d nor young.

It takes an eye to see a partridge in the woods, 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 to 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 boulder, 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 t