Great horned owl - Knowledge

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are chosen by December to January. This species was once thought to be strictly monogamous, but recent analysis indicates one male may mate with two females simultaneously, as was discovered for the first time in 2018 in Reno, Nevada. During courtship in late fall or early winter, the male attracts the attention of his mate by hooting emphatically while leaning over (with the tail folded or cocked) and puffing up his white throat to look like a ball. The white throat may serve as a visual stimulus in the low light conditions typical of when this owl courts. He often flies up and down on a perch, while approaching the potential mate. Eventually, he comes to approach the female and tries to rub his bill against hers while repeatedly bowing. If receptive, the female hoots back when the pair meet but is more subdued in both her hoot and display. The male may convince the female by bringing her freshly caught prey, which they will share. While males often hoot emphatically for about a month or six weeks towards the end of the year, the period where females also hoot is usually only a week to ten days. Pairs typically breed together year after year and may mate for life, although they associate with each other more loosely when their young become mostly independent. Pairs rekindling their reproductive relationship in the winter may perform a milder courtship to strengthen pair bonds before producing young.

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young are covered in whitish gray down, with some brownish about the wings. Gradually the soft juvenile downy plumage comes through the down, being typically a cinnamon-buff color, but with variable hues predicting the eventual color of the mature owls. The extent of down gradually diminishes, developing mature-looking plumage by late summer, although many first year birds still have scattered bits of down into autumn. By late autumn, first-year birds look similar to adults but with a slightly warmer, reddish tinge, less well developed ear tufts and a smaller white throat patch. The nestling owls develop mostly in behavior between two weeks and two months of age, in which time they adapt the ability to defend themselves, grasp foods and climb. Vocally, the young are able to exert weak chips while still in the egg, developing into a raspy chirp shortly after hatching. The calls of the young increase rapidly in intensity, pitch and character, some juvenile males mimicking their father's hooting in fall but usually they conclude with various odd gurgling notes. The earliest competent hooting by juvenile owls is not until January. Young owls move onto nearby branches at 6 weeks and start to fly about a week later. However, the young are not usually competent fliers until they are about 10 to 12 weeks old. The age at which the young leave the nest is variable based on the abundance of food.

4224: 897:, being relatively short as is typical of most owls, is 175 to 252 mm (6.9 to 9.9 in) long. Like other owl species, the great horned owl is capable of "silent flight", which is the way owls fly while making almost no discernable noise, despite their large size. This is made possible thanks to three main components of the owl's wing structure. The leading edge of their feathers have serrations that help to disrupt the turbulence generated by wing flapping, then the softer feathers help deaden the sound, and finally the trailing fringe of the feathers works to finish cutting the sounds made by flight. The structure of the great horned owl wing also allows it to fly at a very low speed for the size of the species, as slow as 2 miles per hour when they are gliding on breezes. 4571:. Including the Magellanic species, there are approximately 5.3 million wild horned owls in the Americas. Most mortality in modern times is human-related, caused by owls flying into man-made objects, including buildings, cars, power lines, or barbed wire. In one study, the leading causes of death for owls were collision with cars, entanglement with wires, flying into buildings and, lastly, electrocution. Among 209 banded nestlings in yet another study, 67% were found dead after independence: 56 were found shot, 41 were trapped, 15 hit by cars, 14 found dead on highways and 14 electrocuted by overhead power lines. Secondary poisoning from pest control efforts is widely reported variously due to anticoagulant rodenticides, strychnine, organophosphates (famphur applied topically to 943:

species, the great horned owl has asymmetrical ear holes that allow for the triangulation of sounds when hunting in the dark. The different-height holes, while still close together, are differentiated enough that the owl is able to use the timing and direction of the sound waves hitting each hole to precisely locate prey even if the prey is located under cover such as snow. The disc-like shape of their faces also helps to direct the sounds they hear toward their ears. While the true nature/purpose of the ear tufts that are present on the great horned owl is unknown, researchers agree that the tufts do not play any role in the hearing ability of the owl. It is estimated that their hearing is up to ten times that of a human being.

1193: 2075: 3965:, might be seen as potential competition for the owls, most others seem to be regarded merely as prey by great horned owls. The great horned owl is both the most prolific and diverse predator in America of other birds of prey, with other accomplished raptor-hunters such as the goshawk and the golden eagle being more restricted in range, habitat and number in North America and thus having a more minor impact. All studies have found raptors are a small portion of this owl's diet but predation can be seriously detrimental for such prey, as raptors tend to be territorial and sparsely distributed as a rule and thus can be effectively decimated by a small number of losses. In the 2381: 3997:

have low populations. Great horned owls were the leading cause of mortality in juvenile spotted owls (30% of losses) and juvenile great grey owls (65% of losses). Less is known about relations with the snowy owl, which may compete with great horned owls for food while invading south for the winter. Anecdotally, both snowy and great horned owls have rarely been reported to dominate or even kill one another depending on the size and disposition of the individual owls, although the snowy's preference for more open areas again acts as something of a buffer. The snowy may be the one North American owl too formidable for the great horned owl to consider as prey.

3989:, great horned owls were responsible for the failure of 78% of eastern screech owl's nests. Long-eared owls and, to a lesser extent, barn owls tend to hunt in open, sparsely treed habitats more so than great horned owls, but since they may return to wooded spots for nesting purposes, they may be more vulnerable there. The long-eared owl and barn owls are often compared to the great horned owl as these medium-sized species often occur in abutting habitats and often hunt primarily the same vole and mice species, although the alternate prey of the great horned tends to be much larger, including the smaller owls themselves. In a pair of studies from 2447:

occasion, the owls may return to the kill site to continue eating if the prey is too heavy to fly with after dismemberment. Many owls will accrue a cache of prey, especially those who are nesting. Caches must be at a safe location, usually the crotch of a tall tree. In northern regions, where large prey is prevalent, an owl may let uneaten food freeze and then thaw it out later using its own body heat. Hunting success seems to require fairly open understory, and experimental testing of microhabitat proved that open areas provided more hunting success on five species of rodent, with cloudy nights and denser bush foliage both decreasing success.

2298: 2372:, incursions into neighboring territories were observed only twice—by females when a neighboring female had died or emigrated, suggesting that territorial defense may be sex-specific. At least four dead great horned owls in Kluane were apparently killed by others of their own species in territorial conflicts. Owls killed by other horned owls are sometimes cannibalized, although the origin of the killing may have been territorial aggression. Northern populations occasionally irrupt south during times of food shortage, but there is no annual migration even at the northern limits of the great horned owl's range. 1694: 2047: 2000: 2413:) sunning themselves on desert rocks. Owls hunt mainly by watching from a snag, pole or other high perch. During hunting forays, they often fly about 50 to 100 m (160 to 330 ft) from perch to perch, stopping to survey for food at each, until they sense a prey item below. From such vantage points, owls dive down to the ground, often with wings folded, to ambush their prey. Effective maximum hunting distance of an owl from an elevated perch is 90 m (300 ft). Due to their short but broad wings, great horned owls are ideally suited for low speed and maneuverability. 4408:, egg-laying can be 3–4 weeks earlier than usual when food is abundant and weather is favorable. For owls found in more tropical climates, the dates of the breeding season are somewhat undefined. There are usually 2 eggs per clutch, but clutches range in size from 1 to 6 eggs (over 3 is uncommon, over 4 is very rare), depending on environmental conditions. The average egg width is 46.5 mm (1.83 in), the average length is 55 mm (2.2 in) and the average weight is 51 g (1.8 oz), although mass could be slightly higher elsewhere because this figure is from 3774:, some of which the great horned owl has even reportedly caught via "hawking", i.e. swooping at on the wing. In some cases, the content of insects in great horned owl pellets may actually be due to the owls eating other birds which have freshly eaten insects in their own stomachs. It is commonly believed that routine insectivory in great horned owls is mainly restricted to inexperienced young owls too unskilled to graduate to larger prey yet. It is clearly inefficient for owls of this size to attempt to raise young on a diet of foods as small as insects. Although rare, 2595: 2067: 878: 837: 789: 1444: 2456: 221: 2943:) and black-tailed jackrabbits predominated in October to December, making up 42.9% by number (and nearly all the biomass), thence dropping to 9.3% by number in April, while voles rose to 32.2% peak in May, down to a minimum of 10.2% by number in June. Further north in Colorado, in the absence of jackrabbits, the mountain cottontails falls to third place by number (12.9%) behind the northern pocket gopher (36.5%) and prairie vole (24.7%) but still dominates the biomass, making up about half. 901: 134: 2290: 4209: 1709: 4429: 2443:

contain skulls up to 3 cm (1.2 in) in width inside them. However, not all prey can be swallowed at once, and owls will also fly with prey to a perch and tear off pieces with their bill. Most dietary studies focus on pellets found under perches and around nests, since they provide a more complete picture of the diversity of prey consumed, but prey remains outside of pellets may provide clues to prey excluded from the pellets and a combination of both is recommended.

3238: 2890: 1069:. These vocalizations may be variously uttered when the birds are disturbed and angered at the nest (frequently preceding an attack on an interloping human or other animal), represent the vocal development of young owls, or are given during courtship and during territorial disputes with other owls. Young owls still in the care of their parents make loud, persistent hissing or loud, piercing screeching sounds that are often confused with the calls of the barn owl. 950:, are large even for an owl and rank proportionately among the largest eyes of all terrestrial vertebrates. The great horned owl has cylindrical eyes which creates more distance from the lens of the eye to the retina, which allows it to act more like a telephoto lens for farther distance sight compared to that possible from round eyes. They are visually highly adapted for nocturnal hunting and provide a wide, almost completely binocular field of view, a large 4627:, spotted owls have been badly affected by considerable great horned owl predation. While at least the ospreys and peregrines have rebounded admirably nonetheless, bird and mammal species that are much rarer overall sometimes fall prey to great horned owls, many in which even sporadic losses can be devastating. Among the species considered threatened, endangered or critically endangered by the IUCN which are also known to be killed by great horned owls are 355: 179: 109: 4476:

longest lived great horned owl was 50 years. A more typical top lifespan of a great horned owl is approximately 13 years. In general, great horned owls are most vulnerable in the early stages of life, although few species press attacks on the owl's nests due to the ferocious defensive abilities of the parents. Occasionally, nestlings and fledglings will fall from the nest too early to escape or to competently defend themselves and fall prey to

4269: 4736:, which are famously intelligent birds, although not as often playful: "It knows its keeper and usually accepts whatever he wishes to do with a good deal of tolerance." Carl D. Marti disagrees with Errington's assessments, noting that their prey selection is not as "completely random as Errington suggested". He further notes that though great horned owls appear to "select their mammalian prey in general relation to the prey populations", 1592:) tend to have a more grayish base, the coastal owls being more richly brown. Otherwise, inland and coastal owls are practically the same. The facial disc can range from gray to reddish-gray to dark rufous. The feet are fairly dusky gray typically, although some buff-footed individuals are known, and legs are more prominently barred with black than in other North American races. This is a large race going on linear measurements, which in 4244:

horned owls tend to examine an area for an abandoned nest, generally from larger birds like hawks, and take over the nest for raising their own young. They nest in a wider variety of sites than any other North American bird. Many nests are in cavernous hollows of dead trees or their branches, and especially in southern states in large trees along the edge of old-growth lots. In mountainous or hilly areas, especially in canyons of the

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such confrontations may turn physical, with various levels of threats distinguished. The highest threat level involves the spreading of wings, bill-clapping, hissing, higher-pitched screams of longer duration, with general body poised to strike with its feet at intruder. If the intruder continues to press the confrontation, the defending owl will "hop" forward and strike it with feet, attempting to grasp and rake with claws.

2813:), in which average adults range from 4,500 to 9,000 g (9.9 to 19.8 lb). This has been determined from owls who have porcupine quills imbedded in them, sometimes resulting in death. On occasion, they are successful in killing porcupine, even adults as determined by the size of the quills left behind and prey remains at bloodied kill sites. Other rodents recorded as secondary prey in North America include 3106:), which can be three times as heavy as the attacking owl. In one single nest, the remains of 57 striped skunks were found. Due to the proclivity of skunk predation, great horned owls nests frequently smell strongly of skunk and occasionally stink so powerfully of skunk that they leave the smell at kill sites or on prey remains. Surprisingly, at least two cases of a great horned owl preying on an adult 2789:, are diurnal and so are largely unavailable to great horned owls as prey. Occasionally though, one will be caught from their leaf nest, nest hole or burrow entrance first thing in the morning or in the late afternoon and approximately 35 species have been successfully predated by these owls. In general larger sized than other rodent families, the species hunting range from the 62 g (2.2 oz) 1990:. Moderately barred and tinged buff or ochraceous on the underside. Feet mottled. This is a largish race, wing chord lengths being inexplicably greater in males, at 350 to 397 mm (13.8 to 15.6 in), than in females, at 327 to 367 mm (12.9 to 14.4 in). Tail length can range from 190 to 233 mm (7.5 to 9.2 in) and a female weighed 1,246 g (2.747 lb). 1311: 4096:(27% of failures). The fact that many of the nests great horned owls use are constructed by accipitrids may lead to localized conflicts, almost always to the detriment of the hawks rather than the owls. While the young of larger diurnal raptors are typically stolen in the night, great horned owls also readily kill large adult raptors both in and out of breeding seasons, including 2389: 1429:

in males and from 1,112 to 2,046 g (2.452 to 4.511 lb), averaging 1,556 g (3.430 lb), in females. Tail length is 200 to 225 mm (7.9 to 8.9 in) and 220 to 240 mm (8.7 to 9.4 in) in males and females, respectively. Bill length is 35 to 43 mm (1.4 to 1.7 in) in both and one bird had a tarsus of 66 mm (2.6 in).

1172:, great horned owls average approximately 1,000 g (2.2 lb), the lightest average mass reported anywhere for this species. Other standard measurements of this race are a tail length of 190 to 235 mm (7.5 to 9.3 in), a tarsus length of about 56 to 58 mm (2.2 to 2.3 in) and a bill length of 35 to 50 mm (1.4 to 2.0 in). 1503:

males and from 825 to 1,668 g (1.819 to 3.677 lb), averaging 1,312.7 g (2.894 lb), in females. Tail length is 175 to 218 mm (6.9 to 8.6 in) and 203 to 230 mm (8.0 to 9.1 in) in males and females, respectively. Bill length is 34 to 41 mm (1.3 to 1.6 in) and one bird had a tarsus of 57 mm (2.2 in).

4252:, cliff ledges, small caves, and other sheltered depressions may be used. Owls living in prairie country, in the absence of other animals' nests, riparian tree-hollows or man-made structures, will use boulders, buttes, railroad cuts, low bushes and even the bare ground as nest sites. Ground nests have also been recorded in the midst of tall grasses in 4425:

parents territory until right before the parents start to reproduce for the next clutch (usually December to January). Birds may not breed for another year or two, and are often vagrants ("floaters") until they establish their own territories. Based on the development of the bursa, great horned owls reach sexual maturity at two years of age.

2241:, the owls use cropland and pasture more than deciduous and total forest cover, indicating preference for fragmented landscapes. In prairies, grasslands and deserts, they can successfully live year round as long as there are rocky canyons, steep gullies and/or wooded coulees with shade-giving trees to provide them shelter and nesting sites. 2248:, but great horned owls can be found up to 2,100 m (6,900 ft) in California and 3,300 m (10,800 ft) in the Rockies. In the Andean Mountains, on the other hand, they have adapted to being a true montane species, often found at least 3,300 m (10,800 ft) above sea level and are regularly recorded in treeless 2315:

as erect and hold themselves as slim as is possible. The kind of posture is well known as a further method of camouflage for other owls, like long-eared owls or great grey owls, especially if humans or other potential mammalian carnivores approach them. The Eurasian eagle owl rarely, if ever, assumes the tall-thin position.

3870:); all four species had diets with more than 90% of the biomass is made up of those lagomorphs. Of these, the great horned owl and golden eagle were able to nest most closely to one another because they had the most strongly dissimilar periods of activity. In California, when compared to the local red-tailed hawks and 962:

owl has relatively weak color vision, especially compared to other bird species. Despite (or perhaps as a result of) the poorer sense of color vision, the owl manages to have excellent night vision. Instead of turning its eyes, an owl must turn its whole head, and the great horned owl can rotate its neck 270°. The

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with two offspring would need to take about a half dozen (voles) to a dozen (mice) of these rodents every night to satisfy their dietary requirements but apparently the accessibility and abundance of these foods is irresistible as their numeric dominance is indisputable. By winter in areas that hold heavy snow,

9960:. Pages 101–107 in Biology and conservation of northern forest owls: Symposium proceedings, February 3–7, Winnipeg, MB. (Nero, R. W., R. J. Clark, R. J. Knapton, and R. H. Hamre, Eds.) General Technical Report, RM-142. Fort Collins, CO: USDA, Forest Service, Rocky Mountain Forest and Range Experiment Station. 2417:

the ground where prey is likely to occur in open country or open woodland. Brief hovering flight (for about 6–18 seconds) has been described, especially in windy areas. On occasion owls may actually walk on the ground in pursuit of small prey or, rarely, inside a chicken coop to prey on the fowl within.

924:. Great horned owls can apply at least 300 psi (2,100 kPa) of crushing power in their talons, a pressure considerably greater than the human hand is capable of exerting. In some big females, the gripping power of the great horned owl may be comparable to much larger raptor species such as the 4731:

felt that they were a bird of "essentially low intelligence" that could only hunt when partially wild and instinctually driven by hunger to hunt whatever they first encounter. He showed captive birds that were provided strips of meat from hatching, rather than having to hunt or to simulate hunting to

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Most tree nests used by great horned owls are constructed by other animals, often from a height of about 4.5 to 22 m (15 to 72 ft) off the ground. They often take over a nest used by some other large bird, sometimes adding feathers to line the nest but usually not much more. Allegedly there

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Great horned owls are some of the earliest-breeding birds in North America, seemingly in part because of the lengthy nightfall at this time of year and additionally the competitive advantage it gives the owl over other raptors. In most of North America, courtship is from October to December and mates

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Both young and adult great grey owls, despite their superficially superior size, are apparently hunted with impunity by great horned owls. In the boreal forests, both the northern hawk owl and great grey owl appear to be in greater danger of great horned owl predation in years where the snowshoe hare

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Due to their very broad dietary habits, the great horned owls share their prey with many other predators, including avian, mammalian and reptilian ones. Almost every study comparing the diets of North American owls illustrates the considerable overlap in the dietary selection of these species, as all

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of bone and other non-digestible bits about 6 to 10 hours later, usually in the same location where the prey was consumed. Great horned owl pellets are dark gray or brown in color and very large, 7.6 to 10.2 cm (3.0 to 4.0 in) long and 3.8 cm (1.5 in) thick, and have been known to

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In most aspects of their behavior, great horned owls are typical of owls and most birds of prey. Like most owls, the great horned owl makes great use of secrecy and stealth. Due to its natural-colored plumage, it is well camouflaged both while active at night and while roosting during the day. During

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linearly; some size overlap does occur though. On average, it is the smallest known subspecies. Males have a wing chord length of 305 to 335 mm (12.0 to 13.2 in), tail length of 175 to 206 mm (6.9 to 8.1 in) and bill length of 33 to 38 mm (1.3 to 1.5 in). A single female

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length is 318–367 mm (12.5–14.4 in), averaging 337.2 mm (13.28 in), in males and 332–381 mm (13.1–15.0 in), averaging 348.9 mm (13.74 in), in females. Body mass ranges from 724 to 1,257 g (1.596 to 2.771 lb), averaging 914.2 g (2.015 lb), in

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length is 305–362 mm (12.0–14.3 in), averaging 332.5 mm (13.09 in), in males and 335–375 mm (13.2–14.8 in), averaging 351.4 mm (13.83 in), in females. Body mass ranges from 680 to 1,272 g (1.499 to 2.804 lb), averaging 991.7 g (2.186 lb), in

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length is 330–354 mm (13.0–13.9 in) in males and 340–376 mm (13.4–14.8 in) in females. The tail in both sexes can range from 184 to 217 mm (7.2 to 8.5 in). Only three birds have had published weights, two males scaling 1,011 and 1,132 g (2.229 and 2.496 lb) and

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Raptorial birds in general tend to have large, conspicuous nests which may make them easier for a hunting owl to locate. The great horned owl gains an advantage by nesting earlier than any other raptor in its range (indeed any bird), as it is able to exploit the other raptors as food while in a more

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Studies comparing the diets of rural and urban great horned owls have identified that the most abundant rodent prey in their environment fulfils the majority of their diet. A study of food niche overlap between closely nested barn and great horned owls living in rural north-eastern Oregon identified

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may be preferred where available since they are particularly dense and provide cover throughout the year. Typically, males have a favorite roosting site not far from the nest, sometimes used over successive years. While roosting, great horned owls may rest in the "tall-thin" position, where they sit

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and tail lengths of 297–340 mm (11.7–13.4 in) and 180 to 198 mm (7.1 to 7.8 in) in males and 303–357 mm (11.9–14.1 in) and 199 to 210 mm (7.8 to 8.3 in) in females. In both sexes, the bill length is 39 to 41 mm (1.5 to 1.6 in) and tarsal length is 54

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length is 323–372 mm (12.7–14.6 in), averaging 346.7 mm (13.65 in), in males and 339–390 mm (13.3–15.4 in), averaging 362.5 mm (14.27 in), in females. Body mass ranges from 865 to 1,460 g (1.907 to 3.219 lb), averaging 1,196.5 g (2.638 lb),

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length of 319–371 mm (12.6–14.6 in), averaging 339 mm (13.3 in), in males and 343–388 mm (13.5–15.3 in), averaging 362.8 mm (14.28 in), in females. Unexpectedly, although it is not the longest-winged, the nominate is the heaviest known race as males weigh from

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The "nominate race" is a medium-hued form, neither darkly saturated nor strikingly pale. Darker gray or somewhat paler individuals are known. It tends to be richly tinged with rufous and barred distinctly blackish-brown below with rather soft contrast. The feet can range from tawny to buff to creamy

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The great horned owl's eye contains both rods and cones like most species that see in color, but the vision of a great horned owl closely resembles that of many other nocturnal species. The peak wavelengths that are observed by the cones is 555 nm and the research suggests that the great horned

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The great horned owl is generally colored for camouflage. The underparts of the species are usually light with some brown horizontal barring; the upper parts and upper wings are generally a mottled brown usually bearing heavy, complex, darker markings. All subspecies are darkly barred to some extent

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through northernmost North America separately from the radiation of the greater and lesser horned owls. One older study suggested that great horned and Eurasian eagle-owls may be conspecific, based on similarities in life history, geographic distribution, and appearance, though this is not supported

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Frequently, the species were denominated a pest due to the perceived threat it posed to domestic fowl and potentially small game. The first genuine nature conservationists, while campaigning against the "Extermination Being Waged Against the Hawks and Owls", continued to advocate the destruction of

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have been reported eating eggs and small nestlings. This can normally only happen when owls are driven from the nest by human activity or are forced to leave the nest to forage by low food resources but on occasion huge flocks of crows have been able to displace owls by harassing them endlessly. In

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dens have reportedly been used as nests, in spite of the inherent risk of sharing space with such potentially dangerous co-inhabitants. Nesting behavior for the great horned owl appears to be more closely related to prey availability than it does to seasonal conditions. There has been some evidence

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More so than diurnal varieties of raptor, fairly significant numbers of owls are hunted, as all species are to some extent nocturnal and thus their corresponding activity can attract the horned owl's unwanted attention. The extent of predation on other owls depends on the habitat preferences of the

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After mammals, birds rank as the next most important general prey group. Birds are usually considerably secondary in the diet but outnumber the mammals in the diet by diversity, as more than 250 species have been killed in North America alone. Statistically, the most significant avian prey seems to

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mice often come to outnumber the voles in the diet since the mice tend to travel over the surface of the snow while the voles make tunnels underneath the snow. In fact, a healthy family of great horned owls can decimate a colony of field rats, thus potentially performing a key role in controlling a

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Most territorial defense is performed by males, but females frequently assist their partners in hooting contests with neighbors or intruders, even during incubation. On occasion, although territory borders may be successfully maintained via vocalizations alone without even seeing the competing owl,

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by snowy owls. They prefer areas where open habitats, which they often hunt in, and woods, where they tend to roost and nest, are juxtaposed. Thus lightly populated rural regions can be ideal. This species can occasionally be found in urban or suburban areas. However, they seem to prefer areas with

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A fairly dark and grey, heavily barred form. Feet pale with dusky mottling. Going on median reported linear measurements (since body mass is unknown), this is the largest bodied subspecies on average. Males have a wing chord length of 350 to 365 mm (13.8 to 14.4 in) and females range from

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appear to be even smaller. Adult great horned owls range in length from 43 to 64 cm (17 to 25 in), with an average of 55 cm (22 in), and possess a wingspan of 91 to 153 cm (3 ft 0 in to 5 ft 0 in), with an average of 122 cm (48 in). Females are

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of North America, Central America, and much of South America can be a dark brownish color overlaid with blackish blotching. The skin of the feet and legs, though almost entirely obscured by feathers, is black. Even tropical great horned owls have feathered legs and feet. The feathers on the feet of

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Occasionally, great horned owls may be killed by their own prey. Although typically able to kill skunks without ill effect, five owls were found blind after getting sprayed in their eyes by skunks. Cases where the quills of porcupines have killed or functionally disabled them have been observed as

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urban areas have large trees used for ornamentation, shade and shelter. The higher nesting within the taller trees was attributed to human avoidance. Both rural and urban nesting sites were often within range of paved roads, likely a result of the great horned owl's tendency to hunt along roadways

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nests more frequently than urban birds, who utilize crow or squirrel nests. Additionally, urban nesting individuals utilize trees that are taller/wider in diameter and nest much higher compared to rural nesting Great Horned Owls. The reason behind this increased tree height is due to the fact that

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Males select nesting sites and bring the females' attention to them by flying to the nest and then stomping on it. Considering the owls' large size, nests with open access are preferred to those enclosed with surrounding branches. Like all owls, great horned owls do not build their own nest. Great

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mobbing a great horned owl, in groups of dozens or even hundreds of crows. In response to mobbing, if the owl flies it alights to the nearest secluded spot. If an owl alights on ground or on exposed branch or ledge, it may respond to swooping and stooping flights of corvids and raptors with threat

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recorded in the diet would appear to be overly small to be as important as they are to a predatory bird of this size. The prominence of these genera is undoubtedly due to the abundance of both genera in the wooded edge habitats frequented by great horned owls. It is estimated that a family of owls

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Prey can vary greatly based on opportunity. According to one author, "Almost any living creature that walks, crawls, flies, or swims, except the large mammals, is the great horned owl's legitimate prey". In fact, the great horned owl has the most diverse prey profile of any raptor in the Americas.

