. Despite their name, these owls do not truly screech. The eastern screech owl's call is a tremolo with a descending, whinny-like quality, like that of a miniature horse. They also produce a monotone purring trill lasting 3–5 seconds. Their voices are unmistakable and follow a noticeably different phrasing than that of the western screech owl.

Adapted from Eastern screech owl on Wikipedia, used under CC BY-SA 4.0.