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Great Horned Owl field guide

Field Guide

Common name	Great Horned Owl
Scientific name	Bubo virginianus
Family	Strigidae
Size	Length: 18-24 in (46-63 cm); female largerNational Audubon Society
Weight	32-88 oz (910 g-2.5 kg); females average about 1.7 kg, males 1.3 kgNational Audubon Society · Animal Diversity Web, University of Michigan Museum of Zoology
Wingspan	3 ft 4 in-4 ft 9 in (1.02-1.45 m)National Audubon Society
Lifespan	Average 13 years in the wild; wild record 28 years; captive record 35 yearsAnimal Diversity Web, University of Michigan Museum of Zoology
Diet	Varied, mostly mammals and birds: rats, mice, rabbits, skunks, some birds up to the size of geeseNational Audubon Society
Active when	Hunts mostly at night, sometimes at duskNational Audubon Society
Range	Found almost throughout North America and much of South America; no regular migrationNational Audubon Society
Conservation status	IUCN Red List: Least Concern; population 5,700,000 (Audubon)National Audubon Society · Animal Diversity Web, University of Michigan Museum of Zoology

Field Marks

Large size, conspicuous "ear" tufts, a white throat, and horizontal bars on the belly.National Audubon Society
The horn-like tufts are feathers, usually darker than the rest of the head; they are not real horns.Animal Diversity Web, University of Michigan Museum of Zoology · BirdNote
Eyes are different shades of yellow; white or tan coloring around a black bill.Animal Diversity Web, University of Michigan Museum of Zoology
Back is darker, mottled with blacks and browns; underbelly white with brown and black bars.Animal Diversity Web, University of Michigan Museum of Zoology
Compare to the smaller Long-eared Owl.National Audubon Society

Habitat

Found in practically all habitats in North America, from swamps to deserts to northern coniferous forests near treeline.National Audubon Society
Most commonly found in interspersed areas of woodland and open fields.Animal Diversity Web, University of Michigan Museum of Zoology
Habitats include grasslands, deserts, swamps, marshes, mangroves, and both rural and urban human settlements.Animal Diversity Web, University of Michigan Museum of Zoology
In breeding season it avoids tundra and unbroken grassland, since it requires some trees or heavy brush for cover.National Audubon Society
Lives at elevations from sea level up to 3352.8 meters (11,000 ft).Animal Diversity Web, University of Michigan Museum of Zoology

Behavior

Watches from a high perch, then swoops down to capture prey in its talons.National Audubon Society
Has extremely good hearing and good vision in low light conditions.National Audubon Society
Takes prey as varied as rabbits, hawks, snakes, and even skunks, and will attack porcupines, often with fatal results for both.National Audubon Society
Eats some birds (especially in the north) up to the size of geese, ducks, hawks, and smaller owls; also snakes, lizards, frogs, insects, scorpions, rarely fish.National Audubon Society
Song is a series of low, far-carrying hoots, hoo, hoo-hoo, hoo, hoo, with second and third notes shorter.National Audubon Society
When a pair calls in a duet, the female usually hoots first, and the male replies at a lower pitch.BirdNote
A pair may call back and forth or overlap their hoots; often heard during dark winter evenings and pre-dawn mornings.BirdNote
Males hoot throughout the year, but females only hoot during mating season.Animal Diversity Web, University of Michigan Museum of Zoology
Great Horned Owls also shriek (an owlet begging or a female defending its nest), adults bark at threats, and they hiss, pop, meow, coo, and snap their bills.BirdNote
Breeding pairs are territorial; hooting mainly sets territory limits, and territory disputes can be fatal. Territories are generally 5.26 to 5.56 sq km.Animal Diversity Web, University of Michigan Museum of Zoology
May begin nesting very early in the north (late winter); in courtship the male performs a display flight and feeds the female.National Audubon Society
Breeding occurs between the months of November and April; owls nest later at higher latitudes.Animal Diversity Web, University of Michigan Museum of Zoology
Typically uses an old nest of a hawk, eagle, crow, or heron, usually 20-60' above ground; also cliff ledges, caves, stumps, sometimes the ground.National Audubon Society
Lays 2-3, sometimes 1-5, rarely 6 eggs; incubation mostly by female, 28-35 days. Young can fly at about 9-10 weeks.National Audubon Society
Crows (Corvus brachyrhynchos) or raccoons sometimes eat their eggs.Animal Diversity Web, University of Michigan Museum of Zoology

Winter

Deep hoots may be heard rolling across the forest on mid-winter nights.National Audubon Society
In the north in winter, may store uneaten prey and later thaw the frozen carcass by "incubating" it.National Audubon Society
No regular migration, but individuals may wander long distances in fall and winter, some moving southward.National Audubon Society
In northern latitudes they tend to have larger core bodies and a longer wingspan.Animal Diversity Web, University of Michigan Museum of Zoology
Nesting in late winter in the north may give young time to learn hunting skills before next winter.National Audubon Society

Questions

How big is a Great Horned Owl?

It is 18-24 in (46-63 cm) long with a wingspan of 3 ft 4 in-4 ft 9 in. Females are larger.National Audubon Society

Are those real horns?

No. They are two tufts of feathers that stick up from the top of the head.BirdNote

What does it eat?

Mostly mammals and birds, such as rats, mice, rabbits, and skunks. It also eats snakes, lizards, frogs, insects, and scorpions.National Audubon Society

Why do two owls hoot back and forth?

A pair duets: the female usually hoots first and the male replies at a lower pitch. Hooting is used to set territory and find mates.BirdNote · Animal Diversity Web, University of Michigan Museum of Zoology

When do they nest?

Breeding occurs between November and April. In the north they may begin nesting very early, in late winter.Animal Diversity Web, University of Michigan Museum of Zoology · National Audubon Society

Where does it nest?

Usually in an old nest of another large bird such as a hawk, eagle, crow, or heron, 20-60' above ground. It adds little or no nest material.National Audubon Society

How long do they live?

The average life expectancy is 13 years. The wild record is 28 years.Animal Diversity Web, University of Michigan Museum of Zoology

Do they eat chickens?

Great horned owls may prey upon poultry raised as livestock. They also eat many rodents considered pests.Animal Diversity Web, University of Michigan Museum of Zoology

Do they migrate?

There is no regular migration. Some individuals wander long distances in fall and winter.National Audubon Society

Clips

Close view of a great horned owl perched among lichen-covered branches, ear tufts raised and yellow eyes looking straight at the camera, with a little snow on a branch at lower right.

Great horned owl stares back from a mobbed perch

A great horned owl perches on the broken tip of a bare branch against a pale blue-gray sky, head turned right, ear tufts raised and white throat showing, thin twigs at right.

Great horned owl hoots from a broken desert snag

Following a morning of crow alarm calls, a birder finds her first great horned owl perched in a lichen-covered tree, and a nesting blue jay later dives at it.

A great horned owl hoots from a bare branch in desert daylight until a second owl flies in and the pair mate.

Sources

Great Horned Owl - Guide to North American Birds, National Audubon Society
Bubo virginianus (great horned owl), Animal Diversity Web, University of Michigan Museum of Zoology
Great Horned Owl Duet, BirdNote
Voices and Vocabularies - Great Horned Owls, BirdNote