"Now, children, you see what good the Sky Sweepers do," said the Doctor.

"Sky Sweepers! We don't call 'em that! We call 'em Chimney Swallows!"

Then the children told Joe about the Bird Brotherhoods.

"Stand on this box," said Joe to Dodo, "and look hard at that small slantways branch, with the little bunch on it!"

"The little round bunch that looks like soft green moss?"

"Yes. Well, that's the Hummer's nest!"

"Oh! oh!" cried Dodo, forgetting to whisper, "I see a mite of a tail and a sharp needle beak sticking over the edge!"

This was too much for Mrs. Hummer, who flew off with a whirr like an angry little spinning-wheel--if such a proper Puritan thing is ever angry; and there in the nest were two tiny eggs, like white beans.

"Come back by the fence and watch," said Joe. "She doesn't like to leave the nest much when it is toward night."

"It's a pity her mate is dead. How lonely she must be!" said Dodo, who had a tender little heart.

"I do not think her mate is dead," said the Doctor; "he is merely staying away, after a custom of his family. The bird whose nest we see there is called the Ruby-throated Hummingbird, because he has a patch of glittering ruby-red feathers under his chin, at the top of his b.u.t.toned-up vest that hardly shows any while shirt-front. He wears a beautiful golden-green dress-coat, with its dark purplish tails deeply forked. His wife looks very much like him, only she has no ruby jewels to wear.

"Bold as this bird is in darting about and chasing larger ones, he is less than four inches long--only about the size of one of the hawk-moths that come out to feed, just as this valiant pygmy lancer leaves the flowers for the night.

"These Hummingbirds live on honey and very small insects, and dread the cold so that they spend the winter southward from Florida. But as soon as real spring warmth comes, they spread over the United States, east of the plains, and north even to the Fur Countries. They are the only kind found in the eastern half of North America, though there are more than a dozen other species in the West, most of them near the Mexican borders of the United States.

"When the Hummers arrive here, early in May, we see the brilliant males darting about--sometimes, I am sorry to say, quarrelling with their rivals and giving shrill cries like the squeaking of young mice. The last of May the dainty nest is made of plant-down and lichen scales.

Then the male goes off by himself and sulks. You may see him feeding, but he keeps away from the nest--selfish bird that he is--until the little ones are ready to fly.

"Meanwhile the mother takes all the care and trouble herself, feeding her little Hummers in a peculiar way. She swallows tiny insects, and when they have remained a little while in her crop she opens her beak, into which the young bird puts its own and sucks the softened food, as a baby does milk from its bottle."

"I was wondering this very morning," said Joe, "how the old bird was going to feed her young ones when those two eggs hatched, without any mate to help her. I'm real glad you came along to explain it, sir.

Somehow the reasons lots of folk give for things aren't reasonable at all."

"Now, children," said the Doctor, "write the Hummingbird table before the twilight comes on."

The Ruby-throated Hummingbird.

Length less than four inches.

Male: shining golden-green above, with dark purplish wings and tail, the latter forked; glittering ruby-red throat; other under parts grayish, with some white on the breast and greenish on the sides.

Female: lacks the ruby throat, and has the tail not forked, but some of its feathers white-tipped.

A Summer Citizen of the eastern United States from Florida to Canada.

Though songless, a jewel of a bird, belonging to the guild of Tree Trappers. Nest a tiny round cup of moss and plant-down stuccoed with lichens; eggs only two, white.

THE CHIMNEY SWIFT

"Now, wouldn't you like to see the big chimney?" asked Joe. "The birds go in and out a good deal this time o' day. It's across the road there, where the old house used to be. The house is all gone, but the chimney is as strong as ever--I can climb up top and look down at the nests inside. See! there it is now!" Looking over the fence, they saw a tall stack of worn gray stones, that looked more like a tower than a chimney.

Small blackish birds kept streaming from the top, circling high in the air and darting down again, all twittering as they dropped one after another out of sight, inside the weather-beaten pile.

"Look, children!" said the Doctor. "These are Chimney Swifts, usually called Chimney Swallows: and their color is like soot, to match the places they live in."

"Aren't they any relations of Swallows?" asked Rap.

"No, my boy; they look like Swallows, but as I think Olive told you once, the Swifts are a family all by themselves. This one lives in the eastern half of the country in summer, and goes far south for the winter. When he lives in a wild region, he chooses a hollow tree for his nesting place, as his ancestors always did before there were any houses or chimneys.

[Ill.u.s.tration: Chimney Swift.]

"The flight of the Swift is so rapid that at times it is almost impossible for the quickest eye to follow him; his wings are very strong, and almost as long as all the rest of his body. Short and blunt as his tail looks when he flies, each feather ends in a hard sharp point which sticks out beyond the soft part. They feed on insects which they catch as they dash through the air, and can also break off dry twigs for nest-building without stopping--sometimes seizing the little sticks in their bills and sometimes in their claws, which are much stronger than those of Swallows."

"How do they make the sticks stay in the chimney? What do they set them on, and how do they perch while they are building?" asked Nat, all in one breath.

"Do you remember how the little Brown Creeper propped himself against the tree when he looked for insects?"

"Yes," said Rap; "he stuck his sharp tail-feathers into the bark and made a bracket of himself."

"The Swift does this also when he fastens twigs together for a nest.

They are glued together into a little openwork basket, and gummed to the wall of the chimney, with a sticky fluid which comes from his own mouth."

"I've got a lot of old nests that fell down the chimney after a storm last winter that wet the glue and made them come unstuck," said Joe; "and I'll give you each one. If you look up the hole where the kitchen fireplace was, you can see the new nests quite plain; for the birds don't build them very near the top."

"Be careful of loose stones!" called the Doctor; but in a flash four young heads had disappeared in the ruins of the great fireplace, where three pairs of trousers and a short brown linen skirt alone were visible.

In a little while they had some milk and strawberries; and before they drove on Joe's father promised to take him up to Orchard Farm to see the birds in the Doctor's wonder room, as soon as haying should be over.

To the children's astonishment they found it was half-past six o'clock; they had been at the farm an hour and a half, and could not stop again until they reached the wood lane where their uncle had promised to look for the Pewee's nest.

"Stay here, little people, and ask all the questions you like of Olive,"

said the Doctor, when they had reached the lane; "for I shall be able to find the nest more easily if you do not frighten the birds by talking."

"Pewee, pewee, pe-e-er!" cried a little voice.

"There he is, crying 'peek-a-boo' again," said Dodo. "Please, Olive, won't you tell us the table for the Chimney Swift now?"

"Certainly; and there is plenty of light yet if you wish to write it down."

The Chimney Swift

Length five and a half inches.

Sooty brown. Sharply pointed tail-feathers.

A Summer Citizen of eastern North America from Florida to the Fur Countries.

An excellent neighbor--a friend of the farmer and his cattle. An officer in the guild of Sky Sweepers, who shoots through the air in the shape of a bow and arrow.