236 FACULTIES OF BIRDS. 



In consequence of the rapidity with which birds 

 traverse the air, extent and acuteness of vision ap- 

 pear to be indispensable, in order to direct them in 

 their flight. Had they, indeed, been formed with 

 eyes like the mole (Talpa lucida, C. BONAPARTE), 

 incapable of seeing more than a few inches' dis- 

 tance, they would have been in constant danger of 

 dashing against every intervening obstacle. " In- 

 deed," says Buffon, " we may consider the celerity 

 with which an animal moves as a just indication of 

 the perfection of its vision. A bird, for instance, 

 that shoots swiftly through the air, must undoubt- 

 edly see better than one which slowly describes 

 a tortuous tract. Among quadrupeds, again, the 

 sloths have a very limited sight." It may accord- 

 ingly be inferred, that birds have more precise ideas 

 than slow-moving caterpillars, of motion and its ac- 

 companying circumstances, such as those of rela- 

 tive velocity, extent of country, the proportional 

 height of eminences, and the various inequalities 

 of hill and dale, mountain and valley. 



The eye of birds, it is worthy of remark, besides 

 being peculiar in structure, is also greatly larger 

 than in most other animals in proportion to the 

 bulk of the head. 



The mere bulk of the eye, however, is rather a 

 fallacious test to trust to; for several birds, in 

 which the globe of the eye is large, have very weak 

 sight, particularly in the daytime, such as the wood- 

 cock and the owls. The woodcock (Scolopax Gal- 

 linago, RAY) has very large, prominent eyes, but 

 it cannot support a strong light, and sees best du- 

 ring twilight ; and, as Colonel Montagu remarks, its 

 eyes seem to be peculiarly calculated for collect- 

 ing the faint rays of light in the darkened vales and 

 sequestered woodlands during nocturnal excursions, 

 thus enabling it to avoid trees and other obstacles. 

 It is probable, indeed, that the proverbial stupidity 

 of the bird arises from this weakness of sight. 



