378 FORM OF THE BILL. 



even on putrid carrion. Their feet sometimes serve for the 

 prehension of their food, but the beak is always the principal 

 organ employed for this purpose ; its form varies according to 

 the nature of the food, and according to the more or less 

 carnivorous regimen of these animals; and hence it furnishes 

 the zoologist with excellent characters for classification. A solid 

 horny substance, more or less hard, covers it externally, and 

 renders its edge sharp ; but it is never armed with true teeth ; 

 hence mastication is very incomplete, and in general there is none 

 whatever. In Birds that live on flesh, and require to tear their 

 prey, Falcons, Eagles, Vultures, for instance, the upper man- 

 dible is very short, very strong, hooked at the extremity, and 

 terminated by a sharp point; sometimes its edges are more or 

 less dentated (or toothed), 

 which makes it a more 

 powerful weapon ; and we 

 may judge the habits of 

 these Birds to be more or 

 less rapacious, according 

 to the degree in which it 

 possesses these characters. 

 Thus the Falcon is, of all 



Birds Of Prey, that whose FlG - 192 BKAK OF JKB FALCON. 



beak is the shortest, most curved, dentated, and strong, in 

 proportion to its size; it is also the most intrepid hunter. 

 While the Kite, which scarcely differs from the Falcon, except 

 in having a weaker beak, less hooked, and not dentated on the 

 edges, as well as less powerful claws, is naturally a coward ; 

 and the Vulture, whose beak is still more elongated, and con- 

 sequently weaker, does not even attack living animals, but feeds 

 on dead bodies. ^Sea Birds, which feed on the flesh of fish too 

 large to be swallowed at a mouthful, are equally remarkable for 

 their thick and hooked beak (Fig. 193); but it is more 

 elongated than in Birds of Prey, and consequently less powerful. 

 When Birds that feed on Fish, seek only fishes and reptiles 

 small enough to be seized and swallowed with facility, the beak 

 becomes straight, is still more elongated, and resembles a long 



