Owls

(Strigidae)

Class Aves

Order Strigiformes

Family Strigidae

Thumbnail description
Typical owls have large, rounded heads, forward-facing eyes, facial discs of feathers, and strong, hooked beaks; solid, stocky bodies with dense feathering; moderately short tails; strong feet with talons; subtle coloration makes these birds well camouflaged

Size
4.7–29.5 in (12–75 cm); 1.4–148 oz (40–4,200 g)

Number of genera, species
25 genera; 189 species

Habitat
Forest, woodlands, tundra, desert, savanna, parkland, urban, coastal, wetlands, mangroves

Conservation status
Critically Endangered: 3 species; Endangered: 4 species; Threatened: 2 species; Vulnerable: 12 species

Distribution
All continents except Antarctica

Evolution and systematics

The oldest known record of an owl, the fossil Ogygoptynx wetmorei from about 58 million years ago (mya), was discovered in Colorado, USA. The available fossil record suggests a major radiation of owls about 50 million years ago, although exactly when the Strigidae appeared is not clear. It seems that the original owls were large in comparison to modern owls. The Tytonidae preceded the Strigidae in the fossil record. Bubo poirrieti, found in France 24–22 mya, and Strix brevis, from western North America, are the earliest records of Strigid owls yet discovered.

Linnaeus put the hawks (Falconiformes) and the owls (Strigiformes) in the same group because of their physical characteristics and carnivorous habits. They retained this classification for 130 years until M. Furbringer, H. von Gadow, and others pointed out the similarities of the owls to the Caprimulgiformes (nightjars, frogmouths, and oilbirds). Most modern taxonomists still consider the Caprimulgiformes to be the closest relatives of the owls, a relationship supported by DNA-DNA hybridization data.

Historically, there have been huge arguments about the number of species and particularly subspecies among the owls. Some disputes have been resolved through the use of DNA to discover who is related to whom; however, at this point, no two books give exactly the same answers. Considering the popularity of owls and the number of species, there are surprisingly few books on owls of the world. The owls of the Northern Hemisphere are covered reasonably well, but those in the Southern Hemisphere are covered rather less well. Handbook of the Birds of the World, volume 5, divides the Strigidae into three subfamilies (Striginae, Surniinae, and Asioninae), six tribes (Otini, Bubonini, Strigini, Surniini, Aegoliini, and Ninoxini), 25 genera, 189 species, and 548 subspecies.

Physical characteristics

The Strigidae, sometimes known as the typical owls, is an enormous and varied family, yet it is very distinct—there is no doubt an owl is an owl. The largest of these owls are the eagle-owls, genus Bubo. The northern race of the Eurasian eagle-owl (Bubo bubo) is a huge bird weighing as much as 9.2 lb (4,200 grams) with a length 23.6–29.5 in (60–75 cm). A close runner-up is Blakiston's eagle-owl (Bubo blakistoni), an extremely rare fishing owl found only in Japan, Siberia, and far northeast China, which is 23.6–28.3 in (60–72 cm) in length. On the other end of the scale are the ridiculously tiny pygmy owls of the genus Glaucidium. The least pygmy owl (Glaucidium minutissimum) lives up to its name, weighing only an average of 1.7 oz (47.8 g). This species is a massive 20% heavier than the elf owl (Micrathene whitneyi), the most delicate of all the owls at 1.4 oz (40.2 g) and only 5.3–6.1 in (13.5–15.5 cm) in length.

Between these two extremes of size are nearly 200 other owl species of every size and color. The males tend to be

smaller than the females, although this is often most noticeable in the owls that feed on vertebrates rather than invertebrates. There are exceptions—male burrowing owls (Athene cunicularia) are slightly larger than the females, as are the males of some of the Ninox species. All the owls have a large, domed, rounded head with forward-facing eyes. Probably the most striking feature of the owls is the facial disc of feathers. This, along with the forward-facing eyes and the bill often almost hidden by feathers, makes them appear to have a "face." The disc, which is more pronounced in the barn owls (Tytonidae), works like a parabolic reflector, focusing sound towards the owl's ears.

Owls have remarkably subtle plumage, with beautiful muted colors including browns, golds, grays, black, creams, and white. There is tremendous variation among the different species, but in all species the plumage has evolved to blend in with various backgrounds and habitats. Camouflage is essential to an owl during daylight hours. As predators, owls are hated and feared by most other birds and, if spotted in the daytime, they are mobbed furiously by many different genera of birds. Even tiny passerines try to drive them away. The mobbing of owls is such a powerful instinct in other birds that even dead, stuffed owls are attacked, with some birds going so far as to physically strike the owls. Consequently the coloration of an owl is crucial as camouflage. Some are so well camouflaged that they become almost invisible when seen against the bark of a tree.

Owls are nocturnal birds, although many can and do hunt in half light and daylight. Their modified hearing and highly specialized feathers allow them to hunt successfully after sunset. Owls use sound as a directional aid to assist in locating prey at night. Their ears are set asymmetrically in their skulls, with one set slightly higher than the other, and one sometimes of larger size. This allows the owl to pinpoint sound very accurately while in flight. In addition to this adaptation, owl feathers have evolved to facilitate silent flight. The surface of most of the feathers is not smooth, but covered in a very fine down. The trailing edge of the flight feathers (primaries and secondaries) is much softer and less defined than that of diurnal birds of prey, and only the outer edge of the leading primary is serrated like a comb. All these adaptations contribute to silent flight, which in turn aids hunting in the dark. Most owls have feathers growing to a greater or lesser extent right down to their talons. These feathered feet give the owls extra protection from biting rodents, and in many species, provide extra insulation against cold temperatures. The exceptions are the fishing owls—they have bare feet more suited for getting wet regularly.

Distribution

With the exception of Antarctica, owls are found throughout the world. Snowy owls (Nyctea scandiaca) inhabit the frozen tundra of the north, living above the tree line during summer months and breeding as far north as 82°50′. A few species, including the snowy owl, circumnavigate the globe and are distributed in both the New World and the Old World. The northern hawk owl (Surnia ulula) and the great gray owl (Strix nebulosa) are also found just south of the tree line all around the top of the world.

The scops-owls (genus Otus) are the largest genus in the Strigidae with 63 species. They could almost be described as island specialists, since 30 of the species are found on large or small islands. Many of them are found on tiny "islands" of habitat. For example, the Madagascar scops-owl (Otus rutilus) is found, as its name implies, throughout Madagascar. The Puerto Rican screech owl (Otus nudipes) is found in Puerto Rico, is thought to be extinct on the Island of Vieques, and may be found on Culebra Island and the Virgin Islands. (Indeed, this is a classic case of how little is really known about many species of owls, particularly the scops-owls.) The island species have the highest number of endangered species— some, like the Seychelles scops-owl (Otus insularis), which is Critically Endangered, are limited to only a single island. Twenty-seven of the 63 species are located in Southeast Asia and 13 species are found in South America. Fifty-five species are found between the tropic of Cancer and the tropic of Capricorn, since these tiny owls generally do not survive well in colder weather.

