s motionless upon the
leaves; this sense needs to be as sharp as that of smell in hounds and
pointers; and yet I know an unkempt youth that seldom fails to see the
bird and shoot it before it takes wing. I think he sees it as soon as it
sees him and before it suspects itself seen. What a training to the eye
is hunting! To pick out the game from its surroundings, the grouse
from the leaves, the gray squirrel from the mossy oak limb it hugs so
closely, the red fox from the ruddy or brown or gray field, the rabbit
from the stubble, or the white hare from the snow requires the best
powers of this sense. A woodchuck, motionless in the fields or upon
a rock, looks very much like a large stone or bowlder, yet a keen eye
knows the difference at a glance, a quarter of a mile away.

A man has a sharper eye than a dog, or a fox, or than any of the wild
creatures, but not so sharp an ear or nose. But in the birds he finds
his match. How quickly the old turkey discovers the hawk, a mere speck
against the sky, and how quickly the hawk discovers you if you happen to
be secreted in the bushes or behind the fence near which he alights!
One advantage the bird surely has, and that is, owing to the form,
structure, and position of the eye, it has a much larger field of
vision--indeed, can probably see in nearly every direction at the same
instant, behind as well as before. Man's field of vision embraces less
than half a circle horizontally, and still less vertically; his brow and
brain prevent him from seeing within many degrees of the zenith without
a movement of the head; the bird on the other hand, takes in nearly the
whole sphere at a glance.

I find I see almost without effort nearly every bird within sight in the
field or wood I pass through (a flit of the wing, a flirt of the tail
are enough, though the flickering leaves do all conspire to hide them),
and that with like ease the birds see me, though, unquestionably, the
chances are immensely in their favor. The eye sees what it has the means
of seeing, truly. You must have the bird in your heart before you can
find it in the bush. The eye must have purpose and aim. No one ever yet
found the walking fern who did not have the walking fern in his mind. A
person whose eye is full of Indian relics picks them up in every field
he walks through.

One season I was interested in the tree-frogs; especially the tiny piper
that one hears about the woods and brushy fields--the hyla of the swam