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Despite reports that they do not hunt on the wing, they also sometimes hunt by flying low over openings on the ground, scanning below for prey activity. Great horned owls can fly at speeds of more than 65 km/h (40 mph) in level flight. Hunting flights are slow, often quartering low above

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length is 330–370 mm (13–15 in), averaging 348.3 mm (13.71 in), in males and 339–400 mm (13.3–15.7 in), averaging 374.7 mm (14.75 in), in females. Tail length is 191 to 245 mm (7.5 to 9.6 in) and 196 to 252 mm (7.7 to 9.9 in) in males and

4420:

The young weigh 34.7 g (1.22 oz) at birth on average and can gain about 33 g (1.2 oz) a day for the first four weeks of life, with typical weights in the range of 800 or 1,000 g (1.8 or 2.2 lb) by 25–29 days for males and females, respectively. When first hatched the

4416:

where the owls are relatively small. The incubation period ranges from 28 to 37 days, averaging 33 days. The female alone usually does all the incubation and rarely moves from the nest, while the male owl captures food and brings it to her, with the first nightly food delivery typically occurring

2318:

Outside of the nesting season, great horned owls may roost wherever their foraging path ends at dawn. Generally great horned owls are active at night, although in some areas they may be active in the late afternoon or early morning. At dusk, the owl utters a few calls before flying to a more open

942:

The outer ear openings, which are concealed by feathers on the sides of the head, are relatively smaller than those of the Eurasian eagle owl, being 2.3 cm (0.91 in) in vertical axis, with the left ear slightly larger than the right. Like most exclusively (or near exclusively) nocturnal

4743:

Arthur C. Bent also noted the variability in temperaments of great horned owls to their handlers, some generally pleasant, though most are eventually aggressive. Most captive specimens, once mature, seem to resent attempts at contact and are often given to attacking their keepers. They will only

6199:

Ridgway, Robert (1919). "The birds of North and Middle America: A descriptive catalogue of the higher groups, genera, species, and subspecies of birds known to occur in North America, from the Arctic lands to the Isthmus of Panama, the West Indies and other islands of the Caribbean Sea, and the

4453:

Studies have shown that nesting in urban areas can influence adult great horned owls to lay eggs earlier than those who nest in rural areas. In Wisconsin, eggs in urban nests hatched a month earlier (January rather than February) than their counterparts in rural areas, probably due to increased

4424:

The young birds stay in an area ranging from 13 to 52 ha from the nest into fall, but will usually disperse up to several thousand hectares by the end of fall. The offspring have been seen still begging for food in late October (5 months after leaving the nest) and most do not fully leave their

4000:

Whereas owls of any age are freely attacked by great horned owls whether nesting or not, when it comes to diurnal raptors, great horned owls are mainly a danger around the nest. They often hunt diurnal raptors when they come across their often relatively conspicuous active platform nests during

3501:, it was found in a small study that birds overall outnumbered mammals in pellets, although most were not determined to species and the ones that were shown a tremendously diverse assemblage of birds with no obvious dietary preference. Although not usually numerically significant, 86 species of 4475:

Great horned owls seem to be the most long-lived owl in North America. Among all owls, they may outrank even the larger Eurasian eagle owl in known longevity records from the wild, with almost 29 years being the highest age for an owl recorded in North America. In captivity, the record for the

2347:

and short-eared owls are true migrants, most North American owls are not migratory and will generally show fidelity to a single territory year around. In great horned owls, mated pairs occupy territories year-round and long-term. Territories are established and maintained through hooting, with

3097:

The most regular predatory association amongst relatively larger carnivores is that with skunks. Due to their poor sense of smell, great horned owls are the only predators to routinely attack these bold mammals with impunity. All six skunk species found in North America are reported as prey,

2446:

Many large prey items are dismembered. Great horned owls may behead large prey before taking it to its nest or eating perch. The legs may also be removed, as may (in some bird prey) the wings. The great horned owl will also crush the bones of its prey to make it more compact for carrying. On

2396:

Hunting tends to peak between 8:30 pm and midnight and then can resume from 4:30 am to sunrise. Hunting tends to be most prolonged during winter by virtue of prey being more scarce. However, great horned owls can learn to target certain prey during daylight in the afternoon when it is more

1394:

This is the palest form of horned owl, with the ground color essentially whitish with a faint buff tinge above; black underside barring variable from indistinct to pronounced, being most often prominent on the upper chest amongst otherwise pale plumage. This race shows little to no reddish

848:

and South America and is the second-heaviest owl in North America, after the closely related but very different-looking snowy owl. It is heavily built, with a barrel-shaped body, a large head, and broad wings. Its size can vary considerably across its range, with populations in interior

2363:

Territoriality appears to place a limit on the number of breeding pairs in a given area. Individuals prevented from establishing a territory live a silent existence as "floaters". Radio-telemetry revealed that such floaters concentrate along boundaries of established territories. At

984: 3529:

only a few species from each have been recorded. Nonetheless, an occasionally unlucky migrant or local breeder is sometimes snatched. Fledgling songbirds are regularly taken in spring and summer. The smallest avian prey known for great horned owls are the 5.8 g (0.20 oz)

2514:). A single owl requires about 50 to 100 g (1.8 to 3.5 oz) of food per day and can subsist on a large kill over several days. Despite the great diversity of prey taken by these predators, in most of the continental United States from the East to the Midwest as well as 2319:

sing-post, i.e. large bare branch or large rocks to deliver song. Normally several perches are used to mark occupied territory or to attract a female. Despite its camouflage and cryptic locations, this species can still sometimes be spotted on its daytime roosts, especially by

983: 1407:

zone in Canada where very pale birds with almost non-existent markings are prominent. Very pale birds are similar to a young female snowy owl from a distance. In this race, the feet range from immaculate white to buff, with little or no mottling. In the west of Canada,

3280:

Usually coveys of quail are partially protected by spending the night roosting communally in dense thickets but should a hunting owl be able to track down the communal roost, losses can be fairly heavy until the roost relocates. Similarly, owls may track down sleeping

1666:

length of 345–365 mm (13.6–14.4 in) in males and 350–382 mm (13.8–15.0 in) in females. The tail in both sexes can range from 185 to 217 mm (7.3 to 8.5 in). Bill length is 40 to 50 mm (1.6 to 2.0 in), again relatively long as in

1021:) and can last for four or five syllables. The call is resonant and has warranted descriptions as varied as "solemn" and "terrifying". The female's call is higher and rises in pitch at the end of the call. Female vocalizations are higher in pitch because of a smaller 3353:), 4 to 8 kg (8.8 to 17.6 lb) on average between the sexes, is probably the largest bird the great horned owl hunts in which they kill adults. Both full-grown wild turkeys and adult domestic turkeys have been hunted and killed. Under normal circumstances, 11203:

Holt, Denver W.; Berkley, Regan; Deppe, Caroline; Enríquez Rocha, Paula L.; Olsen, Penny D.; Petersen, Julie L.; Rangel Salazar, José Luis; Segars, Kelley P. & Wood, Kristin L. (1999). "69. Great Horned Owl". In: del Hoyo, J.; Elliott, A.; Sargatal, J. (eds):

796:

A variable-sized white patch is seen on the throat. The white throat may continue as a streak running down the middle of the breast even when the birds are not displaying, which in particularly pale individuals can widen at the belly into a large white area.

2959:, individual rodents (1159 counted) were more than 10 times more numerous than lagomorphs (114 counted) by quantity and yet the jackrabbit and mountain cottontail still made up approximately half of the biomass. The dependence on lagomorphs also extends into 2331:, perhaps the main predator of crows and their young, crows sometimes congregate from considerable distances to mob owls and caw angrily at them for hours on end. When the owls try to fly off to avoid this harassment, they are often followed by the corvids. 4521:. Most cases where young owls are killed and/or consumed by their siblings or parents appear to occur when the nestling is diseased, impaired or starving or is inadvertently crushed. Adults generally have no natural predators, excepting both North American 11374: 2281:) which may regularly occur in busy suburban settings. 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. 8260:

Dobler, Frederick C., and Kenneth R. Dixon. "The pygmy rabbit Brachylagus idahoensis." Rabbits, hares, and pikas: status survey and conservation action plan (JA Chapman and JEC Flux, eds.). IUCN/SSC Lagomorph Specialist Group, Gland, Switzerland (1990):

3981:

vulnerable state as their own nestlings have become well developed. On average, great horned owls begin nesting about three weeks before red-tailed hawks begin to build nests, although some raptors may locally breed as much as two months after the owls.

1156:

985 to 1,588 g (2.172 to 3.501 lb), averaging 1,318 g (2.906 lb), and females weigh from 1,417 to 2,503 g (3.124 to 5.518 lb), averaging 1,768.5 g (3.899 lb); the prior figures originally from a huge sample around

1028:

On occasion, this species exhibits "an indescribable assemblage of hoots, chuckles, screeches, and squawks, given so rapidly and disconnectedly that the effect is both startling and amusing". Descriptions of some of these odd sounds including a growling

4787:

had mystic owl societies in which initiates were made to adorn a facial mask made of the wing and tail feathers of great horned owls. Some Indian nations regarded the great horned owl as a friendly spirit that could aid in matters of love, such as the

2019:. Overall coloration is similar, but the Magellanic is markedly smaller with smaller feet and a smaller head, with finer, but more numerous brownish bars on the underside, rather than the blotchy, irregular barring typical of great horned owls. Other 3803:

were the most common prey species, while consumption of rats increased as the nesting location became more urban and rats replaced voles as the most abundant and stable food source. A similar focus on rats was found in populations in urban parks in

4545:, juvenile survival in the 9 weeks after dispersal has dropped from 80% to 23.2% in a span of three years in response of instability of food supply. In the Yukon, adults on territory had an average annual survival rate of 90.5%. Anemia, caused by 3606:

are largely unavailable as prey due to their typically diurnal periods of activity. However, some snakes are partially or largely nocturnal, and more than a dozen species are hunted in North America. Snakes hunted range from small, innocuous

2923:, where great horned owls are dependent on the jackrabbits, average brood size rose from 2 at jackrabbit population lows to 3.3 when the jackrabbits were at their peak. At the peak of the population cycle, jackrabbits accounted for 90.2% and 2015:), which may overlap in range. The Magellanic horned owl was once considered a subspecies of the great horned, but is now almost universally considered a distinct species, as is supported by genetic materials, with the great horned being the 1783:

males and from 801 to 1,550 g (1.766 to 3.417 lb), averaging 1,142.2 g (2.518 lb), in females. In both sexes, tail length is 190 to 235 mm (7.5 to 9.3 in) and bill length is 33 to 43 mm (1.3 to 1.7 in).

4284:

have some cases where the owls have reinforced a nest structure or appeared to have reconstructed a nest, but as a rule no owl species has ever been known to actually build a nest. Great horned owls in the Southwest may also use nests in

2437:

Almost all prey are killed by crushing with the owl's feet or by incidentally stabbing of the talons, though some may be bitten about the face as well. Prey is swallowed whole when possible. When prey is swallowed whole, owls regurgitate

4056:, despite their nesting in deeper woods than those that host these owls, the main cause of nest failure was great horned owl predation. Similarly, the great horned owl was the primary cause of nesting failure for both desert-dwelling 5492:

Omote, K.; Nishida, C.; Dick, M. H.; Masuda, R. (2013). "Limited phylogenetic distribution of a long tandem-repeat cluster in the mitochondrial control region in Bubo (Aves, Strigidae) and cluster variation in Blakiston's fish owl

1292:

one female weighing 1,050 g (2.31 lb). The most notable feature of this race is its large bill, at 43 to 52 mm (1.7 to 2.0 in), which is the biggest of any horned owl race despite the otherwise moderate size of

893:, the measured wing area compared to weight, is high, meaning the wings are relatively small in surface area for the bird's weight; the species' wing loading has been described as proportionately the highest among raptors. The 4583:

great horned owls due to their predatory effect on other wildlife. Thus, small bounties were offered in trade for owl bodies. Around the turn of the 20th century, the great horned owl was considered endangered in the state of

6200:

Galapagos Archipelago pt. 8: Families Jacanidae, Oedicnemidae, Haematopodidae, Arenariidae, Aphrizidae, Charadriidae, Scolopacidae, Phalaropodidae, Recurvirostridae, Rynchopidae, Sternidae, Laridae, Stercorariidae, Alcidae".

1975:, but was recently first described and named as a distinct subspecies and makes up the missing piece in the once-muddled distribution of great horned owls in the West and Rockies. Downslope movements into valleys occupied by 593:

by genetic evidence, which places them in separate clades of their genus. Genetic testing indicates that the lesser horned owl, and then the snowy owl, not the Eurasian eagle-owl, are the most closely related living species.

2982:, great horned owls are even more dependent on the snowshoe hare. At the peak of the 10-year hare cycle, snowshoe hares were by far the largest component of both summer and winter diets (77–81% and 90–99%, respectively, in 2425:

may be caught on foot around the base of bushes, through grassy areas, and near culverts and other human structures in range and farm habitat. The great horned owl is generally a poor walker on the ground; it walks like a

4001:

hunting forays in spring and summer, taking numbers of both nestlings and brooding adults. Again, like owls, diurnal raptors are attacked depending on the relative similarity of their habitat preferences to the owl.

3993:, the average weight of prey for long-eared owls was 28 to 30 g (0.99 to 1.06 oz), 46 to 57.1 g (1.62 to 2.01 oz) for barn owl and 177 to 220 g (6.2 to 7.8 oz) for the great horned owl. 4541:, it was apparently unable to dispatch the larger raptor despite several powerful strikes. During their initial dispersal in fall, juvenile owls have a high mortality rate, frequently more than 50%. For owls in the 489:), with which it often shares similar habitat, prey, and nesting habits by day; thus the red-tailed hawk is something of a diurnal ecological equivalent. The great horned owl is one of the earliest nesting birds in 9048:

Tomazzoni, Ana C., Ezequiel Pedó, and Sandra M. Hartz. "Food habits of Great Horned Owls (Bubo virginianus) in the breeding season in Lami Biological Reserve, southern Brazil." Ornitologia Neotropical 15.2 (2004):

4265:

that if prey availability is low enough then the species may forgo mating entirely for a season. Male and female owls of the species have been observed to help incubate the eggs once they have been laid on a nest.

2946:

In central Utah, the lagomorphs (black-tailed jackrabbit/desert cottontail) and Ord's kangaroo rat each made up 39% of the food by number, respectively. The mountain cottontail dominates the biomass of prey in the

3361:) will be ignored in favor of wild prey. On occasion, individual owls, especially inexperienced juveniles, will become habitual fowl killers. These errant owls mainly hunt chickens, though will also take domestic 874:

somewhat larger than males. Mean body weight is 1,608 g (3.545 lb) for females and 1,224 g (2.698 lb) for males. Depending on subspecies, maximum weight can reach 2,503 g (5.518 lb).

3778:-feeding has been recorded in great horned owls, especially ones wintering in Canada and other northern areas during harsh weather. Road kills are sometimes opportunistically eaten. A case of an owl scavenging a 2610:

form the great majority of great horned owl prey by number. Weighing a mere 14 to 31.5 g (0.49 to 1.11 oz) and 20 to 58 g (0.71 to 2.05 oz) on average, the nine species of New World mice in

824:. This can be reddish, brown, or gray in color (depending on geographical and racial variation) and is demarked by a dark rim culminating in bold, blackish side brackets. This species' eyebrow-like "horns" are 10467:"Nesting of Red-Tailed Hawks and Great Horned Owls in a Central New York Urban/Suburban Area (Anidamiento de Buteo jamaicensis y de Bubo virginianus en un area urbana/suburbana de la parte central de New York" 2217:, they are absent from the heart of the deserts and are only found on the vegetated or rocky fringes. Even in North America, they are rare in landscapes including more than 70% old-growth forest, such as the 828:, called plumicorns. The purpose of plumicorns is not fully understood, but the hypothesis that they serve as a visual cue in territorial and sociosexual interactions with other owls is generally accepted. 3373:

or concentrations of roosting water birds, since they tend to roost in relatively open spots. They have been known to predate more than 110 different species of assorted water bird. In prairie wetlands of

2990:). At the lowest point of the hare's cycle, summer diets consisted of only 0–16% snowshoe hare in Alberta and 12.7% in Yukon. When hares were scarce, great horned owls in these regions fed mostly on large 10436:"Nest Site Selection by Urban and Rural Great Horned Owls in the Northeast (Selección del Lugar de Anidamiento por Parte de Bubo Virginianus en Zonas Urbanas y Rurales del Nordeste de los Estados Unidos)" 4391:

and eastern Canada, egg laying is from early March to late April. In the rest of Canada and Alaska, egg laying may be from late March to early May. The latest known date of egg laying was in mid-June in

3368:

While galliforms are widely reported, the few cases where great horned owls locally turn to birds as the primary food source over mammals, these may often be local responses to the abundance of breeding

4828:, causing Raweno to make the owl "covered with mud" (dark camouflage) and doomed to ceaselessly call "whoo whoo", which he used while harassing Raweno by night because Raweno was active during the day. 3313:

first thing in the morning. In the boreal forest, especially in years where the snowshoe hare experiences population decreases, great horned owls prey fairly heavily (approximately 25% of biomass) on

4009:) and red-tailed hawks tend to be most vulnerable, as they prefer the same wooded edges frequented by great horned owls. Other diurnal raptors may be attracted to more enclosed wooded areas, such as 4458:

began nesting five to six weeks earlier than those in rural parts of Manitoba, presumably due to experiencing an extremely warm winter by Winnipeg's standards, as well as benefitting from the local

3365:, turkeys and anything else available. In general, chickens kept in locked cages with enclosed tops overnight are safe from great horned owls; not so chickens left free range or in open enclosures. 3497:

Other assorted birds are taken seemingly at random opportunity. The predatory effect of this species on other raptorial birds, which is often considerable, is explored in the following section. In

3177:, of at least four or five species, are also widely but lightly reported as prey. From both the tropics and the United States, several species of opossum may be taken, down to the size of the tiny 1498:

area is black. Feet are mottled dark. The facial disc is often even darkly mottled. This is a fairly small-bodied race, in fact including the lightest wild great horned owl adult ever weighed. The

4587:

because of the large number of poachers who were illegally hunting and collecting it. Hunting and trapping of great horned owls may continue on a small scale but is now illegal in most countries.

2506:

Estimated mass of individual prey for the owls has ranged from as little as 0.4 g (0.014 oz) to as much as 6.8 kg (15 lb) Most prey is in the range of 4 g (0.14 oz) (

588:

clearly divided once the owl had spread through the Americas, the consensus seems to be that the snowy owl and the great horned owl divided back in Eurasia and the snowy then spread back over the

2306:

the daytime it roosts usually in large trees (including snags & large hollows but usually thick branches) but may occasionally be in crevices or small caves in rocks or in dense shrubbery.

2682:

ssp.) are readily taken. While the northern weighs from 90 to 120 g (3.2 to 4.2 oz), other pocket gophers hunted average from 95 to 545 g (0.209 to 1.202 lb) in mass. From

1267:

Dull, earthy brownish color is typical; birds from the semiarid interior of Brazil often have much white on uppertail- and ear-coverts against a dull gray background (sometimes separated as

6644: 8664:

Storm, G. L.; Andrews, R. D.; Phillips, R. L.; Bishop, R. A.; Siniff, D. B.; Tester, J. R. (1976). "Morphology, reproduction, dispersal, and mortality of midwestern red fox populations".

4804:

also associated this owl with fertility, albeit of a different kind: they believed the calling of the owls into summer predicted hot weather, which produced good peach crops. During the

2952: 1671:

and one bird had a tarsal length of 80 mm (3.1 in), indicating relatively long legs in the race. No published weights are known. Apparently, despite its sizeable wing area,

1609:

females. In both sexes, known bill and tarsal lengths are 35 to 44 mm (1.4 to 1.7 in) and 62 to 70 mm (2.4 to 2.8 in). No weights are known to have been published.

4619:, after they were also hit hard by DDT, were affected by heavy owl predation on nestlings, and the owls were also recorded to take a large toll locally on the threatened colonies of 2169:

The great horned owl is among the world's most adaptable owls or even bird species in terms of habitat. The great horned owl can take up residence in trees that border all manner of

1774:

base to their upper sides. Humeral area is umber in color and the feathers of the feet are white and usually unmarked. A small race, it averages slightly larger in wing length than

912:

is 54–80 mm (2.1–3.1 in). The average foot span of a fully spread foot, from talon to talon, is around 20 cm (7.9 in), as compared to 8 cm (3.1 in) in

3833:

species, besides the primarily insectivorous varieties, rely on many of the same small rodent species for most of their diet, extending from the small northern saw-whet owl and

3006:, the local population of great horned owls can increase threefold from hare population lows to peaks. The dependency on the snowshoe hare by the great horned owl extends into 3914:), red-tailed hawks and golden eagles apparently do not have as large of an impact on the hares, nor do mammalian carnivore generalists that also kill many hares, like the 2434:

and some arboreal mammals directly from tree branches in a glide as well. The stiff feathering of their wings allows owls to produce minimal sound in flight while hunting.

9520:

Tomazzoni, A. C.; Pedó, E.; Hartz, S. M. (2004). "Food habits of Great Horned Owls (Bubo virginianus) in the breeding season in Lami Biological Reserve, southern Brazil".

2900:

Although generally no match for rodents in the sheer quantity of individuals, in terms of prey biomass, the most significant prey of North American great horned owls are

2339:

Typically, great horned owls are highly sedentary, often capable of utilizing a single territory throughout their mature lives. Although some species such as snowy owls,

5216:. Bulletin of the United States National Museum, No. 170. Vol. 2: Orders Falconiformes and Strigiformes. Washington, DC: Smithsonian Institution. pp. 295–348. 3961:

The relationship between great horned owls and other raptorial birds in its range is usually decidedly one-sided. While certain species, such as the red-tailed hawk and

985: 9035:

James T. Pokines "Prey Remains from a Great Horned Owl (Bubo virginianus) Roost in the Icla Valley, Bolivia," Journal of Raptor Research 41(2), 174–175, (1 June 2007).

8879: 10174: 2430:, with a pronounced side-to-side gait. They have been known to wade into shallow water for aquatic prey, although this has been only rarely reported. Owls can snatch 9058:

Gardner, Alfred L. "Virginia opossum." Wild mammals of North America: biology, management, and economics. Johns Hopkins University Press, Baltimore, MD (1982): 3–36.

2746:), both being widespread, numerous and relatively diminutive (at 42 and 48 g (1.5 and 1.7 oz)). Eight known larger species of kangaroo rats, including the 1025:

in the larger sex. Calling seems to peak after rather than before midnight. Usually, territorial hooting decreases in February or March at the onset of egg laying.

10889:. Ecology and Conservation of the Marbled Murrelet. USDA Forest Service General Technical Report PSW-GTR-152. Pacific Southwest Research Station, Albany, CA, 89–98. 3002:. Because fewer of these alternative prey species are available in boreal forests during winter, owls had to emigrate or suffer high mortalities if they stayed. In 3671:) by great horned owls has been reported, in both cases likely when the baby reptiles are attempting to make their way to the security of water. On rare occasion, 2007:

The combination of the species' bulk, prominent ear tufts and barred plumage distinguishes it through much of the range, but it may be easily confused with the

1920:

370 to 390 mm (15 to 15 in). In both sexes, the tail is 220 to 250 mm (8.7 to 9.8 in) and the bill is 38 to 48 mm (1.5 to 1.9 in).

1650:

A dark, cold gray-brown form with heavy fuscous blotching. Arguably this is the darkest colored race on average, though it could be rivaled by individuals from

11048: 10588: 2348:

highest activity before egg-laying and second peak in autumn when juveniles disperse, and can range from an average of 16 km (6.2 sq mi) in

11775: 3161:) have had an estimated weight of only 2 g (0.071 oz). One of the more regularly taken shrews, though, is the larger 19.5 g (0.69 oz) 632:: The most conservative treatments of great horned owl subspecies may describe as few as 10, although an intermediate number is typical in most writings. 4837: 2118:. They are distributed throughout most of North America and very spottily in Central America and then down into South America south to upland regions of 11082: 1151:

and are the legs are typically barred dark to a moderate extent. The facial disc is often a solid cinnamon-red color. This is mid-to-large race, with a

6598:

Rohner, C. (1996). "The numerical response of Great Horned Owls to the snowshoe hare cycle: consequences of non-territorial 'floaters' on demography".

4816:

held owl feathers in their mouths hoping to gain some of the silence that owls use in ambushes while striking their own enemies from other tribes. The

4292:

and red-tailed hawk, as well as large hollows in cacti. The nests they use are often made by most larger types of acciptrids, from species as small as

7880:

Murphy, R. K. (1997). "Importance of prairie wetlands and avian prey to breeding Great Horned Owls (Bubo virginianus) in northwestern North Dakota".

3329:), enough so in the earlier bird to possibly contribute to population reductions. Larger species of galliform are not immune to predation either. On 9703:"Food niche overlap in co-existing Barn Owl Tyto alba (Scopoli 1769) and Great Horned Owl Bubo virginianus Gmelin 1788 in intensively used farmland" 3844:, all nine species of accipitrid, falcon and owl that stayed to breed there were found to be primarily dependent on the same two rodent genera, the 10496: 5001: 11653: 11181: 2162:

and almost all off-shore islands in the Americas, its ability to colonize islands apparently being considerably less than those of barn owls and

8204: 5018: 3462:

have been successfully killed. Medium-sized birds of prey (even other species of owl) are also taken. The nestlings of even larger species like

2166:. Since the division into two species, the great horned owl is the second most widely distributed owl in the Americas, just after the barn owl. 11898: 10939:

The American Bird Conservancy Guide to the 500 Most Important Bird Areas in the United States: Key Sites for Birds and Birding in All 50 States

10722:

The nesting, reproductive performance, and chlorinated hydrocarbon residues in the red-tailed hawk and Great Horned Owl in southcentral Montana

3655:), which in mature specimens can rival the owl in mass and sheer predatory power. The capture of the hatchlings of very large reptiles such as 2471:

Over 500 species have been identified as great horned owl prey, with dozens more identified only to genus or general type (especially numerous

8988: 11903: 11718: 11193:

Ganey, J. L., W. M. Block, J. S. Jenness, R. A. Wilson (1997). "Comparative habitat use of sympatric Mexican spotted and great horned owls."

