Citizen Bird Part 3

"You are right, my boy," said the Doctor, looking at him attentively; "and would you also like to know how this beautiful boat is made? If a ship-builder could plan a vessel that would go through wind and water as birds do, he would be the wisest man in the world. But you see, Rap, a man did _not_ plan any bird.

"I will go down and ask your mother to let you come and hear the stories with the other children--how would you like that, Rap?"

"Will you? Will you really let me come? Oh, I am so glad! I know mother'll let me any day but Monday and Thursday, because I have to watch clothes on those days."

"Wash clothes?" said Dodo in surprise.

"No, watch them," replied Rap, laughing. "Those two days the miller lets mother spread her things to whiten in his big meadow, and I have to watch and see that they are not stolen or don't blow away."

"Isn't it very stupid to sit there so long?"

"Oh, no, it's lovely; for there are lots of birds and things about."

"To-morrow will be Wednesday," said the Doctor. "Come up to Orchard Farm by nine o'clock, Rap, and we will begin our lessons with this little White-throated Sparrow Nat has found."

"And uncle!" cried Dodo, "you must make inch measures on our middle fingers with violet ink, the way you did to Olive's when she was little."

CHAPTER IV

THE BUILDING OF A BIRD

It rained on Wednesday--a warm spring rain, swelling the rivers and ponds, and watering the newly planted garden; but discouraging the birds in their nest-building, and disappointing Nat and Dodo, who wished to have their lesson in the orchard.

"Come in here, children," said the Doctor. "The wonder room, as Dodo calls it, is a good place for a talk about feathers and bones, and the rest of the things birds are built of. I have sent for Rap, too, so that the trio may be complete."

"Feathers and bones for building birds?" said Nat. "What a queer idea for a bird story."

"Not a bird story exactly," answered the Doctor. "But some things are true of all birds, and you must know them if you wish to understand the _reason why_ of any bird in particular."

In a few minutes the three children were seated on the wide settle, with a cheery log fire, to make them forget the outside dampness. Quick, the fidgety little fox-terrier, sat by the hearth, watching a possible mouse hole; and Mr. Wolf, the tawny St. Bernard, chose the rug as a comfortable place for finishing his morning toilet.

Olive presently joined the group. The Doctor took the dead White-throated Sparrow from the table, and began to walk about the room, stopping now in front of the fire and then by the window.

"Here is a Sparrow, different from every other kind of Sparrow, different indeed from any other sort of bird in the world--else it would not be the particular sort of a Sparrow called the White-throated. But there are a good many things that it has in common with all other birds.

Can you tell me some of them?"

"I know!" said Dodo; "it has a good many feathers on it, and I guess all kinds of birds wear feathers, except some when they are very little in the nest."

"Quite right, little girl," said the Doctor. "Every bird has feathers, and no other animal has feathers. So we say, 'A bird is known by its feathers.' But what do you suppose its feathers are for?"

"To make it look nice and pretty," said Dodo promptly.

"To make it lighter, so's it can fly," added Nat.

"To keep it warm, too, I guess," was Rap's answer.

"Well, you are all three partly, but not quite, right. Certainly the beauty of a bird depends most on its feathers, being not even skin-deep, as you may well believe, if you ever noticed a chicken Mammy Bun had plucked. But, Nat, how can feathers make a bird lighter, when every one of them weighs something, and a bird has to carry them all? They make a bird a little heavier than it would be without them. Yet it is quite true that no bird could fly if you clipped its wings. So some of its feathers enable it to fly--the large ones, that grow on the wings. Then, too, the large ones that make the tail help the bird to fly, by acting like a rudder to steer with. Perhaps the small ones too, all over the body, are of some help in flight, because they make a bird smooth, so that it can cut through the air more easily--you know they all lie one way, pointing backward from their roots to their tips. Then when Rap said feathers keep a bird warm, he guessed right. Birds wear plumage as you do clothes, and for the same purpose--to look nice and keep warm."

"But what is 'plumage,' Uncle Roy?" asked Dodo; "I thought you were talking about feathers."

"So I was, missy. Feathers are the plumage, when you take them all together. But see here," added the Doctor, as he spread the Sparrow's wings out, and held them where the children could look closely; "are the wings all plumage, or is there something else?"

"Of course there's something else to wings," said Dodo; "meat and bones, because I've eaten chickens' wings."

"Why didn't you say, Dodo, because there has to be something for the feathers to stick into?" said Nat decidedly.

"You both have very good reasons," said the Doctor. "The plumage of the wings grows out from the skin, just as feathers grow from any other part of the body, only the large ones are fastened to the bones, so that they stay tight in their proper places. If they were loose, they would fly up when the bird beats the air with its wings, and get out of order. See how smoothly they lie one over another! When the bird closes its wings, they come together snugly along its sides. But when the wing is spread, they slide apart--yet not too far to form a broad, flat surface, quite stiff, but light and elastic. By beating the air with the wings birds fly along. It is something like rowing a boat. This surface pushes against the air as the flat blade of an oar pushes against the water.

That is why these large stiff feathers are called the rowers. When the Wise Men talk Latin among themselves, they say _remiges_, for 'remiges'

means rowers."

