OWL (AS. ule, OHG. uwila, ula, huwela, Ger. Eule, owl; probably onomatopoetic in origin). Any of a numerous and well-defined group of birds, the nocturnal birds of prey, constituting the Linnæan genus Strix, now the suborder Striges. Although they were formerly placed unhesitatingly in the order Raptores, of recent years there has been some tendency to separate them from the other birds of prey and place them near the nightjars, which they resemble to a remarkable degree. In appearance the owls are distinguished from all other birds by the large size of their heads and their great eyes, which are directed forward and surrounded by more or less perfect disks of feathers radiating outward and nearly hiding the small hooked bill. The claws are sharp and curved, but, like the bill, less powerful than in the Falconidæ. The outer toe is generally reversible at pleasure, so that the toes can be opposed two and two, to give greater security of grasp. The wings, although generally long, are less adapted for rapid and sustained flight than those of the diurnal birds of prey, and the bony framework by which they are supported, and the muscles which move them, are less powerful. The owls in general take their prey, not by pursuit, but by surprise, to which there is a beautiful adaptation in the softness of their plumage and their consequently noiseless flight, the feathers even of the wings being downy, and not offering as firm a resisting surface to the air as in falcons. The soft and loose plumage adds much to the apparent size of the body, and also of the head; but the head owes its really large size to cavities in the skull between its outer and inner ‘tables’ or bony layers, which cavities communicate with the ear. and are supposed to increase the sense of hearing. This sense is certainly very acute, and the ear is, in many of the species, very large, and has a concealed yet external conch, which is found in few other birds. The feathers immediately surrounding the ear are often arranged in a kind of cone, serving a purpose like that of an ear-trumpet. Owls can see well in twilight or moonlight, but poorly in the glare of the day. The eye itself is highly perfected, and the pupil remarkably contractile. The legs and feet of owls are usually feathered to the toes, and in many species even to the claws.
|Showing the position and external appearance of the ear of a great horned owl; also the filamentous feathers about the beak.|
|1. Section of the eye, showing the interior parts of the pecten at the insertion of the optic nerve (a) by which the vision is regulated under the great possible expansion and contraction of the eye. 2. Sclerotic coat, showing the stave-like pieces, connected by elastic tissue permitting great expansion and contraction.|
The digestive organs much resemble those of the Falconidæ, but there is no crop and the stomach is more muscular. The gullet is very wide throughout, and owls swallow their prey either entire or in very large morsels, the indigestible parts gathering into little lumps or ‘pellets,’ which are ejected after a time. These pellets are to be found numerously where owls roost or nestle, and their examination reveals the bird's bill of fare. The largest species feed on hares, fawns, and gallinaceous birds; others on small mammals, reptiles, birds, and large insects. Although they capture many small birds, mice form the principal element in their diet, and the owls are thus highly beneficial to agriculture, and should everywhere be protected and encouraged by farmers. Some owls also feed largely on fish (see Ketupa), crabs, and the like, which they catch for themselves.
The owl family (Strigidæ) falls into two divisions—the Striginæ and the Buboninæ, which are distinguished by differences in structure especially marked in the shoulder-girdle (consult Evans, Birds, New York, 1900). The former group is typified by the barn owl, the latter by our big barred or ‘cat’ owl. In size, owls vary greatly. The largest known species is the circumpolar gray owl (Syrnium or Scotiaptex nebulosum), from 27 to 28 inches long and more than 5 feet across the wings. The smallest known owl is the curious elf-owl (Micrathene Whitneyi) of Arizona, which is less than six inches long, and is further remarkable as having only 10 tail feathers; all other owls, so far as known, have 12. All owls have a general likeness in colors—a mixture of browns, whites, and yellows, as becomes nocturnal marauders who wish to remain unobserved, especially during the day when they are at rest. The Arctic owl becomes pure white in winter, but is brown in the summer plumage. There is little difference between the sexes, and the young, called ‘owlets’ or ‘howlets,’ resemble the adults. Owls are found in all parts of the world and in all climates, and rather more than 200 species are known. Of these 17 occur in North America, besides a dozen more or less recognizable subspecies; and about 15 species are natives of Europe. Some have a very wide geographical range, especially those of northern regions, and it is doubtful whether several species separately named in Europe and North America are really distinct, e.g. the barn-owl (q.v.). Another very widely distributed bird is the short-eared owl (Asio accipitrinus), which occurs in nearly all parts of the world. It is fifteen inches long, variegated tawny and dark brown, with short ear-tufts of few feathers. It is common in the United States, is somewhat migratory, and is occasionally seen in small flocks. A closely related species, rather more common generally, with long ear-tufts, is the American long-eared owl (Asio Wilsoniana). The hawk-owl, snowy owl, and great horned or eagle owl (qq.v.) are other handsome circumpolar species.