3578:). This is likely due to the fact that the larger passerines usually roost in relatively open spots and have larger, more conspicuous nests. 1279:

is amber, not yellow. The Magellanic horned owl, while somewhat similar in coloring, has yellow eyes like other horned owls, not amber eyes.

11288: 8428:

Rohner, C. (1995). "Great Horned Owls and snowshoe hares: what causes the time lag in the numerical response of predators to cyclic prey?".

6476:

Morrell, T. E.; Yahner, R. H.; Harkness, W. L. (1991). "Factors affecting detection of Great Horned Owls by using broadcast vocalizations".

11863: 11300: 8365:

Llinas-Gutirrez, J.; Arnaud, G.; Acevedo, M. (1991). "Food habits of the Great Horned Owl in the Cape Region of Lower California, Mexico".

5241:

Systema naturae per regna tria naturae : secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis

3808:. Although a stable and highly abundant food source, a diet consisting of primarily rats can be harmful to urban great horned owls due to 7796:

Longland, W. S.; Price, M. V. (1991). "Direct observations of owls and heteromyid rodents: can predation risk explain microhabitat use?".

6884: 6169: 11314:

Rohner, C., and F. I. Doyle (1992). "Food-stressed great horned owl kills adult goshawk: exceptional observation or community process?"

4744:

follow cues when conditioned from an early age but rarely with the same level of success seen in some diurnal birds of prey trained for

4340:

are also regularly used but in general great horned owls are partial to stick nests since they provide a much firmer, safer foundation.

3505:

have been taken by great horned owls. Members from most North American families are known as prey, although among smaller types such as

2154:(where only two records) in Central America and the mangrove forests of northwestern South America. The species is also absent from the 4445:

While urban and rural populations show little difference in productivity, there are differences in nest selection. Rural owls use old

3197:) weighing around 1,000 g (2.2 lb) were found in 12% of pellets weighing about. North American subspecies can prey on larger 1763:

population, which look similar to intergrades, also seem to occur in its range. Resident all-year. This race is likely synonymous with

801:

typically have a smaller white throat patch, often unseen unless actively displaying, and rarely display the white area on the chest.

11108:

Banks, R.C.; Cicero, C.; Dunn, J.L.; Kratter, A.W.; Ouellet, H.; Rasmussen, P.C.; Remsen, J.V. Jr.; Rising, J.A.; Stotz, D.F. (2000).

4732:

obtain food, had no capacity to hunt. On the contrary, William J. Baerg compared behaviorally his captive-raised great horned owls to

2805:); thus, squirrels can provide a very fulfilling meal. An even larger rodent is sometimes attacked as prey by great horned owls, the 8150: 4223: 9331:

Schemnitz, S. D.; Goerndt, D. L.; Jones, H. (1985). "Habitat needs and management of Merriam's turkeys in southcentral New Mexico".

8542:

Bull, E. L.; Heater, T. W. (2001). "Survival, Causes of Mortality, and Reproduction in the American Marten in Northeastern Oregon".

4719:) or other immediate threats and/or restricted populations. Altogether, great horned owls hunt 50 different species from that list. 3985:

other species. Eastern and western screech owls may be most vulnerable since they prefer similar wooded edge habitat. In a block of

11591: 6747:

Holt, D. W.; Berkley, R.; Deppe, C.; Enríquez Rocha, P. L.; Olsen, P. D.; Petersen, J. L.; Wood, K. L. (1999). "Great Horned Owl".

2702:). While the Great Basin species is a relative giant at 22 g (0.78 oz), other hunted pocket mice (which may include both 2487:(nearly 300 species) make up the majority of their diet. Their diet in North America is made up of 87.6% mammals, 6.1% birds, 1.6% 1357:, occasionally ranging beyond this limit especially in years with low prey in the north. This race includes the birds described as 9366:

König, Claus, Friedhelm Weick, and Jan-Hendrik Becking. Owls of the World. 2nd ed. Bloomsbury Publishing, 2009. Web. 23 May. 2023.

8709:

Sovada, M. A.; Roy, C. C.; Bright, J. B.; Gillis, J. R. (1998). "Causes and rates of mortality of swift foxes in western Kansas".

5281:

Zoologie analytique : ou, Méthode naturelle de classification des animaux; endue plus facile a l'aide de tableaux synoptiques

2627:

highly destructive pest. Great horned owls living in the timbered fringes of garbage or refuse dumps may subsist mostly on rats.

2237:

are actually often found near temporary agricultural openings in the midst of large areas of woodland. Similarly in south-central

11666: 6223:

Norberg, R.A. (1977). "Occurrence in independent evolution of bilateral ear asymmetry in owls and implications in owl taxonomy".

1530: 5799:

Mcgillivray, W. B. (1989). "Geographic variation in size and reverse size dimorphism of the Great Horned Owl in North America".

11883: 3217:), have been found around owl nests in the south. 11 species of bat are known to be hunted by great horned owls. One pellet in 6822:

Dickerman, R. W. (1993). "The subspecies of the Great Horned Owls of the central great plains, with notes on adjacent areas".

620:, more than 20 altogether, have been named. However, many of these are not true subspecies and only examples of individual or 11757: 8929: 6756: 6001: 4768: 3828:

An immature red-tailed hawk eats a vole, one of the many prey items that feed both the competing hawks and great horned owls.

552: 11671: 11462: 9958:

Movement strategies, mortality, and behavior of radio-marked Great Gray Owls in southeastern Manitoba and northern Minnesota

8953:

Forbush, Edward H. "The Great Horned Owl (1927)." The Essential Naturalist: Timeless Readings in Natural History (2011): 15.

8883: 11770: 10178: 9629: 8025:

Baumgartner, A. M.; Baumgartner, F. M. (1944). "Hawks and owls in Oklahoma 1939–1942: Food habits and population changes".

3786:) carcass, ultimately tearing off the deer's leg, was captured on a motion capture video camera set out to film wildlife. 4033:) and ferruginous hawks, but this is almost never a total insurance against predation as all of these are recorded prey. 2908:. About a dozen lagomorphs species are known to be hunted by the owl, from the relatively tiny 420 g (0.93 lb) 9173:"An updated checklist of the food items of the great horned owl (Bubo virginianus: Strigiformes: Strigidae) in Oklahoma" 7045: 3122:) as prey was also reportedly observed. Occasionally, domestic carnivores are also prey. A few cases of young or small 2951:

of California, making up 61.1% of the biomass, although are numerically secondary to desert woodrat. Remarkably, in the

11627: 7962: 5473: 4232: 3253:, of which they are known to have preyed on 23 species, basically consisting of all of the native species found in the 7403: 1770:

A pale dusky buff form with indistinct barring, especially on the underside. Darker individuals tend to have a deeper

11827: 11239: 11216: 8972: 8810: 7197: 7028: 5753: 5445: 5275: 4611:

was hampered by great horned owls killing both young and adult peregrines at night. Similarly, as mainly recorded in

939:, the exposed bill portion as measured along the top of the beak, is only 2.1 to 3.3 cm (0.83 to 1.30 in). 570: 11359: 11056: 9971:

Northern hawk-owls in the nearctic boreal forest: prey selection and population consequences of multiple prey cycles

8338:

Marti, C. D.; Kochert, M. N. (1996). "Diet and Trophic Characteristics of Great Horned Owls in Southwestern Idaho".

7079:

Mcgarigal, K.; Fraser, J. D. (1984). "The effect of forest stand age on owl distribution in southwestern Virginia".

4812:

were known to use owl wing-feathers to produce arrows which could strike their enemies with a minimum of sound. The

3450:), both adults and nestlings, were the most numerous prey, present in 93% of 120 pellets. Species as large as adult 2916:

weighing more than 2,000 g (4.4 lb). These species are overall the largest regular prey for this species.

11893: 11604: 9982:

Forsman, E. D., Anthony, R. G., Reid, J. A., Loschl, P. J., Sovern, S. G., Taylor, M., & Seaman, D. E. (2002).

8780: 7619: 7563: 7161:

Smith, D. G.; Murphy, J. R. (1982). "Nest site selection in raptor communities of the Eastern Great Basin Desert".

4808:, the Hopi performed a ceremony with great horned owl feathers in hopes of summoning the heat of summer. Tribes in 4367:, egg laying is from early February to late March. The largest swath of egg-laying owls from central California to 721: 11723: 11253: 1588:

A dark and overall brownish form with heavily barred and mottled underside, with a dull tawny base. Inland birds (

11568: 9283: 4111:

Great horned owls are frequently mobbed by other birds. Most accipitrids will readily mob them, as will falcons.

2107: 1196: 1181: 967: 798: 152: 11152: 11126: 11109: 10596: 6079:

Biology and Conservation of Owls of the Northern Hemisphere, 2nd International Symposium, Gen. Tech. Rep. NC-190

4163:) are among the reported species who have been recorded diving on great horned owls when they discover them. In 2726:) is the most commonly recorded prey species. The same species constituted 75% by number of a small sampling in 11206: 10946: 8691: 8648: 8187: 7363: 7222: 7123: 7003: 6678: 5932: 5663: 5128: 3435: 3390:) came to represent 65% by number and 83% by biomass of the diet of the local owls, also including secondarily 3330: 3178: 2642:, the diversity of this species' diet rises, in sync with the diversity of rodents. Especially important, from 11026: 9353: 11873: 11705: 11097: 10064:. Peregrine falcon populations: their management and recovery. The Peregrine Fund, Boise, Idaho, USA, 587–598 8511:"Food habits of Great Horned Owls, Bubo virginianus, in the northern taiga of the Yukon Territory and Alaska" 8478:"Predator-prey relations and breeding biology of the Great Horned Owl and Red-tailed Hawk in central Alberta" 4628: 3145:

are taken by opportunity and make up the smallest mammalian prey taken by great horned owls, as specimens of

3062:

ssp.), are sometimes taken as prey. In one case, a great horned owl was the likely killer of an adult female

11632: 10644:

Mutual mortality of great horned owl and southern black racer: a potential risk of raptors preying on snakes

10138:

Houston, C. S. and K. A. Wylie. 1985. Peregrine Falcons harass nesting Great Horned Owls. Blue Jay 43:42–43.

7264:

Rohner, C.; Krebs, C. J. (1996). "Owl predation on snowshoe hares: consequences of antipredator behaviour".

2074: 1192: 414:(originally derived from early naturalists' description as the "winged tiger" or "tiger of the air") or the 11433: 8906: 6085:. St. Paul, MN: U.S. Dept. of Agriculture Forest Service, North Central Forest Experiment Station: 553–561. 5289: 4748:

or entertainment, although this does not necessarily correlate with intelligence as posited by Errington.

4595:

Occasionally, these owls may prey on threatened species. Following the devastation to its populations from

1260:. The status of this form, especially the relationships between the scattered subpopulations and with ssp. 613:

and to the west of them. Almost all fossils indicate these owls were larger than modern great horned owls.

11736: 10835:

Differential response of two kangaroo rats (Dipodomys) to the 1997–1998 El Niño southern oscillation event

2265:

less human activity and are most likely to be found in park-like settings in such developed areas, unlike

11506: 11235: 5255: 3162: 2003:

Illustrated comparison of a great horned owl, left, to its closest North American relative, the snowy owl

1327: 621: 536: 10127:

Roost site selection of great horned owls in relation to black fly activity: an anti-parasite behavior?

10010:

The predation ecology of the Northern Harrier (Circus cyaneus hudsonius) on Mallard Island, North Dakota

9475:"Sandhill Crane nesting success and productivity in relation to predator removal in southeastern Oregon" 3141:

Aside from carnivorans, various other mammals are taken as supplemental prey. At least eight species of

2734:

become increasingly important prey, ten species have been reported in the diet but most prominently the

11878: 11511: 11424: 9068:

Wink, J.E.; Senner, S. E.; Goodrich, L. J. (1987). "Food habits of great horned owls in Pennsylvania".

8744:

Kilgore, D.L. (1969). "An ecological study of the swift fox (Vulpes velox) in the Oklahoma panhandle".

8300:

Marti, C. D. (1969). "Some comparisons of the feeding ecology of four owls in north-central Colorado".

5325: 4887: 4801: 4776: 4384: 4348: 4245: 2854: 2635: 2380: 1897: 11169: 9593:

Errington, P. L. (1938). "The Great Horned Owl as an indicator of vulnerability in prey populations".

9172: 5883: 5264:. Vol. Part 2. London: Printed for the author at the College of Physicians. p. 60; Plate 60. 3878:), the diets were most similar in that by number about 15–20% of all three species' diets depended on 1373:

was occasionally used for this subspecies, but it cannot with certainty be assigned to a recognizable

766:, 1817) – east Colombia through the Guianas to north, east Brazil, Argentina, Bolivia and central Peru 11475: 11243: 11083:"Composição da avifauna em oito áreas úmidas da Bacia Hidrográfica do Lago Guaíba, Rio Grande do Sul" 9933:

Spatio-temporal relationships between breeding red-tailed hawks and great horned owls in South Dakota

7325:"Changes in snag populations in northern Arizona mixed-conifer and ponderosa pine forests, 1997–2002" 7240:"Composição da avifauna em oito áreas úmidas da Bacia Hidrográfica do Lago Guaíba, Rio Grande do Sul" 6367:

Fite, K. V. (1973). "Anatomical and behavioral correlates of visual acuity in the Great Horned Owl".

4708: 4648: 4321: 3754:. The occasionally invertebrate prey taken largely consists of common, large insects such as various 2814: 2739: 11346: 9999:. In: Cartron, Jean-Luc, ed. Raptors of New Mexico. Albuquerque, NM: University of New Mexico Press. 6796: 6528:

Petersen, L. (1979). "Ecology of Great Horned Owls and Red-tailed Hawks in southeastern Wisconsin".

5957:

Snyder, N. F. R.; Wiley, J. W. (1976). "Sexual size dimorphism in hawks and owls of North America".

5022: 4796:, who felt the call of this species was a magical love flute designed to ignite human passions. The 11908: 11731: 11583: 11351: 9376:

Monnie, J. B. (1966). "Reintroduction of the Trumpeter Swan to its former prairie breeding range".

8992: 6955:"Notes on Great Horned Owls nesting in the Rocky Mountains, with a description of a new subspecies" 2806: 2695: 1400: 11697: 6931: 5632: 3309:), may also been vulnerable to great horned owls while displaying conspicuously in openings on a 1420:

in the east. In both cases, they may produce intermediate looking hybrids of reddish tone, like a

11888: 10101:

Food-stressed Great Horned Owl kills adult goshawk: exceptional observation or community process?

9774: 6035:

Earhart, C. M.; Johnson, N. K. (1970). "Size dimorphism and food habits of North American Owls".

5235: 4676: 4660: 3286: 3222: 2893: 2668: 2543: 2297: 1693: 1662:

may have a cinnamon facial disc. The largest winged race of owl in South America, this owl has a

712: 506: 435: 332: 220: 156: 11801: 11325: 11297: 10534: 10342:

Physiogenesis of endothermy and its relation to growth in the Great Horned Owl, Bubo virginianus

7379: 6096: 11658: 11493: 11386: 11227: 10274:

Life histories of North American birds with special reference to their breeding habits and eggs

9726:"Raptor Presence Along an Urban–Wildland Gradient: Influences of Prey Abundance and Land Cover" 8276:"Breeding responses of raptors to jackrabbit density in the eastern Great Basin Desert of Utah" 6403: 5708:

Olson, S. L. (1984). "A very large enigmatic owl from the late Pleistocene at Ladds, Georgia".

4664: 3624: 3471: 3434:) weighing approximately 1,250 g (2.76 lb), but nearly all the coots were adults. On 2967:

about a quarter of identified prey was black-tailed jackrabbit and either desert or the larger

2790: 2651: 2559: 1120: 11684: 10408:

Houston, C.S. 1971. Brood size of Great Horned Owls in Saskachetwan. Bird-Banding, 42:103–105.

6177: 2475:) and presumably several more unknown from their relatively little-studied populations in the 2046: 840:

The eyes of great horned owls are among the proportionally largest of terrestrial vertebrates.

11868: 11796: 10872:

Hagen, C. A., Pitman, J. C., Sandercock, B. K., Robel, R. J., & Applegate, R. D. (2007).

10683:

Suggested practices for raptor protection on powerlines: the state of the art in 1981 (No. 4)

10490: 5244:(in Latin). Vol. 1, Part 1 (13th ed.). Lipsiae : Georg. Emanuel. Beer. p. 287. 5207: 4692: 4093: 3531: 3210: 2735: 2460: 2340: 2230: 1999: 1885: 1237: 1088: 1022: 763: 734: 529: 315: 11788: 11619: 10685:. Published and distributed for the Edison Electric Institute by Raptor Research Foundation. 8848:"Nesting ecology of forest-dwelling Great Horned Owls in the Eastern Deciduous Forest Biome" 7404:"Stacey O'Brien : Wesley the Owl: Crows and Ravens: The Corvids and their odd behavior" 4529:

well. Violent fights have been observed between great horned owls after attempts to capture

1123:, may be merely a southerly leg of this race, as its coloring is almost exactly the same as 11822: 11498: 11444: 11289:"Spotted owls, great horned owls, and forest fragmentation in the central Oregon Cascades." 9969:

Rohner, C., Smith, J. N., Stroman, J., Joyce, M., Doyle, F. I., & Boonstra, R. (1995).

9786: 8437: 7805: 7742:

Orians, G.; Kuhlman, F. (1956). "Red-tailed hawk and horned owl populations in Wisconsin".

7273: 6607: 6232: 5841:

Webster, J. D.; Orr, R. T. (1958). "Variation in the Great Horned Owls of Middle America".

5506: 5286:

The book bears the date of 1806 on the title page but was actually published in 1805. See:

4356: 4188: 4105: 3539: 3262: 2948: 2862: 2439: 2115: 1889: 1818: 1779: 1663: 1658:. This race has only minimally the rufous tinge seen in other darkish races, although some 1605: 1499: 1460: 1425: 1288: 1283:

is a medium-sized race, smaller than most in North America but not as small as some of the

1164:, though averaging longer in wing length averages somewhat less heavy. On the contrary, in 1152: 1112: 886: 695:

Dickerman & Johnson, AB, 2008 – south Idaho to north Arizona and north New Mexico (USA)

606: 539:

who had described and illustrated the great horned owl in 1747 in the second volume of his

10287:

Great Horned Owl (Bubo virginianus) nesting in a Great Blue Heron (Ardea herodias) heronry

9255:

Hamerstrom, F. N. (1939). "A study of Wisconsin prairie chicken and sharp-tailed grouse".

8154: 6509: 1799: 1424:

but with sharper contrasting of colors. This is one of the largest-bodied subspecies. The

866: 738: 652:(Oberholser, 1904) – central Alaska to northeast Oregon, Idaho and northwest Montana (USA) 8: 11449: 8835:(Doctoral dissertation). State University of New York at Fredonia, Department of Biology. 6797:"The identity of Pennant's "Wapacuthu Owl" and the subspecific name of the population of 6773: 5769: 4864: 4656: 4636: 4537:. When a peregrine falcon repeatedly attacked a great horned owl near its nest along the 4534: 4497: 4360: 4136: 4037: 3834: 3730:

Many types of invertebrates are recorded as prey. These include mainly insects, but also

3640: 3419: 3302: 3294: 3190: 3047: 2936: 2270: 2266: 2182: 2087: 2055: 1956: 1346: 643: 576:

The great horned owl represents one of the one or two radiations of the genus across the

560: 502: 426:. It is an extremely adaptable bird with a vast range and is the most widely distributed 168: 11365: 11309:

Biology and conservation of owls of the Northern Hemisphere, 2nd International Symposium

10874:

Age‐Specific Survival and Probable Causes of Mortality in Female Lesser Prairie‐Chickens

10846:

Breck, S. W., Biggins, D. E., Livieri, T. M., Matchett, M. R., & Kopcso, V. (2006).

10116:, The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology. 10025:, The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology. 9944:

Barrows, C. W. (1989). Diets of five species of desert owls. Western Birds, 20(1), 1–10.

9922:, The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology. 9790: 8441: 7809: 7717: 7277: 6611: 6511:

Spotted Owls, Great Horned Owls, and forest fragmentation in the Central Oregon Cascades

6307:

Hall, M. I.; Heesy, C. P. (2011). "Eye size, flight speed and Leuckart's Law in birds".

6236: 5510: 2130:, before they give way to the Magellanic horned owl, which thence ranges all the way to 11276: 11156: 11007: 10928:, The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology 10902:, The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology 10478: 10447: 10384:

Post-fledging activities of juvenile Great Horned Owls as determined by radio-telemetry

10217: 9888: 9833: 9755: 9610: 9529: 9502: 9494: 9455: 9428: 9393: 9264: 9237: 9153: 9118: 9077: 8761: 8726: 8669: 8611:

Roger A. Powell, Martes pennanti, Mammalian Species, Issue 156, 8 May 1981, Pages 1–6,

8594: 8559: 8453: 8347: 8317: 8243: 8132: 8093: 8074: 8034: 8007: 7918: 7821: 7759: 7665: 7597: 7525: 7440: 7305: 7289: 7170: 7096: 7061: 6976: 6865: 6722: 6623: 6485: 6458: 6423: 6324: 6289: 6147: 6052: 5974: 5858: 5816: 4995: 4957: 4821: 4751:

A male great horned owl and a female Eurasian eagle-owl produced an apparently healthy

4644: 4409: 4128: 4010: 3800: 3664: 3439: 3334: 2968: 2747: 2683: 2647: 2599: 2555: 2527: 1724: 1464: 753: 629: 470: 370: 215: 10464: 9798: 4711:'s "green list" includes birds with considerable population declines (many classed as 2594: 2522:, great horned owls largely live off just a handful of prey species: three species of 2027:

with the exception of wintering snowy owls. More tropical species with ear tufts, the

11783: 11529: 11249: 11212: 11135:

Dickerman, Robert W. (1 July 2002). "The Taxonomy of the Subarctic Great Horned Owl (

10942: 10556: 10511: 10209: 9880: 9872: 9814:"Presence and Food Preferences of the Great Horned Owl in the Urban Parks of Seattle" 9747: 9702: 9680: 9432: 8968: 8806: 8644: 8410: 8389:"Demographic and dietary responses of Great Horned Owls during a snowshoe hare cycle" 8183: 7958: 7359: 7340: 7297: 7218: 7217:. Svendborg, Denmark: Zoological Museum, University of Copenhagen, and Apollo Books. 7193: 7119: 7024: 6999: 6912: 6752: 6674: 6384: 6380: 6320: 6293: 6281: 6276: 6259: 5997: 5928: 5749: 5522: 5469: 5441: 5124: 4983: 4779:

believed that owls were reincarnations of slain warriors who fly about by night. The

4737: 4728: 4680: 4624: 4604: 4530: 4459: 4176: 4045: 3879: 3859: 3779: 3656: 3648: 3571: 3526: 3514: 3510: 3443: 3270: 2924: 2719: 2476: 2260:. They are generally rare in non-tidal wetland habitat, and are replaced in the high 2226: 2091: 2008: 1916:

to its south, the latter two overlap and possibly hybridize in some of the northeast.

994: 909: 585: 11160: 10236: 9892: 9759: 9533: 9506: 9220:

Errington, P. L. (1932). "Food habits of southern Wisconsin raptors. Part I. Owls".

6980: 6343: 6328: 5279: 5259: 2066: 1675:

is notably smaller overall when specimens are compared side-by-side with those from

877: 624:

variation. Subspecies differences are mainly in color and size and generally follow

11609: 11268: 11254:"A Preliminary Survey of Trends in Avian Evolution From Pleistocene to Recent Time" 11148: 11121: 10999: 10546: 10201: 9864: 9825: 9794: 9737: 9670: 9602: 9486: 9420: 9385: 9229: 9145: 9108: 9014: 8859: 8753: 8718: 8586: 8551: 8522: 8489: 8445: 8400: 8309: 8235: 8124: 8066: 7997: 7908: 7813: 7751: 7657: 7499: 7430: 7336: 7309: 7281: 7088: 7053: 6966: 6857: 6712: 6615: 6450: 6415: 6376: 6316: 6271: 6240: 6205: 6139: 6044: 5966: 5850: 5808: 5644: 5514: 5329: 5239: 5217: 4949: 4882: 4752: 4668: 4600: 4501: 4344: 4329: 4293: 4289: 4184: 4144: 4140: 4132: 4124: 4120: 4116: 4101: 4085: 4065: 4057: 4053: 4026: 4018: 4002: 3977:, the owls were observed to visit nests nightly until all the nestlings were gone. 3962: 3907: 3906:) among all predators. Although locally dependent on the hares as their main food, 3863: 3796: 3632: 3459: 3198: 2131: 2111: 2103: 1861:

had a wing chord of 330 mm (13 in) and tail of 211 mm (8.3 in).

1752: 1534: 1480: 625: 559:. Edwards also owned a preserved specimen, and another specimen formed part of the 11840: 11534: 10772:

Barrows, W. B. 1912. "Michigan bird life". Michigan Agricultural College, Lansing.

9474: 8933: 3285:, which also roost in vegetation but more openly than quail. Some grouse, such as 2598:

A large portion of the great horned owl's food consists of small rodents, such as

11744: 11573: 11521: 11304: 10062:

Peregrine falcon management efforts in California, Oregon, Washington, and Nevada

9136:

Baker, J. K. (1962). "The manner and efficiency of raptor depredations on bats".

