A bird's wing does not look much like our arm and hand, yet the bones show that they are the same. The bird has a shoulder, elbow, and wrist, as we have. He even has fingers, though they are so covered up by feathers that one would never know it. He has not so many fingers as we have, and they are not movable like ours.

A bird's wing is a wonderful flying-machine, which men have been trying to imitate these many years. It is made of long stiff feathers, which fold down smoothly over one another at his side when he is resting, but can spread in an instant into a broad fan, to beat the air and carry him away.

One would not think that feathers could have so much power; but when the wing is spread, the barbs of the feathers hook together with tiny hooks, so small a microscope is needed to see them; and that, together with the edges lapping over each other, makes them almost like one solid surface.

Wings are not alike in shape. The wing of a swallow is long and narrow, while that of a hen or grouse is short and round. We can tell by the shape of a wing how a bird flies.

A long, narrow, pointed wing shows that the bird has an easy, skimming flight,—either he flies great distances, or spends hours at a time on wing (Fig 11).

The short round wing (Fig 12) shows that a bird has a strong flight for short distances. These wings are found mostly on rather heavy birds, like grouse.

The longest wings are seen on water birds, such as the petrel and the frigate-bird. The shortest, also, are found among water birds, those who swim more than they fly, as the auks.

All the feathers of the wing are named, and it will be well to remember that the long stiff quills are called remiges or "rowers." These are firmly rooted in the flesh, and are the hardest to pull out. They are the most important to the safety of the bird.

Birds have also another use for their wings. They are a strong weapon to defend themselves, or to fight others. A large bird can give a severe blow with his wing, and when pigeons fight, it is said they hold up one wing to protect themselves while they strike at the enemy with the other.

Sometimes wings serve as musical instruments. Woodcocks make whistling sounds with their wings as they fly, and mourning doves softly murmuring ones. Ruffed grouse produce with theirs a rolling drum-like effect, and others rattle theirs like castanets.

If wings are not used, they slowly get to be smaller and weaker, each generation having them more and more useless, till after a while they are of no use whatever, and the birds cannot fly at all. This has happened, it is supposed, to the ostrich family and to some birds living in the sea.

The tail of a bird is formed of an equal number of feathers in pairs, most often twelve. When spread they are the shape of a fan (Fig 13), and when closed they lie over each other with the middle pair on top.

The tail feathers are not always of the same length, and that makes a difference in the shape of the end. Sometimes they are even (like Fig. 14), when the tail is said to be "square." Sometimes the middle feathers are a little longer than the outside ones, and then it is "rounded" or "pointed." If the outside feathers are longest, the tail is "forked" (Fig 15).

The feathers of the tail are called rectrices, or "rudders," because they are supposed to be used to steer, or direct the bird's course in flying. But the tail is used also as a brake to check the speed in alighting.

The tail is used more than any other organ to express the emotions. Some birds, like the catbird and thrasher, keep it moving nearly all the time, jerking it this way and that, and tossing it upward.

In woodpeckers and swifts the tail feathers are not soft at the end like others, but the stems or shafts project beyond the feathery part, and are stiff like the tail of a sapsucker (Fig 16) or sharp like this of the chimney swift (Fig. 17). These birds use the tail as a prop to hold them against the tree trunk or chimney wall, and to help them in climbing.

Tail feathers are not so strongly rooted as wing feathers, and are easily pulled out. Sometimes, when a man or boy tries to catch a bird by the tail, the bird will escape, leaving the tail in his hand.