Other well-known American owls are the screech-owls (Megascops asio, with half a dozen subspecies). They are little owls, only nine to ten inches long, with ear-tufts, and are found in all parts of the United States and Canada. They are of special interest because of their remarkable dichromatism (q.v.), some of the birds having the prevailing tint gray, while others are rusty red. The barred owl, without ear-tufts, is a large species, also common throughout the United States. In the Southwestern States are found several species of little owls, which feed largely on insects, and are known as ‘gnome-owls’ and ‘elf-owls.’ They are only six or seven inches long and are not specially nocturnal. They belong to the genera Glaucidium and Micrathene. Another peculiar and interesting species is the burrowing owl (q.v.) of the Plains. It is not the only owl which inhabits holes in the ground. The boobook of Australia (Ninox boobook) is a species of owl, which frequently repeats during the night the cry represented by its name, as if it were a nocturnal cuckoo, as the inhabitants generally believe.
Of British species, one of the most common and familiar, and the one most often referred to in literature, is the ‘tawny,’ ‘brown,’ or ‘ivy’ owl (Syrnium aluco), which is of medium size, and mottled ash-gray and brown, with the under parts lighter. It inhabits church belfries, ruins, ivied walls, and like places, often in a semi-domestic condition. One of the best accounts of it (and of the next named species) is to be found in Charles Waterton's Essays. Another generally interesting species is the ‘little’ owl of Southern Europe, called ‘chevêche’ by the French and ‘civetta’ by the Italians, which is the one regarded by the ancients as the familiar of Minerva, a symbol of wisdom, and hence became the emblem of Athens. It is the Carine noctua of modern ornithology. This small species is brown, mottled with white oval spots, has no ‘horns,’ and its great eyes are surrounded by horizontally oval disks, like big spectacles, giving it a very ‘knowing’ expression. It is numerous, comparatively tame, and lives well in aviaries.
|1. LITTLE OWL of Europe (Carine noctua); symbol of Pallas Athene.||4. GREAT HORNED OWL (Bubo Virginianus); type of Eagle Owls.|
|2. HAWK OWL (Surnia ulula).||5. BARN OWL (Strix flammea).|
|3. BARRED OWL (Syrnium, or Scotiaptex nebulosum).||6. BURROWING OWL (Speotyto cunicularia).|
The owl has from early times been deemed a bird of evil omen, and has been an object of dislike and dread to the superstitious. This is perhaps partly to be ascribed to the manner with which it is often seen, then as suddenly lost to view, when the twilight is deepening into night; partly to the fact that some of the best known ones frequent ruined buildings, while others haunt the deepest solitudes of woods; but, no doubt, chiefly to the cry of some of the species, hollow and lugubrious, but loud and startling, heard during the hours of darkness, and often by the lonely wanderer. It is evidently from this cry that the word ‘owl’ is derived, as well as many of its synonyms in other languages, and of the names appropriated in different countries to particular species, in most of which the sound oo or ow is predominant. Nevertheless the notes of some of the smaller ones, as our common American ‘mottled owl,’ are low and melodious—a pleasant rippling ululation. Many of the owls have also another and very different cry, which has gained for more than one of them the appellation ‘screech-owl,’ and to which, probably, the Latin name strix and some other names are to be referred. The superstitions concerning owls persist and belong to savage as well as to civilized peoples. The folk-lore of the uncivilized world is full of such notions. European peasants connect the birds with death-signs; the Andalusians say they are the Devil's birds and drink the oil from the lamps in saints' shrines; and the Malagasy consider them embodiments of the spirits of the wicked. Even the birds and squirrels of the woods mob the owl unmercifully when one is discovered dozing in its retreat; but this is merely in recognition of a natural enemy taken at a disadvantage.
Bibliography. See standard ornithologies and faunal works, especially Newton, Dictionary of Birds (New York, 1893), and Evans, Birds (New York, 1900). For North America, consult the writings of Wilson, Audubon, Nuttall, Coues, and recent ornithologists, especially Fisher, Hawks and Owls of the United States (Washington, 1893). For superstitions, etc., consult: Brehm, Naturgeschichte der Vögel Deutschlands (Ilmenau, 1831; trans. into English as Bird Life, London, 1874); De Gubernatis, Zoölogical Mythology (London, 1872); De Kay, Bird Gods (New York, 1898); and authorities cited under Folk-Lore.