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 grass, 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 Woodcock 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 coons," said Rap. "Woodpeckers and all those."
"There again the home is suited to the occupation of the bird," said the Doctor; "for Woodpeckers 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 seashore. 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
