110 THE SENSES 



me, at a distance of about fifty yards, turned his head instantly in response 

 to the slightest 'squeak' made to test its hearing. The same sound 

 will often turn a passing Hawk when he might be thought to be beyond 

 its reach. The snapping of the smallest twig throws a whole Heron 

 colony into wildest commotion. Woodpeckers locate the grubs of 

 boring beetles, and Robins apparently listen for crawling worms. 



That birds not only have incredibly acute hearing, but can also 

 distinguish minor differences in sound, is implied by the wide range 

 of sounds which birds themselves produce and which, in the economy 

 of their lives, are obviously not intended to fall on deaf or inappre- 

 ciative ears; as other writers have before remarked. 



A colony of Roseate Spoonbills which I have lately studied from a 

 blind, were not alarmed by various noises made in manipulating a 

 camera, but at a single word, spoken in a low voice, every bird sprang 

 into the air. 



White Egrets, in Florida, have acquired so great a fear of a gun that 

 the birds of a rookery in which my blind was placed left their nests 

 with a rush at the faint report of a gun fired by a guide a mile and a 

 half away. 



Crows immediately respond to an imitation of the call of the Barred 

 Owl, and though this may be uttered but once, they come from some 

 distance directly to the spot whence the hoot proceeded. 



In default of definite experiments, it is on casual observations of this 

 nature that our knowledge of the comparative power of a bird's hearing is 

 based. There is much need for further data here. 



With eyes, the relation between cause and action is more apparent, 

 and without knowing exactly how well a bird can see, we have at least 

 seen enough to be impressed by its marvelous power of vision. Recall 

 a quietly observant Loggerhead Shrike leaving its lookout and flying 

 so directly to a grasshopper in the grass a hundred feet away, that it is 

 clear the insect was seen before starting; or again, Gulls and Petrels 

 picking up small bits of food from waves so boisterous that a man 

 would be lost to sight in them. "Observe," says Coues ('Key,' 5th Ed., 

 p. 185), "an Eagle soaring aloft until he seems to us but a speck in 

 the blue expanse. He is far-sighted; and scanning the earth below, 

 descries an object much smaller than himself, which would be in- 

 visible to us at that distance. He prepares to pounce upon his quarry; 

 in the moment required for the deadly plunge, he becomes near-sighted, 

 sHzes his victim with unerring aim, and sees well how to complete the 

 bloody work begun. A Hummingbird darts so quickly that our eyes 

 cannot follow him, yet instantaneously settles as light as a feather 

 upon a tiny twig. How far off it was, when first perceived, we do not 

 know; but in the intervening fraction of a second the twig has rushed 

 into the focus of distinct vision, from many yards away. A Woodcock 

 tears through the thickest cover as if it were clear space, avoiding 

 every obstacle. The only things to the accurate perception of which 

 birds' eyes appear not to have accommodated themselves are tele- 



