This book also gives interesting details about the hornbill, and how and why he walls up his mate in her nest in the hollow of a tree. Father Hornbill, of course, gets all the meals for Mother Hornbill, while she's setting. She simply _can't_ get out, and you should see him by the time the babies are old enough to leave the nest. He's worn to a shadow!

Rooks, it seems, do a little digging under certain circ.u.mstances.

Selous tells about it in his "Bird Life Glimpses." In this book you will find a delightful description of martins building. It almost makes you want to _be_ a martin. It also tells about the work of the sand martins. You will hardly believe how fast they work. The house-martin's nest is more elaborate than the swallow's. This book tells why the house-martins begin work so early in the morning, and why they have to delay their nest-building if the weather is either too wet or too dry.

White, in his famous "Natural History of Selbourne," tells how worried he was because certain swallows just _would_ build facing southeast and southwest.

Birds, besides being workers of the soil, are great sowers of seeds. Darwin tells how he reared eighty seedlings from a single little clod on a bird's foot. What do you suppose he did that for?

You just look it up in the index to his "Origin of Species."

Doesn't it seem funny that one of the little farmer birds--a burrower--should go into partnership with a lizard? There is one in New Zealand that does that very thing. He is called the t.i.ti. What the t.i.ti does for the lizard is to provide him with a home in his burrow, but what do you suppose the lizard does in return to pay for his lodging? Read about it in Ingersoll's "Wit of the Wild," in the chapter on "Animal Partnerships."

Do you know why the phoebe bird so often uses moss in building her nest? And how the phoebes that make green nests keep them green?

And how Mrs. P. puts a stone roof on her house? You will find all about it in "Wit of the Wild."

The same chapter, "The Phoebe at Home," tells why the phoebe bird took to building under bridges, and why she builds in a carriage shed instead of a barn, as the barn-swallow does.

"Bird Life," by Chapman, is a guide to the study of our common birds. The beauty about this book is that it has seventy-five full-page plates in the natural colors, with brief descriptions, so that all you have to do is to bring the _mind_ picture of the bird you have seen alongside the picture in the book, and there's the answer! n.o.body has written more delightful books on birds than Olive Thorne Miller. "Little Brothers of the Air" is one of them.

You couldn't keep your hands off a book with a name like that, could you? Then there is her "Children's Book of Birds," "True Bird Stories," ill.u.s.trated by Louis Aga.s.siz Fuertes, and "Little Folks in Feathers and Fur," which, as you can see, goes outside the bird family. John Burroughs's "Wake Robin" deals not with robins alone, but with birds and bird habits in general.

But the greatest book about birds--the wonder of the bird and his relations to the whole animal world--is very properly called "The Bird," by C. William Beebe, who is at the head of the bird department of the great New York Zoo. Among other things it tells:

How Nature practised drawing--so to speak--for years before she could finally make a proper bird. (If you have ever tried to draw a bird from memory and realized what a bad job you made out of it, you will sympathize with her.) How they know that the earliest birds Nature made, as well as being very homely, weren't at all smart; not to be mentioned in the same breath with clever Jim Crow, for example. How "a bird's swaddling clothes and his first full-dress are cut from the same piece," the very words of the book. About certain birds that have one set of wings to play in and a new set for flying, like a child wearing jumpers to save his nice clothes! About the world of interesting things you can discover with the bones of a boiled chicken.

And so on for nearly five hundred pages, and as many ill.u.s.trations; the most striking collection of pictures explaining birds that I ever saw.

[Ill.u.s.tration: THE END OF A BUSY SEASON

"And there's the corn and the pumpkins and the carrots and the turnips and the potatoes in the root cellar and the jelly in the jelly-gla.s.ses--we helped make them all."]

CHAPTER X

(OCTOBER)

It is hardly an exaggeration to say that the tip of a root acts like the brain of the lower animals.

--_Darwin._

THE BUSY FINGERS OF THE ROOTS

This has been a very busy season for Mr. Root and his family. It always is, and you can imagine they're all glad when Fall comes and they can lay by for the Winter.

"There's your apple crop, I helped make that," Mr. Root might say. "And there's the corn and the wheat in the granary, and the rye and the oats and the barley; and the hay in the mow; and the pumpkins and the carrots, and the turnips, and the potatoes in the root cellar; and the jelly in the jelly-gla.s.ses, and the jam, and the preserves--we helped make them all.

"And we've been working for you almost since the world began; almost, but not quite--for the earliest plants, the Lichens, for example--didn't have true roots.

"Yes, and--well, I don't want to say anything--Mr. Lichen has been a good neighbor--but he never did amount to much; never could. No plant can amount to much without roots. But with roots and a good start a plant can do almost anything--raise flowers and fruit and nuts, and help grow trees so tall you can hardly see the tops of them. And, it isn't alone what we do for the plants we belong to, but for the soil, for other plants and roots that come after we're dead and gone. For them we even split up rocks, and so start these rocks on their way to becoming soil."

