292 CASSELL S BOOK OF BIRDS. 



immovable, and somewhat compressed at its sides. The margins of the beak are not only very sharp, 

 but are frequently rendered more terrible by the presence of a tooth-like projection from the upper 

 mandible, which fits into a corresponding excavation in the lower jaw. In such species as are without 

 this tooth-shaped appendage the margins of the upper mandible are waved and trenchant, distinctly 

 indicating their carnivorous propensities. The feet are massive and strong, the toes long in proportion 

 to the size of the tarsi, and very motile ; both legs and feet are covered with scale-like plates, and the 

 toes furnished with claws or talons, which arc either curved and sharp or comparatively straight, but in 

 both cases rounded above and channelled beneath in such a manner that the lower part of each claw 

 presents two distinct shaq:> margins. The plumage is generally soft, and formed of large feathers, 

 which are either thick, small, and firm, or broad, soft, and silky, or even woolly in their texture. The 

 bridles, a place between the base of the beak and the eye, and the eye itself are frequently entirely 

 naked, whilst, on the contrary, some members of this group are distinguished by a circle of radiating 

 feathers surrounding the orbit. The quills that form the wings and tail are always of considerable size, 

 and their number in most species is pretty nearly the same — that is to say, ten primaries, and at least 

 twelve or at most sixteen secondaries, form the wings ; the tail is composed almost invariably of 

 twelve quills, which appear placed, as it were, in pairs. In some races the feathers cover not only 

 the tarsi, but even the toes, where they are distinguished by the name of hose, a term that will be 

 frequently employed in our descriptions of the birds with which we are about to deal. The plumage 

 of the Raptorcs is usually dingy and sombre in its hues, though some few species exhibit con- 

 siderable beauty of appearance, and the bare places on the head, the comb, wattles, bridles, cere, 

 beak, feet, and eyes are occasionally brightly coloured. The internal construction of these birds is on 

 a par with their external configuration ; the skeleton is strong, and the sternum so large as to extend 

 over the whole of the fore part of the breast ; the keel is high, the bones of the wings comparatively 

 long, and those of the legs powerfully developed. The bones of the entire skeleton are for the most 

 part without marrow, and thus admit of the entrance of air, received from the large lungs and air-cells 

 which extend throughout the body. The gullet is very dilatable, and is usually enlarged into a crop. 



As we have said in our introductory chapter, the sight of the Raptores is very acute, and their 

 eye adapts itself with remarkable facility to varying distances ; and if any of our readers have tried the 

 experiment of holding their hands alternately close to and at some distance from the eye of a Falcon, 

 they have no doubt been astonished at witnessing the extraordinary dilations and contractions of 

 which the pupil is capable. In some species the sense of hearing is also good, and we shall shortly 

 have fully to describe the high degree of excellence observable in the structure of the ear of an Owl ; 

 their sense of smell, on the contrary, is by no means keen, and that of touch scarcely more acute or 

 reliable. All Birds of Prey are remarkable for great courage, and exhibit such cruelty, rapacity, and 

 running as cannot fail to render them terrible foes to all creatures weaker than themselves. In their 

 relations to each other, on the contrary, the different species exhibit great affection ; they combine 

 readily in the defence of their companions, and do battle for them with the utmost devotion. To what 

 perfection the intelligence of the Birds of Prey has been brought will be seen in our description of 

 some of the services rendered to our forefathers by the Falcons. As regards their voices, few species 

 are capable of uttering more than two or three harsh and unpleasing notes. 



All parts of the world afford everything that is necessary to the existence of these predatory 

 races ; they are as much at their ease upon beds of ice such as environ Greenland or Spitzbergen 

 as upon the glowing sands of an African desert ; they sweep over continents, and exhibit the 

 utmost indifference whether they alight upon the gigantic trees of a primitive forest or upon the 

 steeples of a densely populated city. As winter approaches, such of these winged freebooters 

 as inhabit northern regions wander south, returning in the spring to their native haunts, each bird 



