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. Reécall 
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, 
seizes 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- 