"But, Doctor," said Rap, who was looking sharply at the Sparrow's wing, "all the feathers are not like that. Here are a lot of little ones, in rows on top of the wing in front, and more like them underneath, covering over the roots of the rowing feathers. Have they any name?"

"Oh, yes! Everything you can see about a bird has its own name. Those small feathers are called _coverts_, because they cover over the roots of the rowers. Those on top are the upper coverts; those underneath are the under coverts, or lining of the wings. Now notice those two pretty bands of color across the Sparrow's wing. You see one band is formed by the tips of the longest coverts, and the other band by the tips of the next longest coverts. Those two rows of feathers are the greater and middle coverts, and all the smallest feathers, next to the front edge of the wing, are called lesser coverts. Now look at the tail, Rap, and tell me what you can find."

"Why, there is a bunch of long stiff feathers like rowers, that slide over each other when you spread the tail, and a lot of short feathers that hide the roots of the long ones. Are they rowers and coverts too?"

"A bird does not row with his tail--he steers with it, as if it were a rudder; and the long feathers are therefore called rudder-feathers--or _rectrices_, which is Latin for rudders. But the short ones are called coverts, like those of the wings--upper tail-coverts, and under tail-coverts."

"How funny!" said Dodo, "for a bird to have to row himself and steer himself all at once. I know I should get mixed up if I tried it with a boat. How do feathers grow, Uncle Roy?"

"Just like your hair, little girl," said the Doctor, patting her on the head, "or your nails. Didn't you ever notice the dots all over the skin of a chicken? Each dot is a little hole in the skin where a feather sprouts. It grows in a sheath that pushes out of the hole, like a plant coming up out of the ground from its root. For a while this sheath is full of blood to nourish the growing feather; that is why new feathers look dark and feel soft--pin-feathers they are called. The blood dries up when the feather has unfolded to its full size, leaving it light and dry, with a h.o.r.n.y part at the root that sticks in the hole where it grew, and a spray-like part that makes up most of the feather. The h.o.r.n.y part becomes hollow or contains only a little dry pith; when it is large enough, as in the case of a rowing feather from a Goose's wing, it makes a quill pen to write with. But the very tiniest feather on this Sparrow is built up in the same way.

"See! here is one," continued the Doctor, as he twitched out a feather from the Sparrow's back. "You see the quill part runs in the middle from one end to the other; this is called the _shaft_. On each side of it all along, except just at the root, the spray-like parts grow. They are called the _webs_ or _vanes_. Now look through this magnifying gla.s.s at the web."

The children looked in turn, and each, exclaimed in wonder at the sight.

"Yes, it is very wonderful. The web, that looks so smooth to the naked eye, is made up of a great many small shafts, called _barbs_, that grow out of the main shaft in rows. Every one of these small side-shafts has its own rows of still smaller shafts; and these again have little fringes along their edges, quite curly or like tiny hooks, that catch hold of the next row and hold fast. So the whole feather keeps its shape, though it seems so frail and delicate."

"Are all feathers like this one?" asked Rap.

"All are equally wonderful, and equally beautiful in construction; but there is a good deal of difference in the way the webs hold together.

Almost all feathers that come to the surface are smooth and firm, and there is not much difference except in size, or shape, or color. For example, the largest wing-feather or tail-feather of this Sparrow is quite like the one I pulled out of its back in texture, only the back-feather is smaller and not so stiff. But near the roots of these feathers you notice a fluffy part, where the webs do not hold together firmly. Some feathers are as fluffy as that in their whole length. Such are called down-feathers, because they are so downy. Birds that run about as soon as they are hatched are always clothed in down, like little chickens, before their other feathers sprout; and some birds, like Ducks, wear a warm underclothing of down their whole lives. Then again some feathers do not have any webs at all--only a slender shaft, as fine as a hair."

"Do feathers keep on growing all the time, like my hair?" asked Dodo.

"No, my dear. They stop growing as soon as they are of the right size; and you will find your hair will do the same, when it is long enough--though that won't be for a good many years yet, little girl.

When the blood that has fed the growing feather is all dried up, the feather ceases to grow. Then after a while longer, when it has become ragged and worn, it gets loose in the skin and drops out--as I am sorry to say some of my hair is doing already. That is what we call _moulting_."

"I know about that," interrupted Nat. "It's when hens shed their feathers. But I didn't know that it was moulting when people grow bald."

"It is very much the same thing," said the Doctor, "only we don't call it moulting when people lose their hair. But there is this difference.

Birds wear out their feathers much faster than we do our hair, and need a new suit at least once a year, sometimes oftener. All young birds get their first new clothes when the down is worn out. Old birds generally moult as soon as they have reared their broods, which in this country is late in summer or early in the fall. Many also moult again the following spring, when they put on their wedding dress; and one of the curious things about this change of plumage is, that the new feathers often come out quite unlike those that were cast off. So a bird may differ much in appearance at different seasons and ages--in fact, most birds do. The male also differs in many cases from the female, being more handsomely dressed than his mate."

"I don't think that's fair," said Dodo. "I shouldn't like Nat to have nicer clothes than I wear."