Their plumage is streaked with diversely-arranged markings, and is quite as soft and delicate as the down of fledglings. These peculiarities are probably owing to the special conditions of their existence. Constantly deprived as they are of the rays of the sun, the action of which upon colour of plumage cannot be doubted, they are not arrayed in those splendid hues which clothe diurnal birds of tropical regions.
Owing to the structure and nature of their feathers, nocturnal birds of prey fly without making the least noise. They can, therefore, pounce unawares on their victims, seizing them before they have any idea of necessity for escape. When they lay hold of their prey it is immediately devoured—an easy matter on account of the enormous expansion of their bills. Their stomach afterwards separates the indigestible parts, such as bones, hair, and feathers, and when these are rolled together in the shape of a ball or pellet, they are ejected by vomiting. Diurnal birds of prey which subsist on living animals possess the same power.
With the exception of the Barn Owl, nocturnal birds of prey all lay eggs of a spherical shape. They live in couples, only assembling in flocks at the epoch of migration; they never, however, hunt in common. They do not build any nest, but deposit their eggs in cavities in old trunks of trees or ruined habitations. They exhale a disagreeable and unwholesome smell, which is no doubt owing to their exclusively animal diet.
A nocturnal bird of prey, unless forced, never comes out of its lurking-place during day. When compelled by circumstances to do so, it is assailed by all the Passerines of the neighbourhood, which resent its intrusion, and avenge the oppression exercised over them during the night, by combined attacks. It places itself in the strangest postures, ruffles up its feathers, and balances its head with a stupid look, making its bill crack, when so assaulted. It does not, however, try to defend itself, and passively receives the blows of its feathered enemies, which do it but little harm. This natural antipathy of small birds for their nocturnal destroyers has been taken advantage of for purposes of sport. The method of catching birds by calling is founded upon it. Imitating the voice of an Owl, the birds flock together and perch on the trees or bushes in the suspected neighbourhood, where twigs covered with birdlime have been abundantly scattered. This operation must take place about an hour before sunset; if later, it would not be successful. This way of catching birds was in use in the days of antiquity, for Aristotle has given us a description of it.
The Owl has given rise to more fables and prejudices than any living creature, doubtless in consequence of its peculiarities. Although inoffensive in general, and even useful—for they destroy a large quantity of rats and mice—in the rural districts nocturnal birds of prey have occasioned so much superstition and terror, that they have been hunted down with the utmost animosity.
The Greeks dedicated the Owl to Minerva, the goddess of wisdom, no doubt on account of the calm and grave attitude which distinguishes it, and gives it the air of a philosopher meditating on the problems of life.
Mr. Swainson divides Owls into three groups—namely, Typical Owls, Horned Owls, and Hawk Owls; for simplicity and brevity we prefer making only two families—namely, those with horns and those without.
Horned Owls.
Horned Owls are distinguished by two tufts or horns of feathers placed on each side of their head. They are subdivided into three genera—the Great Horned Owls, the Long-eared Owls, and Small Horned Owls.
The Common Great Owl (Bubo maximus), [Fig. 274], is the most remarkable of the family on account of its size and strength. Its height is, on an average, two feet, and it is justly acknowledged as the king of nocturnal birds. Its bill and claws are of a black colour, very strong and hooked. Its plumage is russet, variegated with black spots and brown stripes; its wings, when extended, are not less than five feet across. Its eyes are large and fixed, with black pupils surrounded with yellow. It bears light with less inconvenience than the other nocturnal birds, and therefore goes out sooner in the evening and returns home later in the morning. This bird makes its home among the clefts of rocks, or in the recesses of old towers situated on the mountains, which elevated ground it but rarely leaves to descend into the plain. Its cry, huibou, houhou, bouhou, ouhou, resounding in the silence of the night, is a source of terror to those animals which form its prey. It feeds principally upon hares, rabbits, moles, rats, and mice. Now and then, and especially when rearing its young, which are very voracious, it devours toads, frogs, and small reptiles.