Digital painting of a great horned owl. Painted with photoshop.
Individual Great Horned Owls range in length from 18-27 in (46–68 cm) and have a wingspan of 40-60.5 in (101–153 cm);
Females are larger than males, an average adult being 22 in (55 cm) long with a 49 in (124 cm) wingspan and weighing about 3.1 lbs (1400 g).
Adults have large ear tufts, a reddish, brown or gray face and a white patch on the throat. The iris is yellow, except the amber-eyed South American Great Horned Owl (B. V. nacurutu). Its “horns” are neither ears nor horns, simply tufts of feathers. The underparts are light with brown barring; the upper parts are mottled brown. The legs and feet are covered in feathers up to the talons. There are individual and regional variations in color; birds from the sub-Arctic are a washed-out, light-buff color, while those from Central America can be a dark chocolate brown.
The breeding habitat of the Great Horned Owl extends from subarctic North America through much of Central America and South America south to Tierra del Fuego. They are absent from southern Guatemala, El Salvador and Nicaragua to Panama in Central, and Amazonia and the southwest in South America, as well as from the West Indies and indeed most off-shore islands.
Within their habitat they can take up residence in trees that include deciduous, coniferous, and mixed forests, tropical rainforests, pampas, prairie, mountainous areas, deserts, subarctic tundra, rocky coasts, mangrove swamp forests, and some urban areas. It is less common in the more extreme areas (i.e. the heart of the deserts, extremely dense rainforests and in mountainous regions), generally absent from non-tidal wetland habitat6, and missing from the high Arctic tundra. All mated Great Horned Owls are permanent residents of their territories, but unmated and younger birds move freely in search of company and a territory, and leave regions with little food in winter.
Great Horned Owl eggs, nestlings and fledgings may be preyed on by foxes, coyotes, or wild or feral cats. There are almost no predators of adults, but they may be killed in confrontations with eagles, Snowy Owls and, mostly, other Great Horned Owls. Far-ranging as it is, it is not considered a globally threatened species by the IUCN
These birds hunt at night by waiting on a high perch and swooping down on prey. Prey is varied. Predominantly small to medium-sized mammals such as hares, rabbits, raccoons, rats, squirrels, mice, moles, voles, marmots, cats, shrews, bats, armadillos, weasels and gerbils. It is even a natural predator of porcupines and skunks (like most birds it has poor sense of smell). Birds also comprise a large portion of a Great Horned Owl’s diet, ranging in size from kinglets to Great Blue Herons. Waterbirds, especially coots and ducks, are hunted; even raptors, up to the size of Snowy Owls, are sometimes taken. The owls sometimes eat farmers’ chickens and small to medium and largish dogs. But reptiles, amphibians, fish, crustaceans and even insects only count for occasional prey. Cannibalism has been recorded. These birds also have 500 pounds per square inch of crushing power in their talons. An average adult human male has about 60 pounds per square inch in his hands. In northern regions, where larger prey that
cannot be eaten quickly are most prevalent, they may let uneaten food freeze and then thaw it out later using their own body heat. They also tend to eat and regurgitate food in the same locations.
Great Horned Owls are some of the earliest-breeding birds in North America. They breed in late January or early February and are often heard calling to each other in the fall, starting in October. They choose a mate by December and are often heard duetting before this time. For owls found in more tropical climates, the dates of the breeding season are somewhat undefined. They often take over a nest used by some other large bird, sometimes adding feathers to line the nest but usually not much more. Old crow and raven (Corvus), Red-tailed Hawk (Buteo jamaicensis) or large squirrel nests are often favored in North America. However, they are far from dependent on the old nests of others and may use cavities in trees and snags, cliffs, deserted buildings, and artificial platforms.
There are usually 2 eggs per clutch, with a clutch ranging in size from 1 to 5 eggs (5 is very rare). The average egg width is 1.8 in (46.5 mm), the average length is 2.2 in (55.2 mm) and the average weight is 1.8 oz (51 g). The incubation period ranges from 30 to 37 days, averaging 33 days. Brooding is almost continuous until the offspring are about 2 weeks old, after which it decreases. Young owls move onto nearby branches at 6 weeks and start to fly about a week later. The offspring have still been seen begging for food in late October (5 months after leaving the nest) and most do not separate from their parents until right before they start to reproduce for the next clutch (usually December). Birds may not breed for another year or two, and are often vagrants (“floaters”) until they mate, establish their own territories, and settle down.