8057:

Fitch, H. S. (1947). "Predation by owls in the Sierran foothills of California".

7952: 7882:

United States Department of Agricultural, Forest Service General Technical Report

7190:

Atlas of wintering North American birds: an analysis of Christmas bird count data

5631:

Artuso, C.; Houston, C. S.; Smith, D. G.; Rohner, C. (2020). Poole, A. F. (ed.).

4805: 4712: 4700: 4542: 4397: 4380: 4347:, eggs may be laid as early as late November to as late as early January. In the 4257: 4249: 3915: 3883: 3809: 3063: 3039: 3023: 2964: 2762: 2687: 2631: 2406: 2328: 2163: 1936: 1838: 1760: 1526: 1468: 870: 845: 725: 671: 610: 602: 515: 482: 11814: 11710: 10850:

Recovery of the black-footed ferret-progress and continuing challenges, 203–209.

10848:

Does Predator Management Enhance Survival of Reintroduced Black-footed Ferrets?

10512:"Early breeding records and nesting phenology of Great Horned Owls in Wisconsin" 9852: 7777:

Einarsen, A. S. (1956). "Determination of some predator species by food signs".

7324: 6074: 5518: 4300:

and golden eagle, though perhaps most often those of red-tailed hawks and other

4256:

and in the midst of brushy spots on desert ground. Even the burrow entrances of

935:

of the great horned owl is 3.3–5.2 cm (1.3–2.0 in) long, although the

836: 788: 11311:. St. Paul, MN: US Department of Agriculture, Forest Service. pp. 347–362. 10709:

Effects of strychnine on the behavior of Great Horned Owls and Red-tailed Hawks

10358:

The postnatal development of two broods of Great Horned Owls (Bubo virginianus)

9868: 5211: 4934: 4517:, unlike many other raptorial birds. Siblicide occurred at 9 of 2,711 nests in 4368: 4148: 3871: 3487: 3463: 3426:. 77% of the ducks in that study were juveniles, the largest duck being a male 3411: 3338: 2344: 2249: 2221:

forest of the Rockies. They have only been recorded a handful of times in true

2202: 1817:, and is only slightly larger at median than the following race. This race has 1632: 1557:

is often now considered a mere clinal variation of the same race from interior

1276: 963: 921: 913: 804:

Individual and regional variations in overall color occur, with birds from the

658: 548: 10809:

Recovery Plan for the Pacific Pocket Mouse, Perognathus longimembris pacificus

10746:

Buck, J. A., L. W. Brewer, M. J. Hooper, G. P. Cobb, and R. J. Kendall. 1996.

6886:

Smithsonian Contributions to Knowledge: Life Histories of North American Birds

6073:

Johnson, D. H. (1998). Duncan, J. R.; Johnson, D. H.; Nicholls, T. H. (eds.).

5686: 2455: 2301:

Great horned owls are typically sluggish and passive but aware during daytime.

1443: 481:

despite its notably larger size. The great horned owl is also compared to the

11857: 11679: 10937:

Chipley, R.M., Fenwick, G.H., Parr, M.J. & Pashley, D.M., editors, 2003.

10560: 10302:. Brigham Young University Science Bulletin Biological Services, 10(4):16–25. 10213: 9876: 9751: 9684: 9675: 9654: 8832:

Breeding biology of broad-winged and red-shouldered hawks in western New York

8414: 8275: 7140: 6566:

Baumgartner, F. M. (1938). "Courtship and nesting of the great horned owls".

6285: 6209: 4873: 4789: 4547: 4376: 4196: 3895: 3771: 3716: 3563: 3479: 3383: 3322: 3314: 3258: 3254: 3241: 3174: 3170: 3099: 3031: 2870: 2830: 2786: 2579: 2535: 2464: 2320: 2289: 2261: 2214: 2210: 1964: 1712: 1702: 1452: 1217: 936: 809: 772: 510: 490: 188: 183: 133: 59: 9446:

Schreiber, R. W.; Risebrough, R. W. (1972). "Studies of the Brown Pelican".

9036: 4820:

felt the origin of the great horned owl was due to an unformed owl annoying

4567:

The great horned owl is not considered a globally threatened species by the

4428: 4208: 3086:) are often juveniles presumably snatched from the mouths of dens by night. 1727:

southeastwards through arid regions of southeastern California and southern

1708: 11409: 10192:

Morse, Douglass H. (April 1971). "Great Horned Owls and Nesting Seabirds".

9884: 8226:

Wiley, J.W. (1969). "A Case of Great Horned Owl Predation on a Porcupine".

7301: 7141:"Habitat characteristics of Great Horned Owls in southcentral Pennsylvania" 6244: 5526: 5333: 4909: 4784: 4771:

admired the great horned owl for their "strength, courage and beauty". The

4620: 4608: 4538: 4518: 4446: 4393: 4332:

nests have been used, the latter sometimes right in the midst of an active

4317: 4156: 3712: 3608: 3518: 3451: 3375: 3244:

are often a favored food source for great horned owls living near wetlands.

3154: 2909: 2822: 2798: 2731: 2691: 2575: 2496: 2472: 2422: 2398: 2238: 2178: 2086:

of North America, where they are found up to the northwestern and southern

1379: 1354: 1339: 1229: 925: 900: 890: 686: 524: 463: 11326:"Owl predation on snowshoe hares: consequences of antipredator behaviour." 9424: 6388: 5648: 4740:

seem to be selected as prey "out of relation to their population status".

3237: 2889: 1486:

Very rich brown, dark underside barring distinct, less pronounced than in

477:), a closely related species, which occupies the same ecological niche in 11749: 11692: 11640: 11485: 11418: 10670:

Movements, population fluctuations, and mortality among great horned owls

10551: 10162:

Competitive relationships among kingbirds (Tyrannus) in trans-Pecos Texas

6441:

Miller, A. H. (1934). "The vocal apparatus of some North American owls".

5491: 4813: 4772: 4612: 4388: 4172: 4112: 3899: 3855: 3845: 3813: 3763: 3616: 3395: 3346: 3250: 3146: 2834: 2774: 2710: 2704: 2672: 2664: 2571: 2365: 2244:

In mountainous areas of North America, they are usually absent above the

2159: 2155: 2139: 2036: 2028: 2016: 1940: 1566: 1387:

is probably based on wandering individuals and/or various intergrades of

1144: 1108: 947: 821: 702: 667: 594: 34: 10748:

Monitoring Great Horned Owls for pesticide exposure in southcentral Iowa

9851:

Stone, Ward B.; Okoniewski, Joseph C.; Stedelin, James R. (April 1999).

9742: 9725: 9081: 7957:(1st ed.). Mechanicsburg, PA: Stackpole Books. pp. 33, 80–81. 7380:"Great Horned Owl Overview, All About Birds, Cornell Lab of Ornithology" 7174: 7065: 6971: 6954: 6673:. Ithaca, NY: Comstock Publishing Associates, Cornell University Press. 5978: 2134:, the southern tip of the continent. It is absent or rare from southern 813:

the great horned owl are the second-longest known in any owl (after the

11835: 11596: 11280: 11011: 10763:. Proceedings of International Congregation of Ornithology, 15:437–452. 10482: 10466: 10451: 10435: 10360:. University of Kansas Publishing Museum of Natural History, 1:157–173. 10221: 9837: 9813: 9614: 9548: 9498: 9459: 9397: 9268: 9241: 9157: 9122: 8765: 8730: 8673: 8598: 8563: 8457: 8351: 8321: 8247: 8136: 8078: 8038: 8011: 7922: 7897:"Comparative food habits of Bubo owls in Mediterranean-type ecosystems" 7855: 7825: 7763: 7669: 7601: 7444: 7293: 7285: 7100: 6916: 6869: 6726: 6489: 6462: 6427: 6151: 6056: 5862: 5820: 5221: 4987: 4961: 4809: 4756: 4688: 4413: 4301: 4297: 4217: 3886:

in the hawk and the rattlesnake and desert woodrats and other assorted

3850: 3767: 3724: 3672: 3455: 3370: 3362: 3310: 2913: 2715: 2622: 2551: 2523: 2222: 2206: 2174: 2147: 2099: 2024: 1952: 1331: 1165: 858: 617: 565: 493:, often laying eggs weeks or even months before other raptorial birds. 469:

In ornithological study, the great horned owl is often compared to the

354: 292: 79: 44: 11110:"Forty-Second Supplement to the AOU Checklist of North American Birds" 11107: 11027:"The rearing of a hybrid Virginian x European Eagle-Owl at Dudley Zoo" 10075:

Northern goshawk diets in ponderosa pine forests on the Kaibab Plateau

10036:

The role of territoriality in the social organization of Harris' Hawks

5664:"Catalogue of fossil birds, Part 4 (Columbiformes through Piciformes)" 4343:

The stage at which eggs are laid is variable across North America. In

2209:. It is less common in the more extreme areas of the Americas. In the 2023:

may superficially be somewhat similar, but the species is generically

946:

The great horned owl's eyes, just slightly smaller than the eyes of a

108: 11645: 11555: 10913:

Flocking and annual cycle of the pinon jay, Gymnorhinus cyanocephalus

10125:

Rohner, C., Krebs, C. J., Hunter, D. B., & Currie, D. C. (2000).

9549:"Great horned owl predation of Atlantic loggerhead turtle hatchlings" 9310:"Analysis of Great Horned Owl pellets with Rhinoceros Auklet remains" 9097:"Food of a Family of Great Horned Owls, Bubo virginianus, in Florida" 8864: 8847: 8527: 8510: 8494: 8477: 8405: 8388: 8092:

Murphy, J. R.; Camenzind, F. J.; Smith, D. G.; Weston, J. B. (1969).

7504: 7487: 7057: 5970: 5884:"Great Horned Owl – Bubo virginianus – Information, Pictures, Sounds" 4514: 4364: 4277: 4268: 3986: 3966: 3935: 3923: 3739: 3599: 3506: 3502: 3423: 3206: 3091: 3019: 2492: 2463:

depicting a great horned owl with one of its primary prey species, a

2311: 2245: 2170: 2143: 2135: 2119: 2083: 2020: 1968: 1628: 1604:(which may itself be a discontinuous eastern wing of this race). The 1582: 1404: 1241: 1092: 1062: 814: 805: 459: 431: 232: 84: 11380: 11272: 11003: 10205: 9829: 9606: 9389: 9233: 9149: 9113: 9096: 8757: 8722: 8590: 8555: 8449: 8313: 8239: 8128: 8070: 8002: 7985: 7913: 7896: 7817: 7755: 7661: 7435: 7418: 7239: 7092: 6861: 6717: 6700: 6627: 6454: 6419: 6143: 6048: 5854: 5812: 4953: 3205:) readily, and can be a major predator of this species. Remnants of 1643:. Resident all-year round. Presumably synonymous with the described 11560: 11547: 11403: 11221:

Houston, C. S.; Smith, D. G.; Rohner, C. (1998). Great Horned Owl (

10965: 10535:"January initiation of suburban great horned owl nests in Manitoba" 9853:"Poisoning of Wildlife with Anticoagulant Rodenticides in New York" 9490: 9195: 7459: 6848:

Taverner, P. A. (1942). "Canadian Races of the Great Horned Owls".

6225:

Philosophical Transactions of the Royal Society of London, Series B

4817: 4745: 4584: 4552: 4455: 4337: 4081: 3990: 3841: 3824: 3759: 3747: 3731: 3700: 3692: 3684: 3683:

are reported as prey. On rare occasions, fish are taken including

3555: 3055: 2932: 2782: 2758: 2727: 2678: 2643: 2427: 2234: 2095: 2082:

The breeding habitat of the great horned owl extends high into the

1881: 1740: 1736: 1636: 1574: 1549:

to northern California. Includes the previously described form of

1517: 1403:

where owls are often medium-grayish and more heavily marked to the

1343: 1319: 1245: 1213: 1157: 917: 825: 661:, 1877 – coastal southeast Alaska to coastal north California (USA) 581: 577: 556: 544: 427: 423: 282: 252: 74: 69: 54: 49: 39: 11298:"Non-territorial floaters in great horned owls (Bubo virginianus)" 10859:

Berger, D. D., Hamerstrom, F., & Hamerstrom Jr, F. N. (1963).

9571: 9309: 8830: 8612: 7718:"The Great Horned Owl and its prey in north-central United States" 7645: 7588:

Vaughan, T.A. (1954). "Diurnal foraging by the Great Horned Owl".

4359:, egg laying may begin from late December to early February. From 2953:

Morley Nelson Snake River Birds of Prey National Conservation Area

2931:) for another 8.7% of prey biomass. In the short-grass prairie of 1813:

is smaller than all North American horned owls, even the smallish

1399:

shows a very high degree of clinal variation, ranging from in the

11762: 11470: 6911:(Revised ed.). Ottawa: National Museum of Natural Sciences. 6619: 4841: 4780: 4493: 4405: 4333: 4253: 4164: 4069: 3974: 3805: 3775: 3708: 3595: 3551: 3427: 3407: 3354: 3107: 3087: 3071: 3003: 2983: 2846: 2714:

ssp.) can average nearly as light as 8 g (0.28 oz). In

2495:

with the remaining 4.7% being made up by insects, other assorted

2488: 2353: 2253: 2190: 2123: 1971:

of California. This race was included in the presumed subspecies

1948: 1893: 1771: 1601: 1570: 1542: 1495: 1350: 1335: 1233: 1225: 1104: 854: 478: 455: 442:, although it freely hunts any animal it can overtake, including 89: 64: 10761:

Residue levels of chemical pollutants in North American birdlife

7716:

Errington, P. L.; Hamerstrom, F.; Hamerstrom, F. N. Jr. (1940).

7646:"Hunting methods and success of newly-fledged Great Horned Owls" 7526:"Breeding ecology of raptors in the eastern Great Basin of Utah" 6402:

Jacobs, Gerald H.; Crognale, Michael; Fenwick, John (May 1987).

3546:). Somewhat larger bodied families are more prominent, i.e. the 1809:

in both hue and ventral markings. Going on linear measurements,

1212:, A lowland form occurring in disjunct populations from eastern 1176:

also tends to have relatively the longest ear tufts on any race.

1131:

type owls are discontinuous in range, with only paler owls from

11457: 10465:

Minor, William, Minor, Maureen & Ingraldi, Michael (1993).

10373:. University of California, Publication on Zoology, 40:331–362. 9918:

Bibles, Brent D., Richard L. Glinski and R. Roy Johnson. 2002.

6170:"Powerful feet and talons help birds of prey make their living" 6130:

Marti, C. D. (1974). "Feeding ecology of four sympatric owls".

4825: 4733: 4616: 4572: 4559:

ssp.), was a leading cause of juvenile mortality in the Yukon.

4485: 4481: 4285: 4261: 4097: 4073: 3943: 3931: 3919: 3887: 3755: 3743: 3603: 3547: 3498: 3282: 3186: 3115: 3079: 3007: 2995: 2991: 2960: 2905: 2766: 2660: 2639: 2607: 2519: 2515: 2480: 2418: 2198: 2194: 2151: 1877: 1842: 1744: 1732: 1593: 1562: 1558: 1546: 1472: 1284: 1221: 1100: 955: 951: 850: 601:

owls in North America, which may either be distinct species or

589: 447: 443: 242: 10887:

Nest success and the effects of predation on marbled murrelets

10419:

Bursa regression, gonad cycle and molt of the Great Horned Owl

9284:"Predation's role in the cyclic fluctuations of Ruffed Grouse" 8115:

Fitch, H. S. (1940). "Some observations on horned owl nests".

6746: 5770:"Great Horned Owl - Sierra Nevada Aquatic Research Laboratory" 5294:, and the potential confusion caused by Froriep's translation 3070:), though young ones are typically taken. Prey in the form of 11809: 11542: 10707:

Cheney, C. D., S. B. Vander Wall, and R. J. Poehlmann. 1987.

10681:

Olendorff, R. R., Miller, A. D., & Lehman, R. N. (1981).

10237:"Great Horned Owl Nest – Interesting Facts & Information" 7715: 7530:

Brigham Young University Science Bulletin Biological Services

6344:"Great Horned Owl Eyes – How Far Can a Great Horned Owl See?" 4793: 4522: 4509: 4352: 4309: 4168: 3891: 3862:

as the primary prey with golden eagles, red-tailed hawks and

3583: 3567: 3403: 3391: 3218: 3142: 2987: 2979: 2956: 2507: 2369: 2349: 2252:

zones at 4,100 to 4,500 m (13,500 to 14,800 ft) in

2218: 2186: 1960: 1944: 1888:). Its southern breeding range seems to be delineated by the 1852:

but even darker and more heavily barred, like a miniaturized

1624: 1578: 1374: 1096: 862: 808:

showing a washed-out, light-buff color, while those from the

792:

Great horned owl showing much of its camouflage pattern/color

535:. Gmelin based his description on that of English naturalist 520: 205: 199: 10861:

The effect of raptors on prairie chickens on booming grounds

9659:) in rural and urban areas of southwestern British Columbia" 9411:

Knopf, F. L.; Evans, R. M. (2020). "American White Pelican (

8364: 7046:"Bird populations of aspen forests in Western North America" 6530:

Wisconsin Department of Natural Resources Technical Bulletin

4072:(39% and 40% of failures, respectively), wetland-inhabiting 3018:

Other mammals are taken readily as well. Several species of

1892:. In winter, this race may disperses southwards throughout 11153:

10.1674/0003-0031(2002)148[0198:TTOTSG]2.0.CO;2

11127:

10.1642/0004-8038(2000)117[0847:FSSTTA]2.0.CO;2

8098:

Brigham Young University Science Bulletin-Biological Series

7620:"Predation Ecology of Coexistng Great Horned and Barn Owls" 6996:

A guide to the birds of Mexico and northern Central America

4797: 4716: 4590: 4568: 4505: 4401: 4372: 4305: 4195:). In addition, there are several documented incidences of 3951: 3751: 3735: 3680: 3676: 3579: 3522: 3399: 3379: 3169:), which was represented in more than 2% of pellets in the 2999: 2920: 2901: 2896:

are an important food source for western great horned owls.

2567: 2511: 2500: 2484: 2431: 2307: 2257: 2127: 1904:, although it is distributed far to the east of that race. 1728: 1640: 1310: 1054: 932: 894: 451: 439: 262: 10990:

Baerg, W. J. (1926). "Trying to Tame a Great Horned Owl".

8663: 8091: 6774:"On the validity of Bubo virginianus occidentalis (Stone)" 3594:

The great horned owl rarely misses an opportunity to hunt

3586:

tend to be grabbed off of their communal roosts by night.

2388: 11242:, Washington, D.C. Online version, retrieved 2006-12-05. 10696:

Secondary poisoning of owls by anticoagulant rodenticides

10657:

Behavior of peregrine falcons in the New York City region

10642:

Perry, R. W., Brown, R. E., & Rudolph, D. C. (2001).

10300:

Nesting ecology of the Great Horned Owl, Bubo virginianus

8577:

Mendall, H. L. (1944). "Food of Hawks and Owls N Maine".

7986:"Food of the great horned owl and barn owl in east Texas" 5687:"Avifauna of the Pleistocene cave deposits of California" 4596: 4489: 4477: 3720: 3131: 3123: 3075: 2754:) averaging at 152 g (5.4 oz), are also taken. 1046: 419: 272: 10049:

Growth and brood reduction of mid-Atlantic coast ospreys

8641:

A guide to the mammals of the southeastern United States

5691:

University of California Bulletin, Department of Geology

5668:

Bulletin of the Florida State Museum, Biological Science

5630: 4623:. Where clear-cutting occurs in old-growth areas of the 4454:

protection from wind and cold. Nesting owls at sites in

3819: 3138:) being killed by great horned owls have been reported. 1573:. These forms may be reported in winter as far south as 680:

Hoy, PR, 1853 – central west Canada to north Idaho (USA)

11080: 10833:

Kelt, D. A., Wilson, J. A., & Konno, E. S. (2005).

10397:

Spatiotemporal ecology of four sympatric raptor species

10386:. Ph.D. thesis. University of South Dakota, Vermillion. 9850: 7549:

Spatiotemporal ecology of four sympatric raptor species

5710:

Special Publication, Carnegie Museum of Natural History

2352:

to an average of 2.1 km (0.81 sq mi) in

670:, 1854 – coastal central California (USA) to northwest 10720:

Seidensticker IV, J. C. and H. V. Reynolds III. 1971.

10261:

Notes on nesting Great Horned Owls in southern Arizona

10149:

Comparative mobbing behavior of scrub and Mexican jays

8845: 8024: 6514:(Master's Thesis). Corvallis: Oregon State University. 6260:"The missing link for success in hearing aid fittings" 4862: 4551:

and the drinking of blood by swarming, blood-drinking

3795:

voles as by far the most common prey. In southwestern

3114:) have been reported. One instance of an owl taking a 2043:), are much smaller. Other large owls lack ear tufts. 1361:(based on a wintering individual, as was the original 1248:; resident all-year. Includes the proposed subspecies 817:). The bill is dark gunmetal-gray, as are the talons. 11362:, a compilation of various sources pertaining to owls 11081:

Accordi, Iury Almeida; Barcellos, Andre (June 2006).

10876:. The Journal of wildlife management, 71(2), 518–525. 10796:

Distribution and biology of the Spotted Owl in Oregon

10794:

Forsman, E. D., E. C. Meslow, and H. M. Wight. 1984.

10783:

Peregrine Falcon restoration: Expectation vs. reality

10618:

Mortality of Great Horned Owls associated with skunks

10344:. Compilation of Biochemical Physiology, 68A:167–173. 10326:

Breeding birds of Ontario: nidiology and distribution

9984:

Natal and breeding dispersal of northern spotted owls

9330: 8708: 8333: 8331: 7854:

Cromrich, L. A.; Holt, D. W.; Leasure, S. M. (2002).

7488:"Recoveries of Saskatchewan-banded Great Horned Owls" 7458:

Millard, J. B.; Craig, T. H.; Markham, O. D. (1978).

6475: 6401: 5435: 4727:

From experimentally raising young owls in captivity,

1982:

A medium gray form, intermediate in coloring between

10276:. Smithsonian Contributions to Knowledge 28:376–389. 10088:

Adult male osprey killed at nest by Great Horned Owl

9170: 8094:"Nesting ecology of raptorial birds in central Utah" 7023:(2 ed.). Princeton, NJ: Princeton Univ. Press. 5324: 3973:), for example, in a study of one breeding block of 2584:

Microtus pennsylvanicus, ochrogaster & pinetorum

11307:. In: Duncan, JR; Johnson, DH; Nicholls, TH (eds): 10898:Woolfenden, Glen E. and John W. Fitzpatrick. 1996. 10781:Cade, T. J., P. T. Redig, and H. B. Tordoff. 1989. 10012:. Master's Thesis. Univ. of N. Dakota, Grand Forks. 9445: 9307: 9171:Kittredge, V. C.; Wilson, P. W.; Caire, W. (2007). 8991:. Help Find Lost Pets. May 27, 2010. Archived from 8880:"Blakeman answers questions about nest maintenance" 7856:"Trophic niche of North American great horned owls" 7853: 7457: 6075:"Wing loading in 15 species of North American owls" 4212:

Nestlings of the Rocky Mountains great horned owl (

1264:

and the Magellanic horned owl, deserves more study.

1127:, although with rather smaller body size. However, 908:The legs, feet, and talons are large and powerful. 889:length is 297–400 mm (11.7–15.7 in). The 844:The great horned owl is the heaviest extant owl in 563:. The great horned owl is now placed in the genus 10399:. Ph.D. thesis. University of Minnesota, St. Paul. 10175:"These Owl Chicks Have Two Moms and a Dad—a First" 9519: 9308:Hayward, J. L.; Galusha, J. G.; Frias, G. (1993). 9070:Proceedings of the Pennsylvania Academy of Science 9067: 8846:Bosakowski, T.; Speiser, R.; Smith, D. G. (1989). 8794: 8387:Adamcik, R. S.; Todd, A. W.; Keith, L. B. (1978). 8328: 7419:"Territory and population in the Great Horned Owl" 6932:"On an unnamed population of the Great Horned Owl" 5922: 4888:10.2305/IUCN.UK.2018-2.RLTS.T61752071A132039486.en 4470: 1342:. Non-breeding birds are regularly found south to 1139:found in the in-between range before the northern 10966:"Studies on the Behavior of the Great Horned Owl" 4824:, the almighty creator, while Raweno created the 2293:Composite photo of great horned owl flight phases 1483:, California (see also below). Resident all-year. 1334:; southern limit unclear but at least reaches to 11855: 11324:Rohner, Christoph, and Charles J. Krebs (1996). 11292:Thesis. Oregon State University, Corvallis, USA. 10655:Herbert, R. A., & Herbert, K. G. S. (1965). 10340:Turner, Jr., J. C. and L. McClanahan, Jr. 1981. 9653:Hindmarch, Sofi; Elliott, John E. (2015-02-04). 9652: 9288:Proceeding International Congress of Ornithology 8386: 7237: 7116:Arkansas birds: their distribution and abundance 6952: 5021:. The Cornell Lab of Ornithology. Archived from 4025:), or more open plain and meadow areas, such as 747:(Oberholser, 1904) – south Mexico to west Panama 10807:Brylski, P., Hays, L., & Avery, J. (1998). 10352: 10350: 9723: 9419:. Ithaca, NY, USA: Cornell Lab of Ornithology. 8475: 7078: 6742: 6740: 6738: 6736: 6701:"Variation in South American Great Horned Owls" 6645:"Bird Master Database Search- Bubo virginianus" 5923:Craighead, J. J.; Craighead, F. C. Jr. (1956). 5878: 5876: 5874: 5872: 5643:. Ithaca, NY, USA: Cornell Lab of Ornithology. 4500:consume eggs and nestlings from tree nests and 4436:) with juvenile in nest near Madison, Wisconsin 2405:) while they are building their leaf nests and 2334: 1719:) on top of a Joshua tree in the summer of 2018 1596:owls outmatch those of all other races but for 775:, 1905 – northeast Brazil (central north Bahia) 715:, 1788) – southeast Canada to central, east USA 11371:– USGS Patuxent Bird Identification InfoCenter 10863:. The Journal of Wildlife Management, 778–791. 10735:Effects of pesticides on owls in North America 10060:Walton, B. J., & Thelander, C. G. (1988). 9215: 9213: 8898: 8471: 8469: 8467: 7946: 7944: 7942: 7940: 7938: 7936: 7934: 7932: 7711: 7709: 7707: 7705: 7703: 7701: 7699: 7118:. Fayetteville: University of Arkansas Press. 6561: 6559: 6557: 6555: 6553: 6551: 6549: 6547: 6545: 6543: 6034: 5794: 5792: 5790: 5788: 5786: 5213:Life Histories of North American Birds of Prey 2233:, they appear to use old-growth forest but in 1168:, within the range of the possibly synonymous 831: 10959: 10957: 10955: 10750:. Journal of Wildlife Management, 60:321–331. 10021:Bechard, Marc J. and Josef K. Schmutz. 1995. 9931:Dunstan, T. C., & Harrell, B. E. (1973). 9572:"Great Horned Owl Observed Hawking "Insects"" 9333:Proceedings of National Wild Turkey Symposium 9007: 8805:. Princeton, NJ: Princeton University Press. 7795: 7741: 7697: 7695: 7693: 7691: 7689: 7687: 7685: 7683: 7681: 7679: 7212: 7138: 7018: 6794: 6202:Bulletin of the United States National Museum 4379:is from late February to early April. In the 3858:, the owls share black-tailed jackrabbit and 2070:A great horned owl in a barn, Ontario, Canada 1416:and may do the same with this similarly dark 1099:; northeastwards in distribution to southern 701:(Oberholser, 1904) – northeast Canada to the 635:Fifteen subspecies are currently recognised: 11182:Bulletin of the British Ornithologists' Club 10900:Florida Scrub-Jay (Aphelocoma coerulescens) 10495:: CS1 maint: multiple names: authors list ( 10347: 10112:Bechard, Marc J. and Theodor R. Swem. 2002. 10047:Steidl, R. J., & Griffin, C. R. (1991). 9775:"Urban effects on native avifauna: a review" 9354:"Great Horned Owl | the Peregrine Fund" 9248: 8628:. Minnesota Department of Natural Resources. 8476:Mcinvaille, W. B. Jr.; Keith, L. B. (1974). 8337: 6733: 6668: 5918: 5916: 5914: 5912: 5910: 5908: 5906: 5904: 5902: 5900: 5869: 5000:: CS1 maint: multiple names: authors list ( 4513:general, great horned owls rarely engage in 1963:. Westwards, it is presumed to occur to the 1459:Central and southern California west of the 11211:: 185, plate 10. Lynx Edicions, Barcelona. 10911:Balda, R. P., & Bateman, G. C. (1971). 10822:Habitat relations of the giant kangaroo rat 10589:"Interesting Facts About Great Horned Owls" 10356:Hoffmeister, D. F. and H. W. Setzer. 1947. 10034:Dawson, J. W., & Mannan, R. W. (1991). 9472: 9303: 9301: 9210: 8907:"Chihuahua survives owl attack in Illinois" 8839: 8824: 8822: 8464: 8382: 8380: 8273: 7929: 7894: 7849: 7847: 7845: 7843: 7841: 7839: 7837: 7835: 7722:Iowa Agricultural Express Research Bulletin 7564:"Great horned owl attacking squirrel nests" 7523: 7481: 7479: 7477: 7416: 7263: 7160: 6843: 6841: 6839: 6837: 6565: 6540: 6523: 6521: 6503: 6501: 6499: 5956: 5798: 5783: 5626: 5624: 5622: 5620: 5618: 5616: 5614: 5612: 5610: 5608: 5606: 5604: 5602: 5600: 5598: 5596: 5594: 5592: 5590: 5588: 5586: 5584: 5582: 5580: 5578: 5576: 5574: 5572: 5570: 5568: 5566: 5564: 5562: 5560: 5558: 5556: 5463: 4977: 4272:A brooding female common great horned owl ( 2658:), although assorted other pocket gophers ( 2586:); and one introduced pest, the brown rat. 2450: 2392:Closeup of great horned owl toes and talons 2384:His piercing yellow eyes and his ear tufts. 2061: 1755:, if not elsewhere; vagrant individuals of 916:, 13 to 15 cm (5.1 to 5.9 in) in 10952: 10885:Nelson, S. K., & Hamer, T. E. (1995). 10371:The behavior of some young raptorial birds 10336: 10334: 9995:Stoleson, S. H., & Sadoti, G. (2010). 9952: 9950: 9773:Chace, Jameson F.; Walsh, John J. (2006). 9772: 9655:"Comparing the diet of Great Horned Owls ( 9569: 9513: 9410: 9281: 9254: 9164: 8541: 8508: 8295: 8293: 8153:. Birdnote.org. 2008-08-29. Archived from 7676: 7643: 7613: 7611: 7460:"Cannibalism by an adult Great Horned Owl" 7322: 7259: 7257: 7019:Ridgely, R. S.; Gwynne, J. A. Jr. (1989). 6993: 6889:. The Smithsonian Institution. p. 383 6694: 6692: 6690: 6163: 6161: 6068: 6066: 6030: 6028: 6026: 6024: 6022: 6020: 6018: 6016: 6014: 5840: 5836: 5834: 5832: 5830: 5739: 5737: 5735: 5733: 5731: 5729: 5727: 5725: 5723: 5554: 5552: 5550: 5548: 5546: 5544: 5542: 5540: 5538: 5536: 5459: 5457: 5440:(2nd ed.). London: Christopher Helm. 4562: 4465: 3894:, the great horned owl's prolificacy as a 2730:. In semi-desert and other arid habitats, 1856:. It is considerably (5–10%) smaller than 1798:Endemic to the southern two-thirds of the 519:. He placed it with the other owls in the 446:and other small mammals, larger mid-sized 353: 177: 132: 107: 11167: 11134: 11125: 10985: 10983: 10963: 10926:Kirtland's Warbler (Setophaga kirtlandii) 10737:. Journal of Raptor Research, 30:198–206. 10711:. Journal of Raptor Research, 21:103–110. 10550: 10376: 10289:. Journal of Raptor Research, 22 (2): 62. 10147:Cully, J. F., & Ligon, J. D. (1976). 10073:Boal, C. W., & Mannan, R. W. (1994). 9741: 9724:Rullman, Stan; Marzluff, John M. (2014). 9674: 9592: 9219: 9112: 9037:https://doi.org/10.3356/0892-1016(2007)41 8932:. Bedford Audubon Society. Archived from 8863: 8526: 8493: 8404: 8269: 8267: 8173: 8171: 8001: 7912: 7875: 7873: 7737: 7735: 7519: 7517: 7515: 7503: 7434: 7113: 6970: 6953:Dickerman, R. W.; Johnson, A. B. (2008). 6821: 6771: 6716: 6664: 6662: 6593: 6591: 6589: 6587: 6585: 6583: 6581: 6579: 6577: 6306: 6275: 5952: 5950: 5948: 5946: 5944: 5897: 5431: 5429: 5427: 5425: 5423: 5421: 5419: 5417: 5415: 5413: 5411: 5409: 5407: 5405: 5403: 5401: 5399: 5397: 5395: 5393: 5391: 5389: 5387: 5385: 5383: 5381: 5379: 5377: 5375: 5013: 5011: 4973: 4971: 4886: 4440: 3882:, but the largest portion was made up of 3837:to the great horned and great grey owls. 3442:, where they are no native land mammals, 2054:) perched on the top of a Joshua tree in 1994: 1912:to its west and quite differently marked 1900:. This subspecies may be synonymous with 1697:Desert great horned owl (wet feathered) ( 11168:Dickerman, Robert W. (29 January 2004). 10694:Mendenhall, V. M. and L. F. Pank. 1980. 10649: 10328:. Vol. 1. Royal Ontario Museum, Toronto. 10119: 9925: 9415:), version 1.0". In Poole, A. F. (ed.). 9298: 9177:Proceedings- Oklahoma Academy of Science 8965:Wildlife and Natural Resource Management 8819: 8377: 8052: 8050: 8048: 7983: 7977: 7832: 7776: 7474: 7353: 7192:. Chicago: University of Chicago Press. 7156: 7154: 6847: 6834: 6639: 6637: 6527: 6518: 6496: 6125: 6123: 6121: 6119: 6117: 5661: 5487: 5485: 5373: 5371: 5369: 5367: 5365: 5363: 5361: 5359: 5357: 5355: 5114: 5112: 5110: 5108: 5106: 5104: 5102: 5100: 5098: 5096: 5094: 5092: 5090: 5088: 5086: 5084: 5082: 5080: 5078: 5076: 5074: 5072: 5070: 5068: 5066: 5064: 5062: 5060: 4591:Effect on conservation-dependent species 4427: 4267: 4222: 4207: 3823: 3236: 2888: 2593: 2454: 2387: 2379: 2296: 2288: 2073: 2065: 2045: 1998: 1707: 1692: 1516: 1442: 1309: 1191: 981: 899: 876: 835: 787: 543:. Edwards had seen a live specimen from 10837:. Journal of Mammalogy, 86(2), 265–274. 10824:. Journal of Mammalogy, 13(4), 305–320. 10698:. Wildlife Society Bulletin, 8:311–315. 10646:. The Wilson Bulletin, 113(3), 345–347. 10331: 10285:Burkholder, G. & Smith, D.G. 1988. 10103:Journal of Raptor Research, 26:261–263. 10077:. Studies in Avian Biology, 16, 97–102. 9947: 9811: 8828: 8743: 8685: 8683: 8623: 8576: 8290: 8085: 7888: 7617: 7608: 7587: 7561: 7485: 7254: 6906: 6882: 6698: 6687: 6507: 6257: 6222: 6198: 6192: 6158: 6072: 6063: 6011: 5991: 5827: 5746:Owls of the World: A Photographic Guide 5743: 5720: 5533: 5454: 5436:König, Claus; Weick, Friedhelm (2008). 5287: 5284:(in French). Paris: Allais. p. 34. 5274: 5254: 5202: 5200: 5198: 5196: 5194: 5192: 5190: 5188: 5186: 5184: 5182: 5180: 5178: 5176: 5174: 5172: 5170: 5168: 5166: 5164: 5162: 5160: 5058: 5056: 5054: 5052: 5050: 5048: 5046: 5044: 5042: 5040: 4978:Austing, G.R.; Holt, Jr., J.B. (1966). 4762: 4181:Aphelocoma wollweberi & californica 3494:) have also been killed by these owls. 3410:, as well as upland-based species like 3378:, avian prey, primarily represented by 2797:) to the 5,775 g (12.732 lb) 1208:Originally named as a separate species 1091:eastwards from at least as far west as 509:in his revised and expanded edition of 11856: 11248: 11024: 10980: 10633:. Time-Life International (Nederland). 10532: 10429: 10427: 10234: 9696: 9694: 9648: 9646: 9546: 9375: 9348: 9346: 9193: 9088: 8800: 8427: 8264: 8202: 8177: 8168: 8108: 7879: 7870: 7732: 7551:(Ph.D.). St. Paul: Univ. of Minnesota. 7546: 7512: 7238:Accordi, I. A.; Barcellos, A. (2006). 7139:Morrell, T. E.; Yahner, R. H. (1994). 6929: 6795:Browning, M. R.; Banks, R. C. (1990). 6659: 6597: 6574: 6440: 6404:"Cone Pigment of the Great Horned Owl" 6341: 6097:"The Silent Flight of Owls, Explained" 5941: 5684: 5320: 5318: 5234: 5158: 5156: 5154: 5152: 5150: 5148: 5146: 5144: 5142: 5140: 5008: 4968: 4858: 4856: 3789: 2986:; 83–86% and 75–98%, respectively, in 1805:A medium-pale form, fairly similar to 1275:. It is the only subspecies where the 920:, and 18 cm (7.1 in) in the 865:being smallest, though those from the 689:, 1897 – southwest USA to south Mexico 11899:Taxa named by Johann Friedrich Gmelin 11385: 11384: 11209:(Volume 5: Barn-owls to Hummingbirds) 11049:"Great Horned Owl (Bubo virginianus)" 10989: 10759:Keith, J. A. and I. M. Gruchy. 1972. 10575:New Great Horned Owl longevity record 10509: 10433: 10191: 9700: 9196:"Predation on bats by hawks and owls" 9135: 9094: 9061: 9015:"Great Horned Owl – Bubo virginianus" 8927: 8904: 8638: 8299: 8225: 8114: 8056: 8045: 7950: 7151: 7043: 6749:Handbook of Birds of the World, Vol 5 6669:Stiles, F. G.; Skutch, A. F. (1989). 6634: 6258:Traynor, Robert M. (September 1997). 6129: 6114: 5707: 5499:Molecular Phylogenetics and Evolution 5482: 5352: 5340:. International Ornithologists' Union 5118: 4982:. Philadelphia: Lippingcott Company. 4932: 4525:and other owls of their own species. 3820:Interspecific predatory relationships 3639:) and formidable, large species like 3221:was found to be composed entirely of 2564:Peromyscus leucopus & maniculatus 430:in the Americas. Its primary diet is 11904:Extant Pleistocene first appearances 9997:Zone-tailed Hawk (Buteo albonotatus) 9627: 8962: 8778: 8680: 8274:Smith, D. G.; Murphy, J. R. (1979). 7895:Jaksić, F. M.; Marti, C. D. (1984). 7524:Smith, D. G.; Murphy, J. R. (1973). 7347: 7187: 6366: 5468:. Poyser Monographs. A&C Black. 5206: 5037: 4933:Seton, Ernest E. T. (January 1885). 4227:Juvenile coastal great horned owls ( 4193:Tyrannus verticalis & vociferans 3898:hunter places it second only to the 3538:) and the 6.2 g (0.22 oz) 3130:) and several of juvenile and adult 1301:Northern/sub-Arctic great horned owl 966:is yellow, except in the amber-eyed 11864:IUCN Red List least concern species 11225:). In: Poole, A.; Gill, F. (eds.): 10811:. U.S. Fish & Wildlife Service. 10586: 10526: 10503: 10424: 10324:Peck, G. K. and R. D. James. 1983. 9805: 9691: 9643: 9630:"Great Horned Owl on Motion Camera" 9343: 9282:Keith, L. B.; Rusch, D. H. (1988). 8882:. Blakeman on Hawks. Archived from 8689: 8205:"Great horned owl versus porcupine" 8182:. St. John's, NF: Jesperson Press. 7644:Smith, D. G.; Smith, B. A. (1972). 7358:. Philadelphia, PA: Running Press. 7323:Ganey, J. L.; Vojta, S. C. (2005). 6994:Howell, S. N. G.; Webb, S. (1995). 6824:Kansas Ornithology Society Bulletin 6647:. Florida Museum of Natural History 6167: 5985: 5315: 5261:A Natural History of Uncommon Birds 5137: 4874:IUCN Red List of Threatened Species 4853: 3840:In a long-term study of a block of 3554:(14 species) and, secondarily, the 2375: 1876:Breeds in eastern Canada (northern 1822:to 65 mm (2.1 to 2.6 in). 997:is normally a low-pitched but loud 756:, 1884 – Colombia to northwest Peru 541:A Natural History of Uncommon Birds 13: 11073: 10164:. Wilson Bulletin, 86(4), 357–373. 10099:Rohner, C. and F. I. Doyle. 1992. 9595:The Journal of Wildlife Management 8711:The Journal of Wildlife Management 8579:The Journal of Wildlife Management 7114:James, D. A.; Neal, J. C. (1986). 6671:A guide to the birds of Costa Rica 5992:Dunning, John B. Jr., ed. (1992). 4831: 4233:Tule Lake National Wildlife Refuge 4200:display and raising of its wings. 3345:) are an important prey item. The 3094:of up to adult size may be taken. 2566:); approximately three species of 1979:might occur, but this needs study. 1271:). This race is less fuscous than 1119:from Central America south of the 14: 11920: 11633:great-horned-owl-bubo-virginianus 11339: 11139:) Nesting in the United States". 11090:Revista Brasileira de Ornitologia 10941:. Random House Trade Paperbacks, 10114:Rough-legged Hawk (Buteo lagopus) 9799:10.1016/j.landurbplan.2004.08.007 9570:Duncan, J.R.; Lane, P.A. (1998). 8905:Olson, Karen (January 19, 2011). 8643:. University of Tennessee Press. 7244:Revista Brasileira de Ornitologia 5994:CRC Handbook of Avian Body Masses 5290:"The two 'editions' of Duméril's 4980:The World of the Great Horned Owl 4504:may take the rare unguarded egg. 2510:) to 2,300 g (5.1 lb) ( 1701:) waiting out a rainstorm in the 857:being largest and populations in 505:in 1788 by the German naturalist 11041: 11018: 10931: 10918: 10905: 10892: 10879: 10866: 10853: 10840: 10827: 10814: 10801: 10788: 10775: 10766: 10753: 10740: 10727: 10714: 10701: 10688: 10675: 10662: 10636: 10623: 10610: 10580: 10567: 10533:Artuso, Christian (2007-03-01). 10458: 10411: 10402: 10389: 10363: 10318: 10305: 10292: 10279: 10266: 10253: 10228: 10185: 10167: 10154: 10141: 10132: 10106: 10093: 10080: 10067: 10054: 10041: 10028: 10023:Ferruginous Hawk (Buteo regalis) 10015: 10002: 9989: 9976: 9963: 9938: 9912: 9907:Bird Enemies of the Varying Hare 9899: 9844: 9766: 9717: 9621: 9586: 9563: 9540: 9466: 9439: 9404: 9369: 9360: 9324: 9275: 9187: 9129: 9052: 9042: 9029: 8989:"Beware of the Great Horned Owl" 8981: 8956: 8947: 8921: 8872: 8772: 8737: 8702: 8657: 8632: 8617: 8605: 8570: 8535: 8502: 8421: 8358: 7213:Fjeldså, J.; Krabbe, N. (1990). 6998:. New York: Oxford Univ. Press. 6321:10.1111/j.1469-7998.2010.00771.x 6277:10.1097/00025572-199709000-00001 5927:. Harrisburg, PA: Stackpole Co. 5338:IOC World Bird List Version 12.2 3890:in the great horned owl. In the 3872:western diamondback rattlesnakes 3013: 1925:Rocky Mountains great horned owl 1908:is surrounded by the much paler 1827:Baja California great horned owl 1778:but weighs less on average. The 1451:) stretching, Bernal Hill Park, 954:surface and a predominantly rod 799:South American great horned owls 219: 32: 11141:The American Midland Naturalist 11053:Alberta Environment & Parks 10672:. The Wilson Bulletin, 155–162. 9935:. Raptor Research, 7(2), 49–54. 8613:https://doi.org/10.2307/3504050 8254: 8219: 8196: 8143: 8018: 7789: 7770: 7637: 7581: 7555: 7540: 7451: 7410: 7396: 7372: 7316: 7231: 7206: 7181: 7132: 7107: 7072: 7037: 7012: 6987: 6946: 6923: 6900: 6876: 6815: 6788: 6765: 6469: 6434: 6395: 6360: 6335: 6300: 6251: 6216: 6089: 5762: 5701: 5678: 5655: 5268: 5121:Owls of the Northern Hemisphere 4863:BirdLife International (2018). 4579:)), organochlorines, and PCBs. 4471:Longevity and natural mortality 4432:Adult common great horned owl ( 4203: 2718:, the 159 g (5.6 oz) 2108:Okak, Newfoundland and Labrador 1939:population breeds south of the 1197:South American great horned owl 1182:South American great horned owl 1078:Common/eastern great horned owl 968:South American great horned owl 569:that was introduced in 1805 by 389: 153:Reifel Migratory Bird Sanctuary 11375:Great Horned Owl photo gallery 11240:American Ornithologists' Union 11207:Handbook of Birds of the World 11172:Bubo virginianus sclariventris 10724:. Wilson Bulletin, 83:408–418. 10090:. Passenger Pigeon 55:269–270. 9378:Journal of Wildlife Management 7341:10.1093/forestscience/51.5.396 7081:Journal of Wildlife Management 7021:A guide to the birds of Panama 5464:Potapov, E.; Sale, R. (2013). 5248: 5228: 4926: 4902: 3179:dwarf fat-tailed mouse opossum 2744:Dipodomys ordii & merriami 1383:. The population described as 1115:. Resident all-year. The race 779: 1: 11884:Provincial symbols of Alberta 11092:(in Portuguese and English). 10263:. Raptor Research, 7:109–111. 9663:The Canadian Field-Naturalist 8509:Weir, D.; Hanson, A. (1989). 6751:. Lynx Edicions. p. 69. 6168:Lee, Carol (March 26, 2006). 5288:Gregory, Steven M.S. (2010). 4847: 4767:Many warrior-based tribes of 4304:. Secondly in popularity are 3589: 2884: 2690:a very important food is the 1870:Bubo virginianus heterocnemis 1866:Northeastern great horned owl 1614:North Andean great horned owl 1447:California great horned owl ( 1072: 820:All great horned owls have a 11377:at VIREO (Drexel University) 11137:Bubo virginianus subarcticus 11096:(2): 101–115. Archived from 10471:Journal of Field Ornithology 10440:Journal of Field Ornithology 10177:. 2018-05-02. Archived from 10129:The Condor, 102(4), 950–955. 9986:. Wildlife Monographs, 1–35. 9857:Journal of Wildlife Diseases 9779:Landscape and Urban Planning 8340:Journal of Field Ornithology 6936:Ontario Museum, Contribution 6381:10.1016/0042-6989(73)90101-6 4836:The great horned owl is the 4722: 4599:, the reintroduction of the 2483:(more than 200 species) and 2335:Territoriality and movements 1581:, but these are in times of 1553:. The often-recognized race 1490:but more pronounced than in 1412:may hybridize with the dark 1330:region east to the southern 1305:Bubo virginianus subarcticus 1203:) with its notably dark eyes 1082:Bubo virginianus virginianus 7: 11236:Academy of Natural Sciences 9920:Gray Hawk (Buteo plagiatus) 9473:Littlefield, C. D. (2003). 8746:American Midland Naturalist 8698:. Braintree, Massachusetts. 8626:Fewer Fishers in the Forest 8302:The Southwestern Naturalist 7417:Baumgartner, F. M. (1939). 5519:10.1016/j.ympev.2012.11.015 4629:Townsend's ground squirrels 3934:and larger varieties (i.e. 3623:) to venomous species like 3163:northern short-tailed shrew 2615:and eight species voles in 2327:). Since owls are, next to 2284: 1831:Bubo virginianus elachistus 1715:, desert great horned owl ( 1688:Bubo virginianus pallescens 1618:Bubo virginianus nigrescens 1434:California great horned owl 1328:Mackenzie, British Columbia 1314:Northern great horned owl ( 832:Physiology and measurements 609:, but predominantly in the 597:fossils have been found of 496: 362:Global range (all year) of 10: 11925: 10924:Mayfield, Harold F. 1992. 10798:. Wildlife Monographs, 87. 10510:Stout, William E. (2008). 10421:. Bird-Banding 36:102–112. 9869:10.7589/0090-3558-35.2.187 9730:Journal of Raptor Research 9576:Journal of Raptor Research 8367:Journal of Raptor Research 7860:Journal of Raptor Research 7145:Journal of Raptor Research 6959:Journal of Raptor Research 6805:Journal of Raptor Research 4615:, attempts to reintroduce 4385:Northwestern United States 3669:Alligator mississippiensis 3054:) and various other small 2855:northern grasshopper mouse 2636:Southwestern United States 2589: 1898:Northeastern United States 1521:Coastal great horned owl ( 1512:Bubo virginianus saturatus 1438:Bubo virginianus pacificus 11393: 11238:, Philadelphia, PA & 10369:Sumner, Jr., E. L. 1934. 10160:Ohlendorf, H. M. (1974). 9812:Lambert, Anthony (1981). 9413:Pelecanus erythrorhynchos 9017:. Raptor Education Center 8852:Canadian Field-Naturalist 8781:"Skunks as Prey for Owls" 8515:Canadian Field-Naturalist 8482:Canadian Field-Naturalist 8393:Canadian Field-Naturalist 7951:Smith, Dwight G. (2002). 7492:Canadian Field-Naturalist 7050:Ornithological Monographs 6883:Bendire, Charles (1892). 6772:Dickerman, R. W. (1991). 6600:Journal of Animal Ecology 6478:Wildlife Society Bulletin 6174:Lubbock Avalanche-Journal 5959:Ornithological Monographs 4881:: e.T61752071A132039486. 4709:American Bird Conservancy 4322:black-crowned night heron 3476:Pelecanus eryhtrorhynchos 3307:Centrocercus urophasianus 2050:Desert great horned owl ( 1792:Bubo virginianus mayensis 1377:and is thus considered a 1187:Bubo virginianus nacurutu 904:Great horned owl (Canada) 501:The great horned owl was 376: 369: 361: 352: 345: 340: 321: 314: 216:Scientific classification 214: 197: 175: 166: 140: 131: 115: 106: 23: 11352:Internet Bird Collection 11347:"Great Horned Owl media" 10964:Errington, P.L. (1932). 10008:Sutherland, J. E. 1987. 9676:10.22621/cfn.v128i4.1634 9632:. Twin Cities Naturalist 9553:Florida Field Naturalist 7984:Parmalee, P. W. (1954). 6801:from west of Hudson Bay" 6210:10.5479/si.03629236.50.i 5925:Hawks, owls and wildlife 5236:Gmelin, Johann Friedrich 4677:ivory-billed woodpeckers 4673:Brachyramphus marmoratus 4171:, they may be mobbed by 3359:Gallus gallus domesticus 3299:Tympanuchus phasianellus 3232: 3223:Mexican free-tailed bats 2894:Black-tailed jackrabbits 2807:North American porcupine 2696:Great Basin pocket mouse 2560:North American deermouse 2451:Prey and trophic ecology 2062:Distribution and habitat 1929:Bubo virginianus pinorum 1788:Yucatán great horned owl 1545:coast from southeastern 1508:Coastal great horned owl 1467:, south to Northwestern 1401:Contiguous United States 1035:whar, whah, wha-a-a-a-ah 1001:(or also transcribed as 977: 144:Coastal great horned owl 11894:Birds described in 1788 11287:Johnson, D. H. (1993). 11025:Risdon, D.H.S. (1951). 10668:Stewart, P. A. (1969). 10587:Sky, Big (2016-10-10). 9522:Ornitologia Neotropical 8829:Crocoll, S. T. (1984). 8803:Carnivores of the World 8544:Northwestern Naturalist 8151:"Great Horned Owl Menu" 7779:Oregon State Monographs 7618:Rudolph, S. G. (1978). 7562:Packard, R. L. (1954). 7486:Houston, C. S. (1978). 7215:Birds of the high Andes 6907:Godfrey, W. E. (1986). 6699:Traylor, M. A. (1958). 6508:Johnson, D. H. (1993). 5305:Zoological Bibliography 5276:Duméril, A. M. Constant 4685:Aphelocoma coerulescens 4665:lesser prairie chickens 4563:Human-related mortality 4466:Mortality and longevity 4235:, Oregon, United States 3472:American white pelicans 3287:greater prairie chicken 2973:Sylvilagus cunicularius 2740:Merriam's kangaroo rats 2544:black-tailed jackrabbit 1684:Desert great horned owl 993:The great horned owl's 507:Johann Friedrich Gmelin 157:Delta, British Columbia 119:Common great horned owl 11228:Birds of North America 11170:"Notes on the type of 10629:Peterson, R. T. 1968. 10616:Garcelon, D. K. 1981. 10593:Visit Big Sky, Montana 9194:Twente, J. W. (1954). 8930:"The Great Horned Owl" 7547:Fuller, M. R. (1979). 7163:Great Basin Naturalist 7044:Flack, J.A.O. (1976). 6930:Snyder, L. L. (1961). 6245:10.1098/rstb.1977.0116 5685:Miller, L. H. (1911). 5332:, eds. (August 2022). 5208:Bent, Arthur Cleveland 4649:Stephens' kangaroo rat 4633:Urocitellus townsendii 4577:Bos primigenius taurus 4548:Leucocytozoon ziemanni 4441:Urban vs rural nesting 4437: 4280: 4236: 4220: 4084:(21% of failures) and 4064:) and forest-dwelling 3829: 3784:Odocoileus virginianus 3653:Pantherophis obsoletus 3629:Agkistrodon piscivorus 3484:Pelecanus occidentalis 3327:Falcipennis canadensis 3245: 3136:Felis silvestris catus 3128:Canis lupus familiaris 2897: 2791:gray-collared chipmunk 2652:northern pocket gopher 2603: 2467: 2393: 2385: 2341:northern saw-whet owls 2302: 2294: 2079: 2078:The same owl in flight 2071: 2058: 2004: 1995:Species identification 1720: 1705: 1538: 1455: 1322: 1204: 1121:Isthmus of Tehuantepec 1033:note pair, a laughing 990: 989:Audio great horned owl 905: 882: 841: 793: 605:, from as far east as 11797:Paleobiology Database 10820:Grinnell, J. (1932). 10382:Dunstan, T. C. 1970. 10311:Austing, G. R. 1968. 10272:Bendire, C. E. 1892. 10235:WALEED (2018-08-29). 9425:10.2173/bow.amwpel.01 9095:Burns, B. J. (1952). 8801:Hunter, Luke (2011). 8696:Birdwatching Magazine 8692:"Great Silent Hunter" 8639:Brown, L. N. (1997). 7384:www.allaboutbirds.org 6342:WALEED (2018-08-24). 5662:Brodkorb, P. (1971). 5649:10.2173/bow.grhowl.01 4641:Perognathus pacificus 4431: 4326:Nycticorax nycticorax 4271: 4226: 4211: 4094:Western United States 3827: 3532:blue-grey gnatcatcher 3448:Cerorhinca monocerata 3240: 3227:Tadarida brasiliensis 3211:nine-banded armadillo 3203:Didelphis virginianus 3195:Didelphis albiventris 3098:including full-grown 2892: 2859:Onychomys leucogaster 2597: 2532:Sylvilagus floridanus 2461:Louis Agassiz Fuertes 2458: 2399:eastern fox squirrels 2391: 2383: 2325:Corvus brachyrhynchos 2300: 2292: 2231:Appalachian Mountains 2193:, mountainous areas, 2077: 2069: 2049: 2002: 1731:eastwards to western 1711: 1696: 1520: 1446: 1313: 1238:Buenos Aires Province 1195: 1143:reappears back up in 1089:Eastern United States 988: 931:The hard, inflexible 903: 881:Great horned owl wing 880: 839: 791: 646:, 1904) – west Alaska 410:), also known as the 11874:Owls of the Americas 11031:Avicultural Magazine 10577:. Blue Jay 50:91–92. 10552:10.29173/bluejay5871 10417:Weller, M. W. 1965. 10395:Fuller, M. R. 1979. 9956:Duncan, J. R. 1987. 8967:. Cengage Learning. 8779:Huey, L. M. (1931). 8624:Axelson, G. (2012). 5744:Mikkola, H. (2012). 5296:Analytische Zoologie 5119:Voous, K.H. (1988). 4910:"Appendices | CITES" 4763:Iconography and myth 4697:Setophaga kirtlandii 4657:black-footed ferrets 4498:American black bears 4336:. The leaf nests of 4137:red-shouldered hawks 4127:, red-tailed hawks, 4106:rough-legged buzzard 4062:Parabuteo unicinctus 3633:prairie rattlesnakes 3540:ruby-crowned kinglet 3263:ring-necked pheasant 3215:Dasypus novemcinctus 2941:Sylvilagus nuttallii 2929:Sylvilagus audubonii 2863:northern pygmy mouse 2795:Tamias cinereicollis 2397:vulnerable, such as 2271:western screech owls 2183:tropical rainforests 2116:Prince Edward Island 1890:Saint Lawrence River 1848:Similar in color to 1845:. Resident all-year. 1802:. Resident all-year. 1326:Breeding range from 1113:Prince Edward Island 11366:Great Horned Owl – 11360:Information on Owls 11296:Rohner, C. (1997). 10315:. Audubon 70:72–79. 10298:Smith, D. G. 1969. 10259:Mader, W. J. 1973. 10151:. The Auk, 116–125. 10051:. The Auk, 363–370. 10038:. The Auk, 661–672. 9909:. The Auk, 372–373. 9791:2006LUrbP..74...46C 9743:10.3356/jrr-13-32.1 9547:Toland, B. (1991). 9479:The Wilson Bulletin 9448:The Wilson Bulletin 9257:The Wilson Bulletin 9200:The Wilson Bulletin 8788:The Wilson Bulletin 8666:Wildlife Monographs 8442:1995Oikos..74...61R 8203:Eifrig, H. (1909). 8178:Powell, B. (1984). 8027:The Wilson Bulletin 7810:1991Ecol...72.2261L 7627:The Wilson Bulletin 7571:The Wilson Bulletin 7278:1996Oecol.108..303R 6972:10.3356/JRR-06-75.1 6909:The birds of Canada 6612:1996JAnEc..65..359R 6568:The Wilson Bulletin 6264:The Hearing Journal 6237:1977RSPTB.280..375N 5633:"Great Horned Owl ( 5511:2013MolPE..66..889O 5292:Zoologie analytique 4693:Kirtland's warblers 4653:Dipodomys stephensi 4645:giant kangaroo rats 4637:Pacific pocket mice 4488:, or wild or feral 4371:to as far north as 4361:Southern California 4038:red-shouldered hawk 4011:sharp-shinned hawks 3848:and the two common 3835:eastern screech owl 3790:Urban vs rural diet 3697:Lepomis macrochirus 3665:American alligators 3645:Lampropeltis getula 3621:Hypsiglena torquata 3536:Polioptila caerulea 3420:sharp-tailed grouse 3351:Meleagris gallopavo 3303:greater sage-grouse 3295:sharp-tailed grouse 3275:Colinus virginianus 3267:Phasianus colchicus 3191:white-eared opossum 3048:black-footed ferret 3028:Bassariscus astutus 3020:mammalian carnivore 2937:mountain cottontail 2827:Ochrotomys nuttalli 2088:Mackenzie Mountains 2056:Landers, California 1957:Guadalupe Mountains 1747:; intergrades with 1569:, and northwestern 1475:. Intergrades with 561:Leverian collection 347:About 12, see text 307:B. virginianus 169:Conservation status 30:Pleistocene–present 11303:2016-02-22 at the 11250:Howard, Hildegarde 10915:. Condor, 287–302. 10785:. Loon 61:160–162. 10733:Blus, L. J. 1996. 10573:Nero, R. W. 1992. 10485:– via JSTOR. 10454:– via JSTOR. 10434:Smith, D. (1999). 10086:Cold, C. W. 1993. 9973:. Condor, 208–220. 9417:Birds of the World 8690:Ray, J.D. (2012). 8180:Labrador by choice 7286:10.1007/BF00334655 6309:Journal of Zoology 5641:Birds of the World 5328:; Donsker, David; 5019:"Great Horned Owl" 4964:– via JSTOR. 4705:Euphagus carolinus 4681:Florida scrub jays 4456:Winnipeg, Manitoba 4438: 4410:Los Angeles County 4404:and north-central 4400:. In northwestern 4316:ssp.) nests. Even 4281: 4237: 4221: 4189:Cassin's kingbirds 4177:western scrub jays 4015:Accipiter striatus 4007:Accipiter cooperii 3912:Accipiter gentilis 3830: 3657:loggerhead turtles 3641:common king snakes 3527:tyrant flycatchers 3444:rhinoceros auklets 3432:Anas platyrhnychos 3291:Tympanuchus cupido 3246: 3183:Thylamys velutinus 3167:Blarina brevicauda 2994:, mice and voles, 2969:Mexican cottontail 2925:desert cottontails 2898: 2851:Ondatra zibethicus 2811:Erethizon dorsatum 2748:giant kangaroo rat 2700:Perognathus parvus 2656:Thomomys talpoides 2634:, California, the 2604: 2556:white-footed mouse 2550:); two species of 2548:Lepus californicus 2528:eastern cottontail 2468: 2394: 2386: 2303: 2295: 2205:forests, and some 2080: 2072: 2059: 2005: 1906:B. v. heterocnemis 1735:and southwards to 1725:San Joaquin Valley 1721: 1706: 1539: 1465:San Joaquin Valley 1456: 1323: 1205: 991: 906: 883: 842: 794: 785:along the sides. 741:(southeast Mexico) 699:B. v. heterocnemis 616:A large number of 578:Bering land bridge 553:Earl of Burlington 503:formally described 471:Eurasian eagle-owl 11879:Pleistocene birds 11851: 11850: 11784:Open Tree of Life 11387:Taxon identifiers 10659:. The Auk, 62–94. 10620:. Murrelet 62:26. 10516:The Passer Pigeon 9701:Kopij, G (2012). 8963:Deal, K. (2010). 8928:Johansson, Tait. 7356:Owls of the world 7354:Hume, R. (1991). 7188:Root, T. (1988). 6758:978-84-87334-25-2 6003:978-0-8493-4258-5 5748:. Firefly Books. 5438:Owls of the World 5330:Rasmussen, Pamela 4935:"Manitoban Notes" 4729:Paul L. Errington 4669:marbled murrelets 4625:Pacific Northwest 4460:urban heat island 4434:B. v. virginianus 4417:soon after dark. 4276:) on her nest in 4274:B. v. virginianus 4145:peregrine falcons 4141:American kestrels 4133:ferruginous hawks 4117:northern goshawks 4086:peregrine falcons 4078:Pandion haliaetus 4046:broad-winged hawk 4027:Northern harriers 4023:Buteo albonotatus 4019:zone-tailed hawks 3908:northern goshawks 3864:ferruginous hawks 3860:desert cottontail 3780:white-tailed deer 3689:Carassius auratus 3572:European starling 3550:(14 species) and 3544:Regulus calendula 3468:Cygnus buccinator 3460:great blue herons 3436:Protection Island 3331:Protection Island 3271:northern bobwhite 3104:Mephitis mephitis 2949:Sierran foothills 2724:Sigmodon hispidus 2720:hispid cotton rat 2600:white-footed mice 2227:Amazon rainforest 2092:Keewatin, Ontario 2009:lesser horned owl 1896:to as far as the 1800:Yucatán Peninsula 1397:B. v. subarcticus 1391:with other races. 1369:. The older name 1316:B. v. subarcticus 1174:B. v. virginianus 1162:B. v. subarcticus 1160:. In comparison, 1117:B. v. mesembrinus 1037:, a high-pitched 999:ho-ho-hoo hoo hoo 986: 867:Yucatán Peninsula 826:tufts of feathers 745:B. v. mesembrinus 739:Yucatán Peninsula 709:B. v. virginianus 678:B. v. subarcticus 586:lesser horned owl 487:Buteo jamaicensis 432:rabbits and hares 398: 397: 385: 209: 192: 123:B. v. virginianus 11916: 11844: 11843: 11841:Bubo-virginianus 11831: 11830: 11818: 11817: 11805: 11804: 11792: 11791: 11779: 11778: 11776:great-horned-owl 11766: 11765: 11753: 11752: 11740: 11739: 11727: 11726: 11714: 11713: 11711:NHMSYS0001689429 11701: 11700: 11688: 11687: 11675: 11674: 11662: 11661: 11649: 11648: 11636: 11635: 11623: 11622: 11620:great-horned-owl 11613: 11612: 11600: 11599: 11587: 11586: 11577: 11576: 11564: 11563: 11551: 11550: 11538: 11537: 11525: 11524: 11515: 11514: 11502: 11501: 11489: 11488: 11479: 11478: 11476:FC366114BD3B51A0 11466: 11465: 11463:bubo-virginianus 11453: 11452: 11450:Bubo_virginianus 11440: 11439: 11429: 11428: 11427: 11425:Bubo virginianus 11414: 11413: 11412: 11395:Bubo virginianus 11382: 11381: 11368:Bubo virginianus 11356: 11284: 11258: 11223:Bubo virginianus 11190: 11178: 11164: 11131: 11129: 11104: 11102: 11087: 11068: 11067: 11065: 11064: 11055:. Archived from 11045: 11039: 11038: 11022: 11016: 11015: 10987: 10978: 10977: 10961: 10950: 10935: 10929: 10922: 10916: 10909: 10903: 10896: 10890: 10883: 10877: 10870: 10864: 10857: 10851: 10844: 10838: 10831: 10825: 10818: 10812: 10805: 10799: 10792: 10786: 10779: 10773: 10770: 10764: 10757: 10751: 10744: 10738: 10731: 10725: 10718: 10712: 10705: 10699: 10692: 10686: 10679: 10673: 10666: 10660: 10653: 10647: 10640: 10634: 10627: 10621: 10614: 10608: 10607: 10605: 10604: 10595:. Archived from 10584: 10578: 10571: 10565: 10564: 10554: 10530: 10524: 10523: 10507: 10501: 10500: 10494: 10486: 10462: 10456: 10455: 10431: 10422: 10415: 10409: 10406: 10400: 10393: 10387: 10380: 10374: 10367: 10361: 10354: 10345: 10338: 10329: 10322: 10316: 10309: 10303: 10296: 10290: 10283: 10277: 10270: 10264: 10257: 10251: 10250: 10248: 10247: 10241:Great Horned Owl 10232: 10226: 10225: 10189: 10183: 10182: 10171: 10165: 10158: 10152: 10145: 10139: 10136: 10130: 10123: 10117: 10110: 10104: 10097: 10091: 10084: 10078: 10071: 10065: 10058: 10052: 10045: 10039: 10032: 10026: 10019: 10013: 10006: 10000: 9993: 9987: 9980: 9974: 9967: 9961: 9954: 9945: 9942: 9936: 9929: 9923: 9916: 9910: 9903: 9897: 9896: 9848: 9842: 9841: 9809: 9803: 9802: 9770: 9764: 9763: 9745: 9721: 9715: 9714: 9698: 9689: 9688: 9678: 9657:Bubo virginianus 9650: 9641: 9640: 9638: 9637: 9625: 9619: 9618: 9590: 9584: 9583: 9567: 9561: 9560: 9544: 9538: 9537: 9517: 9511: 9510: 9470: 9464: 9463: 9443: 9437: 9436: 9408: 9402: 9401: 9373: 9367: 9364: 9358: 9357: 9350: 9341: 9340: 9328: 9322: 9321: 9305: 9296: 9295: 9279: 9273: 9272: 9252: 9246: 9245: 9217: 9208: 9207: 9191: 9185: 9184: 9168: 9162: 9161: 9133: 9127: 9126: 9116: 9092: 9086: 9085: 9065: 9059: 9056: 9050: 9046: 9040: 9033: 9027: 9026: 9024: 9022: 9011: 9005: 9004: 9002: 9000: 8985: 8979: 8978: 8960: 8954: 8951: 8945: 8944: 8942: 8941: 8925: 8919: 8918: 8916: 8914: 8902: 8896: 8895: 8893: 8891: 8876: 8870: 8869: 8867: 8865:10.5962/p.356054 8843: 8837: 8836: 8826: 8817: 8816: 8798: 8792: 8791: 8785: 8776: 8770: 8769: 8741: 8735: 8734: 8717:(4): 1300–1306. 8706: 8700: 8699: 8687: 8678: 8677: 8661: 8655: 8654: 8636: 8630: 8629: 8621: 8615: 8609: 8603: 8602: 8574: 8568: 8567: 8539: 8533: 8532: 8530: 8528:10.5962/p.356045 8506: 8500: 8499: 8497: 8495:10.5962/p.344317 8473: 8462: 8461: 8425: 8419: 8418: 8408: 8406:10.5962/p.346661 8384: 8375: 8374: 8362: 8356: 8355: 8335: 8326: 8325: 8297: 8288: 8287: 8271: 8262: 8258: 8252: 8251: 8223: 8217: 8216: 8200: 8194: 8193: 8175: 8166: 8165: 8163: 8162: 8147: 8141: 8140: 8112: 8106: 8105: 8089: 8083: 8082: 8054: 8043: 8042: 8022: 8016: 8015: 8005: 7981: 7975: 7974: 7972: 7971: 7954:Great Horned Owl 7948: 7927: 7926: 7916: 7892: 7886: 7885: 7877: 7868: 7867: 7851: 7830: 7829: 7804:(6): 2261–2273. 7793: 7787: 7786: 7774: 7768: 7767: 7739: 7730: 7729: 7713: 7674: 7673: 7641: 7635: 7634: 7624: 7615: 7606: 7605: 7585: 7579: 7578: 7568: 7559: 7553: 7552: 7544: 7538: 7537: 7521: 7510: 7509: 7507: 7505:10.5962/p.346633 7483: 7472: 7471: 7455: 7449: 7448: 7438: 7414: 7408: 7407: 7400: 7394: 7393: 7391: 7390: 7376: 7370: 7369: 7351: 7345: 7344: 7320: 7314: 7313: 7261: 7252: 7251: 7235: 7229: 7228: 7210: 7204: 7203: 7185: 7179: 7178: 7158: 7149: 7148: 7136: 7130: 7129: 7111: 7105: 7104: 7087:(4): 1393–1398. 7076: 7070: 7069: 7058:10.2307/40166754 7041: 7035: 7034: 7016: 7010: 7009: 6991: 6985: 6984: 6974: 6950: 6944: 6943: 6927: 6921: 6920: 6904: 6898: 6897: 6895: 6894: 6880: 6874: 6873: 6845: 6832: 6831: 6819: 6813: 6812: 6799:Bubo virginianus 6792: 6786: 6785: 6769: 6763: 6762: 6744: 6731: 6730: 6720: 6696: 6685: 6684: 6666: 6657: 6656: 6654: 6652: 6641: 6632: 6631: 6595: 6572: 6571: 6563: 6538: 6537: 6525: 6516: 6515: 6505: 6494: 6493: 6473: 6467: 6466: 6438: 6432: 6431: 6399: 6393: 6392: 6364: 6358: 6357: 6355: 6354: 6348:Great Horned Owl 6339: 6333: 6332: 6304: 6298: 6297: 6279: 6255: 6249: 6248: 6231:(973): 375–408. 