IF YOU were a bird, could you think of any way of earning a living more delightful than sailing about in the air all day, playing cross-tag on the wing with your companions, skimming low across the meadows, ponds and marshes, or rising high above them and darting hither and thither wherever you pleased, without knowing what it means to feel tired? Swallows are as much in their element when in the air as fish are in water; but don't imagine they are there simply for fun. Their long, bladelike wings, which cut the air with such easy, but powerful strokes, propel them enormous distances before they have collected enough mosquitoes, gnats and other little gauzy-winged insects to supply such great energy and satisfy their hunger. With mouth widely gaping, leaving an opening in the front of their broad heads that stretches from ear to ear, they get a tremendous draught down their little throats, but they gather in a dinner piece-meal just as the chimney swift, whip-poor-will and night-hawk do. Viscid saliva in the bird's mouth glues the little victims as fast as if they were caught on sticky fly-paper; then, when enough have been trapped to make a pellet, the swallow swallows them in a ball, although one swallow does not make a dinner, any more than one swallow makes a summer.

These sociable birds delight to live in companies, even during the nesting season when most feathered couples, however glad to flock at other times, prefer to be alone. As soon as the young birds can take wing, one family party unites with another, one colony with another, until often enormous numbers assemble in the marshes in August and September. You see them strung like beads along the telegraph wires, perched on the fences, circling over the meadows and ponds, zigzagging across the sky. Millions of swallows have been noted in some of these autumnal flocks. Usually they go to sleep among the reeds and grasses in a favourite marsh where the bands return year after year; but some prefer trees. Comparatively little perching is done except at night, for swallows' feet are very small and weak.

At sunrise, the birds scatter in small bands to pick up on the wing the long continued meal, which lasts till late in the afternoon. Those who have gone too far abroad and must travel back to the roost after sundown shoot across the sky with incredible swiftness lest darkness overtake them. Relying upon their speed of flight to carry them beyond the reach of enemies, they migrate boldly by daylight instead of at night as the timid little vireos and warblers do. During every day the swallows are with us they must consume billions and trillions of blood-sucking insects that would pester other animals beside ourselves. Think of the mosquito bites alone that they prevent! Every one of us is greatly in their debt.

Male and female swallows are dressed so nearly alike that you can scarcely tell one from the other. Both twitter merrily but neither really sings. 

There is a picturesque old inn beside a post road in New Jersey with a five-storied martin house set up on a pole above its quaint swinging sign. For over thirty years a record was kept on the pole showing the dates of the coming and going of the martins in April and September, which did not vary by more than two or three days during all that time. The inn-keeper locked up in his safe every night the registers on which were entered the arrivals and departures of his human guests, but he valued far more the record of his bird visitors which interested everybody who stopped at his inn.

One day, while he was away, a man who was painting a fence for him thought he would surprise him by freshening up the old, weather-beaten pole. Alas! He painted over every precious mark. You may be sure the surprise recoiled upon him like a boomerang when the wrathful inn-keeper returned. However, the martins continue to come back to their old home year after year and rear their broods on little heaps of leaves in every room in the house, which is the cheerful fact of the story. 

Young barn swallows cradled under the rafters

Baby barn swallows learning to walk a plank 

These glossy, blue-black iridescent swallows, grayish white underneath, the largest of their graceful tribe, have always been great favourites. Even the Indians in the Southern States used to hang gourds for them to nest in about their camps-a practice continued by the Negroes around their cabins to this day. Strangely enough these birds which nested and slept in hollow trees before the coming of the white men, were among the first to take advantage of his presence. Now, in the Eastern United States, at least, the pampered darlings of luxury positively refuse to live where people do not put up houses for their comfort. In the sparsely settled West, however, they still condescend to live in trees, but only when they must, like the chimney-swifts, who, by the way are no relation. Plenty of people persist in calling them chimney swallows, which is precisely what they are not. Not even the little house wren has adapted itself so quickly to civilised men's homes, as the swift and purple martin.

Intelligent people, who are only just beginning to realise what birds do for us and how very much more they might be induced to do, are putting up boxes for the martins, not only near their own houses, that the birds may rid the air of mosquitoes, but in their gardens and orchards that incalculable numbers of injurious pests in the winged stage may be destroyed. When martins return to us in spring from Central and South America, where they have passed the winter,. insects are just beginning to fly, and if they can be captured then, before they have a chance to lay their eggs, you see how much trouble and money are saved for the farmers by their tireless allies, the swallows. Unfortunately, purple martins are not so common at the North as they were before the coming of those saucy little immigrants, the English sparrows, who take possession, by fair means or by foul, of every house that they can find. In the South, where the martins are still very numerous, a peach grower I know has set up in his orchard rows of poles, with a house on each, either for them or for bluebirds. He says these bird partners are of inestimable value in keeping his fruit trees free from insects. The curculio, one of the worst enemies every fruit grower has to fight, destroying as it does millions of dollars worth of crops every year, is practically unknown in that Georgia planter's orchard. Some day farmers all over the United States will wake up and copy his good idea.

A colony of martins circling about a house give it a delightful home-like air. Their very soft, sweet conversation with one another as they fly, sounds like rippling, musical laughter. 

