Their generic name sufficiently indicates that they live only by rapine, and are naturally plunderers and bloodthirsty. They correspond, in the class of Birds, with the Carnivora among Mammalia. Like them, they live on animals, either dead or living; like them, too, they possess the strength and adroitness which are necessary to satisfy their sanguinary appetites.
With her ever-admirable foresight Nature has wisely limited the reproduction of these destructive creatures—the largest only lay two eggs a year; the others, on an average, five or six. It is a singular thing that the female is often nearly a third bigger than the male; hence the name of "tarsel," given to the latter in certain species.
The Raptores present none of the grace and charming prattle of other races of birds. They enjoy no powers of song; their sole utterance consists either of harsh cries or strange and plaintive modulations. Their plumage, which is nearly always of a sombre colour, is sad and monotonous in its appearance. Destruction is the sole object of their existence; they are the terror of all the rest of the feathered creation, among which they every day make numerous victims. They live alone, or in couples, in the most deserted places; it is only exceptionally that they gather together in flocks, and then merely to devour in common some putrid carrion. They are of a despotic and combative temperament, and will not suffer any rivals in their neighbourhood. They practise absolutism in its strictest form, and reign as lords and masters in the districts which they choose for their territory.
The Raptores are met with over the whole surface of the globe; the larger species inhabit lofty mountains, or seek a hiding-place in the face of inaccessible and solitary cliffs.
This order is divided into two sub-orders, the Nocturnal and the Diurnal. This division is a very rational one, for it is founded on dissimilarity of habits, which is owing to a difference of organisation.
Nocturnal Birds or Prey.
Nocturnal birds of prey are distinguished by large staring eyes, directed straight in front, and surrounded by a circle of slender and stiff feathers, which, by their circular radiation round the face, form a nearly complete disk, to which the name of facial disk has been given; by the large development of their head; by very short bills, devoid of cere, which is replaced by a plain skin covered with hairs; by tarsi feathered down to the claws; by the mobility of the outside toe, which can be turned either forwards or backwards; by very strong, sharp, and retractile claws; by abundant and soft plumage; and by tails which are generally short.
But the original characteristic of these birds, and that which has contributed to their union in one group, is their inability to bear the light of mid-day, and the faculty they possess of being able to see in twilight, owing to the pupils of their eyes having enormous powers of dilation. They therefore remain hidden in their retreats while the sun is high, and do not begin to hunt until the luminary has approached the horizon, when they are able to distinguish with surprising clearness the objects on which they prey.
We are not, however, bound to believe that these birds can see in the midst of perfect darkness. When the night is thoroughly obscure they again become subject to the law common to all. The epithet of "nocturnal," which is applied to them, is, therefore, not strictly accurate, and must not be taken literally. They manifest the greatest amount of activity when the moon diffuses her light over the earth; then it is that they revel in their destructive instincts, levying a heavy tax on all weaker animal life.
The Raptores have the sense of hearing strongly developed, owing to the large cavities existing in their skulls, which communicate with the internal ear, and thus increase the capacity of this organ.