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Great Horned Owl

CONSERVATION STATUS : LEAST CONCERN
COMMON EXTINCT
Classification:

Order: Strigiformes
Genus & Species: Bubo virginianus
Family: Strigidae

Status:

Listed as Least Concern on the IUCN Red List.

Range:

North and South America.

Habitat:

Highly variable. Found in forests, deserts, and shrub lands. Prefer open spaces to hunt and trees for roosting.

Activity:

Nocturnal with spurts of activity at dusk and just before dawn.

Size:

17 to 25 inches long; males average 2.75 pounds and females average 3.5 pounds. Wingspan 40-57 inches (3.3-5 feet).

Longevity:

Average of 13 years in the wild and 20 years in captivity.

Diet:

Diet in the Wild: Have the most diverse diet of all North American raptors. Primarily rodents and rabbits but will take opossums, skunks, stray cats, foxes, and porcupines. Other foods include birds and invertebrates, but can also take large prey such as ospreys, peregrine falcons, prairie falcons, and other owls. Newly fledged birds will eat a larger percentage of invertebrates than adults.

Diet in the Zoo: Mice, rats, and quail.

Description:

This is the second heaviest North American owl; snowy owls are heaviest.  Great horned owl’s eyes are very large and cannot move, but the head can easily move 270 degrees. Flight feathers have fringes on both the leading and trailing edge that muffle wind sounds as the owls fly towards their prey. The velvety feather surfaces also reduce flight noise.

Reproduction:

1-4 eggs per clutch, average 2.5. Incubation 30-37 days.  Incubation begins after 1st egg is laid.  One brood per year. Eggs are near spherical, white, and about 2 inches in length.

Ecology, Adaptations, Etc:

These raptors are very good hunters. Owls have large eyes, pupils that open widely in the dark, and retinas containing many rod cells for excellent night vision. Their eyes do not move in their sockets, but they can swivel their heads more than 180 degrees. Although they have good eyesight, they use their ears more than their eyes. Hearing is very sensitive due in part to the facial disc (which can be flexed by the owl) directing sound to the ears. Their ears are so sensitive that they can even hear a mouse moving under snow. They accurately pounce on their prey by keeping the sound equal in each ear (binaural location) as they silently fly to make the kill.

Comments:

Most owls do not “hoot,” but great horned owls do. Their call is a muffled low tone repeated usually five times. Even though females are larger than males, the male has a larger voice box and a deeper voice. Pairs often call together with audible differences in pitch. Males hoot throughout the year, while females only hoot during mating season.