BIRDS IN GENERAL. 



discern its food from above with astonishing 

 sagacity. A hawk, for instance, perceives 

 a lark at a distance which neither men nor 

 dogs could spy ; a kite, from an almost im- 

 perceptible height in the clouds, darts down 

 on its prey with the most unerring aim. The 

 sight of birds, therefore, exceeds what we 

 know in most other animals, and excels them 

 both in strength and precision. 



All birds want the external ear standing 

 out from the head ; they are only furnished 

 with holes that convey sounds to the auditory 

 canal. It is true, indeed, that the horned 

 owl, and one or two more birds, seem to have 

 external ears ; but what bears that resem- 

 blance are only feathers sticking out on each 

 side of the head, but no way necessary to the 

 sense of hearing. It is probable, however, 

 that the feathers encompassing the ear-hole* 

 in birds, supply the defect of the exterior car, 

 and collect sounds to be transmitted to the in- 

 ternal sensory. The extreme delicacy of this 

 organ is easily proved by the readiness with 

 which birds learn tunes, or repeat words, and 

 the great exactness of their pronunciation. 



The sense of smelling seems not less vivid 

 in the generality of birds. Many of them 

 wind their prey at an immense distance, while 

 others are equally protected by this sense 

 against their insidious pursuers. In decoys, 

 where ducks are caught, the men who attend 

 them universally keep a piece of turf burning 

 near their mouths, upon which they breathe, 

 lest the fowl should smell them, and conse- 

 quently fly away. The universality of this 

 practice puts the necessity of it beyond a 

 doubt, and proves the extreme delicacy of the 

 sense of smelling, at least in this species of 

 the feathered creation. 



Next to the parts for flight, let us view the 

 legs and feet ministering to motion. They 

 are both made light, for the easier transporta- 

 tion through the air. The toes in some are 

 webbed, to fit them for the waters; in others 

 they are separate, for the better holding ob- 

 jects, or clinging to trees for safety. Such as 

 have long legs have also long necks, as other- 

 wise they would be incapable of gathering up 

 their food either by land or water. But it does 

 not hold, however, that those who have long 

 necks should have long legs, since we see that 

 swans and geese, whose necks are extremely 

 long, have very short legs, and these chiefly 

 employed in swimming. 



Thus every external part, hitherto noticed, 

 appears adapted to the life and situation of the 

 animal ; nor are the inward parts, though less 

 immediately appropriated to flight, less ne- 

 cessary to safety. The bones of every part 

 of the body are extremely light and thin ; and 

 all the muscles, except that immediately mov- 

 ing the wings, extremely slight and feeble. 



The tail, which is composed of quill feathers, 

 serves to counterbalance the head and neck ; 

 it guides the animal's flight, like a rudder, 

 and greatly assists it either in its ascent or 

 when descending. 



If we go on to examine birds internally, 

 we shall find the same wonderful conformation 

 fitting them for a life in air, and increasing 

 the surface by diminishing the solidity. In 

 the first place their lungs, which are common- 

 ly called the sole, stick fast tcr tire sides of the 

 ribs and back, and can be very little dilated 

 or contracted. But to make up for this, 

 which might impede their breathing, the ends 

 of the branches of the wind-pipe open into 

 them, while these have openings into the ca- 

 vity of the belly, and convey the air drawn 

 in by breathing into certain receptacles like 

 bladders, running along the length of the 

 whole body. Nor are these openings obscure, 

 or difficult to be discerned ; for a probe thrust 

 into the lungs of a fowl will easily find a pas- 

 sage into the belly ; and air blown into the 

 wind-pipe will be seen to distend the animal's 

 body like a bladder. In quadrupeds this pas- 

 sage is stopped by the midriff; but in fowls 

 the communication is obvious; and, conse- 

 quently, they have a much greater facility of 

 taking a long and large inspiration. It is 

 sometimes also seen that the wind-pipe makes 

 many convolutions within the body of a bird, 

 and it is then called the labyrinth ; but of 

 what use these convolutions are, or why the 

 wind-pipe should make so many turnings 

 within the body of some birds, is a difficulty 

 for which no naturalist has been able to ac- 

 count. 



This difference of the wind-pipe often ob- 

 tains in animals that, to all appearance, are of 

 the same species. Thus in the tame swan, 

 the wind-pipe makes but a straight passage 

 into the lungs ; while in the wild swan, which 

 to all external appearance seems the same 

 animal, the wind-pipe pierces through the 

 breast-bone, and there has several turnings 

 before it comes out again, and goes to enter 

 the lungs. It is not to form the voice that 

 these turnings are found, since the fowls that 

 are without them are vocal; and those, parti- 

 cularly the bird just now mentioned, that have 

 them, are silent. Whence, therefore, some 

 birds derive that loud and various modulation 

 in their warblings, is not easily to be account- 

 ed for ; at least the knife of the anatomist 

 goes but a short way in the investigation. 

 All we are certain of is, that birds have much 

 louder voices, in respect to their bulk, than 

 animals of any other kind ; for the bellowing 

 of an ox is not louder than the scream of a 

 peacock. 



In these particulars, birds pretty much re- 

 semble each other in their internal conibrma- 