Do you know where there is an old-fashioned, weather-worn barn, with its hospitable doors standing open, where you could not find at least one pair of barn swallows at home beneath its roof? These birds, you will notice, prefer dilapidated old farm buildings, whose doors are off their hinges, and whose loose shingles or broken clapboards offer plenty of entrances and exits. If you like to play around a barn as well as every child I know, you must be already acquainted with the exquisite, dark steel-blue swallows with glistening reddish buff breasts, and deeply forked tails, that dart and glide in and out of the openings, merrily twittering as they fly. While you tumble about in the hay among the rafters the swallows go and come, so that, quite unconsciously, you will associate them with happy hours as long as you live.

High up on some beam, too high for the children to reach, let us hope, a pair of barn swallows will plaster their mud cradle. Did you ever see them gathering pellets of wet soil in their bills at some roadside puddle? It is, perhaps, the only time you can ever catch them with their feet on the earth. Each mud pill must be carried to the barn and fastened on to the rafter. Countless trips are made to the puddle before a sufficient number of pellets are worked into the deep mud walls of the ample nursery. Usually grass is mixed with the mud, but some swallows make their bricks without straw. A lining of fine hay and plenty of feathers from the chicken yard seem to be essential for their comfort, which is a pity, because almost always chicken feathers are infested with lice, and lice kill more young birds than we like to think about. When there is a nestful of fledglings to feed, sticky little pellets of insects, caught on the wing, are carried to them by both parents from daylight to dusk. Do notice how tirelessly they work!

In a family famous for graceful, rapid flight, the barn swallow easily excels all his relations. The deep fork in his tail enables him to steer himself with those marvellously quick, erratic turns, which make his course through the air resemble forked lightning. But with what exquisite grace he can also glide and skim across the water, fields and meadows without an apparent movement of the wing! His flight seems the very poetry of motion. The ease of it accounts for the very wide distribution of barn swallows from southern Brazil in winter to Greenland and Alaska in summer. What a journey to take twice a year! 

More than any other bird family, the swallows are becoming increasingly dependent for shelter upon man, at least when they are nesting; and as this is the season when they are most valuable to him because of the enormous numbers of insects they prevent from multiplying, let us hope that familiarity with us will never breed contempt and cause them to return to their old, uncivilised building sites. In the sparsely settled West, the cliff swallow still fastens its queer, gourd-shaped, mud nest against projecting rocks, but in the East it is so quick to take advantage of the eaves of the barns and other out-buildings, that its old name does not apply, and we know it here only as an eave swallow.

The barn swallow, as we have seen, chooses to nest upon the rafters inside the barn, but the eave swallow is content to stay outside under the shelter of a projecting roof. In such a place you find not one, but several or many mud tenements plastered in a row against the wall, for eave swallows are always remarkably sociable, even at the nesting season. A photograph of a colony I have seen shows one hundred and fifteen nests nearly all of which touch one another.

Although so often noticed circling about barns, you may know by the rusty patch on the lower part of his steel-blue back, the crescent-shaped white mark on his forehead, and the notched, not deeply forked tail, that the eave swallow is not the barn swallow, which it otherwise resembles.

Perhaps you have seen a sand bank somewhere, probably near a river or pond, where the side of the bank was filled with holes as if a small cannon had been trained against it as a target. In and out of the holes fly the smallest of the swallows, with no lovely metallic blue or glistening buff in their dull plumage, which is plain brownish gray above, white underneath, with a grayish band across the breast. Only their cousin, the rough-winged swallow, whose breast is brownish gray, is so plainly dressed.

The giggling twitter of the bank swallows as they wheel and dart through the air above you, proves that they are never too busy hunting for a dinner to speak a cheerful word to their friends. Year after year a colony will return to a favourite bank, whose face has been honeycombed with such care. Think of the labour and patience required for so small a bird to dig a tunnel two feet deep, more or less! Some nests have been placed as far as four feet from the entrance. You are not surprised at the big kingfisher, who also tunnels a hole in a bank for his family, because his long, strong bill makes digging comparatively easy; but for the small-billed, weak-footed swallow, the work must be difficult indeed. What a pity they cannot hire moles to make the tunnels with their strong, flat, spade-like feet. No wonder the birds become attached to the tunnels that have cost so much labour. When there are no longer any baby swallows on the heaps of twigs, grass and feathers at the end of them, the birds use them as resting places by day as well as by night until it is time to gather in vast flocks and speed away to the tropics. 

Probably this is the most abundant swallow that we have; certainly countless numbers assemble every year in the Long Island and Jersey marshes, perch on the telegraph wires and skim, with much circling, above the meadows and streams in a perfect ecstasy of flight. At a little distance the bird appears to be black above and white below, but as he suddenly wheels past, you see that his coat is a lustrous dark steel green. Immature birds are brownish gray. All have white breasts.

As the tree swallows are the only members of their family who spend the winter in the Southeastern United States, they can easily arrive at the North some time before their relatives from the tropics overtake them. And they are the last to leave. Myriads remain in the vicinity of New York until the middle of October. There is plenty of time to rear two broods, which accounts for the great size of the flocks. By the Fourth of July the young of the first broods are off hunting for little gauzy-winged insects over the low lands; and about a month later the parents join their flock, bringing with them more youngsters than you could count. They sleep every night in the marshes, clinging to the reeds.

Like the cliff swallow, the tree swallow is fast losing the right to its name. It takes so kindly to the boxes we set up for martins, bluebirds and wrens that, where sparrows do not interfere, it now prefers them to the hollow trees, which once were its only shelter. But some tree swallows still cling to old-fashioned ways and at least rest in hollow trees and stumps, even if they do not nest in them. Some day they may become as dependent upon us as the martins and, like them, refuse to nest where boxes are not provided.