| Class: | Aves |
| Order: | Strigiformes |
| Family: | Strigidae |
| Size: | Height: 18 to 25 inches (46 to 64 cm) Wingspan: 52 to 55 inches (132 to 140 cm) |
| Weight: | 5 to 6.5 pounds (2.26 to 2.9 kg) |
| Diet: | Small mammals, birds, invertebrates, fish and reptiles |
| Distribution: | North, Central and South America |
| Young: | 1 to 5, once a year |
| Animal Predators: | Other great horned owls and occasionally northern goshawks |
| IUCN Status: | No special status |
| Terms: | Young: Owlet Group: Parliament |
| Lifespan: | Up to 13 years in the wild and up to 38 years in captivity |
· The great horned owl is the provincial bird of Alberta.
· The great horned owl controls harmful rat and mice populations throughout North America.
· Although they can see during the day, these owls have better vision at night.
· They are sometimes referred to as “hoot owls,” “cat owls,” “winged tigers” or “winged wolverines.”
· The species name for this owl is the Latinised form of Virginia, where it was first spotted.
Great horned owls are night predators with enormous yellow eyes and very sharp night vision. Their back and wings are a mixture of brown, grey and black, while their undersides are pale, with fine brown bars. The white throat and prominent ear tufts are distinguishing characteristics. The female is considerably larger (10 to 20 percent) than the male. The male’s territorial call sounds like “hoo, hoo-hoo, hoo, hoo.” Females also hoot, but they have higher-pitched voices than the males. Both males and females have soft feathers, but also sharp claws and beak and are capable of killing prey two to three times larger than themselves.
Great horned owls usually take over the nest of some other raptor rather than building their own. Hollow trees, ledges and promontories have all served as nest sites for these large birds. They can be found in practically all forested and semi-forested regions of North, Central, and South America, from sea level to timberline. Their home territory is fairly small, ranging approximately 800 acres. During harsh winters, some Canadian great horned owls move to the northern United States, but return to their territory in the spring.
Owls eat their prey whole, later regurgitating the indigestible items such as fur, feathers, teeth, and/or bones. They eat a wide variety of prey (over 250 different types), including rabbits, hares, porcupines, shrews, birds, skunks, squirrels, mice, voles, domestic cats, bats, birds and fish. Smaller birds who see a great horned owl during the day may mob it, in retaliation for these large predators hunting them at night and also to warn other birds and small animals of its location. Mobbing refers to when a group of prey species harasses a predator species, in this case by approaching the predator while wing-flapping and making loud vocalizations.
Mating occurs in early January, with females producing one to five white eggs (but usually only two or three) in March or April. The male brings food to the female, who stays with the eggs constantly. A month later, the downy hatchlings are born with closed eyes that open in a week. The female stays with them for up to three weeks, while the male guards the nest and brings food. When the owlets reach one month, they begin to learn to fly but stay with their parents until they are fully mature. They then disperse sometime in the fall, although they remain within 150 miles (250 km) of their birth site.
Pairs mate for life and defend their territory vigorously against other great horned owls. These birds have good eyesight during the day, and excellent eyesight at night. They glide silently through the air, making them efficient hunters.
Along with other birds of prey, these birds are protected in many U.S. states.
http://animaldiversity.ummz.umich.edu/accounts/bubo/b._virginianus$narrative.html
http://www.owlpages.com/species/bubo/virginianus/Default.htm
http://www.mbr-pwrc.usgs.gov/id/framlst/i3750id.html
http://www.animalsoftherainforest.com/greathorned.htm
http://www.ai-design.com/stargig/raptor/global/content/report/GreatHornedOwl.html
http://museum.nhm.uga.edu/gawildlife/birds/strigiformes/bvirginianus.html
http://www.vims.edu/cbnerr/species/great_horned_owl.html
http://www.discoverit.co.uk/falconry/hornedow.htm
Great Horned Owl Wildlife Fact File, IM Pub, US