"Oh, I remember that now," said Nat. "And after the young are hatched and the old birds need new coats, they keep rather still while they shed their feathers, because they feel weak and can't fly well."

"Then when the new feathers come they are sometimes quite different from the old ones, and seldom quite so bright--why is this, Nat?" asked the Doctor. But Nat could not think, and Rap answered: "Because in the autumn when they make the long journeys the leaves are falling from the trees, and if they were very bright the cannibal birds would see them too quickly." "Have I told you about the Bluebird, and how, though he only sheds his feathers once a year, yet his winter coat is rusty and not bright clear blue as it is in spring?"

"I think not," answered Nat.

"Well, the outside edges of its feathers are blue, but a little deeper in the feather is brownish. So when they have worn the same feathers many months, and rubbed in and out of their little houses and bathed a great deal and cleaned their feathers off every day in the dust, as birds always do, the blue ends wear off and the rusty parts show. It is quite worth while to tell little people things when they have the patience to listen and the interest to remember."

"Yes, uncle, but it's the way you tell us about birds that makes us remember. You talk as if they were real people."

"Oh, oh, Nat!" laughed the Doctor, "if you flatter me so I shall have to hide my head in a bush like an Ostrich. Birds _are_ people, though of another race from ours, and I am happy if I can make you think so. Ah!

we must be near a Redwing's nest--what a commotion the colony is making!"

"Colony? I thought a colony was a lot of people who went off into a strange wild land and made a new home," said Nat.

"That is one meaning of the word, but another one is when a number of people of the same race or trade live close to each other. A bird colony is a collection of the homes of many birds of the same family. After the nesting season almost all birds live in flocks of different sizes, each particular kind flocking by itself; but during the migrations great flocks are often made up of smaller flocks of various kinds of birds.

During the nesting season it is quite different; the majority of birds prefer a quiet home life, each pair being independent of any others.

Certain flocks, however, keep together, and all build their nests in a particular swamp or wood, and sometimes, it is said, male birds build nests to sleep in while the females are sitting. The Redwings nest in colonies; so do the Herons, who eat frogs and nest near water, and the little brown-cloaked Bank Swallows, who live in holes that they dig for themselves in high banks."

There were some twenty pairs of birds in this Redwing colony, who seemed to be much frightened by the approach of visitors.

"Here is a nest in this alder bush," said the Doctor; "step carefully on the gra.s.s hummocks, and look at it for a moment, Nat. See how neatly it is made of the dried leaves of flags and gra.s.ses, woven in and out between three upright stalks."

"Isn't it pretty?" said Nat; "so even and deep like a cup, and not at all ragged and mussy like a Robin's nest. There are a great many different kinds of nests, aren't there, uncle?"

"Yes, the nests of birds are almost as different as their songs and other habits, and the higher the order the brood belongs to the better built is the nest. The lower orders often only make a hollow in the ground or gra.s.s, but do not collect material and _build_ in the true sense. None such can be called architects."

"What is an architect?" asked Nat, who thought it was a pretty big name for any sort of a bird. "An architect, my boy," said the Doctor, "is anybody who knows how to build anything as it ought to be built, to look the best and be the most useful, whether it is a house or a nest."

"I wonder why nests are so different," said Rap, looking down the lane toward the river where the sun was streaming in and so many little birds were flying to and fro that they seemed like last year's leaves being blown about.

"Because, as the habits of the birds cause them to live in different places, and feed in various ways, so their homes must be suitable to their surroundings, and be built in the best way to protect the young birds from harm--to keep them safe from House People, cannibal birds, and bad weather.

"The trim Thrushes and Sparrows, who are all brownish birds, and find their insect or seed food on or near the ground, build open nests low down in trees and bushes, or on the earth itself; but the gorgeous Baltimore Oriole, with his flaming feathers, makes a long pocket-shaped nest of string and strong plant fibres, which he swings high up in an elm tree, where it cannot be reached from below, and the leaves hide this cradle while the winds rock it. He knows that it would never do to trust his brilliant feathers down by the ground.

"The frail Hummingbird has no real strength to fight enemies bigger than its tiny self, but it has been given for protection the power of flying as quick as a whizzing bullet, and courage enough to attack even a Kingbird in defence of its nest, which is a tiny circle of down, covered with lichens, and is so fastened across a branch that it looks like a knot of the limb itself. The Woodc.o.c.k you saw that snowy day, Rap, knows the protection of color and draws together for a nest a few leaves of the hue of her own feathers. This nest and the bird upon it are so blended together that few eyes could separate them."

"Some birds do not make any nests, but live in holes like squirrels and c.o.o.ns," said Rap. "Woodp.e.c.k.e.rs and all those."

"There again the home is suited to the occupation of the bird," said the Doctor; "for Woodp.e.c.k.e.rs are Tree Trappers, who find their food by creeping about trees and picking insects and grubs from the bark. What more natural than that they should have a house close at hand in some tree whose wood is soft enough to be hollowed out? You see they have a bill like a chisel for gouging out insects, and with this same tool they make their homes."

"Bluebirds and Wrens and Martins like to live in holes and boxes, though they can't make holes for themselves," said Rap.

