It is very easy to know this family. They are small birds with long pointed wings, always sailing around in the air as if they could never tire. Their beaks are short, but very wide at the head, and the mouth opens as far back as the eyes. They have small and weak feet, so when they alight, it is usually on a small twig or telegraph wire, or on the flat top of a fence or roof.

Swallows wear no gay colors. Nearly all of them look black and white as they sail about in the air. But when you see them closely, you see they are glossy dark blue or green, sometimes with changeable colors, but all dark, on the back.

The Barn Swallow has a dull reddish breast, and his back is rich blue, almost black. He has a deeply forked tail, and a row of white spots on the shorter tail feathers. When he spreads his tail, it is very beautiful.

He is called barn swallow because he prefers a barn for a nesting-place. Up on the beams, close under the roof, the pair build their mud cradle. It is interesting to see them at work. When they have chosen a place, they go to some puddle in the road. They stand around it on their tiny feet, holding their wings straight up like a butterfly's. Then they take up some of the wet earth in their beaks, and work it around till it is made into a little pill. With this pill they fly to the place they have selected, and stick it on to the beam. Then they go back for more. So they go on, till they have built up the walls of the nest, an inch thick, and three or four inches high. Sometimes they put layers of fine grass in, but often they use nothing but mud. Then they line it with feathers which they pick up in the chicken yard.

Some swallows build a platform beside the nest, where one of the pair can rest at night; and when the little ones get big enough to fill up the nest, both parents can sleep there.

When the swallows are flying about low over the grass, looking as if they were at play, they are really catching tiny insects as they go. And when they have nestlings to feed, they collect a mouthful which they make up into a sort of little ball. Then they fly to the nest and feed it to one of the little ones.

Thus they keep the air clear and free from insects, and they do not a bit of harm, for they never touch our fruit or vegetables.

Barn swallows are social, and always go in flocks. They sing, too,—a sweet little song, but not very loud. It is charming to hear them in a barn when five or six of them sing together. But one may often hear the little song from a single bird flying over.

They are friendly among themselves, and they like to alight on a roof and chatter away a long time. In one place where I was staying, they liked to gather on a piazza roof right under my window. They often woke me in the morning with their sweet little voices.

One morning the sound was so near, it seemed as if they must be in the room, and I opened my eyes to see. There on the sill close to the screen was one of the pretty fellows. He was looking in at the open window, and evidently keeping watch of me. When I moved a little, he gave the alarm, and the whole party flew away.

The chatter of barn swallows always seems to me like talk, and men who study bird ways agree that birds have some sort of language. The swallows have many different notes. One is a general warning of danger, but there is another note for a man, another for a cat, and a still different one when they find something good to eat, which they call the others to share.

"The variety of bird speech," says a man who has studied birds a long time, "is very great." And of all bird voices, swallows' are the most like human speech. If you lie on the hay in the barn very quiet, and listen to them when they come in and fly about, you will see that this is true. It seems sometimes as if you could almost make out words.

Swallows more than any other birds like to make use of our buildings for their own homes. Barn swallows take the beams inside the barns, Eave Swallows settle under the eaves outside, and Purple Martins, the largest of the family, choose bird-houses which we put up for them.

It is said that purple martins will not stay anywhere that men have not made houses for them. But I have seen them living in a place not put up for them, though perhaps they thought it was. It was under a terra-cotta covering to a cornice on a business block in the middle of a busy city. The terra-cotta was shaped like a large pipe cut in half, the long way. This half cylinder was laid on top of the brick cornice, and that made a little roof, you see. The whole length of that cornice was thus made into one long room, with a brick floor and terra-cotta roof, and an entrance at the end. That room must have had a dozen martin nests, for a flock was all the time sailing about in the air, above the roofs of the houses.

As these birds eat only flying insects, they cannot stay with us when it is too cool for insects to fly abroad. So they leave us very early. When the little ones are out of the nest and can fly well, swallows from all the country around collect in great flocks, and go to some swamp, or lonely place where people do not go much. There the young ones are taught and exercised every day in flying. And some day we shall go out and find them all gone, not a swallow to be seen. They have started for their winter home, which is far south, in tropical countries, where insects never fail; but it is a comfort to think that next summer we shall have them back with us again.

The swallows I have mentioned, barn swallow, eave swallow, and purple martin, are found all over our country.

Let me tell you a story that shows the purple martin has a good deal of sense. One of these birds built in a box under a window, fixed so that the owner could open it and take out eggs. He took out several, one at a time, and at last he took out one of the birds.

The mate of the stolen bird went off and in a few days came back with another mate. The box was too good to give up, so both the birds went to work to make it safe against the nest robber. They built up a wall of mud before the too handy back door. The egg thief could not get in without breaking down the wall, and he was ashamed to do that. So the birds kept their pleasant home, and reared their family there.