BmDS. 307 



They again appear in the fields of Pisa, regularly about the 

 twentieth of February, to anticipate the spring. 



In these journeys, it is amazing to conceive the heights to 

 which they ascend when they fly. Their note is the loudest of 

 all other birds ; and that is often heard in the clouds, when the 

 bird itself is entirely unseen. As it is light for its size, and 

 spreads a large expanse of wing, it is capable of floating at the 

 greatest height, where the air is lightest ; and as it secures its 

 safety, and is entirely out of the reach of man, it flies in tracts 

 which would be too fatiguing for any other birds to move for- 

 ward in. 



In these aerial journeys, though unseen themselves, they ha\e 

 the distinctest vision of every object below. They govern and 

 direct their flight by their cries ; and exhort each other to pro- 

 ceed or to descend, when a fit opportunity offers for depredation. 

 Their voice, as was observed, is the loudest of all the feathered 

 tribe ; and its peculiar clangour arises from the very extraordinary 

 fength and contortion of the windpipe. In quadrupeds, the 

 windpipe is short, and the glottis, or cartilages that form the 

 voice, are at that end of it which is next the mouth ; in water- 

 fowl, the windpipe is longer, but the cartihiges that form the 

 voice are at the other end, which lies down in their belly. By 

 this means they have much louder voices, in proportion to their 

 size, than any other animal whatever ; for the note when formed 

 below, is reverberated through all the rings of the windpipe, till 

 it reaches the air. But the voice of the duck or the goose, is 

 nothing to be compared to that of the crane, whose windpipe is 

 not only made in the same manner with theirs, but is above 

 twenty times as long. Nature seems to have bestowed much 

 pains in lengthening out this organ. From the outside, it enters 

 through the flesh into the breast-bone, which hath a great cavity 

 within to receive it. There being thrice reflected, it goes out 

 again at the same hole, and so turns down to the lungs, and thus 

 enters the body a second time. The loud clangorous sound 

 which the bird is thus enabled to produce, is, when near, almost 

 deafening : however, it is particularly serviceable to the animal 

 itself, eitlier during its migrations, or its stay ; by it the flock is 

 encouraged in their journeys ; and if, while tiiey are feeding, 

 which is usually performed in j)rofouiid silence, they are invaded 