"Yes, the habits of many birds have changed since the country has become civilized and House People are to be found in all parts of it. Many birds, who have always been favorites with man, and have been protected by him, have gradually grown less wild, or almost tame, and now prefer living near houses and barns to building in wilder places. The Bluebird, Martin, and Wren are three very popular birds. They appreciate cosy homes and are grateful for the boxes built for them, though we know that before they had such things they must have nested in tree holes." "I wonder where the Chimney Swifts lived before there were any chimneys,"

said Rap, looking across the fields to where an old stone chimney stood--the only thing left standing of an old farmhouse. Above this chimney, Swifts were circling in shifting curves, now diving inside it, now disappearing afar in the air.

"We think they must have lived in hollow trees as the Tree Swallows do now," said the Doctor; "but when House People began to clear the land they naturally cut down the dead trees first, and so the birds moved to the chimneys."

"I used to call those birds Chimney 'Swallows,' but Olive says they are made more like Hummingbirds and Nighthawks than real Swallows,"

continued Rap.

"Nighthawks?" said Nat. "I thought Olive said Hawks were cannibal birds.

How are they relations of Swallows?"

"That is a mistake a great many people make," said the Doctor; "for the Nighthawk is not a real Hawk, but a shy bird, who has a rapid hawk-like flight, though it eats nothing but beetles, moths, and other insects.

Hark! Do you hear that cry high in the air?"

"As if something was saying 'shirk-shirk'?" said Nat.

"Yes; that is a Nighthawk on its way home. Look! he is over us now, and you can see two large white spots like holes in his wings. By these you can tell it from any of the real Hawks."

"Does he build high up in a tree?" asked Rap. "I have never found his nest."

"There is a good reason for that," said the Doctor. "There is no nest.

Two eggs are laid on the bare ground, that is about the same color as the bird itself; and the eggs look too much like streaky pebbles to be easily seen. When the young are hatched they keep still until they are able to fly, and are colored so exactly like the place upon which they rest that it is almost impossible to see them, even if you know where they are."

"How much there is to learn!" sighed Nat. "I'm afraid you will have to make us a big book instead of a little one, Uncle Roy, to teach us all these things. Olive and Rap have such a start of us. Dodo and I don't know much of anything, and even what I thought I knew about birds isn't very true."

"Don't be discouraged, my boy; you do not need a big book--a little one will do for the present. What you need is patience, a pair of keen eyes, and a good memory. With these and a little help from Olive, Rap, and your old uncle, you can learn to know a hundred kinds of every-day birds--those that can be found easily, and have either the sweetest songs, the gayest plumage, or the most interesting habits. Some we shall find here in the lane and swamp meadow, or by the river. Others have made their home in my orchard for years. And I am going to put in the book more than a hundred beautiful pictures for you and Dodo, drawn so naturally that you can tell every one of the birds by them, and that will make it easier for you to understand what you read.

"For some of the water birds we must go up to the lake or in the summer make a trip over to the seash.o.r.e. How do you like that? Yes, you too, Rap. By and by, when you know these hundred birds by name and by sight, you will be so far along on the road into Birdland that you can choose your own way, and branch off right and left on whatever path seems most attractive to you; but then you will need big books, and have to learn long hard Latin names."

"What birds will you begin with, please, Doctor Roy," said Rap, "the singers or the cannibals?"

"The singers, because they will interest Dodo and Nat the most easily, as they do you. Then we will talk about the birds that only croak and call; then the cannibal birds; next those that coo, and those that scratch for a living. Then we must leave dry land and go close to the water to find the birds that wade; and finally, we must go to the lake or sea itself for the birds that swim and dive."

"Why, here's Quick!" cried Nat, as the little fox-terrier came leaping down the lane, tracking them, nose to the ground. "How did you get out of the barn, sir?"

"I suspect that Dodo has discovered that we are missing and is looking for us," said the Doctor. "There is the breakfast bell. Do you realize, my lads, that we have been out two hours?"

"I often come out early in the morning," said Rap, "so it doesn't seem strange to me."

"I'm starving, Uncle Roy," said Nat, "though I am only beginning to feel it."

"Think how much worse you would have felt if you had not eaten some bread and milk before you started."

"Yes, indeed," said Nat. "Do many sicknesses come from not eating enough?" "Not so many as come from eating too much!" laughed the Doctor. "Won't you come up to breakfast with us, Rap? There is always room at my table, you know, for children who love their Bird Brothers."

"I can't," said Rap regretfully; "you see it's Thursday and I have to mind clothes!"

There was a merry breakfast party that morning at Orchard Farm; Nat had so much to tell, and the Doctor said he felt twenty years younger after his walk with the boys. A letter had also arrived which made Nat and Dodo very happy; it was from their mother, who said: "We are delighted to hear that the Doctor is going to tell you bird stories this summer.

Be sure to ask Olive to tell you all she knows about the flowers too.

When we come home this autumn, perhaps your uncle will ask us to the Farm for a visit, and then we shall see your friend Rap."

"Uncle, uncle!" cried both the children, "will you ask mother and father to come here for a little? It will be lovely, and--and then we shan't have to go away so soon either."

"I have already asked them for a long visit, you little rogues," said the Doctor. "You seem to forget that your mother is my sister, whom I wish very much to see."

"And does Olive know all the flowers," chimed in Dodo, "and will you tell us about everything?"