pair will return to the same nesting burrow, or one close by, for many years in succession. Once settled, the female lines the burrow with dry material, including cattle dung. Indeed, the pair will often deposit dung outside the burrow entrance: once thought to be a means of repelling predators, this is now believed to encourage dung beetles and other insects on which the owls can feed. The female lays six to nine eggs (a maximum of twelve), one day apart, which she incubates for twenty-eight to thirty days. The male, meanwhile, provides food and aggressively defends the small area around the burrow.
In productive habitat, the Burrowing Owl may form loose colonies. This enables it to cooperate in sounding the alarm and warding off predators. Another ingenious defense system is deployed by the young chicks in the burrow: if disturbed, they make a harsh alarm call that sounds uncannily like the warning rattle of a rattlesnake. This is a prime example of Batesian mimicry, in which a vulnerable animal imitates a more dangerous one in order to deceive a potential predator. And this species certainly has many predators, from larger owls and other raptors to badgers, skunks, armadillos, and even domestic cats and dogs.
Globally, the Burrowing Owl is classed as Least Concern, with an estimated population of two million individuals. However, its wide distribution belies the fact that it is declining in many areas. Today, it is endangered in Canada, threatened in Mexico, and of special concern in Florida. Among the threats it faces are the loss of habitat to agricultural intensification, pesticides, and control programs for prairie dogs. Conservationists try to relocate Burrowing Owls whose burrows are threatened by a development project by enticing them to new burrows and perches constructed on safe alternative quarters nearby.
Burrowing Owls often find a home in human environments.
A Burrowing Owl drives an American Badger away from its nesting burrow.
Frogs feature among a wide variety of prey for this species.
The Great Horned Owl held an iconic status among the native peoples of North America.
GREAT HORNED OWL
BUBO VIRGINIANUS
APPEARANCE
Medium-large to large owl with prominent ear tufts; plumage variable across its range; rusty-brown to ocher facial disk, with blackish rim, whitish eyebrows, yellow-orange eyes, and white throat; upper parts warm brownish-buff, patterned in gray, black, and white; crown, tail, and flight feathers strongly barred; under parts brownish buff, with blackish blotches and crossbars and sometimes a white stripe down the center.
SIZE
length 17 – 25 in. (43 – 64 cm)
weight 2.6 – 5.5 lb (1.2 – 2.5 kg)
wingspan 3 – 5 ft (91– 153 cm)
DISTRIBUTION
All of North America south of the northern treeline; Central America into northern South America, from coastal Venezuela to Peru; discontinuous population south of the Amazon Basin in southern and eastern Brazil and Argentina.
STATUS
Least Concern
THE SIZE, FEROCITY, AND BEAUTY of this impressive owl made it a subject of veneration among many Native American peoples. In the southwest, the Pima believed that it was a reincarnation of slain warriors who fly about by night, whereas the Arikara of the Great Plains conducted mystical initiation ceremonies, wearing facial masks adorned with its wing and tail feathers. For others, it was a spiritual intermediary in matters of love or crop fertility, and the Hopi used its feathers in a winter solstice ceremony in the hope of summoning the heat of summer. Today, it remains North America’s best-known owl, and it is the provincial bird of Alberta.
Within North America, the Great Horned Owl is unmistakable. Resembling a slightly smaller version of the Eurasian Eagle Owl, it is a typical member of the Bubo genus, with a large powerful body, broad wings, and prominent ear tufts. Its only rival for size on the continent is the slightly heavier Snowy Owl and, like its Arctic cousin, it is an apex predator wherever it occurs. First described to science by early settlers in the Virginia colonies, hence its scientific name virginianus, it is also known as the “hoot owl” and “winged tiger”—the latter a reference to its strong, stripe-like barring. In general, this owl has a rusty-brown to ocher facial disk, with a prominent rim and eyebrows that accentuate the stern expression of the bright yellow-orange eyes. Its ear tufts are long and tousled, and held erect when alarmed or roosting. Upper parts are a warm brownish-buff, finely marked and mottled in gray, black, and white; under parts are brownish-buff, paler toward the belly, with strong blackish blotches and crossbars. The white throat is especially prominent when inflated during the bird’s territorial calling, and it may continue as a whitish stripe down the center of the breast.
The Great Horned Owl occurs across the entirety of North America and down through Central America into northern South America. In southern and western South America, it is replaced by the similar but slightly smaller and paler Magellanic Horned Owl (Bubo magellanicus), with which it was once thought to be conspecific until DNA research proved otherwise. Taxonomists recognize up to twenty subspecies, which differ in size and markings. Birds in forested regions tend to be darker and those in northern regions larger, thereby following Bergman’s rule, which states that individuals of any species tend to be larger in the colder parts of its range, because a higher body mass to surface area ratio helps to preserve heat. Northernmost populations may migrate south in winter, depending on weather conditions.
This species has a very wide habitat tolerance, found from dense forests to desert fringes, from open plains to city parks, and ranging up to 14,700 feet (4,500 m) in the Andes. Wherever it occurs, however, the Great Horned Owl requires mature trees for roosting and nesting and open ground or clearings in which to hunt. It generally becomes active around dusk and roosts by day, typically against a tree trunk, where its camouflage patterning is highly effective. In some regions, it may be out and about in the early morning or late afternoon.
The Great Horned Owl takes a variety of prey, which is one explanation for its success. Small to medium-sized mammals are at the top of the menu: typically, rabbits and hares, but also everything from small rodents to bats, squirrels, armadillos, raccoons, muskrats, porcupines, and domestic cats. Birds are also taken and range from crows, pigeons, and woodpeckers to grouse, herons, turkeys, and raptors, including all other North American owls except the Snowy Owl. Its standard hunting technique is to watch from an elevated perch, then swoop down with wings folded, before swinging its lethal talons forward to grab the prey. It may also hunt by quartering the ground like a Short-eared Owl. Such is the power of this owl—with feet that can exert 300 pounds of pressure per square inch (136 kg per 6.5 sq cm), about five times that of a human hand—that it can kill prey weighing up to three times its own weight. It is also highly versatile and has been known to wade into water to capture fish or even walk into an open hencoop to seize a chicken. Observations suggest that for hunting it relies more on eyesight than hearing, and indeed its eyes are almost as big as those of a human.
The Great Horned Owl is largely monogamous, with a pairdefending the same breeding territory for up to eight years. Outside the breeding season, however, it is solitary and does not get together with its mate until late winter to renew its bond. The male’s courtship song is a sequence of deep mellow hoots, with an emphasis on the central one: “hoo hoo HOOO hoo hoo.” He may call from dusk to midnight, and again just before dawn. The female responds with a similar but higher-pitched call.