LESSON XXVIII.
THE BIRD.
ON THE WING.
ON THE WING.
A bird is an animal which comes from an egg, wears feathers, and is built for flying. Even the few birds which run, and do not fly, are all built on the general plan of flyers.
An egg was described in lesson seven of this book. All of you have seen plenty of eggs. The eggs of birds are usually hatched by the mother-bird sitting upon them for a certain number of days, or weeks, and keeping them warm with her body.Some few birds, as the ostrich, hide their eggs in the sand to be hatched by sun heat. One or two other kinds of birds hide their eggs in earth or leaves.
I shall tell you of only a few things about the bird’s body. I wish to tell you just enough about birds to interest you, so that you will try to learn more about them.
The first thing for you to notice about the body of the bird is, that it is built for lightness. The bones are thin, and most of them are hollow. Your bones, and the bones of four-legged animals, are either solid, or hollow and filled in the centre with marrow. But the bird’s bones are made to give it the greatest possible size, with the least possible weight.
Not only are the bird’s bones hollow, but it is able to send warm air from its lungs through them. Thus they not only do not weigh the bird down, but really help to keep it up in the air.
The bird has more bones in its neck than men or beasts have. The bird’s neck is long, and bends easily. Its head and neck divide the air before it as it flies. Even birds which look short-necked have really more bones in the back of the neck than you have. They owe the short look to the feathers.
The body of the bird is built on theboat plan. It is an air-boat. Its breast-bone serves as a keel. It is placed low down, and is large and sharp. In very strong, flying birds, as the eagle, this keel is very large. To this are fastened the many strong muscles which move the wings. The few birds which do not fly, as the ostrich and penguin, have the breast-bone flattened or “raft-shape.”
The ribs of the bird form a large, light, boat-shaped frame. Its tail is made of a number of backbone pieces, crowded close together. This tail moves easily, and serves the bird as a rudder, to steer and steady its way through the air.
If you strip all the meat off a chicken’s wing-bones, you will see a kind of a rude pattern of a man’s arm and hand, with a thumb and two fingers. The length of the wing usually depends on the length of the upper wing-bone. But in humming-birds and swifts, the lower part of the wing is the longer.
In some birds, the wing, when spread out, is much longer than all the body. The wing folds up, something like a crab’s claw, or as you would shut a knife. In birds that are walkers, and not flyers, the first wing-bone is short. The penguin, which never flies, has a little short wing, which looks like a hand, without any arm.
Now, we come to the bird’s legs. In your leg, the thigh-bone, the one from the hip to the knee, is the longest. In birds, it is the shortest. Even in very long-legged birds, as the stork, the thigh-bone is short. The length comes in the bone from the knee to the foot.
Thus, when the bird flies, its large, hollow, air-filled thigh-bone is drawn up to the body, and the lower part of the leg is held backward, and does not hinder the flight.
The foot of most birds has four toes. But some, as the ostrich, have less. I shall talk to you about feet in the next lesson.
The first thing you notice about the bird’s head is the beak. I shall tell you about beaks, also, in the next lesson. Now, I shall only say, that the beak is the horny, outer end of the jaw-bone. Birds never have any teeth. The beak often forms the larger part of the bird’s head. The head is small for the body, and nearly flat on top.
When you see a bird with two things like horns on its head, as some owls have, do not think that they are either horns or ears. Birds have no horns. These things are only feather head-dresses. Birds have ears, but the ear-hole is hidden under the feathers. Birds have very keen sight, very keenpower of smell.[24]They have loud, clear voices. Many of them have very sweet voices. I suppose they have as good a sense of taste as we have. I notice that parrots like sugar and cake, and many birds like fruit.
What do birds have instead of teeth? They have inside of the body a gizzard. It is part of the stomach. It is so made that it can grind up the food as teeth would. Some birds swallow bits of shell and gravel, which help the grinding.
The food goes into a bag called a crop. From the crop it goes to the gizzard, where it is ground. Mother birds feed their very young birds with food which has been softened in this way.
When you look at a bird, you will first of all notice the feathers. They are its clothing, and help it in flying. Next to the body grows a soft down. There are patches on the body where only down grows. These spots, bare of feathers, give room for the play or motion of the larger feathers. Such spots do not show, as the over-lapping of the large and small feathers covers them.
The tail and wing feathers are the largest. The quill part of the feather is hollow. You cannot movethe hairs on your head. The bird can move its feathers, and turns the large ones flat or sideways, as it changes its flight. The smaller feathers are called coverts. They are laid on one close over the other. They are chiefly for clothes, as the large ones are chiefly for flying.
Many birds have splendid feathers. Have you seen the great train of a peacock? But the peacock is not a bird that flies much. His tail would hinder him in the air. All he can do in flying is to rise to a roof or the limb of a tree. Some other birds have one or two long gay tail plumes which do not hinder their flight.
When the little bird is first hatched it has no feathers. Have you seen the wee chicks, just out of the shell? They are dressed in down. What fluffy balls they are!
Peep into the robin’s nest, and see the nearly naked birds. They have for clothes only a few long hairs. Do not touch them. Do not go when the mother bird is there. But peep in each day, and watch how the feathers grow. Or, you can watch feathers grow on your baby canary. They grow very fast.
When first the robins begin to fly, notice that their feathers are not quite like those of the old bird.The young robin’s breast is spotted, not plain red. His feathers lie loosely. He looks puffy. Birds moult or cast their coats. They drop their feathers in hot weather. This gives them a chance to change old broken feathers for new ones. They get warm new coats for winter. They do not drop all the feathers at once. But some feathers go and some come, until the moult is over.
Most birds have some little bags of oil in their skin, on the back part of their bodies. They can press the oil out of these bags with their bills. Have you ever watched birds preening, or dressing themselves? They are spreading this oil over their feathers to keep them soft and clean.
Birds are very lovely creatures. They have graceful, elegant shapes, eyes bright like jewels, and very fine bright colors. They are also very wonderful in their ways. And many of them are very useful.
FOOTNOTES:[24]Some naturalists deny that birds have the sense of smell to any degree, but experiments with blind birds seem to prove that this sense is well developed.
[24]Some naturalists deny that birds have the sense of smell to any degree, but experiments with blind birds seem to prove that this sense is well developed.
[24]Some naturalists deny that birds have the sense of smell to any degree, but experiments with blind birds seem to prove that this sense is well developed.