Among the eagle-owls, the great horned owl (Bubo virginianus) has the greatest range, extending from Alaska to Argentina. The Eurasian eagle-owl is similarly widespread in the Old World, ranging from Spain and Norway to eastern China, Russia, and northern Hokkaido in Japan. As with any species covering such a wide range there are many subspecies, 14 within the Eurasian eagle-owl and 12 in the great horned owl.

Of the seven species of fishing owls, three occur in southeastern Asia and three in Africa. The northern most and also most endangered is Blakiston's eagle-owl, which inhabits southeastern Siberia, Manchuria, Sakhalin Island, Hokkaido, and the southern Kuril Islands.

The wood-owls (genus Strix) are spread quite evenly throughout the world, although, as their name implies, they are mainly found in the world's forests. The tribe Ninoxini, genus Ninox, is all found through Southeast Asia and Australia with one species found in New Zealand. There are two exceptions in this distribution—the brown hawk-owl (Ninox scutulata), which ranges from India north to Siberia and Japan, and the white-browed hawk-owl (Ninox superciliaris), which occurs only in Madagascar and is also the only Ninox with brown eyes instead of yellow. (Its relationship to Ninox requires further research.) The most widespread of the typical owls is the short-eared owl (Asio flammeus), occurring in North and South America, Europe, Asia, and some parts of Africa, but not in Australasia.

Habitat

Owls have evolved to inhabit just about every remaining forest on Earth. With a few exceptions, the bulk of the typical owl species prefer to inhabit forests or woodlands. The richer the forest the higher the number of owl species that inhabit it, so both lowland and, less commonly, high-altitude tropical forests are home to many species. Because of the natural inaccessibility of the high-altitude forests, far less is known about the species that live there. The lowland tropical forests are relatively accessible to humans and have been extensively exploited and so the species living there are more likely to be threatened. All but a few of the scops-owls inhabit either rainforest or other forested and wooded areas, as do most of the eagle-owls. One exception is Savigny's eagle-owl (Bubo ascalaphus), also known as the desert eagle-owl, its glorious buff and sandy coloration making it an obvious desert dweller. Another species whose coloration is well adapted to the desert environment is Hume's owl (Strix butleri), which inhabits rocky gorges, desert wadis, and palm groves.

The fishing owls of the genera Ketupa and Scotopelia are more specialized and are found along the lakes, rivers, or swamps that are home to the fish upon which they prey.

The more northern species of pygmy-owls, such as the Eurasian pygmy-owl (Glaucidium passerinum) or the northern pygmy-owl (Glaucidium californicum), prefer either coniferous or deciduous forests and forest edges. A few, such as the pearl-spotted owlet (Glaucidium perlatum), occur in more open scrub land. The more southern species inhabit a wider variety of forests from the sparse open forests, scrub land, coastal and

thorn scrub, which the ferruginous pygmy-owl (Glaucidium brasilianum) inhabits, to the dense primary forests that are preferred by the red-chested owlet (Glaucidium tephronotum).

One of the best known of the open habitat owls is the burrowing owl. This active and marvelous little owl inhabits the arid desert plains, grasslands, and prairies through North and South America, sometimes living close to human habitation. Unlike many owls, they are very obvious in their habits and thus are noticed more than many other species.

Apart from the white-browed hawk-owl of Madagascar, which occurs in varied terrain from open scrubland through forests to rocky coastal ravines, all the other Ninox species inhabit forests of some type depending on their range.

The last grouping of owls, the Asio species, all tend to inhabit various forests with the exception of the widely distributed short-eared owl and the marsh owl (Asio capensis). The latter inhabits open marshland and the short-eared owl encompasses a huge range that includes moorland, tundra, grasslands, marshlands, and montane forests.

Although not the most widespread, the great horned owl probably inhabits more varied habitats than any other owl species. Its adaptability has allowed it to survive in almost all habitats and its lack of fear of humans increases the numbers of habitats it can utilize.

The quality of the habitat dictates how well owls can survive there. If it is a rich, undisturbed habitat, owls will do well, but human disturbance generally reduces the numbers of owl species and limits their ability to utilize what is available. The long-term impact of habitat changes on owls is uncertain because so little is known about many of these species. Nest sites are crucial for good owl habitat, particularly as they rely on holes in trees, crevices, or other birds' nests. But even with good available nest sites, owls cannot flourish without a sufficient prey base. For example, owls that rely on the cyclical

lemming population will produce a population explosion in a good lemming year. However, the habitat cannot sustain the increased numbers for long and there is usually a large dieoff of owls when the prey base declines. Although some owls are coping with the effects of humans on habitat, many are not. Migrating owls can be affected by habitat changes at both wintering and breeding destinations on their migration and little is known about the migration of owls.

Behavior

Since they are nocturnal, owls generally do not do a great deal during the day, apart from hiding. This habit of keeping very still and thus allowing people to approach fairly closely gives the mistaken impression that owls are tame. They are, in fact, trying to avoid attention by not moving. Owls will pull their feathers tight to their bodies and lean close to the tree or rocks in which they are perching in order to blend into the background and avoid detection. Having said that, owls do enjoy sunshine occasionally, and after periods of dull weather will find a quiet place and sun themselves, sometimes lying down and spreading their wings and tail to catch the warmth. They also enjoy bathing.

Some of the owl species are more active during the day, and several populations have no choice in the matter. Owls living in the far north, where daylight extends nearly 24 hours during summer months, have to hunt regularly during daylight. Other owls living where daylight hours are long during the summer also have no option but to hunt in daylight to feed growing young. Some species seem to choose to be active during the day—probably the most active are the burrowing owl and the little owl (Athene noctua), which is particularly dayactive during the summer. Many owls are crepuscular and will be seen hunting at dawn and dusk in the half light.

Most owls are solitary except during the breeding season. A few group together in the winter in roosts, such as the long-eared owl (Asio otus). This species normally has roosts of up to 20 individuals, but numbers as high as 100 have been reported. In addition, marsh owls and short-eared owls gather in winter roosts. Oddly, these three species and the burrowing owl are the only species that might be termed loose colony nesters.

Little is known about the social behavior of owls, since it is difficult to study bird behavior in the dark. It is known that much of their socializing is done vocally. Owls produce a huge variety of calls from the pig-like grunting of snowy owls to the classic twit twooooo hooting of the tawny owl and the deep hooting of the large eagle-owls. The little owl has a yelping call that is often heard during daylight hours in the summer. The southern boobook owl (Ninox boobook) is named after its call, which has a gentle cuckoo-like sound. Some species have been reclassified and re-identified by their differing calls. Many owls have a wide variety of calls, and the warning call of some of the eagle-owls sounds like a dog barking. Heard unexpectedly at night, these calls can be quite startling!

In addition to using their voices to contact potential mates, call to their young, warn off intruders, and mark territories, owls also convey messages by their physical stance. When vocalizing many owls lean forward and display a flash of white throat feathers that must be very visible at night. Different positions of the ear tufts are used to communicate as well. Owls also adopt an aggressive posture in defense by opening their wings, lifting and turning them so the backs of the wings face forward, and puffing up all their body feathers. This makes the owls appear to be more than double their actual size. When combined with loud clapping sounds that the owls produce with their beaks, this posture makes the owls appear formidable indeed.

Most owls are sedentary. Only a very few species from the more extreme climates (both far north and far south) are migratory, although little is known about their specific movements. Burrowing owls disperse and move south from their northern ranges in North America, but the more southern populations such as those in Florida are sedentary. Snowy owls move south for the winter months as do northern hawk-owls (Surnia ulula). Brown hawk-owls in the north of their range move south for overwintering as well.

Owls appear to defend only the territory directly surrounding their nesting area, rather than the whole of the range in which they regularly hunt. Territorial behavior occurs much more during the courtship and breeding season than in the winter. This behavior also is more prevalent in sedentary species, as opposed to migratory species, particularly those with fixed nests sites, such as cavities or caves.

As stated earlier, most owls are not active in the daytime, but quickly become active when dusk falls. Contrary to popular belief, owls cannot see well when it is extremely dark. Owls are able to see better in low light than humans are, but they cannot see in total blackness anymore than humans or other animals can. Owls' eyes have huge pupils that provide good vision in low levels of light and consequently the early and late parts of the night are generally preferred for hunting.

Feeding ecology and diet

Were is not for the humble voles, owls would be a less well-established family. Owls catch a variety of prey, but voles feature highly in many owl diets, and some owls are completely reliant on them.

Insects make up the bulk of the diet of most tiny owls, such as the Scops and Glaucidium species. These species also take small birds, reptiles, and amphibians. Small owls, such as the smaller members of the Ninox and Strix genera, have a similar diet, but also take slightly larger prey, such as birds and small mammals. Medium owls, such as Ural owls, take accordingly larger prey, adding mammals such as rats and young rabbits and other similarly sized creatures. Snakes are taken

by owls as well, although they do not form a large part of owl diets, since snakes prefer to be out in the heat of the day and owls do not. The largest of the owls, the eagle-owls, take quite large prey, such as rabbits, pheasants, and even hares. Great horned owls are probably the most rapacious of the owls and have been known to kill red-tailed hawks (Buteo jamaicencis), but this relatively rare occurrence tends to happen over nest disputes. Some owls, such as the great gray owl, may appear large, but are, in fact, quite small under an impressive coat of feathers. They rely on voles and lemmings for the bulk of their diet. The size of an owl's feet is usually an indication of the size prey that it is capable of taking, although there are exceptions. The little owl is able to take baby rabbits that are as large if not larger than the owl itself.

Some owls specialize in particular kinds of prey. The fishing-owls (Ketupa), as their name implies, specialize in fish and the spectacled owl (Pulsatrix perspicillata) is known to prey upon crayfish and small crabs. Many owls will take bats if the chance arises.

As with diurnal birds of prey, owls use their well developed feet to catch their prey. They are, as far as is known, totally carnivorous. A very few of the diurnal birds of prey eat some plant matter, but owls are not generally known to do so. However, since they often swallow their prey whole, owls consume some vegetable matter secondhand.

The hunting methods of owls are similar to those employed by many of the diurnal raptors with the exception of vultures and falcons. No owls swoop on their prey from a great height, nor do any owls specialize in feeding on carrion. As a general rule they do not soar either. Like many hunting birds, owls favor "still hunting." A number of favorite perches are regularly used in the home hunting range and the owls sit watching and listening for potential prey.

Hawk-owls, as their name implies, have a hawk-like shape and can use a hunting technique similar to that of the accipiters. The northern hawk-owl, in particular, is agile in the air and will take birds on the wing. Generally most owls prefer the perching method of hunting. They sit and wait for prey to appear and then drop or glide from their elevated perch to attack. Only owls with lighter wing loading, such as the long-eared owl and the short-eared owl do a great deal of aerial hunting. These species will quarter the ground, floating above rough grassland and reed beds or moorland to locate potential prey.

Most owls cache or hide excess food and come back to find and eat it later. All owls regurgitate a casting or pellet of indigestible food that is composed of the fur, feathers, and bones of their prey. Unlike many other aspects of owls' lives, a great deal is known about their diets because of this pellet, which contains much information about exactly what owls have been consuming.

Reproductive biology

Owls are generally monogamous, and some, such as the Ural owl (Strix uralensis) and some of the small scops-owls, form pairs for life. Others pair up for one breeding season and may find a new mate the following season. Some owls are known to be polygamous; often mating behavior is species reliant on the fluctuations of vole and lemming populations. When there is a population explosion of prey species, the owls can afford to take two mates and try for two different broods of young. This has been documented in several northern species such as the snowy owl and the tawny owl (Strix aluco), but is best known among the boreal or Tengmalm's owl (Aegolius funereus).

Owls court their mates through calls and by providing food and nest sites. After calling females into their territory, males offer food to prove their suitability as a provider for young and often show females potential nest sites. Owls do not build nests of their own, but rather nest in shallow scrapes in the ground among tree roots, in shallow caves, in the cavity of a tree, or in old buildings, ruins, and wall cavities. A few owls, such as the burrowing owl, even nest underground. This owl often uses the burrows of other mammals, and its close relative, the little owl, has been known to nest in rabbit holes. Many larger owls use the nests of other birds, such as raptors and corvids. The owl's own regurgitated pellets often are used to line the nest.

All owls lay white, fairly rounded eggs. The number of eggs varies from species to species. The average clutch size is two to four eggs. Some eagle-owls and fishing-owls lay only one egg in a clutch. Burrowing owls can lay up to 10 eggs in a clutch, and snowy owls and northern hawk-owls increase their clutches up to 13 in good vole or lemming years. Incubation is done almost solely by the female, who stays with the hatched young until their secondary down has grown and they can thermoregulate.

The male owl provides all the food for his mate during incubation and also provides all the food for the young for the first two weeks or so of their lives. He delivers vast amounts of prey to feed growing young. Once the young are large enough, the female will join him in hunting and providing food.

Young owls wander from the nest before they can fly. They climb using their beaks and talons to scramble up trees to return to the safety of the nest when necessary. Although owls fledge in approximately the same amount of time as similarly sized diurnal birds of prey, they do seem to develop more slowly and the last of the natal down can be visible for some time after young have fledged. Like diurnal birds of prey, young owls are reliant on parental care for some period after fledging, although generally little is known about the length of their dependency.

Conservation status

At least eight identifiable species of owls have become extinct in the last 300 years and the number is probably higher than that. Like many other species, owls have suffered from human disturbance. As noted by del Hoyo, Elliott, and Sargatal: "According to BirdLife International's 1994 appraisal of globally threatened birds, 21 (11%) of the 189 species of Strigids known to be alive today are in danger of extinction, and another 14 (7.4%) are classified as Near Threatened." Most of these are island species and most inhabit tropical forests. Even though we are sadly uninformed about the status and biology of many species of owls, it seems logical that if forests are removed, then those species reliant on them also will be lost.

As of 2000, seven species of owls are listed as Critically Endangered. The saddest example is probably the forest owlet (Athene blewitti) of India, rediscovered in 1997 after 113 years since the last verified record. Within six months of this exciting discovery, tree cutting had devastated the habitat of this illusive owl, dramatically reducing its chances of survival.

As with so many taxa, habitat destruction is the main cause for decline in most owl species; however, other factors also contribute. Blakiston's fish-owl—the second largest owl and supposedly highly revered in Japan—is one of the world's rarest owls, and is classified as Endangered. Habitat destruction, shooting, encroaching human populations, and destruction of the rivers where it fishes threaten the future survival of this owl.

Because owls are low and slow flyers, roads and motor vehicle traffic pose a significant danger to them, especially when roads cut through islands of habitat. Many owls are killed on the roads and this problem increases as traffic increases.

A great deal of research is needed to assess and understand the needs of owls worldwide. In addition, education to teach people the value of their natural resources and give a national sense of pride in their wildlife is crucial to the conservation of owls. As with all species, conservation of natural habitat is paramount to the survival of owls.

Significance to humans

Owls have a long history with humans. The relationship is probably not as close as that between humans and diurnal birds of prey, but, nevertheless, owls abound in myths, poems, paintings, and folklore. It is probably the owls' almost human "face" that makes them so popular with many people. However, owls are probably hated and feared in some cultures as much as they are liked and revered in others.

In Indian law and in Greek mythology owls represent wisdom. In many countries owls were believed to be a symbol of bad luck or death, while in others they were believed to guard the souls of women or ward off famine or plague. In a few places, owls have been eaten as food, but more often, particularly in Southeast Asia, owl body parts are used for medical purposes by traditional healers. In Africa, owls are not particularly popular and can be killed for many reasons.

Historically, in Europe, tame owls were tethered to attract corvids and other birds. When these birds came to mob the owl, they were shot by hunters and gamekeepers. Today owls are used in a similar way by scientists to attract falcons, harriers, or kites, so that they can be trapped for scientific research.

Owls have appeared on artifacts for thousands of years. Clay models and sculptures of owls or other artistic representations of owls can be found in many cultures. Today representations of owls are popular with collectors.

Because owls are active at a time when most humans are not, there generally is not a great deal of interaction between them. However, during the breeding season some owls become extremely defensive and may attack anything that comes within their nesting area. When people venture near a nest, either by mistake (as when walking a dog late at night) or on purpose, problems may arise. Owls are not generally aggressive, but can be potentially dangerous when defending their nesting areas from humans. The massive size difference between humans and owls makes owls perceive humans as potential predators.

In Europe, owls are very popular birds to keep in captivity among special interest groups. This led to some very successful captive breeding programs with over 50 species of owls bred so far. In the United Kingdom, barn owls (Tyto alba) have been bred and released under special license to increase dwindling numbers; in Canada and the United States, burrowing owls have been bred and released. It is important to remember, however, that the habitat has to be suitable and the cause for the birds' decline has to be mitigated before captive breeding and release programs can be successful.

Species accounts

List of Species

Eurasian scops-owl

Otus scops

subfamily

Striginae, Tribe Otini

taxonomy

Strix scops Linnaeus, 1758 Italy. Six subspecies are recognized.

other common names

English: European scops-owl, common scops-owl; French: Petit-duc scops; German: Zwergohreule; Spanish: Autillo Europeo.

physical characteristics

6.3–7.9 in (16–20 cm); 2.1–4.8 oz (60–135 g). Both gray-brown and rufous-brown color phases occur. Head features a gray facial disc, darker around the yellow eyes, and small ear tufts. Upperparts are gray-brown to rufous-brown with dark streaks, bars, and lines. Underparts are lighter brown to buffish white with dark streaks, bars, and lines. Buffish white leg feathers and gray feet.

distribution

France, and all Mediterranean countries to northern Turkey; Volga River east and to Lower Baikal, Altai and Tien Shan; Iberia, Balearic Islands and North Africa; southern Asia Minor, Jordan and Israel and onto northwest Pakistan.

habitat

Prefers open, rather than dense, woodland, including woodland parks in towns, plantations, and scrubland.

behavior

Northern birds are mostly migratory, while the southern birds are more sedentary. Migratory birds travel to Africa to winter. This owl is largely nocturnal, but occasionally is active during the day.

feeding ecology and diet

Mainly insectivorous; crickets and grasshoppers form much of its diet. Prey is taken by a short pounce from a perch or sometimes these owls will run after prey on the ground.

reproductive biology

Nests in cavities, using tree cavities or holes in walls and old buildings. Lays two to six eggs. Incubation is generally 24–25 days. Young fledge at about 30 days and are cared for by their parents for about five weeks.

conservation status

Not globally threatened, or considered rare. Locally common in parts of its range.

significance to humans

None known.

Seychelles scops-owl

Otus insularis

subfamily

Striginae, Tribe Otini

taxonomy

Gymnoscops insularis Tristam, 1880, Mahé Island, Seychelles. Monotypic.

other common names

English: Bare-legged scops-owl; French: Petit-duc scieur; German: Seychelleneule; Spanish: Autillo de Seychelles.

physical characteristics

7.9 in (20 cm). Weights not given. Overall color is yellowish brown or rufous. Head features minute ear tufts and the legs are bare.

distribution

Mahé Island in Seychelles

habitat

Secondary forest on upper slopes and in valleys at elevations of 820–1, 969 ft (250–600 m), usually close to water.

behavior

Strictly nocturnal. Very little else is known.

feeding ecology and diet

Insects, tree frogs, and lizards.

reproductive biology

Almost nothing known, but this owl is suspected of nesting in crevices and cavities in rocks on the ground. It may lay only one egg.

conservation status

Critically Endangered. The extremely small population (estimated at 180–360 as of 2000) remains threatened by habitat destruction for housing development and forest clearance for agriculture and by introduced predators (e.g., rats, cats, etc.). Morne Seychellois National Park encompasses much of the highland forest where this species occurs.

significance to humans

None known.

Eastern screech-owl

Otus asio

subfamily

Striginae, Tribe Otini

taxonomy

Strix asio Linnaeus, 1758, South Carolina. Six subspecies are recognized.

other common names

English: Common screech-owl; French: Petit-duc maculé; German: Ostkreischeule; Spanish: Autillo Yanqui.

physical characteristics

6.3–9.8 in (16–25 cm). Female, 6.8 oz (194 g). Male, 5.9 oz (166 g). As with many scops-owls, there are two different color phases—a brown phase and a gray phase. Its erect ear tufts can be flattened to give the head a rounded appearance. This is probably the best known small owl in eastern North America.

distribution

Southern central and eastern Canada to Florida and northeastern Mexico.

habitat

Forest and woodlands.

behavior

Sedentary. Hunts in open woodland probably to avoid detection by other predators. Mostly nocturnal, but also hunts at dawn and dusk and, occasionally, during the day.

feeding ecology and diet

Insects, worms, crayfish, small birds, and rodents. Makes straight perch-to-prey strikes and also hunts on the ground.

reproductive biology

Cavity nester; prefers holes in trees. Clutch size is usually three to four, but may be as many as seven. Incubation is at least 26 days. Young fledge in 25–27 days, but remain dependent on the parents for eight to 10 weeks.

conservation status

Not globally threatened; numbers decrease when forests are cleared.

significance to humans

None known.

Southern white-faced owl

Ptilopsis granti

subfamily

Striginae, Tribe Otini

taxonomy

Pisorhina leucotis granti Kollibay, 1910, Namibia. Until recently this bird was placed in the genus Otus. It is very closely related, but was shown to be different by molecular biology; it has larger eyes than Otus species. Monotypic.

other common names

English: White-faced scops-owl, white-faced owl; French: Petit-duc de Grant; German: Südbüscheleule; Spanish: Autillo Cariblanco Sureño.

physical characteristics

8.7–9.4 in (22–24 cm). Female, 4.4–9.7 oz (125–275 g). Male, 6.5–7.8 oz (185–220 g). Head features long ear tufts, a whitish facial disc with a black rim, and orange-red to red eyes. Upperparts are darker gray with black markings. Underparts are lighter gray with thin dark streaks and lines.

distribution

Africa from equator on down.

habitat

Savanna, open woodlands, and forest edges.

behavior

Sedentary, although it can be nomadic in drier parts of its range.

feeding ecology and diet

Large insects, small mammals, birds, and reptiles. Will hunt from perches including telegraph poles and even street lamps.

reproductive biology

Uses old nests of other birds, such as pigeons, or nests in a cavity in a tree or branch. Lays two to three eggs. Incubation is 30–32 days. Young leave nest at four weeks.

conservation status

Not globally threatened. Reasonably common in most of its range as of 2002.

significance to humans

None known.

Great horned owl

Bubo virginianus

subfamily

Striginae, Tribe Bubonini

taxonomy

Strix virginiana J.F. Gmelin, 1788, Virginia. Twelve races are tentatively identified.

other common names

French: Grand-duc d'Amérique; German: Virginiauhu; Spanish: Búho Americano.

physical characteristics

20–23.6 in (51–60 cm). Female, 2.2–5.5 lb (1,000–2, 500 g). Male, 1.5–3.2 lb (680–1, 450 g). A large, powerful owl with a rust-colored facial disc, large, erect ear tufts, yellow eyes, and a white chin and throat. Upperparts are grayish to gray-brown,

mottled and barred. Underparts are brownish with a reddish tinge, also mottled. The fully feathered legs and feet are buff to tawny.

distribution

Alaska to Hudson Bay through the United States, Mexico, and Central America; in South American from Colombia to the Guianas, Bolivia to northeastern Brazil and south to east-central Argentina.

habitat

Every type of woodland, farmland, desert with scrub, mountainous areas, mangroves, and urban areas.

behavior

Mainly resident and territorial. Makes deep hooting calls to announce its presence. Hunts mostly at dusk or during the night, occasionally during the day.

feeding ecology and diet

Still hunts from a perch; makes shallow, gliding drops to its prey; very rapacious. Takes a huge variety of prey including birds as large geese, mammals (up to 90% of its diet), fish, snakes, insects, and even other owls.

reproductive biology

Utilizes old nests of other large birds, or nests in hollows in trees and, sometimes, in caves or among tree roots. The breeding season varies from December to July because of this owl's wide range. It tends to breed earlier than other owls in the same locality. Lays one to three eggs. Incubation is 28–30 days. Young remain in the nest for 35–45 days and are cared for by their parents for up to five months.

conservation status

Not globally threatened. It is a very common owl throughout its range.

significance to humans

None known.

Eurasian eagle-owl

Bubo bubo

subfamily

Striginae, Tribe Bubonini

taxonomy

Strix bubo Linnaeus, 1758, Sweden. Fourteen subspecies are recognized.

other common names

English: Common, great, or northern eagle-owl; French: Grand-duc d'Europe; German: Uhu; Spanish: Búho Real.

physical characteristics

23.6–29.5 in (60–75 cm). Female, 2.2–5.5 lb (1, 750–4, 200 g). Male, 1.5–3.2 lb (1, 500–2, 800 g). The largest owl, it is almost barrel-shaped. It has prominent, erect ear tufts, golden to orange eyes, and a powerful, black beak. Legs and feet are fully feathered. The subspecies vary in size, overall color, and intensity of dark markings.

distribution

Europe from Spain to northern Norway and Finland on through Asia to Pacific, south to Iraq and Iran, Pakistan, and China.

habitat

The Eurasian eagle-owl is less able to cope with human habitation than its United States counterpart the great horned owl. It is found in more inaccessible areas—rocky terrains, wilderness, forests and woodlands, and rocky farmlands.

behavior

This owl is territorial and mainly sedentary except in the very north of its range. It is primarily nocturnal, but is sometimes active at dawn and dusk as well. At the northern edge of its range, this owl is active during the day in summer.

feeding ecology and diet

Feeds mainly on mammals from voles to hares (hedgehogs are important in some areas), birds up to pheasant size, and occasionally diurnal birds of prey. It usually hunts from an open perch.

reproductive biology

Often nests in rocky crevices and caves; will use old birds' nests, but seems to prefer the ground. Lays two to four eggs. Incubation is 34–36 days. Young fledge at 10 weeks. An average of 1.6 young are produced per successful nest.

conservation status

Not globally threatened, but uncommon to rare throughout its range.

significance to humans

None known

Barred eagle-owl

Bubo sumatranus

subfamily

Striginae, Tribe Bubonini

taxonomy

Strix sumatrana Raffles, 1822, Sumatra. Two subspecies are recognized.

other common names

English: Malay eagle-owl, Malaysian eagle-owl; French: Grand-duc bruyant; German: Malaienuhu; Spanish: Búho Malayo.

physical characteristics

15.7–18.1 in (40–46 cm). This owl has a whitish face, dark brown, outward-directed ear tufts marked with white, and brown eyes. Upperparts are dark brown barred with rufous buff. Underparts are grayish white barred with brown. Beak and feet are yellow.

distribution

Southern Myanmar, peninsular Thailand, south to Sumatra and Bangka Island.

habitat

Evergreen and semi-evergreen forests, plantations, and even wooded gardens.

behavior

Sedentary; territorial in nest area; nocturnal and crepuscular.

feeding ecology and diet

Large insects, small mammals, snakes, and small birds. Still hunter from a perch.

reproductive biology

Usually lays one egg either in a large cavity or in and old hawk's nest. Incubation and fledging periods are not known.

conservation status

Not globally threatened, this owl is reasonably common and adaptable.

significance to humans

None known.

Blakiston's eagle-owl

Bubo blakistoni

subfamily

Striginae, Tribe Bubonini

taxonomy

Bubo blakistoni Seebolm, 1884, Japan. Four subspecies are recognized.

other common names

English: Blakiston's fish-owl; French: Grand-duc Blakiston; German: Riesenfischuhu; Spanish: Búho Manchú.

physical characteristics

23.6–28.3 in (60–72 cm). One of the world's largest owls, it has a pale gray-brown facial disc, broad, horizontal ear tufts, yellow-orange eyes, and a white throat. Upperparts are buff-brown with darker streaks. Underparts are lighter buff-brown with thin, darker streaks. The legs are feathered almost to the base of the dark gray-brown toes.

distribution

Western Manchuria, eastern Siberia, far northeast China, Sakhalin Island, Hokkaido, and southern Kuril Islands.

habitat

Dense forests along rivers and sometimes on sea coast.

behavior

Sedentary. Highly territorial. Forages mainly at night or at dusk, but sometimes during the day.

feeding ecology and diet

Primarily fish, but also crustaceans, frogs, birds, and small mammals. Relies on areas of clear, slower moving water to hunt. Takes prey from a perched position or even wading in the water.

reproductive biology

Nests in large holes in trees and broken branches, and also sometimes on the ground in tree roots or cavities. Normally lays two eggs. Incubation is 35–37 days. Young leave the nest

at 35–40 days, but remain with their parents for several months.

conservation status

Endangered. One of the world's rarest owls, its population has declined precipitously since the 1950s. Major threats include habitat destruction due to riverside development and deforestation. Depletion of the fish on which it depends for food (due to overfishing) also has a negative impact on the species. Attempts at captive breeding have been unsuccessful.

significance to humans

None known.

Snowy owl

Nyctea scandiaca

subfamily

Striginae, Tribe Bubonini

taxonomy

Strix scandiaca Linnaeus, 1758, Lappland. Monotypic.

other common names

English: Snow owl; French: Harfang des neiges; German Schnee-Eule; Spansih: Búho Nival.

physical characteristics

21.7–27.6 in (55–70 cm). Female, 1.7–6.5 lb (780–2, 950 g). Male, 1.5–5.5 lb (700–2, 500 g). Heavy-bodied white owl with a large head, no ear tufts, yellow eyes, and a blackish beak nearly concealed by feathers. Males may have sparse gray or brown spots and bars. Females have more prominent dark barring, both above and below. Legs and feet are feathered.

distribution

Arctic Circle.

habitat

Open, treeless tundra and moorlands.

behavior

Migratory and nomadic; movements probably due to fluctuations in prey populations. It is most active at dawn and dusk; forages during the day in summer.

feeding ecology and diet

Lemmings and voles form the bulk of its diet, however, it also preys on birds (up to size of ptarmigan), mammals (up to the size of snowshoe hares), and fish. Hunts from a perch; usually captures prey on the ground after a low, gliding flight from the perch.

reproductive biology

A ground nesting species that lays later in the year as spring comes later. Clutch size normally is three to five eggs, but up to 11 eggs may be laid in a year when vole or lemming populations are high. Incubation is 31–33 days. Young leave the nest at 20–28 days, but do not fly well until about 50 days.

conservation status

Not globally threatened. Status of North American populations appears stable, but European populations may be declining.

significance to humans

None known.

Asian brown wood-owl

Strix leptogrammica

subfamily

Striginae, Tribe Strigini

taxonomy

Strix leptogrammica Temminck, 1831, Borneo. Fourteen subspecies are recognized.

other common names

English: Himalayan brown Owl, Himalayan wood-owl, Bartel's wood-owl, Malaysian wood-owl; French: Chouette leptogramme; German: Malaienkauz; Spanish: Cárabo Oriental.

physical characteristics

15.7–21.7 in (40–55 cm). 17.6–24 oz (500–700 g). The owl has a whitish to light brown facial disc, brown eyes surrounded by a black band, a brown chin, and a white throat. Upperparts are

lighter chestnut brown with some white or light bars on the shoulders, wings, and tail. Underparts are white to buff with fine brown bars (leptogrammica means finely barred stomach). Legs are feathered.

distribution

Forested areas on the west and east of India, Himalayas through to the coast of China, most of southeastern Asia including Sri Lanka, southern Thailand, Malay Peninsula, Borneo.

habitat

Thick, undisturbed forests both evergreen and deciduous.

behavior

Sedentary; like most of the wood-owls it is very nocturnal and secretive.

feeding ecology and diet

Small mammals, birds (up to the size of pheasants), fruit bats, reptiles, and some insects. Still hunting from perch.

reproductive biology

Nests in tree cavities, caves, and sometimes on cliff ledges. Lays two eggs. Incubation is 30–33 days.

conservation status

Not globally threatened. Suffers from deforestation, but is secure in national parks and protected areas throughout its range.

significance to humans

None known.

Tawny owl

Strix aluco

subfamily

Striginae, Tribe Strigini

taxonomy

Strix aluco Linnaeus, 1758, Sweden. Eleven subspecies are recognized.

other common names

English: Eurasian tawny owl, Eurasian wood-owl, tawny wood-owl, brown owl; French: Chouette hulotte; German: Waldkauz; Spanish: Cárabo Común.

physical characteristics

14.6–15.4 in (37–39 cm). Female, 19.5 oz (553 g). Male, 15.5 oz (440 g). Medium-sized, stocky owl with a large, round head and blackish brown eyes. Overall color varies from brown to rufous to gray with intermediates between these hues. Upperparts are mottled with darker streaks. Underparts are paler, also dark streaked with variable thin bars. Legs and most of the gray toes are feathered.

distribution

Great Britain except for Ireland, southern Scandinavia to North Africa through the Middle East to western Iran; Pakistan, northwest India, Nepal to southeast China and northern Indochina, Korea, and Taiwan.

habitat

Open forests and woodlands, farmland with woods, parks, urban areas with parks and gardens.

behavior

Sedentary. This is a very vocal owl with wide range of calls. Chiefly nocturnal.

feeding ecology and diet

Wide variety of prey, including mammals (up to the size of squirrels and small rabbits), birds (up to the size of pigeons), amphibians, reptiles, insects, and occasionally fish. It has been known to take smaller owls. Still hunts from a perch; most prey is located by sound.

reproductive biology

Generally nests in cavities, but will use old magpie nests. Mates for life. Usually lays three to five eggs, but has been known to lay up to nine. Incubation is 28–30 days. Normally two young are reared. Young fledge in 32–37 days and are independent about three months after fledging.

conservation status

Not globally threatened. Common throughout its range.

significance to humans

None known.

Spectacled owl

Pulsatrix perspicillata

subfamily

Striginae, Tribe Strigini

taxonomy

Strix perspicillata Latham, 1790, Cayenne. Six subspecies are recognized.

other common names

French: Chouette à lunettes; German: Brillenkauz; Spanish: Lechuzón de Anteojos.

physical characteristics

16.9–20.5 in (43–52 cm). 1.3–2.75 lb (590–1, 250 g). A largish owl, it has a brown facial disc, white eyebrows and lores, and yellow eyes. Head and neck are very dark blackish brown and the throat is white. The rest of the upperparts are dark brown with gray-brown bands on the flight feathers and tail. Underparts are buff with a brown breast band. Legs and toes are feathered.

distribution

Central America through to northeast Argentina; not found in high Andes.

habitat

Tropical and dry forests, scattered trees, coffee plantations, and forested streams.

behavior

Sedentary. Nocturnal. Very vocal.

feeding ecology and diet

Mainly vertebrates, including mammals (up to the size of skunks), bats, birds, frogs, and lizards. Also takes crabs and crayfish. Hunts from a perch.

reproductive biology

Cavity nester. Lays two eggs, but usually only one young survives. The chick leaves the nest in five to six weeks, but remains with the parents for up to a year after fledging. Juveniles take one to three years to develop adult plumage.

conservation status

Not globally threatened. Fairly common where it is found.

significance to humans

None known.

Northern hawk-owl

Surnia ulula

subfamily

Surninae, Tribe Surniini

taxonomy

Strix ulula Linnaeus, 1758, Sweden. Three subspecies are recognized.

other common names

English: Hawk owl; French: Chouette épervière; German: Sperbereule; Spanish: Cárabo Gavilán.

physical characteristics

14.2–15.4 in (36–39 cm). Female, 11.3–12.2 oz (320–345 g). Male, 9.5–11.3 oz (270–320 g). This owl has a broad head, a whitish facial disc bordered with a broad black band, and yellow eyes. Upperparts are dark brownish black with white spotting. Underparts are whitish with heavy chocolate brown bars. The long tail is barred, and the legs and feet are covered with white feathers.

distribution

Alaska through Canada to Newfoundland; Scandinavia through to eastern China.

habitat

Northern forests up to the tree line, forest steppes, and some farmlands.

behavior

Nomadic; follows the abundance of prey species. Will winter in open land and use farm haystacks as hunting perches. Diurnal and nocturnal.

feeding ecology and diet

Prey consists of small mammals (including voles, lemmings, and even young hares), birds, insects, and amphibians. Hunts from a perch; will take birds from the air; hovers well; will take prey under snow, locating it by sound alone.

reproductive biology

Nests in tree cavities or on the tops of broken stumps. Lays six to ten eggs, up to thirteen in good vole years. Incubation is 25–30 days. Young fledge at 25–35 days. Parents will try to distract predators by disabled display to draw attention away from young. Young become independent at about 75 days.

conservation status

Not globally threatened. As with many of the species reliant on fluctuations in prey numbers, this owl's numbers rise and fall accordingly.

significance to humans

None known.

Pearl-spotted owlet

Glaucidium perlatum

subfamily

Surninae, Tribe Surniini

taxonomy

Strix perlatum Vieillot, 1817, Senegal. Two subspecies are recognized.

other common names

English: Pearl-spotted owl; French: Chevêchette perlée; German: Perlkauz; Spanish: Mochelo Perlado.

physical characteristics

6.7–7.9 in (17–20 cm). Female, 2.2–5.2 oz (61–147 g). Male, 1.3–3 oz (36–86 g). A small owl with a cinnamon head, whitish facial disc, white eyebrows, and yellow eyes. Upperparts are cinnamon with white spots; flight feathers are dark brown with reddish bars. Underparts are white with broad brown streaks. The longish tail is brown with incomplete white bars.

distribution

Gambia to Sudan, Ethiopia, Uganda to north and east South Africa, Angola, and Namibia.

habitat

Bushveld, open and dense woodlands, and grasslands.

behavior

Sedentary. Territorial throughout the year. An energetic hunter that takes prey considerably larger than itself at times. Hunts chiefly at night, but is the most diurnal African owl, especially in winter. False white "eye" patches on backs of wings may act as a deterrent to predators.

feeding ecology and diet

Many insects, arthropods, small mammals, birds (up to the size of doves), lizards, and bats. Hunts from perch and will chase birds in flight.

reproductive biology

Cavity nester, especially using old nests of barbets or woodpeckers. Normally lays three eggs. Incubation is about 29 days. Usually rears one or two young. Young fledge in about 31 days.

conservation status

Not globally threatened. Widespread and locally common.

significance to humans

None known.

Burrowing owl

Athene cunicularia

subfamily

Surninae, Tribe Surniini

taxonomy

Strix cunicularia Molina, 1782, Chile. Nineteen subspecies are recognized.

other common names

French: Chevêche des terriers; German: Kaninchenkauz; Spanish: Mochelo de Madriguera.

physical characteristics

7.5–9.8 in (19–25 cm). Female, 4.2–8.8 oz (120–250 g). Male, 4.6–6.5 oz (130–185 g). This owl has a round head with an oval, buff to white facial ruff, yellow eyes, and a white chin and throat. Upperparts are brown with buff to white spots on the crown of the head, back, and shoulders. Underparts are buff to white with brown bars. The tail is short and the long legs are covered with white to buff feathers.

distribution

Southwest Canada to El Salvador, Florida, Bahamas, Cuba, and Isle of Pines; Venezuela, Colombia, Ecuador, Bolivia, southern Brazil to Tierra del Fuego.

habitat

Arid, dry, open plains, deserts, savanna, farmlands, roadsides, and golf courses.

behavior

Very active during the day. Lives in loose colonies. Sentries give alarm calls if predators are seen. Uses burrows for roosting and hiding as well as breeding. Northern races migrate south, southern races are sedentary.

feeding ecology and diet

Mainly insects, also small mammals and small birds. Hunts on the ground, running and hopping after insects. Also will hover over tall grass cover and will take prey in flight on occasion.

reproductive biology

Nests underground; will dig its own burrow or use the burrow of ground-dwelling mammals. Lays six to 11 eggs. Incubation is 28–30 days. Young fledge after about 44 days. First breeding at one year of age.

conservation status

Not globally threatened, although listed as Endangered in some northern United States and some Canadian provinces. Declining over some parts of its range and expanding over others.

significance to humans

None known.

Northern saw-whet owl

Aegolius acadicus

subfamily

Surniinae, Tribe Aegoliini

taxonomy

Strix acadica J.F. Gmelin, 1788, Nova Scotia. Two subspecies are recognized.

other common names

English: Saw-whet owl, Queen Charlotte owl; French: Petite Nyctale; German: Sägekauz; Spanish: Mochuelo Cabezón.

physical characteristics

7.1–8.7 in (18–22 cm). Female, 3.5 oz (100 g). Male, 2.6 oz (75g). One of the smallest owls, it has a large, round head with a buff to brownish facial disc, white eyebrows, and a white patch between the yellow to golden eyes. Forehead and crown of head are brown with white streaks. Upperparts are brown with white or buff spots on the nape of the neck, shoulders, and wing-coverts. Underparts are white tinged with buff and spotted or streaked with reddish brown. The short legs are heavily feathered to the talons.

distribution

Southern Alaska to southern United States through to eastern Canada down to northern Florida. Also a strip through the highlands of California and Mexico.

habitat

Forests; typically prefers coniferous forests.

behavior

Nocturnal, but occasionally may forage during the day. Migrates south to winter, although some birds are present in the breeding range all year round. The call of the male during mating season sounds like a saw being sharpened, giving the species its common name.

feeding ecology and diet

Mainly small mammals, especially mice and voles, some small birds, and insects. Hunts from a perch; locates prey using acute hearing and low-light vision.

reproductive biology

Nests in cavities, such as old woodpecker holes. Lays five to seven eggs. Incubation is 27–29 days. There is some evidence of polyandry in good vole years.

conservation status

Not globally threatened. Populations are stable, but vulnerable to reduction with loss of habitat.

significance to humans

None known.

Southern boobook owl

Ninox boobook

subfamily

Surniinae, Tribe Ninoxini

taxonomy

Strix boobook Latham, 1801, Sydney area, New South Wales. Tentatively, ten subspecies are recognized.

other common names

English: Boobook owl, streaked boobook, northern boobook, Australian boobook, red boobook, dark boobook owl; French: Ninoxe d'Australie; German: Boobookkauz; Spanish: Nìnox Australiano.

physical characteristics

9.8–14.2 in (25–36 cm). Female, 11.1 oz (315 g). Male, 8.8 oz (250 g). This owl takes its name for its most common call, a repeated double hoot that sounds like "boo-book." It has a round head with an indistinct facial disc, white eyebrows, and eyes that vary in color from yellow to hazel. Upperparts are dark brown with white spots. Underparts are whitish with reddish brown streaks and spots.

distribution

Australia, southern New Guinea, Roti, Timor, Alor, Let, Moa, Babar, and Kai Islands.

habitat

Very varied habitat, including dry and wet forests, semi-arid deserts, and farmlands.

behavior

Mainly sedentary. The most southern races may winter farther north. Largely nocturnal, but partly crepuscular.

feeding ecology and diet

Mainly insectivorous, but also takes small birds, mammals, reptiles, and bats, especially during the breeding season. Hunts from a perch in forest clearings and edges.

reproductive biology

Nests in cavities, both natural and in man-made structures. Lays three to five eggs. Incubation is about 30 days. Chicks fledge at about five weeks. Young stay with parents for up to three months after fledging.

conservation status

Not globally threatened. Widespread and generally common throughout most of its range, but vulnerable to habitat destruction that destroys preferred nesting sites in tree hollows.

significance to humans

None known.

Short-eared owl

Asio flammeus

subfamily

Asioninae

taxonomy

Strix flammea Pontoppidan, 1763, Denmark. Ten subspecies are recognized.

other common names

French: Hibou des marais; German: Sumpfohreule; Spanish: Búho Campestre.

physical characteristics

14.6–15.4 in (37–39 cm). Female, 9.9–17.6 oz (280–500 g). Male, 7.1–15.9 oz (200–450 g). Huge range gives wide differences in size. A medium-sized owl with a large, round head and very small ear tufts that are hard to see. Round, grayish white facial disc, white chin, and white, brown, and buff facial ruff and forehead. The yellow eyes are surrounded by black. Upperparts are brown and buff. Underparts are whitish to pale buff with vertical streaks. Large, buff wing patches on the upper

wings and dark wrist markings on the underwings. Feet and legs are whitish buff.

distribution

Canada and United States; northeast Venezuela, Guyana, Colombia, Ecuador, southern Peru, west-central Bolivia, Paraguay, and southeastern Brazil to Tierra del Fuego; Iceland, England, Europe below the tree line through Asia to Russia and China. Winters in India, Southeast Asia, southern China, and parts of Africa.

habitat

Marsh lands and grasslands, open areas, tundra, and moorland.

behavior

Diurnal, crepuscular, and nocturnal. Very migratory. These birds are seen throughout the year in the southern part of the breeding range, although they may not be the same birds. Breeding areas are reliant on a good prey base. This owl will winter in groups and roost on the ground or in low trees.

feeding ecology and diet

One of the most aerial hunters, its light wing-loading allows this owl to hunt by quartering the ground in low-level flight seeking prey. Preys on small mammals, including mice, voles, shrews, moles and even young rabbits and hares; also small birds less frequently.

reproductive biology

Males display to females with dramatic flights, aerobatics, and clapping of wings. This owl nests on the ground in cover— grasses, heather, reeds; some line the nest with grass and feathers, making this one of the very few owls to attempt any form of nest building. Lays five to 10 eggs. Increased clutch sizes in vole and lemming years. Incubation is 26–29 days. Young leave the nest before they can fly at about 12–18 days and hide in vegetation.

conservation status

Not globally threatened, but probably declining slowly due to drainage of wetlands, human encroachment and disturbance. This owl occurs in a number of protected areas throughout its range.

significance to humans

None known.

Resources

Books

Burton, John, A. Owls of the World. Rev. ed. London: Peter Lowe, 1992.

del Hoyo, Josep, Andrew Elliott, and Jordi Sargatal. Handbook of the Birds of the World. Vol. 5, Barn-owls to Hummingbirds. Barcelona: Lynx Edicions, 1999.

Eckert, Allan W. The Owls of North America. New York: Doubleday, 1974.

Hume, Rob, and T. Boyer. Owls of the World. Limpsfield, UK: Dragon's World, 1991.

Johnsgard, Paul A. North American Owls. Biology and Natural History. Washington, DC: Smithsonian Institution Press, 1988.

Mikkola, Heimo. Owls of Europe. Calton, UK: Poyser, 1983.

Monroe, Burt L., and Charles G. Sibley. A World Checklist of Birds. New Haven, CT: Yale University Press, 1993.

Nero, Robert W. The Great Gray Owl, Phantom of the Northern Forest. Washington, DC: Smithsonian Institution, 1980.

Parry-Jones, J. Understanding Owls. Newton Abbott, UK: David and Charles, 1998.

Poole, Alan, and Frank Gill, eds. The Birds of North America. "Snowy Owl," No. 10 (1992); "Great Gray Owl," No. 41 (1993); "Northern Saw-whet Owl," No. 42 (1993); "Burrowing Owl," No. 61 (1993); "Short-eared Owl," No. 62 (1993); "Boreal Owl." No. 63 (1993); "Flamulated Owl." No. 93 (1994); "Long-eared Owl," No. 133 (1994); "Eastern Screech Owl," No. 165 (1995); "Spotted Owl," No. 179 (1995); "Northern Hawk Owl," No. 356 (1998); "Great Horned Owl," No. 372 (1998). Philadelphia: Academy of Natural Sciences and American Ornithologists' Union, 1993–1998.

Sterry, Paul. Owls: A Portrait of the Animal World. Leicester, UK: Magna Books, 1995.

Tarboton, Warwick, and Rudy Erasmus. Owls and Owling in Southern Africa. Cape Town: Struik Publishers, 1998.

Voous, Karel H. Owls of the Northern Hemisphere. London: Collins, 1988.

Weinstein, Krystyna. The Owl in Art, Myth and Legend. New York: Crescent Books, 1998.

Jemima Parry-Jones, MBE

Christine Jeryan, MLS