BIRDS' FACULTY OF SIGHT 121 



Birds are entirely dependent on their senses 

 of sight and hearing ; these faculties, therefore, 

 are highly developed and, in many cases, 

 specialized, as may be seen in the owl-tribe. 

 The eyes of birds who feed and fly at night 

 (Scolopacidae, plovers, nightjars, etc.) are 

 specially adapted, as also birds who obtain 

 their food under water (cormorants, divers, 

 grebes and others) . On inspection the eyes of 

 these water-birds are seen to be curiously 

 modified to suit the density of the element in 

 which they function. 



The faculty of sight is all-important to birds, 

 and it is this class (Aves) alone which is exempt 

 from blindness in any degree. Truly, it may 

 be said, the eyes of the bird are the windows 

 of its soul. This, I beheve, is practically the 

 case, namely, that the bird's vision includes 

 an all-round view, a fact that renders any 

 attempt to " put salt on its tail " a futile 

 undertaking. But, I question whether from 

 the bird's point of view there is an angle of 

 parallax — ^which is to say, that a bird is 

 incapable of visuahzing an object with both 

 eyes at the same time. Obviously, this would 

 be unnecessary to a creature that only requires 

 to see, not to concentrate. 



That birds such as woodcock, snipe et hoc 

 genus, can see all round without turning the 