6220: 6214: 6213: 6196: 6190: 6189: 6187: 6185: 6176:. Archived from 6165: 6156: 6155: 6127: 6112: 6111: 6109: 6108: 6093: 6087: 6086: 6070: 6061: 6060: 6032: 6009: 6007: 5989: 5983: 5982: 5971:10.2307/40166710 5954: 5939: 5938: 5920: 5895: 5894: 5892: 5891: 5880: 5867: 5866: 5838: 5825: 5824: 5796: 5781: 5780: 5778: 5777: 5766: 5760: 5759: 5741: 5718: 5717: 5705: 5699: 5698: 5682: 5676: 5675: 5659: 5653: 5652: 5635:Bubo virginianus 5628: 5531: 5530: 5489: 5480: 5479: 5461: 5452: 5451: 5433: 5350: 5349: 5347: 5345: 5322: 5313: 5312: 5302: 5285: 5272: 5266: 5265: 5252: 5246: 5245: 5232: 5226: 5225: 5204: 5135: 5134: 5116: 5035: 5034: 5032: 5030: 5015: 5006: 5005: 4999: 4991: 4975: 4966: 4965: 4939: 4930: 4924: 4923: 4921: 4920: 4906: 4900: 4899: 4897: 4895: 4890: 4867:Bubo virginianus 4860: 4769:Native Americans 4701:rusty blackbirds 4601:peregrine falcon 4502:Virginia opossum 4345:Southern Florida 4330:great blue heron 4129:Swainson's hawks 4102:northern goshawk 4090:Falco peregrinus 4066:northern goshawk 4050:Buteo brachyurus 4031:Circus hudsonius 3963:northern goshawk 3884:ground squirrels 3854:species. In the 3801:Townsend's voles 3797:British Columbia 3649:black rat snakes 3576:Sturnus vulgaris 3388:Fulica americana 3355:domestic chicken 3335:Washington state 3199:Virginia opossum 3052:Mustela nigripes 3044:Martes americana 3040:American martens 2978:In the northern 2831:red-backed voles 2815:flying squirrels 2803:Marmota caligata 2763:ground squirrels 2752:Dipodomys ingens 2694:, primarily the 2648:Washington state 2540:Lepus americanus 2376:Hunting behavior 2329:red-tailed hawks 2312:coniferous trees 2201:, rocky coasts, 2164:short-eared owls 2132:Tierra del Fuego 2112:Anticosti Island 2052:B. v. pallescens 1753:San Diego County 1717:B. v. pallescens 1699:B. v. pallescens 1639:to northwestern 1555:B. v. lagophonus 1551:B. v. leucomelas 1535:British Columbia 1481:San Diego County 987: 751:B. v. nigrescens 719:B. v. elachistus 684:B. v. pallescens 650:B. v. lagophonus 630:Bergmann's rules 407:Bubo virginianus 402:great horned owl 383: 381:Strix virginiana 357: 327: 325:Bubo virginianus 224: 223: 203: 186: 181: 180: 136: 111: 101: 31: 27:Temporal range: 24:Great horned owl 21: 20: 11924: 11923: 11919: 11918: 11917: 11915: 11914: 11913: 11909:Birds of Mexico 11854: 11853: 11852: 11847: 11839: 11834: 11826: 11821: 11813: 11808: 11800: 11795: 11787: 11782: 11774: 11769: 11761: 11756: 11748: 11745:Observation.org 11743: 11735: 11730: 11722: 11717: 11709: 11704: 11696: 11691: 11683: 11678: 11670: 11665: 11657: 11652: 11644: 11639: 11631: 11626: 11618: 11616: 11608: 11603: 11595: 11590: 11582: 11580: 11572: 11567: 11559: 11554: 11546: 11541: 11533: 11528: 11520: 11518: 11510: 11505: 11497: 11492: 11484: 11482: 11474: 11469: 11461: 11456: 11448: 11443: 11437: 11432: 11423: 11422: 11417: 11408: 11407: 11402: 11389: 11345: 11342: 11337: 11305:Wayback Machine 11273:10.2307/1364422 11256: 11176: 11100: 11085: 11076: 11074:Further reading 11071: 11062: 11060: 11047: 11046: 11042: 11023: 11019: 11004:10.2307/4074915 10988: 10981: 10970:Wilson Bulletin 10962: 10953: 10936: 10932: 10923: 10919: 10910: 10906: 10897: 10893: 10884: 10880: 10871: 10867: 10858: 10854: 10845: 10841: 10832: 10828: 10819: 10815: 10806: 10802: 10793: 10789: 10780: 10776: 10771: 10767: 10758: 10754: 10745: 10741: 10732: 10728: 10719: 10715: 10706: 10702: 10693: 10689: 10680: 10676: 10667: 10663: 10654: 10650: 10641: 10637: 10628: 10624: 10615: 10611: 10602: 10600: 10585: 10581: 10572: 10568: 10531: 10527: 10508: 10504: 10488: 10487: 10463: 10459: 10432: 10425: 10416: 10412: 10407: 10403: 10394: 10390: 10381: 10377: 10368: 10364: 10355: 10348: 10339: 10332: 10323: 10319: 10310: 10306: 10297: 10293: 10284: 10280: 10271: 10267: 10258: 10254: 10245: 10243: 10233: 10229: 10206:10.2307/4083889 10190: 10186: 10181:on May 3, 2018. 10173: 10172: 10168: 10159: 10155: 10146: 10142: 10137: 10133: 10124: 10120: 10111: 10107: 10098: 10094: 10085: 10081: 10072: 10068: 10059: 10055: 10046: 10042: 10033: 10029: 10020: 10016: 10007: 10003: 9994: 9990: 9981: 9977: 9968: 9964: 9955: 9948: 9943: 9939: 9930: 9926: 9917: 9913: 9904: 9900: 9849: 9845: 9830:10.2307/3534439 9810: 9806: 9771: 9767: 9722: 9718: 9699: 9692: 9651: 9644: 9635: 9633: 9626: 9622: 9607:10.2307/3795666 9591: 9587: 9568: 9564: 9545: 9541: 9518: 9514: 9471: 9467: 9444: 9440: 9409: 9405: 9390:10.2307/3798274 9374: 9370: 9365: 9361: 9352: 9351: 9344: 9329: 9325: 9306: 9299: 9280: 9276: 9253: 9249: 9234:10.2307/1363563 9218: 9211: 9192: 9188: 9169: 9165: 9150:10.2307/1365473 9134: 9130: 9114:10.2307/4081300 9093: 9089: 9066: 9062: 9057: 9053: 9047: 9043: 9034: 9030: 9020: 9018: 9013: 9012: 9008: 8998: 8996: 8995:on 3 March 2012 8987: 8986: 8982: 8975: 8961: 8957: 8952: 8948: 8939: 8937: 8926: 8922: 8912: 8910: 8903: 8899: 8889: 8887: 8886:on 4 March 2016 8878: 8877: 8873: 8844: 8840: 8827: 8820: 8813: 8799: 8795: 8783: 8777: 8773: 8758:10.2307/2423986 8742: 8738: 8723:10.2307/3801994 8707: 8703: 8688: 8681: 8662: 8658: 8651: 8637: 8633: 8622: 8618: 8610: 8606: 8591:10.2307/3795698 8575: 8571: 8556:10.2307/3536640 8540: 8536: 8507: 8503: 8474: 8465: 8450:10.2307/3545675 8426: 8422: 8385: 8378: 8363: 8359: 8336: 8329: 8314:10.2307/3668871 8298: 8291: 8280:Raptor Research 8272: 8265: 8259: 8255: 8240:10.2307/1366054 8224: 8220: 8201: 8197: 8190: 8176: 8169: 8160: 8158: 8149: 8148: 8144: 8129:10.2307/1364321 8113: 8109: 8090: 8086: 8071:10.2307/1364108 8055: 8046: 8023: 8019: 8003:10.2307/4081546 7982: 7978: 7969: 7967: 7965: 7949: 7930: 7914:10.2307/1366997 7893: 7889: 7878: 7871: 7852: 7833: 7818:10.2307/1941576 7794: 7790: 7775: 7771: 7756:10.2307/1365056 7740: 7733: 7728:(277): 757–850. 7714: 7677: 7662:10.2307/4511863 7642: 7638: 7622: 7616: 7609: 7590:Wilson Bulletin 7586: 7582: 7566: 7560: 7556: 7545: 7541: 7522: 7513: 7484: 7475: 7464:Wilson Bulletin 7456: 7452: 7436:10.2307/4079048 7415: 7411: 7402: 7401: 7397: 7388: 7386: 7378: 7377: 7373: 7366: 7352: 7348: 7321: 7317: 7262: 7255: 7236: 7232: 7225: 7211: 7207: 7200: 7186: 7182: 7159: 7152: 7137: 7133: 7126: 7112: 7108: 7093:10.2307/3801804 7077: 7073: 7042: 7038: 7031: 7017: 7013: 7006: 6992: 6988: 6951: 6947: 6928: 6924: 6905: 6901: 6892: 6890: 6881: 6877: 6862:10.2307/4079554 6846: 6835: 6820: 6816: 6793: 6789: 6770: 6766: 6759: 6745: 6734: 6718:10.2307/4081883 6697: 6688: 6681: 6667: 6660: 6650: 6648: 6643: 6642: 6635: 6596: 6575: 6564: 6541: 6526: 6519: 6506: 6497: 6474: 6470: 6455:10.2307/1363856 6439: 6435: 6420:10.2307/1368502 6400: 6396: 6369:Vision Research 6365: 6361: 6352: 6350: 6340: 6336: 6305: 6301: 6256: 6252: 6221: 6217: 6197: 6193: 6183: 6181: 6166: 6159: 6144:10.2307/1365983 6128: 6115: 6106: 6104: 6095: 6094: 6090: 6071: 6064: 6049:10.2307/1366002 6033: 6012: 6004: 5990: 5986: 5955: 5942: 5935: 5921: 5898: 5889: 5887: 5882: 5881: 5870: 5855:10.2307/4081882 5839: 5828: 5813:10.2307/1368060 5797: 5784: 5775: 5773: 5768: 5767: 5763: 5756: 5742: 5721: 5706: 5702: 5683: 5679: 5660: 5656: 5637:), version 1.0" 5629: 5534: 5495:Bubo blakistoni 5490: 5483: 5476: 5462: 5455: 5448: 5434: 5353: 5343: 5341: 5323: 5316: 5300: 5273: 5269: 5256:Edwards, George 5253: 5249: 5233: 5229: 5205: 5138: 5131: 5117: 5038: 5028: 5026: 5017: 5016: 5009: 4993: 4992: 4976: 4969: 4954:10.2307/4625166 4937: 4931: 4927: 4918: 4916: 4908: 4907: 4903: 4893: 4891: 4861: 4854: 4850: 4838:provincial bird 4834: 4832:Provincial bird 4806:winter solstice 4765: 4725: 4713:near threatened 4593: 4565: 4543:Yukon Territory 4492:. Occasionally 4473: 4468: 4443: 4398:Yukon Territory 4381:Rocky Mountains 4258:American badger 4250:Rocky Mountains 4229:B. v. saturatus 4206: 4153:Falco mexicanus 4149:prairie falcons 3971:Buteo plagiatus 3904:Lynx canadensis 3822: 3810:bioaccumulation 3792: 3661:Caretta caretta 3637:Crotalus virdis 3592: 3492:Grus canadensis 3488:sandhill cranes 3464:trumpeter swans 3319:Bonasa umbellus 3235: 3151:Cryptotis parva 3068:Martes pennanti 3016: 2965:Baja California 2887: 2867:Baiomys taylori 2688:Baja California 2592: 2453: 2411:Sauromalus ater 2378: 2337: 2287: 2064: 2013:B. magellanicus 1997: 1937:Rocky Mountains 1839:Baja California 1761:Rocky Mountains 1531:North Vancouver 1527:Grouse Mountain 1523:B. v. saturatus 1469:Baja California 1463:except for the 1449:B. v. pacificus 1075: 1041:; a weak, soft 982: 980: 914:long-eared owls 871:Baja California 834: 782: 726:Baja California 724:, 1902 – south 672:Baja California 665:B. v. pacificus 656:B. v. saturatus 611:Rocky Mountains 603:paleosubspecies 595:Pleistocene era 528:and coined the 516:Systema Naturae 499: 483:red-tailed hawk 394: 336: 329: 323: 310: 218: 210: 193: 182: 178: 171: 162: 148:B. v. saturatus 127: 102: 100: 99: 98: 97: 92: 87: 82: 77: 72: 67: 62: 57: 52: 47: 42: 37: 29: 28: 25: 17: 12: 11: 5: 11922: 11912: 11911: 11906: 11901: 11896: 11891: 11889:Apex predators 11886: 11881: 11876: 11871: 11866: 11849: 11848: 11846: 11845: 11832: 11819: 11806: 11793: 11780: 11767: 11754: 11741: 11728: 11715: 11702: 11689: 11676: 11663: 11650: 11637: 11624: 11614: 11601: 11588: 11578: 11565: 11552: 11539: 11526: 11516: 11503: 11490: 11480: 11467: 11454: 11441: 11430: 11415: 11399: 11397: 11391: 11390: 11379: 11378: 11372: 11363: 11357: 11341: 11340:External links 11338: 11336: 11335: 11322: 11316:J. Raptor Res. 11312: 11294: 11285: 11246: 11244:(HTML preview) 11219: 11201: 11195:J. Wildl. Res. 11191: 11165: 11147:(1): 198–199. 11132: 11120:(3): 847–858. 11105: 11103:on 2008-12-19. 11077: 11075: 11072: 11070: 11069: 11040: 11017: 10998:(2): 214–217. 10979: 10951: 10930: 10917: 10904: 10891: 10878: 10865: 10852: 10839: 10826: 10813: 10800: 10787: 10774: 10765: 10752: 10739: 10726: 10713: 10700: 10687: 10674: 10661: 10648: 10635: 10622: 10609: 10579: 10566: 10525: 10502: 10477:(4): 433–439. 10457: 10446:(4): 535–542. 10423: 10410: 10401: 10388: 10375: 10362: 10346: 10330: 10317: 10313:The owls and I 10304: 10291: 10278: 10265: 10252: 10227: 10200:(2): 426–427. 10184: 10166: 10153: 10140: 10131: 10118: 10105: 10092: 10079: 10066: 10053: 10040: 10027: 10014: 10001: 9988: 9975: 9962: 9946: 9937: 9924: 9911: 9898: 9863:(2): 187–193. 9843: 9804: 9765: 9736:(3): 257–272. 9716: 9690: 9642: 9620: 9601:(4): 190–205. 9585: 9562: 9539: 9528:(2): 279–282. 9512: 9491:10.1676/02-108 9485:(3): 263–269. 9465: 9454:(2): 119–135. 9438: 9403: 9384:(4): 691–696. 9368: 9359: 9342: 9323: 9297: 9274: 9263:(2): 105–120. 9247: 9228:(4): 176–186. 9209: 9186: 9163: 9144:(6): 500–504. 9128: 9087: 9076:(2): 133–137. 9060: 9051: 9041: 9028: 9006: 8980: 8973: 8955: 8946: 8920: 8897: 8871: 8838: 8818: 8811: 8793: 8771: 8752:(2): 513–534. 8736: 8701: 8679: 8656: 8649: 8631: 8616: 8604: 8585:(3): 198–208. 8569: 8534: 8501: 8463: 8420: 8399:(2): 156–166. 8376: 8357: 8346:(4): 499–506. 8327: 8308:(2): 163–170. 8289: 8263: 8253: 8218: 8195: 8188: 8167: 8142: 8107: 8084: 8065:(4): 137–151. 8044: 8033:(4): 209–215. 8017: 7996:(4): 469–470. 7976: 7964:978-0811726894 7963: 7928: 7907:(3): 288–296. 7887: 7869: 7831: 7788: 7769: 7750:(5): 371–385. 7731: 7675: 7636: 7607: 7580: 7554: 7539: 7511: 7473: 7450: 7429:(3): 274–282. 7409: 7395: 7371: 7364: 7346: 7335:(5): 396–405. 7329:Forest Science 7315: 7272:(2): 303–310. 7253: 7230: 7223: 7205: 7198: 7180: 7169:(3): 395–404. 7150: 7147:(28): 164–170. 7131: 7124: 7106: 7071: 7036: 7029: 7011: 7004: 6986: 6945: 6922: 6899: 6875: 6856:(2): 234–245. 6833: 6814: 6787: 6764: 6757: 6732: 6711:(2): 143–149. 6686: 6679: 6658: 6633: 6606:(3): 359–370. 6573: 6539: 6517: 6495: 6484:(4): 481–488. 6468: 6449:(5): 204–213. 6433: 6394: 6375:(2): 219–230. 6359: 6334: 6315:(4): 291–297. 6299: 6250: 6215: 6191: 6180:on 3 July 2017 6157: 6113: 6088: 6062: 6043:(3): 251–264. 6010: 6002: 5984: 5940: 5933: 5896: 5886:. Owlpages.com 5868: 5849:(2): 134–142. 5826: 5807:(4): 777–786. 5782: 5761: 5754: 5719: 5700: 5677: 5654: 5532: 5505:(3): 889–897. 5481: 5475:978-0713688177 5474: 5453: 5446: 5351: 5314: 5267: 5247: 5227: 5136: 5129: 5036: 5025:on 5 July 2017 5007: 4967: 4925: 4901: 4851: 4849: 4846: 4833: 4830: 4764: 4761: 4724: 4721: 4592: 4589: 4564: 4561: 4472: 4469: 4467: 4464: 4442: 4439: 4369:South Carolina 4294:Cooper's hawks 4205: 4202: 4197:American crows 4125:Harris's hawks 4121:Cooper's hawks 4058:Harris's hawks 4052:) breeding in 4042:Buteo lineatus 4036:In a study of 4003:Cooper's hawks 3892:boreal forests 3876:Crotalus atrox 3821: 3818: 3791: 3788: 3591: 3588: 3480:brown pelicans 3412:grey partridge 3343:Pavo cristatus 3339:common peafowl 3242:American coots 3234: 3231: 3159:Sorex cinereus 3100:striped skunks 3032:American minks 3015: 3012: 2886: 2883: 2787:tree squirrels 2591: 2588: 2580:woodland voles 2552:New World mice 2452: 2449: 2377: 2374: 2336: 2333: 2321:American crows 2286: 2283: 2279:M. kennicottii 2275:Megascops asio 2250:Puna grassland 2215:Sonora Deserts 2203:mangrove swamp 2063: 2060: 1996: 1993: 1992: 1991: 1980: 1922: 1921: 1917: 1863: 1862: 1846: 1824: 1823: 1811:B. v. mayensis 1803: 1785: 1784: 1768: 1681: 1680: 1648: 1611: 1610: 1586: 1505: 1504: 1484: 1431: 1430: 1392: 1298: 1297: 1294:B. v. nacurutu 1281:B. v. nacurutu 1265: 1210:Strix nacurutu 1201:B. v. nacurutu 1178: 1177: 1148: 1074: 1071: 1059:ke-yah, ke-yah 1057:-like note of 979: 976: 972:B. v. nacurutu 922:great grey owl 833: 830: 781: 778: 777: 776: 767: 760:B. v. nacurutu 757: 748: 742: 732:B. v. mayensis 729: 716: 706: 696: 690: 681: 675: 662: 653: 647: 640:B. v. algistus 584:. Whereas the 537:George Edwards 533:Strix virginia 498: 495: 422:native to the 396: 395: 393: 392: 386: 377: 374: 373: 367: 366: 364:B. virginianus 359: 358: 350: 349: 343: 342: 338: 337: 330: 319: 318: 312: 311: 304: 302: 298: 297: 290: 286: 285: 280: 276: 275: 270: 266: 265: 260: 256: 255: 250: 246: 245: 240: 236: 235: 230: 226: 225: 212: 211: 198: 195: 194: 176: 173: 172: 167: 164: 163: 161: 160: 150: 145: 141: 138: 137: 129: 128: 126: 125: 120: 116: 113: 112: 104: 103: 95: 94: 93: 88: 83: 78: 73: 68: 63: 58: 53: 48: 43: 38: 33: 26: 16:Species of owl 15: 9: 6: 4: 3: 2: 11921: 11910: 11907: 11905: 11902: 11900: 11897: 11895: 11892: 11890: 11887: 11885: 11882: 11880: 11877: 11875: 11872: 11870: 11867: 11865: 11862: 11861: 11859: 11842: 11837: 11833: 11829: 11824: 11820: 11816: 11811: 11807: 11803: 11798: 11794: 11790: 11785: 11781: 11777: 11772: 11768: 11764: 11759: 11755: 11751: 11746: 11742: 11738: 11733: 11729: 11725: 11720: 11716: 11712: 11707: 11703: 11699: 11694: 11690: 11686: 11681: 11677: 11673: 11668: 11664: 11660: 11655: 11651: 11647: 11642: 11638: 11634: 11629: 11625: 11621: 11615: 11611: 11606: 11602: 11598: 11593: 11589: 11585: 11579: 11575: 11570: 11566: 11562: 11557: 11553: 11549: 11544: 11540: 11536: 11531: 11527: 11523: 11517: 11513: 11508: 11504: 11500: 11495: 11491: 11487: 11481: 11477: 11472: 11468: 11464: 11459: 11455: 11451: 11446: 11442: 11435: 11431: 11426: 11420: 11416: 11411: 11405: 11401: 11400: 11398: 11396: 11392: 11388: 11383: 11376: 11373: 11370: 11369: 11364: 11361: 11358: 11354: 11353: 11348: 11344: 11343: 11334:(2): 303–310. 11333: 11330: 11327: 11323: 11320: 11317: 11313: 11310: 11306: 11302: 11299: 11295: 11293: 11290: 11286: 11282: 11278: 11274: 11270: 11266: 11262: 11255: 11251: 11247: 11245: 11241: 11237: 11233: 11230: 11229: 11224: 11220: 11218: 11217:84-87334-25-3 11214: 11210: 11208: 11202: 11200:(2): 115–123. 11199: 11196: 11192: 11188: 11184: 11183: 11175: 11173: 11166: 11162: 11158: 11154: 11150: 11146: 11142: 11138: 11133: 11128: 11123: 11119: 11115: 11111: 11106: 11099: 11095: 11091: 11084: 11079: 11078: 11059:on 2018-03-06 11058: 11054: 11050: 11044: 11036: 11032: 11028: 11021: 11013: 11009: 11005: 11001: 10997: 10993: 10986: 10984: 10976:(4): 212–220. 10975: 10971: 10967: 10960: 10958: 10956: 10948: 10944: 10940: 10934: 10927: 10921: 10914: 10908: 10901: 10895: 10888: 10882: 10875: 10869: 10862: 10856: 10849: 10843: 10836: 10830: 10823: 10817: 10810: 10804: 10797: 10791: 10784: 10778: 10769: 10762: 10756: 10749: 10743: 10736: 10730: 10723: 10717: 10710: 10704: 10697: 10691: 10684: 10678: 10671: 10665: 10658: 10652: 10645: 10639: 10632: 10626: 10619: 10613: 10599:on 2020-02-21 10598: 10594: 10590: 10583: 10576: 10570: 10562: 10558: 10553: 10548: 10544: 10540: 10536: 10529: 10521: 10517: 10513: 10506: 10498: 10492: 10484: 10480: 10476: 10472: 10468: 10461: 10453: 10449: 10445: 10441: 10437: 10430: 10428: 10420: 10414: 10405: 10398: 10392: 10385: 10379: 10372: 10366: 10359: 10353: 10351: 10343: 10337: 10335: 10327: 10321: 10314: 10308: 10301: 10295: 10288: 10282: 10275: 10269: 10262: 10256: 10242: 10238: 10231: 10223: 10219: 10215: 10211: 10207: 10203: 10199: 10195: 10188: 10180: 10176: 10170: 10163: 10157: 10150: 10144: 10135: 10128: 10122: 10115: 10109: 10102: 10096: 10089: 10083: 10076: 10070: 10063: 10057: 10050: 10044: 10037: 10031: 10024: 10018: 10011: 10005: 9998: 9992: 9985: 9979: 9972: 9966: 9959: 9953: 9951: 9941: 9934: 9928: 9921: 9915: 9908: 9905:WLM. (1918). 9902: 9894: 9890: 9886: 9882: 9878: 9874: 9870: 9866: 9862: 9858: 9854: 9847: 9839: 9835: 9831: 9827: 9823: 9819: 9815: 9808: 9800: 9796: 9792: 9788: 9784: 9780: 9776: 9769: 9761: 9757: 9753: 9749: 9744: 9739: 9735: 9731: 9727: 9720: 9712: 9708: 9704: 9697: 9695: 9686: 9682: 9677: 9672: 9668: 9664: 9660: 9658: 9649: 9647: 9631: 9624: 9616: 9612: 9608: 9604: 9600: 9596: 9589: 9581: 9577: 9573: 9566: 9558: 9554: 9550: 9543: 9535: 9531: 9527: 9523: 9516: 9508: 9504: 9500: 9496: 9492: 9488: 9484: 9480: 9476: 9469: 9461: 9457: 9453: 9449: 9442: 9434: 9430: 9426: 9422: 9418: 9414: 9407: 9399: 9395: 9391: 9387: 9383: 9379: 9372: 9363: 9355: 9349: 9347: 9338: 9334: 9327: 9320:(1): 133–135. 9319: 9315: 9311: 9304: 9302: 9293: 9289: 9285: 9278: 9270: 9266: 9262: 9258: 9251: 9243: 9239: 9235: 9231: 9227: 9223: 9216: 9214: 9206:(2): 135–136. 9205: 9201: 9197: 9190: 9182: 9178: 9174: 9167: 9159: 9155: 9151: 9147: 9143: 9139: 9132: 9124: 9120: 9115: 9110: 9106: 9102: 9098: 9091: 9083: 9079: 9075: 9071: 9064: 9055: 9045: 9038: 9032: 9016: 9010: 8994: 8990: 8984: 8976: 8974:9781305627741 8970: 8966: 8959: 8950: 8936:on 2012-03-20 8935: 8931: 8924: 8908: 8901: 8885: 8881: 8875: 8866: 8861: 8857: 8853: 8849: 8842: 8834: 8833: 8825: 8823: 8814: 8812:9780691152288 8808: 8804: 8797: 8789: 8782: 8775: 8767: 8763: 8759: 8755: 8751: 8747: 8740: 8732: 8728: 8724: 8720: 8716: 8712: 8705: 8697: 8693: 8686: 8684: 8675: 8671: 8667: 8660: 8652: 8646: 8642: 8635: 8627: 8620: 8614: 8608: 8600: 8596: 8592: 8588: 8584: 8580: 8573: 8565: 8561: 8557: 8553: 8549: 8545: 8538: 8529: 8524: 8520: 8516: 8512: 8505: 8496: 8491: 8487: 8483: 8479: 8472: 8470: 8468: 8459: 8455: 8451: 8447: 8443: 8439: 8435: 8431: 8424: 8416: 8412: 8407: 8402: 8398: 8394: 8390: 8383: 8381: 8373:(4): 140–141. 8372: 8368: 8361: 8353: 8349: 8345: 8341: 8334: 8332: 8323: 8319: 8315: 8311: 8307: 8303: 8296: 8294: 8285: 8281: 8277: 8270: 8268: 8257: 8249: 8245: 8241: 8237: 8233: 8229: 8222: 8214: 8210: 8206: 8199: 8191: 8185: 8181: 8174: 8172: 8157:on 2012-03-10 8156: 8152: 8146: 8138: 8134: 8130: 8126: 8122: 8118: 8111: 8103: 8099: 8095: 8088: 8080: 8076: 8072: 8068: 8064: 8060: 8053: 8051: 8049: 8040: 8036: 8032: 8028: 8021: 8013: 8009: 8004: 7999: 7995: 7991: 7987: 7980: 7966: 7960: 7956: 7955: 7947: 7945: 7943: 7941: 7939: 7937: 7935: 7933: 7924: 7920: 7915: 7910: 7906: 7902: 7898: 7891: 7883: 7876: 7874: 7865: 7861: 7857: 7850: 7848: 7846: 7844: 7842: 7840: 7838: 7836: 7827: 7823: 7819: 7815: 7811: 7807: 7803: 7799: 7792: 7784: 7780: 7773: 7765: 7761: 7757: 7753: 7749: 7745: 7738: 7736: 7727: 7723: 7719: 7712: 7710: 7708: 7706: 7704: 7702: 7700: 7698: 7696: 7694: 7692: 7690: 7688: 7686: 7684: 7682: 7680: 7671: 7667: 7663: 7659: 7655: 7651: 7647: 7640: 7633:(1): 134–137. 7632: 7628: 7621: 7614: 7612: 7603: 7599: 7595: 7591: 7584: 7576: 7572: 7565: 7558: 7550: 7543: 7535: 7531: 7527: 7520: 7518: 7516: 7506: 7501: 7497: 7493: 7489: 7482: 7480: 7478: 7469: 7465: 7461: 7454: 7446: 7442: 7437: 7432: 7428: 7424: 7420: 7413: 7406:. 2010-04-13. 7405: 7399: 7385: 7381: 7375: 7367: 7361: 7357: 7350: 7342: 7338: 7334: 7330: 7326: 7319: 7311: 7307: 7303: 7299: 7295: 7291: 7287: 7283: 7279: 7275: 7271: 7267: 7260: 7258: 7250:(2): 101–115. 