Barred owl

Name and taxonomy

Benjamin Smith Barton, a naturalist in Philadelphia, described the barred owl in 1799. The name points to the dusky marks that run in several directions across the underside. The bird belongs to Strix, the genus that gave the true owl family its name. People also call it the northern barred owl, the striped owl, the hoot owl and the eight hooter.

Three subspecies are usually accepted after the fulvous and cinereous forms were split away. The northern race covers most of the range and includes every western bird. A southern race lives from the Carolina coast through Georgia and Florida and averages smallest. A third race holds most of Texas and shows paler, gingery-cream ground colour.

Evolution and relatives

The barred owl sits between the Ural owl and the tawny owl in size. Its short, curved claws and its habits resemble those of the tawny owl of Europe. Some authors once grouped it with the spotted owl as a single superspecies. Genetic tests reject that, because the two lines split very early in North America. The two species can still interbreed, and the young are nicknamed sparred owls.

Pleistocene fossils that probably belong to this species come from Florida, Tennessee and Ontario. A larger, longer-legged fossil owl from California now sits in its own genus, Oraristrix. Western and eastern populations of the northern race may have parted about 7,000 years ago. That gap suggests a history in remote Canadian forest that nobody has yet traced.

Appearance

The plumage is grey-brown above, scalloped with white bars on the back and mantle. The throat and upper chest carry crescent-shaped bars across the body. The belly is boldly streaked from top to bottom in blackish or dusky brown. The facial disc is pale grey-brown with faint rings, and the bill is straw-yellow. Dark brown eyes set this owl apart from the yellow-eyed owls around it.

Adults measure 40 to 63 cm long, and the tail runs 18.2 to 25.7 cm. The wingspan is 96 to 125 cm. Females are the larger sex, at 610 to 1,150 g against 468 to 812 g in males. Feathers cover the legs and toes down to dark grey talons. Young birds look like dull adults, and a few rare albinos are pure white with brown eyes.

Habitat and range

The species holds most of the eastern United States and southern Canada. Old deciduous and mixed forest suits it best, and swampy bottomland is a favourite. Old growth offers nest hollows, open flight lanes below the canopy and cover from mobbing. Water is usually somewhere nearby, whether a river margin or wet ground. In North Carolina most birds sat in blocks of at least 86 to 370 hectares of woodland.

Suburbs with big old trees also suit the bird, and it counts as a local synanthrope. Owls in Charlotte, North Carolina increased faster in suburbs than in old growth. Easy rodent prey probably explains that, though cars and collisions kill more birds there. In parts of New Jersey great horned owls push barred owls out of edge habitat. In suburban Ohio, forest covered 41.4% of barred owl range and low-density housing 29.8%. Birds in Saskatchewan chose areas with at least 66% forest cover. GBIF holds records of the species from 10 countries.

Diet and hunting

The barred owl waits on a perch and glides from one to the next until it sees prey. Soft, comb-edged flight feathers let it close in silence, sometimes from only 6 to 10 metres. Among 2,234 prey items in one wide study, 76% were mammals and 15.8% invertebrates. Voles, deermice, rats, woodrats, chipmunks and flying squirrels lead the list. The mean size of prey in the east was estimated at 33.5 grams. Winter food can be almost all rodents, and voles made 91.5% of 118 items in New Jersey.

More than 100 bird species turn up in the diet, from swallows to grouse. Frogs, salamanders, lizards, snakes, crayfish and insects fill out the rest. The owl wades into shallow water for fish, which few owls do. It also plunges through snow for voles in their winter tunnels. Flying squirrels alone can supply up to 25.6% of the food by weight. A pellet of fur and bone measures about 3.5 cm across and 7.2 cm long.

Behaviour and social life

Adults hold a territory all year and keep the same borders for many years. Thirteen tracked territories in Minnesota averaged 273 hectares. Seven in Michigan averaged 282 hectares, and ten in Wisconsin 337.9 hectares. Ranges overlap widely between a pair in the breeding season and then shrink apart. Birds sing from perches near the edge of the ground they claim.

The species is mainly nocturnal, with peaks just after sunset and before dawn. It is more active by day than most owls, especially under heavy cloud. By day it hides in thick foliage, usually at least 5 metres above the ground. Small birds, crows and woodpeckers mob it whenever they find the roost. The bird does not migrate, and winter recoveries in the north lay within 10 km.

