The Great Horned owl

Nov 28, 2010 Features / Columnists, Interesting Creatures in Guyana

A Great Horned Owl

The Great Horned Owl, Bubo virginianus, also known as the Tiger Owl, is a large owl native to the Americas. It is an adaptable bird with a vast range and is the most widely distributed true owl in the Americas. The Magellanic Horned Owl (B. magellanicus) of the southern South America (extending north to the central Andes) is frequently included as a subspecies of this species too.
Great Horned Owls range in length from 18-27 inches (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 grey 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 colour; birds from the sub-Arctic are a washed-out, light-buff colour, while those from Central America can be a dark chocolate brown.
Their call is a low-pitched but loud ho-ho-hoo hoo hoo; sometimes it is only four syllables instead of five. The female’s call is higher and rises in pitch at the end of the call. Young owls make hissing or screeching sounds that are often confused with the calls of Barn Owls.
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 habitat, 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.
Great Horned Owl eggs, nestlings and fledglings 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, and, mostly, other Great Horned Owls. Far-ranging as it is, it is not considered a globally threatened species by the IUCN.
Owls have spectacular binocular vision allowing them to pinpoint prey and see in low light. The eyes of Great Horned Owls are nearly as large as those of humans and are immobile within their circular bone sockets. Instead of turning their eyes, they turn their heads. Therefore, their neck must be able to turn a full 270 degrees in order to see in other directions without moving its entire body.
An owl’s hearing is as good – if not better – than its vision; they have better depth perception and better perception of sound elevation (up-down direction) than humans. This is due to owl ears not being placed in the same position on either side of their head: the right ear is typically set higher in the skull and at a slightly different angle. By tilting or turning its head until the sound is the same in each ear, an owl can pinpoint both the horizontal and vertical direction of a sound.
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, shrews, bats, armadillos, weasels and gerbils. It is even a natural predator of much larger prey like porcupines, cats 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. 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.

(Wikipedia – The Free Online Encyclopedia)