7249: 7245: 7241: 7234: 7226: 7220: 7216: 7209: 7201: 7199:9780226725406 7195: 7191: 7184: 7176: 7172: 7168: 7164: 7157: 7155: 7146: 7142: 7135: 7127: 7121: 7117: 7110: 7102: 7098: 7094: 7090: 7086: 7082: 7075: 7067: 7063: 7059: 7055: 7051: 7047: 7040: 7032: 7030:9780691025124 7026: 7022: 7015: 7007: 7001: 6997: 6990: 6982: 6978: 6973: 6968: 6964: 6960: 6956: 6949: 6941: 6937: 6933: 6926: 6918: 6914: 6910: 6903: 6888: 6887: 6879: 6871: 6867: 6863: 6859: 6855: 6851: 6844: 6842: 6840: 6838: 6829: 6825: 6818: 6810: 6806: 6802: 6800: 6791: 6783: 6779: 6775: 6768: 6760: 6754: 6750: 6743: 6741: 6739: 6737: 6728: 6724: 6719: 6714: 6710: 6706: 6702: 6695: 6693: 6691: 6682: 6676: 6672: 6665: 6663: 6651:September 23, 6646: 6640: 6638: 6629: 6625: 6621: 6617: 6613: 6609: 6605: 6601: 6594: 6592: 6590: 6588: 6586: 6584: 6582: 6580: 6578: 6569: 6562: 6560: 6558: 6556: 6554: 6552: 6550: 6548: 6546: 6544: 6535: 6531: 6524: 6522: 6513: 6512: 6504: 6502: 6500: 6491: 6487: 6483: 6479: 6472: 6464: 6460: 6456: 6452: 6448: 6444: 6437: 6429: 6425: 6421: 6417: 6413: 6409: 6405: 6398: 6390: 6386: 6382: 6378: 6374: 6370: 6363: 6349: 6345: 6338: 6330: 6326: 6322: 6318: 6314: 6310: 6303: 6295: 6291: 6287: 6283: 6278: 6273: 6269: 6265: 6261: 6254: 6246: 6242: 6238: 6234: 6230: 6226: 6219: 6211: 6207: 6204:(50): i-852. 6203: 6195: 6179: 6175: 6171: 6164: 6162: 6153: 6149: 6145: 6141: 6137: 6133: 6126: 6124: 6122: 6120: 6118: 6102: 6098: 6092: 6084: 6080: 6076: 6069: 6067: 6058: 6054: 6050: 6046: 6042: 6038: 6031: 6029: 6027: 6025: 6023: 6021: 6019: 6017: 6015: 6005: 5999: 5996:. CRC Press. 5995: 5988: 5980: 5976: 5972: 5968: 5964: 5960: 5953: 5951: 5949: 5947: 5945: 5936: 5930: 5926: 5919: 5917: 5915: 5913: 5911: 5909: 5907: 5905: 5903: 5901: 5885: 5879: 5877: 5875: 5873: 5864: 5860: 5856: 5852: 5848: 5844: 5837: 5835: 5833: 5831: 5822: 5818: 5814: 5810: 5806: 5802: 5795: 5793: 5791: 5789: 5787: 5771: 5765: 5757: 5755:9781770851368 5751: 5747: 5740: 5738: 5736: 5734: 5732: 5730: 5728: 5726: 5724: 5715: 5711: 5704: 5696: 5692: 5688: 5681: 5673: 5669: 5665: 5658: 5650: 5646: 5642: 5638: 5636: 5627: 5625: 5623: 5621: 5619: 5617: 5615: 5613: 5611: 5609: 5607: 5605: 5603: 5601: 5599: 5597: 5595: 5593: 5591: 5589: 5587: 5585: 5583: 5581: 5579: 5577: 5575: 5573: 5571: 5569: 5567: 5565: 5563: 5561: 5559: 5557: 5555: 5553: 5551: 5549: 5547: 5545: 5543: 5541: 5539: 5537: 5528: 5524: 5520: 5516: 5512: 5508: 5504: 5500: 5496: 5488: 5486: 5477: 5471: 5467: 5466:The Snowy Owl 5460: 5458: 5449: 5447:9781408108840 5443: 5439: 5432: 5430: 5428: 5426: 5424: 5422: 5420: 5418: 5416: 5414: 5412: 5410: 5408: 5406: 5404: 5402: 5400: 5398: 5396: 5394: 5392: 5390: 5388: 5386: 5384: 5382: 5380: 5378: 5376: 5374: 5372: 5370: 5368: 5366: 5364: 5362: 5360: 5358: 5356: 5339: 5335: 5331: 5327: 5321: 5319: 5310: 5306: 5299: 5297: 5293: 5283: 5282: 5277: 5271: 5263: 5262: 5257: 5251: 5243: 5242: 5237: 5231: 5223: 5219: 5215: 5214: 5209: 5203: 5201: 5199: 5197: 5195: 5193: 5191: 5189: 5187: 5185: 5183: 5181: 5179: 5177: 5175: 5173: 5171: 5169: 5167: 5165: 5163: 5161: 5159: 5157: 5155: 5153: 5151: 5149: 5147: 5145: 5143: 5141: 5132: 5126: 5123:. MIT Press. 5122: 5115: 5113: 5111: 5109: 5107: 5105: 5103: 5101: 5099: 5097: 5095: 5093: 5091: 5089: 5087: 5085: 5083: 5081: 5079: 5077: 5075: 5073: 5071: 5069: 5067: 5065: 5063: 5061: 5059: 5057: 5055: 5053: 5051: 5049: 5047: 5045: 5043: 5041: 5024: 5020: 5014: 5012: 5003: 4997: 4989: 4985: 4981: 4974: 4972: 4963: 4959: 4955: 4951: 4947: 4943: 4936: 4929: 4915: 4911: 4905: 4889: 4884: 4880: 4876: 4875: 4870: 4868: 4859: 4857: 4852: 4845: 4843: 4839: 4829: 4827: 4823: 4819: 4815: 4811: 4807: 4803: 4799: 4795: 4791: 4790:Passamaquoddy 4786: 4782: 4778: 4774: 4770: 4760: 4759:in England. 4758: 4754: 4749: 4747: 4741: 4739: 4735: 4730: 4720: 4718: 4714: 4710: 4706: 4702: 4698: 4694: 4690: 4686: 4682: 4678: 4674: 4670: 4666: 4662: 4658: 4654: 4650: 4646: 4642: 4638: 4634: 4630: 4626: 4622: 4621:roseate terns 4618: 4614: 4610: 4609:Hudson Rivers 4606: 4602: 4598: 4588: 4586: 4580: 4578: 4574: 4570: 4560: 4558: 4554: 4550: 4549: 4544: 4540: 4536: 4532: 4526: 4524: 4520: 4516: 4511: 4507: 4503: 4499: 4495: 4491: 4487: 4483: 4479: 4463: 4461: 4457: 4451: 4448: 4435: 4430: 4426: 4422: 4418: 4415: 4411: 4407: 4403: 4399: 4395: 4390: 4386: 4382: 4378: 4377:Massachusetts 4374: 4370: 4366: 4362: 4358: 4354: 4351:, from south 4350: 4346: 4341: 4339: 4335: 4331: 4327: 4323: 4319: 4315: 4311: 4307: 4303: 4299: 4295: 4291: 4290:Harris's hawk 4287: 4279: 4275: 4270: 4266: 4263: 4259: 4255: 4251: 4247: 4241: 4234: 4230: 4225: 4219: 4215: 4214:B. v. pinorum 4210: 4201: 4198: 4194: 4190: 4186: 4182: 4178: 4174: 4170: 4166: 4162: 4158: 4157:common ravens 4154: 4150: 4146: 4142: 4138: 4134: 4130: 4126: 4122: 4118: 4114: 4109: 4107: 4103: 4099: 4095: 4091: 4087: 4083: 4079: 4075: 4071: 4067: 4063: 4059: 4055: 4051: 4047: 4043: 4039: 4034: 4032: 4028: 4024: 4020: 4016: 4012: 4008: 4004: 3998: 3994: 3992: 3988: 3982: 3978: 3976: 3972: 3968: 3964: 3959: 3957: 3953: 3949: 3948:Puma concolor 3945: 3941: 3937: 3933: 3929: 3925: 3921: 3917: 3913: 3909: 3905: 3901: 3897: 3896:snowshoe hare 3893: 3889: 3885: 3881: 3877: 3873: 3869: 3868:Buteo regalis 3865: 3861: 3857: 3853: 3852: 3847: 3843: 3838: 3836: 3826: 3817: 3815: 3811: 3807: 3802: 3798: 3787: 3785: 3781: 3777: 3773: 3769: 3765: 3761: 3757: 3753: 3749: 3745: 3741: 3737: 3733: 3728: 3726: 3725:dace and chub 3722: 3718: 3714: 3710: 3707:ssp.), other 3706: 3702: 3698: 3694: 3690: 3686: 3682: 3678: 3674: 3670: 3666: 3662: 3658: 3654: 3650: 3646: 3642: 3638: 3634: 3630: 3626: 3622: 3618: 3614: 3610: 3609:garter snakes 3605: 3601: 3597: 3587: 3585: 3581: 3577: 3573: 3569: 3565: 3561: 3557: 3553: 3549: 3545: 3541: 3537: 3533: 3528: 3524: 3520: 3516: 3512: 3508: 3504: 3500: 3495: 3493: 3489: 3485: 3481: 3477: 3473: 3469: 3465: 3461: 3457: 3453: 3449: 3445: 3441: 3437: 3433: 3429: 3425: 3421: 3417: 3416:Perdix perdix 3413: 3409: 3405: 3401: 3397: 3393: 3389: 3385: 3384:American coot 3381: 3377: 3372: 3366: 3364: 3360: 3356: 3352: 3348: 3344: 3340: 3337:, introduced 3336: 3332: 3328: 3324: 3323:spruce grouse 3320: 3316: 3315:ruffed grouse 3312: 3308: 3304: 3300: 3296: 3292: 3288: 3284: 3278: 3276: 3272: 3268: 3264: 3260: 3259:Upper Midwest 3256: 3255:United States 3252: 3243: 3239: 3230: 3228: 3224: 3220: 3216: 3212: 3209:, presumably 3208: 3204: 3200: 3196: 3192: 3188: 3184: 3180: 3176: 3172: 3171:Upper Midwest 3168: 3164: 3160: 3156: 3152: 3148: 3144: 3139: 3137: 3133: 3129: 3125: 3121: 3117: 3113: 3112:Procyon lotor 3109: 3105: 3101: 3095: 3093: 3089: 3085: 3084:Canis latrans 3081: 3077: 3073: 3069: 3065: 3061: 3057: 3053: 3049: 3045: 3041: 3037: 3036:Neogale vison 3033: 3029: 3025: 3021: 3014:Other mammals 3011: 3009: 3005: 3001: 2997: 2993: 2989: 2985: 2981: 2980:boreal forest 2976: 2974: 2970: 2966: 2962: 2958: 2954: 2950: 2944: 2942: 2938: 2934: 2930: 2926: 2922: 2917: 2915: 2911: 2907: 2903: 2895: 2891: 2882: 2880: 2876: 2872: 2868: 2864: 2860: 2856: 2852: 2848: 2844: 2840: 2836: 2832: 2828: 2824: 2820: 2816: 2812: 2808: 2804: 2800: 2796: 2792: 2788: 2784: 2780: 2776: 2772: 2768: 2764: 2760: 2755: 2753: 2749: 2745: 2741: 2737: 2733: 2732:kangaroo rats 2729: 2725: 2721: 2717: 2713: 2712: 2707: 2706: 2701: 2697: 2693: 2689: 2685: 2681: 2680: 2675: 2674: 2670: 2666: 2662: 2657: 2653: 2649: 2645: 2641: 2638:and northern 2637: 2633: 2628: 2625: 2624: 2618: 2614: 2609: 2601: 2596: 2587: 2585: 2581: 2577: 2573: 2569: 2565: 2561: 2557: 2553: 2549: 2545: 2541: 2537: 2536:snowshoe hare 2533: 2529: 2525: 2521: 2517: 2513: 2509: 2504: 2502: 2498: 2497:invertebrates 2494: 2490: 2486: 2482: 2478: 2474: 2473:invertebrates 2466: 2465:snowshoe hare 2462: 2457: 2448: 2444: 2441: 2435: 2433: 2429: 2424: 2423:invertebrates 2420: 2414: 2412: 2408: 2404: 2403:Sciurus niger 2400: 2390: 2382: 2373: 2371: 2367: 2361: 2357: 2355: 2351: 2346: 2342: 2332: 2330: 2326: 2322: 2316: 2313: 2309: 2299: 2291: 2282: 2280: 2276: 2272: 2268: 2263: 2262:Arctic tundra 2259: 2255: 2251: 2247: 2242: 2240: 2236: 2232: 2228: 2224: 2220: 2216: 2212: 2208: 2204: 2200: 2196: 2192: 2188: 2184: 2180: 2176: 2172: 2167: 2165: 2161: 2157: 2153: 2149: 2145: 2141: 2137: 2133: 2129: 2125: 2121: 2117: 2113: 2109: 2105: 2101: 2097: 2093: 2089: 2085: 2076: 2068: 2057: 2053: 2048: 2044: 2042: 2038: 2034: 2030: 2026: 2022: 2018: 2014: 2010: 2001: 1989: 1985: 1981: 1978: 1974: 1970: 1966: 1965:Modoc Plateau 1962: 1958: 1954: 1950: 1946: 1942: 1938: 1934: 1933: 1932: 1930: 1926: 1918: 1915: 1911: 1907: 1903: 1899: 1895: 1891: 1887: 1883: 1879: 1875: 1874: 1873: 1871: 1867: 1859: 1855: 1851: 1847: 1844: 1840: 1836: 1835: 1834: 1832: 1828: 1820: 1816: 1812: 1808: 1804: 1801: 1797: 1796: 1795: 1793: 1789: 1781: 1777: 1773: 1769: 1766: 1762: 1758: 1754: 1750: 1746: 1742: 1738: 1734: 1730: 1726: 1723: 1722: 1718: 1714: 1713:Mojave Desert 1710: 1704: 1703:Mojave Desert 1700: 1695: 1691: 1689: 1685: 1678: 1674: 1670: 1665: 1661: 1657: 1653: 1649: 1646: 1642: 1638: 1634: 1630: 1626: 1623: 1622: 1621: 1619: 1615: 1607: 1603: 1599: 1595: 1591: 1587: 1584: 1580: 1576: 1572: 1568: 1564: 1560: 1556: 1552: 1548: 1544: 1541: 1540: 1536: 1532: 1528: 1524: 1519: 1515: 1513: 1509: 1501: 1497: 1493: 1489: 1485: 1482: 1478: 1474: 1470: 1466: 1462: 1461:Sierra Nevada 1458: 1457: 1454: 1453:San Francisco 1450: 1445: 1441: 1439: 1435: 1427: 1423: 1419: 1415: 1411: 1406: 1402: 1398: 1393: 1390: 1386: 1382: 1381: 1376: 1372: 1368: 1367:sclariventris 1364: 1360: 1356: 1352: 1348: 1345: 1341: 1337: 1333: 1329: 1325: 1324: 1321: 1317: 1312: 1308: 1306: 1302: 1295: 1290: 1286: 1282: 1278: 1274: 1270: 1266: 1263: 1259: 1255: 1251: 1247: 1243: 1239: 1235: 1231: 1228:south of the 1227: 1223: 1219: 1215: 1211: 1207: 1206: 1202: 1198: 1194: 1190: 1188: 1184: 1183: 1175: 1171: 1167: 1163: 1159: 1154: 1149: 1146: 1142: 1138: 1134: 1130: 1126: 1122: 1118: 1114: 1110: 1106: 1102: 1098: 1094: 1090: 1087: 1086: 1085: 1083: 1079: 1070: 1068: 1064: 1060: 1056: 1052: 1048: 1044: 1040: 1039:ank, ank, ank 1036: 1032: 1026: 1024: 1020: 1016: 1012: 1008: 1007:who-hoo-ho-oo 1004: 1000: 996: 975: 973: 969: 965: 959: 957: 953: 949: 944: 940: 938: 934: 929: 927: 923: 919: 915: 911: 910:Tarsal length 902: 898: 896: 892: 888: 879: 875: 872: 868: 864: 860: 856: 852: 847: 838: 829: 827: 823: 818: 816: 811: 810:Pacific Coast 807: 802: 800: 790: 786: 774: 771: 770:B. v. deserti 768: 765: 761: 758: 755: 752: 749: 746: 743: 740: 736: 733: 730: 727: 723: 720: 717: 714: 710: 707: 704: 700: 697: 694: 693:B. v. pinorum 691: 688: 685: 682: 679: 676: 673: 669: 666: 663: 660: 657: 654: 651: 648: 645: 641: 638: 637: 636: 633: 631: 627: 623: 619: 614: 612: 608: 604: 600: 596: 591: 587: 583: 579: 574: 572: 571:André Duméril 568: 567: 562: 558: 554: 550: 546: 542: 538: 534: 531: 530:binomial name 527: 526: 522: 518: 517: 512: 511:Carl Linnaeus 508: 504: 494: 492: 491:North America 488: 484: 480: 476: 472: 467: 465: 464:invertebrates 461: 457: 453: 449: 445: 441: 437: 436:rats and mice 433: 429: 425: 421: 418:, is a large 417: 413: 409: 408: 403: 391: 387: 382: 379: 378: 375: 372: 368: 365: 360: 356: 351: 348: 344: 339: 334: 328: 326: 320: 317: 316:Binomial name 313: 309: 308: 303: 300: 299: 296: 295: 291: 288: 287: 284: 281: 278: 277: 274: 271: 268: 267: 264: 261: 258: 257: 254: 251: 248: 247: 244: 241: 238: 237: 234: 231: 228: 227: 222: 217: 213: 207: 201: 196: 190: 185: 184:Least Concern 174: 170: 165: 158: 154: 151: 149: 146: 143: 142: 139: 135: 130: 124: 121: 118: 117: 114: 110: 105: 91: 86: 81: 76: 71: 66: 61: 56: 51: 46: 41: 36: 22: 19: 11869:Bubo (genus) 11394: 11367: 11350: 11331: 11328: 11321:(4): 261–63. 11318: 11315: 11308: 11291: 11267:(1): 10–13. 11264: 11260: 11231: 11226: 11222: 11205: 11197: 11194: 11186: 11180: 11171: 11144: 11140: 11136: 11117: 11113: 11098:the original 11093: 11089: 11061:. 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Retrieved 5772:. 2022-08-08 5764: 5745: 5713: 5709: 5703: 5694: 5690: 5680: 5671: 5667: 5657: 5640: 5634: 5502: 5498: 5494: 5465: 5437: 5342:. Retrieved 5337: 5308: 5304: 5295: 5291: 5280: 5270: 5260: 5250: 5240: 5230: 5212: 5120: 5027:. Retrieved 5023:the original 4979: 4948:(1): 21–24. 4945: 4941: 4928: 4917:. Retrieved 4913: 4904: 4892:. Retrieved 4878: 4872: 4866: 4835: 4785:Great Plains 4766: 4750: 4742: 4726: 4704: 4696: 4684: 4672: 4652: 4640: 4632: 4594: 4581: 4576: 4566: 4556: 4546: 4539:Hudson River 4535:black racers 4527: 4519:Saskatchewan 4474: 4452: 4444: 4433: 4423: 4419: 4394:Saskatchewan 4363:to northern 4342: 4325: 4318:Canada goose 4313: 4282: 4273: 4242: 4238: 4228: 4213: 4204:Reproduction 4192: 4180: 4173:Mexican jays 4161:Corvus corax 4160: 4152: 4113:Hen harriers 4110: 4089: 4077: 4061: 4049: 4041: 4035: 4030: 4022: 4014: 4006: 3999: 3995: 3983: 3979: 3970: 3960: 3955: 3947: 3939: 3927: 3911: 3903: 3875: 3867: 3849: 3839: 3831: 3814:rodenticides 3793: 3783: 3764:grasshoppers 3729: 3704: 3696: 3688: 3668: 3660: 3652: 3644: 3636: 3628: 3625:cottonmouths 3620: 3617:night snakes 3612: 3593: 3575: 3559: 3543: 3535: 3496: 3491: 3483: 3475: 3467: 3452:Canada geese 3447: 3431: 3415: 3387: 3376:North Dakota 3367: 3358: 3350: 3342: 3326: 3318: 3306: 3298: 3290: 3279: 3274: 3266: 3247: 3226: 3214: 3202: 3194: 3182: 3166: 3158: 3155:masked shrew 3150: 3140: 3135: 3127: 3119: 3111: 3103: 3096: 3083: 3067: 3059: 3051: 3043: 3035: 3027: 3017: 2977: 2972: 2945: 2940: 2928: 2918: 2910:pygmy rabbit 2899: 2878: 2874: 2871:jumping mice 2866: 2858: 2850: 2842: 2838: 2835:bog lemmings 2826: 2823:golden mouse 2818: 2810: 2802: 2799:hoary marmot 2794: 2778: 2775:prairie dogs 2770: 2761:, including 2756: 2751: 2743: 2723: 2709: 2703: 2699: 2677: 2659: 2655: 2629: 2621: 2616: 2612: 2605: 2583: 2563: 2547: 2539: 2531: 2505: 2469: 2459:Painting by 2445: 2436: 2415: 2410: 2407:chuckawallas 2402: 2395: 2362: 2358: 2338: 2324: 2317: 2304: 2278: 2274: 2243: 2239:Pennsylvania 2225:such as the 2197:, subarctic 2168: 2081: 2051: 2040: 2032: 2012: 2006: 1987: 1983: 1976: 1973:occidentalis 1972: 1928: 1924: 1923: 1913: 1909: 1905: 1901: 1886:Newfoundland 1869: 1865: 1864: 1857: 1853: 1849: 1830: 1826: 1825: 1814: 1810: 1806: 1791: 1787: 1786: 1775: 1765:melanocercus 1764: 1756: 1748: 1739:and western 1716: 1698: 1687: 1683: 1682: 1676: 1672: 1668: 1659: 1655: 1651: 1644: 1617: 1613: 1612: 1598:heterocnemis 1597: 1589: 1554: 1550: 1522: 1511: 1507: 1506: 1491: 1487: 1476: 1448: 1437: 1433: 1432: 1421: 1418:heterocnemis 1417: 1413: 1409: 1396: 1395:coloration. 1388: 1384: 1380:nomen dubium 1378: 1370: 1366: 1362: 1359:occidentalis 1358: 1355:South Dakota 1340:North Dakota 1315: 1304: 1300: 1299: 1293: 1280: 1272: 1268: 1261: 1257: 1253: 1249: 1244:and western 1240:in northern 1230:Amazon Basin 1220:; also from 1209: 1200: 1186: 1180: 1179: 1173: 1169: 1161: 1140: 1136: 1132: 1128: 1124: 1116: 1081: 1077: 1076: 1066: 1058: 1051:meee-owwwwww 1050: 1042: 1038: 1034: 1030: 1027: 1018: 1015:whoo-hoo-o-o 1014: 1010: 1006: 1003:bu-bubu booh 1002: 998: 992: 971: 960: 945: 941: 930: 926:golden eagle 907: 891:wing loading 884: 843: 819: 803: 795: 783: 769: 759: 750: 744: 731: 718: 708: 698: 692: 683: 677: 664: 655: 649: 639: 634: 615: 598: 575: 564: 540: 532: 523: 514: 500: 486: 474: 468: 415: 411: 406: 405: 401: 399: 384:Gmelin, 1788 380: 363: 346: 324: 322: 306: 305: 293: 273:Strigiformes 147: 122: 18: 11732:Neotropical 11693:NatureServe 11641:iNaturalist 11419:Wikispecies 7866:(1): 58–65. 5344:24 December 5326:Gill, Frank 5222:10088/10016 4894:20 February 4738:cottontails 4689:pinyon jays 4613:New England 4605:Mississippi 4389:New England 4387:, northern 4288:, built by 3940:Canis lupus 3900:Canada lynx 3880:cottontails 3856:Great Basin 3846:meadow vole 3673:salamanders 3602:. However, 3519:cardinalids 3371:water birds 3347:wild turkey 3189:, juvenile 3147:least shrew 3092:swift foxes 2914:jackrabbits 2879:Napaeozapus 2845:ssp.), the 2821:ssp.), the 2711:Chaetodipus 2705:Perognathus 2692:pocket mice 2673:Pappogeomys 2665:Cratogeomys 2512:jackrabbits 2366:Kluane Lake 2223:rainforests 2207:urban areas 2160:Haida Gwaii 2156:West Indies 2140:El Salvador 2094:, northern 2041:A. clamator 2037:striped owl 2029:stygian owl 2017:paraspecies 1941:Snake River 1914:virginianus 1910:subarcticus 1645:columbianus 1635:zones from 1567:Snake River 1422:virginianus 1410:subarcticus 1389:subarcticus 1363:subarcticus 1287:races. The 1170:mesembrinus 1145:South Texas 1141:virginianus 1129:mesembrinus 1125:virginianus 1109:Nova Scotia 1103:, southern 948:human being 822:facial disc 780:Description 703:Great Lakes 341:Subspecies 202:Appendix II 11858:Categories 11836:Xeno-canto 11063:2018-01-08 11037:: 199–201. 10947:0812970365 10603:2020-02-21 10522:: 381–388. 10246:2020-02-21 9824:(1): 2–5. 9713:: 179–181. 9669:(4): 393. 9636:2016-11-29 9559:: 117–119. 9339:: 199–232. 9294:: 699–732. 9222:The Condor 9138:The Condor 8940:2012-02-09 8650:0870499661 8550:(1): 1–6. 8228:The Condor 8189:0920502318 8161:2012-02-09 8117:The Condor 8104:(4): 1–36. 8059:The Condor 7970:2013-03-21 7901:The Condor 7884:: 286–298. 7744:The Condor 7656:(2): 142. 7596:(2): 148. 7536:(3): 1–76. 7389:2024-05-12 7365:1561380326 7224:8788757161 7125:0938626388 7005:0198540124 6917:B003XVMPTC 6893:2012-02-09 6784:: 964–965. 6680:0801496004 6570:: 274–285. 6414:(2): 434. 6408:The Condor 6353:2020-02-21 6107:2020-02-21 5934:0486221237 5890:2012-02-09 5776:2024-08-13 5697:: 385–400. 5130:0262220350 4988:B0006BN8QG 4919:2022-01-14 4848:References 4810:New Mexico 4757:Dudley Zoo 4553:blackflies 4531:rat snakes 4302:buteonines 4298:bald eagle 4218:New Mexico 3851:Peromyscus 3768:water bugs 3740:centipedes 3615:ssp.) and 3613:Thamnophis 3600:amphibians 3590:Other prey 3507:chickadees 3456:snow goose 3440:Washington 3424:passerines 3404:shorebirds 3394:, smaller 3363:guineafowl 3251:galliforms 3120:Lynx rufus 3022:, such as 2885:Lagomorphs 2843:Synaptomys 2716:East Texas 2684:Washington 2676:and other 2669:Zygogeomys 2623:Peromyscus 2613:Peromyscus 2542:) and the 2493:amphibians 2477:Neotropics 2345:long-eared 2310:and other 2175:coniferous 2148:Costa Rica 2100:Fort Chimo 2033:A. stygius 2025:allopatric 2021:eagle-owls 1988:pallescens 1977:pallescens 1955:, and the 1953:New Mexico 1819:wing chord 1815:pallescens 1807:pallescens 1780:wing chord 1673:nigrescens 1664:wing chord 1660:nigrescens 1656:elachistus 1606:wing chord 1590:lagophonus 1500:wing chord 1492:pallescens 1477:pallescens 1426:wing chord 1332:Hudson Bay 1289:wing chord 1273:nigrescens 1262:nigrescens 1166:Costa Rica 1153:wing chord 1133:pallescens 1073:Subspecies 1031:krrooo-ooo 1011:who-ho-o-o 887:wing chord 859:California 713:Gmelin, JF 644:Oberholser 618:subspecies 460:amphibians 11329:Oecologia 11189:(1): 5–6. 10631:The Birds 10561:2562-5667 10214:0004-8038 9877:0090-3558 9752:0892-1016 9685:0008-3550 9628:Mona, K. 9433:216485857 8858:: 65–69. 8521:: 12–17. 8415:0008-3550 8234:(1): 73. 7577:(4): 272. 7498:: 61–66. 7470:(3): 449. 7266:Oecologia 6294:147068859 6286:0745-7472 6270:(9): 10. 5311:(1): 6–8. 4996:cite book 4914:cites.org 4802:Southwest 4777:Southwest 4755:young at 4723:Captivity 4515:siblicide 4365:Louisiana 4349:southeast 4338:squirrels 4278:Louisiana 4246:Southwest 4092:) in the 3987:Wisconsin 3967:gray hawk 3928:Gulo gulo 3924:wolverine 3748:scorpions 3701:bullheads 3556:kingbirds 3525:and most 3503:passerine 3257:. In the 3207:armadillo 3056:mustelids 3024:ringtails 3010:as well. 2912:to adult 2819:Glaucomys 2783:chipmunks 2759:squirrels 2524:lagomorph 2246:tree line 2229:. 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