Communication and senses

The usual song is a run of eight accented hoots that drops in pitch at the end. Birders learn it as the phrase who cooks for you, drawled on the last note. The call probably carries well beyond 0.8 km through forest. Another call rises through several notes and ends on a long oo-aw. Other sounds run to cackles, caws, gurgles and screams, which is unusual in this genus.

An annoyed bird hisses about three times in three seconds and claps its bill. The female's voice is higher, and observers could sex 87 to 94% of calls in one study. The eyes are very large and hold many rod cells, which suits hunting in low light. Like other owls, the bird finds prey by ear as well as by sight. Birds answer a recording of their own species more readily than any eastern hawk.

Reproduction and life cycle

Pairs normally stay together for life and duet through the winter. The male bows, nods and half spreads his wings in courtship. The favourite nest is a hollow trunk or a broken snag in an old tree. Across 25 studies the mean nest tree stood 18.2 metres high and measured 65.7 cm across. Where hollows are scarce the birds take over hawk nests or squirrel dreys.

The female lays 2 to 3 eggs, and 5 at the most, straight onto the floor of the hollow. The eggs are pure white and weigh about 45.5 grams each. She lays at two or three day intervals and incubates alone for about 28 days. The male brings all the food to her during that month. A hatchling weighs about 46 grams and cannot feed itself.

The female broods the owlets for three weeks and then starts hunting again. Owlets leave the nest at about 36 to 39 days and often fall to the ground. They climb back up the trunk with their feet and bill while flapping hard. Parents feed them until the autumn, when the young disperse. Most birds first breed at two years old, and a few at three.

Predators and threats

The great horned owl kills barred owls of every age and is the main predator. Raccoons probably take eggs, nestlings and fledglings. Northern goshawks also kill nestlings and grown birds. Cars, traps set for fur-bearing mammals and hunting accidents kill others. A few adults have even eaten members of their own species. One owl died from the bite of a rodent that was defending itself.

Aspergillosis, a lung infection, kills forest owls including this one. About 15% of barred owls tested in Georgia carried West Nile virus. In one necropsy study 26.7% of birds carried the toxoplasmosis parasite. Worms, flies and feather lice are common and rarely fatal on their own. Logging removes the old hollow trees that the species needs for nesting.

Population and conservation

The barred owl is one of the commonest owls in North America. Partners in Flight puts the world total at up to 3 million birds. Canada holds an estimated 10,000 to 50,000 pairs. The Canadian Maritimes carry the densest known population, with 3,600 pairs. Iowa, Tennessee and Maryland show the highest United States densities.

The conservation problem here runs the other way, because the owl threatens another species. Barred owls survive at an estimated 91% a year against 82% for spotted owls. Where barred owls moved within 0.8 km of a spotted owl nest, 39% of spotted owls vanished. In 2023 the United States Fish and Wildlife Service drafted a plan to shoot large numbers of them. The plan would cull more than half a million birds in the Pacific Northwest.

Relationship with humans

This owl lives close to people and often nests in suburban woodland. It takes rats and mice, which helps farmers and gardeners. Its loud song is probably the owl call most Americans know. Birders draw it in by playing recordings, and it answers readily. Some birds ignore a climber at the nest, while others strike hard at intruders.

There are accounts of nesting owls knocking people out of trees. Attacks seem to follow repeated disturbance rather than a single visit. Human changes to the land let the species cross the Great Plains. Fire suppression and tree planting built the wooded corridors it followed. Wildlife officers now shoot the bird in the west to protect the spotted owl.

In culture and myth

John James Audubon drew the barred owl as Plate 46 of Birds of America. The prints appeared in London between 1827 and 1838, and the bird faces a grey squirrel. Robert Havell's London workshop engraved and coloured the image. The Brooklyn Museum owns the original aquatint. The nickname eight hooter comes from the count of notes in the song.

Most Native American nations read an owl call as a warning of death. Apache and Seminole parents told children to stay inside when owls called. Hopi story names Mongwu, the great horned owl, who punishes villagers that break the rules. The Tlingit and the Mohave both hold owl clans, and Northwest Coast carvers use the owl as a crest. Among the Creek, dancers perform a screech owl dance and also a horned owl dance. Audubon showed the owl threatening a squirrel, which probably says how people then saw the bird.