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Home -> Kingdom Animalia -> Phylum Chordata -> Subphylum Vertebrata -> Class Aves -> Order Strigiformes -> Family Strigidae -> Species Bubo virginianus

Bubo virginianus
great horned owl



2008/07/20 02:33:02.075 GMT-4

By Elizabeth J. Axley

Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Class: Aves
Order: Strigiformes
Family: Strigidae
Genus: Bubo
Species: Bubo virginianus

Geographic Range

The great horned owl has a large geographic range. It is found throughout the forests of North, Central, and South America, from the Arctic regions in the North to the Straits of Magellan in the South.

Biogeographic Regions:
nearctic (native ); neotropical (native ).

Habitat

Within its range the great horned owl can be found in dense woodlands of hardwoods and conifers, along cliffs and rocky canyons, and in forest openings. In general, the great horned owl is solitary and inhabits unsettled places.

Physical Description

Mass
1450 g (average)
(51.04 oz)
[External Source: AnAge]


Basal Metabolic Rate


The great horned owl, the fiercest and most powerful of the common owls, is visually stunning. It is sometimes called the cat owl because of its catlike ears, eyes, shape of head, and appearance when huddled up on its nest. The great horned owl is highly recognizable for the feather tufts on its head that resemble horns. The upper parts of the owl's body are sooty brown with gray-brown mottling, and its dark underparts make its white throat standout. The great horned owl measures approximately .5 m. in length and has a wingspan of approximately 1.4 m from tip to tip.

Some key physical features:
endothermic ; bilateral symmetry .

Reproduction

Time to hatching
27 days (average)
[External Source: AnAge]


Age at sexual or reproductive maturity (female)
730 days (average)
[External Source: AnAge]


Age at sexual or reproductive maturity (male)
730 days (average)
[External Source: AnAge]


The courtship of the great horned owl usually begins in late January or early February. The mating rituals of the owl include the singing of love songs between the female and male. After mating the owls will use the abandoned nest of another bird, usually a hawk or crow. The eggs usually number 2-3, and rarely as many as 5. The great horned owl raises one family each year. The male and the female will both incubate the eggs, which will hatch in approximately 4 weeks. The great horned owl is also known to be a very protective parent, guarding the young until they mature fully and can leave the family (at approx. 1-2 months old).

Key reproductive features:
iteroparous ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; oviparous .

Behavior

The great horned owl spends the majority of its time hunting. The owl can see during the day, but has even better vision at night. The silent flight of this owl can be attributed to its loose, soft feathers. These two factors, and the fact that its prey is most active at night make it most advantageous for the great horned owl to hunt at night.

When there are young in its nest, the great horned owl is known to be very hostile. The owl has been observed flying near intruders snapping its bill and hooting. Overall, the great horned owl is a powerful, swift, and graceful bird of prey.

Key behaviors:
flies; motile .

Food Habits

Owls as a group eat their prey whole and regurgitate the unwanted parts (bones, fur, and feathers) in pellets. The food habits of the great horned owl are best ascertained by studying the remains of its prey in these pellets.

The great horned owl is a bird of prey that feeds on a varied assortment of animal life. It does the majority of its hunting at night, preferring to feed on small mammals, such as rabbits, woodchucks, mice, rats, squirrels, and skunks. The great horned owl is also known to feed on birds such as ducks, game birds, quails, and occasionally geese or turkeys.

Economic Importance for Humans: Negative

The great horned owl is capable of destroying game birds and animals. Poultry is also a favorite of the owls because they are easily captured. The occasional domestic cat can also fall victim to the great horned owl.

Economic Importance for Humans: Positive

The great horned owl controls harmful rat and mice populations throughout the United States. They kill domestic cats which in turn would have killed wild birds that humans value.

Conservation Status

IUCN Red List: [link]:
Least Concern.

US Migratory Bird Act: [link]:
Protected.

US Federal List: [link]:
No special status.

CITES: [link]:
Appendix II.

State of Michigan List: [link]:
No special status.

Despite the reputation that the great horned owl has gotten from angry poultry raisers, they are not as harmful as thought in the past. That they control pest populations has been recognized. Now, the great horned owl and other birds of prey are given complete protection in most states throughout the United States.

Contributors

Elizabeth J. Axley (author), University of Michigan.

References

Bent, Arthur. 1937. Life Histories of North American Birds of Prey , Part 2. Smithsonian Institute: Washington D.C.: 295-322.

Grosvenor, Gilbert and Alexander Wetmore. 1937. The Book of Birds., volume II . National Geographic Society, Washington D.C.: 8-9.

Crum, Robert. 1989. Calling the Owls. Sierra 74: 73-74.

McGillivray, W. Bruce. 1989. Geographic variation in size and reverse size dimorphism of the Great Horned Owl in North America. The Condor 91: 777- 786

Payne, Nancy Marie. 1994. The Great Horned Owl. The Conservationist 49: 40.

2008/07/20 02:33:03.836 GMT-4

To cite this page: Axley, E. 2001. "Bubo virginianus" (On-line), Animal Diversity Web. Accessed July 25, 2008 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Bubo_virginianus.html.

Disclaimer: The Animal Diversity Web is an educational resource written largely by and for college students. ADW doesn't cover all species in the world, nor does it include all the latest scientific information about organisms we describe. Though we edit our accounts for accuracy, we cannot guarantee all information in those accounts. While ADW staff and contributors provide references to books and websites that we believe are reputable, we cannot necessarily endorse the contents of references beyond our control.

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