Great Horned Owl (Bubo virginianus)
Status: Along with other birds of prey, these birds are protected in many U.S. states.
Size: Up to 2 feet in height, 5 foot wingspan, 5 to 6.5 lbs.
Characteristics: Nocturnal, aggressive, solitary.
Area: North and South America.
Offspring: One to five eggs, once (rarely twice) per year.
· The great horned owl is the provincial bird of Alberta.
· The great horned owl controls harmful rat and mice populations throughout the United States.
· 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.
The great horned owl is a night predator with enormous yellow eyes and very sharp night vision. The female is considerably larger than the male (10% to 20%). The male’s territorial call sounds like “hoo-hoo, hoo, hoo.” Both males and females have sharp claws and beaks and are capable of killing prey two to three times larger than themselves. 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. 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 and geese.
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 same territory in the spring. Pairs mate for life and defend their territory vigorously against other great horned owls.
Mating occurs in early winter, 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, able to fly and hunt. They then disperse sometime in the fall, although they remain within 80 kilometres of their birth site. Great horned owls have lived up to 13 years in the wild, and 38 years in captivity.