The Children's Book of Birds

by Olive Thorne Miller

Birds' eyes also are of many colors. Besides our common black, brown, blue, and gray, birds have light and dark green, bright red, pale and deep yellow and orange, even white.

They have, like us, two eyelids. But while we use the upper one to close our eyes, most birds use the lower one. They have also a third eyelid, inside the others, a thin, white sort of skin, that moves across the eye from side to side, and is called the "nictitating membrane."

There are other ways in which birds' eyes differ from ours. The men who try to know exactly how birds are made have found out that birds' eyes make everything look much larger than it is, in other words, they are like magnifying glasses, or microscopes, so that a tiny insect egg, that we can hardly see, looks very big to a warbler.

Stranger still, when a bird is far off, his eyes are like telescopes. That is, when a hawk is soaring about far above the earth, he can see a mouse on the ground as well as if he had a telescope to look through. And the gulls who sail about over the shore, and follow steamers on sea voyages, can see small fish and tiny bits of bread thrown out by the passengers, even when they are lost to us in the foam made by the vessel.

Mr. Frank Bolles had a pet barred owl, and used to take him out with him. He says that the bird's sight was wonderful, better than his own aided by a strong glass. Many times the bird would see and watch a hawk so far off that Mr. Bolles with his glass could not see him until he came nearer, and then he looked no bigger than a dot against the sky.

There is a story told of some small birds migrating over the island of Heligoland, suddenly coming down in a flock on to a man's garden, and beginning at once to work among the leaves as if they were feeding.

The owner of the garden knew they did not eat leaves, so he shot a few and found them stuffed with small caterpillars. Then he looked at the plants and found many more caterpillars, each in the curled-up end of a leaf. The insects could not be seen, yet the birds, while flying over, no doubt saw the curled leaves and knew they were there.

Such eyes must be of great use in helping birds to find their food, and to avoid their enemies. But think what giants we must look to them! It is no wonder they are afraid of us.

Perhaps even more useful to a bird than his eyes are his ears, though they are so nicely covered up by the feathers that we cannot see them. The tufts of feathers that stand up on some owls' heads, and are called ears, are not ears at all, but merely decorations, like the crests of some birds and the long tail feathers of others.

But because they cannot be seen, we must not think birds have no ears; they have very good ones indeed. They can hear much better than we can.