I. ALL IN THE DAY'S WORK

It's a fact. Roots do split rocks. Hundreds of times I've been in the cracks of rocks that were split in that way. I mean right when the splitting was going on. This happened oftenest where trees grew on the stony flanks of mountains. Seeds of the pines, say, dropped in crevices by the wind, sprout in the soil they find there, and then, as these shoots grow up into trees, the enlarged roots, in their search for more soil, thrust themselves deeper and deeper into the original lodging-place, and so split even big rocks. The tap-roots do the heaviest part of this pioneer work. After the older and larger roots have broken up the rock, the smaller roots and fibres, feeling their way about among the stones, enter the smaller openings and by their growth divide the rock again and again.

But it's a lot of hard work for little return, so far as these early settlers are concerned; just a bare living. All these rock fragments, in the course of the years, become soil, but the amount of decay is small in the lifetime of the tree that does the breaking.

A root, as you doubtless know, tapers. This enables it to enter a rock crevice like a wedge. As it pushes its way in farther and farther it is growing bigger and bigger, and it is this steady pressure that breaks the rock. Even the tiny root of a bean grows with a force of several pounds, and the power exerted by the growth of big roots is something tremendous. At Amherst Agricultural College, one time, they harnessed up a squash to see how hard it could push by growing. From a force of sixty pounds, when it was a mere baby, what do you suppose its push amounted to when it had reached full squashhood in October? Nearly 5,000 pounds; over two tons!

[Ill.u.s.tration: HOW A LITTLE ROOT SPLIT A GRANITE BLOCK

The little winged seed from which this pine-tree grew was carried by the wind one day into a tiny crack in that big granite block. As the treelet grew the tap root split the rock, penetrated to the earth below and fed the trunk until it became, as you see, a tree 40 feet high and 18 inches in diameter!]

But don't think because roots can and do split rocks, if need be, that they go about looking for such hard work. On the contrary. In travelling through the soil they always choose the easiest route, the softest spots. They use their brains as well as their muscles, and what they do with these brains is almost unbelievable.

Yet the roots are such modest, retiring folks, always hiding, that it was a long time before the wise men--the science people--found out what all they do. It took a lot of science people and the wisest--including the great Darwin--to get the story, and they haven't got it all yet, as you will see. It was Darwin who first thought of having Mr. Root write out his autobiography--or part of it--the story of his travels; for he does travel, not only forward--as everybody knows--but around and around. A regular globe-trotter!

[Ill.u.s.tration: WHY BABY PLANTS BACK INTO THE WORLD

Most plants back into the world out of the seed like that. Why? To protect their tender first leaves. Suppose you were taking some very valuable thing, easily injured--baby brother, say--through a swinging door and you had to use both hands to carry him. You wouldn't open the door by pushing that dear, little tender head of his against it, would you? You'd open it by backing through.]

Mr. Darwin was a wonderful hand at that sort of thing--getting nature people to tell their stories. He was an inventor, like Mr. Edison; only, instead of inventing telephones for human beings to talk with, he invented ways of talking for nature people. You saw how he fixed it so that the earthworms could tell what they knew about geometry and botany.

Well, in the case of the roots, what did he do one day but take a piece of gla.s.s, smoke it all over with lampblack--you'd have thought he was going to look at an eclipse--and then set it so that Mr. Root could use it as a kind of writing-desk. In a hitching, jerky sort of way roots turn round and round as they grow forward. In the ground, to be sure, a root can't move as freely nor as fast as it did out in the open and over this smooth gla.s.s, but it does turn, slowly, little by little. The very first change in a growing seed is the putting out of a tiny root, and from the first this root feels its way along, like one trying to find something in a dark room. Thus it searches out the most mellow soil and also any little cracks down which it can pa.s.s.

[Ill.u.s.tration: CHARLES DARWIN

The great naturalist.]

"Here's a fine opening for a live young chap," we can imagine one of these roots saying when it comes to an empty earthworm's burrow or a vacancy left by some other little root that has decayed and gone away.

Roots always help themselves, when they can, to ready-made openings, and it is this round-and-round motion that enables them to find these openings.

But even this isn't all. A root not only moves forward and bends down--so that it may always keep under cover and away from the light--but it has a kind of rocking motion, swinging back and forth, like a winding river between its banks, and for a somewhat similar reason.

"It's looking for a soft spot!" says the high school boy, "just as the river does."

NO HIT-OR-MISS METHODS FOR MR. ROOT

Exactly. But not in the sense that this phrase is used in slang. The root has certain work to do, and it does it in the quickest and best way. It can get food more quickly out of mellow soil than out of hard, and so it constantly hunts it up. I mean just that--_hunts it up_. For it isn't by aimless rocking back and forth that roots just _happen_ upon the mellow places. It's the other way around; it's from a careful feeling along for the mellow places that the rocking motion results.

"But how on earth do the roots do this? What makes them do it?"

That's what any live boy would ask, wouldn't he? So you may be sure that's what the science people asked, and this is the answer: