Once upon a time, it was four millions of years ago. There were no people then all the way from Florida to Alaska. There was, indeed, in all this distance, no land to walk upon, except islands in the west where the Rocky Mountains are now. That is the only place where the country that is now the United States of America stuck up out of the water. Everywhere else were the waves of the sea. There were no people, even on the Rocky Mountain Islands. None at all.

No, the creatures that visited those island shores in those old days were not people, but birds. Nearly as large as men they were, and they had teeth on their long slender jaws, and they had no wings. They came to the islands, perhaps, only at nesting-time; for their legs and feet were fitted for swimming and not walking, and they lived upon fish in the sea. So they dwelt, with no man to see them, on the water that stretched from sea to sea; and what their voices were like, no man knows.

A million years, perhaps, passed by, and then another million, and maybe another million still; and the birds without wings and with teeth were no more. In their places were other birds, much smaller—birds with wings and no teeth; but something like them, for all that: for their feet also were fitted for swimming and not walking, and they, too, visited the shore little, if at all, except at nesting-time, and they lived upon fish in the water.

And what their voices were like, all men may know who will go to the wilderness lakes and listen; for, wonderful as it may seem, these second birds have come down to us through perhaps a million years, and live to-day, giving a strange clear cry before a storm, and at other times calling weirdly in lone places, so that men who are within hearing always say, "The loons are laughing."

Gavia was a loon who had spent the winter of 1919-1920 on the Atlantic Ocean. There had hardly been, perhaps, in a million years a handsomer loon afloat on any sea. Even in her winter coat she was beautiful; and when she put on her spring suit, she was lovelier still.

She and her mate had enjoyed the sea-fishing and had joined a company of forty for swimming parties and other loon festivities; for life on the ocean waves has many interests, and there is never a lack of entertainment. The salt-water bathing, diving, and such other activities as the sea affords, were pleasant for them all. Then, too, the winter months made a chance for rest, a change from home-duties, and a freedom from looking out for the children, that gave the loons a care-free manner as they rode the waves far out at sea.

Considering all this, it seems strange, does it not, that when the spring of 1920 had gone no further than to melt the ice in the northern lakes, Gavia and her mate left the sea and took strong flight inland.

What made them go, I cannot explain. I do not understand it well enough. I do not really know what urges the salmon to leave the Atlantic Ocean in the spring and travel up the Penobscot or the St. John River. I never felt quite sure why Peter Piper left Brazil for the shore where the blue-bells nod. All I can tell you about it is that a feeling came over the loons that is called a migration instinct; and, almost before Gavia and her mate knew what was happening to them, they had flown far and far from the Ocean, and were laughing weirdly over the cold waters of Immer Lake.

The shore was dark with the deep green of fir trees, whose straight trunks had blisters on them where drops of fragrant balsam lay hidden in the bark. And here and there trees with white slender trunks leaned out over the water, and the bark on these peeled up like pieces of thin and pretty paper. Three wonderful vines trailed through the woodland, and each in its season blossomed into pink and fragrant bells. But what these were, and how they looked, is not a part of this story, for Gavia never wandered among them. Her summer paths lay upon and under the water of the lake, as her winter trails had been upon and under the water of the sea.

Ah, if she loved the water so, why did she suddenly begin to stay out of it? If she delighted so in swimming and diving and chasing wild wing-races over the surface, why did she spend the day quietly in one place?

Of course you have guessed it! Gavia was on her nest. She had hidden her two babies among the bulrushes for safety, and must stay there herself to keep them warm. They were not yet out of their eggshells, so the only care they needed for many a long day and night was constant warmth enough for growth. They lay near each other, the two big eggs, of a color that some might call brown and some might call green, with dark-brown spots splashed over them.

The nest Gavia and her mate had prepared for them was a heap of old wet reeds and other dead water-plants, which they had piled up among the stems of the rushes until it reached six inches or more out of the water. They were really in the centre of a nest island, with water all about them. So, you see, Gavia was within splashing distance of her fishing-pool after all.

She and her mate, indeed, were in the habit of making their nests here in the cove; though the two pairs of Neighbor Loons, who built year after year farther up the lake, chose places on the island near the water-line in the spring; and when the water sank lower later on, they were left high and dry where they had to flounder back and forth to and from the nest, as awkward on land as they were graceful in the water.

Faithful to her unhatched young as Gavia was, it is not likely that she alone kept them warm for nearly thirty days and nights; for Father Loon remained close at hand, and would he not help her with this task?

Gavia, sitting on her nest, did not look like herself of the early winter months when she had played among the ocean waves. For her head and neck were now a beautiful green, and she wore two white striped collars, while the back of her feather coat was neatly checked off with little white squarish spots. Father Loon wore the same style that she did. Summer and winter, they dressed alike.

Yes, a handsome couple, indeed, waited that long month for the birth of their twins, growing all this time inside those two strong eggshells. At last, however, the nest held the two babies, all feathered with down from the very first, black on their backs and gray shading into white beneath.

Did I say the nest held them? Well, so it did for a few hours. After that, they swam the waters of Immer Lake, and their nest was home no longer. Peter Piper's children themselves were not more quick to run than Gavia's twins were to swim and dive.

I think, perhaps, they were named Olair; for Gavia often spoke in a very soft mellow tone, saying, "Olair"; and her voice, though a bit sad, had a pleasing sound. So we will call them the two Olairs.

They were darlings, those baby loons, swimming about (though not very fast at first), and diving out of sight in the water every now and then (but not staying under very long at the beginning). Then, when they were tired or in a hurry, they would ride on the backs of Gavia and Father Loon: and they liked it fine, sailing over the water with no trouble at all, just as if they were in a boat, with someone else to do the rowing.

Oh, yes, they were darlings! Had you seen one of them, you could hardly have helped wanting to cuddle him. But do you think you could catch one, even the youngest? Not a bit of it. If you had given chase in a boat, the wee-est loon would have sailed off faster yet on the back of his father; and when you grew tired and stopped, you would have heard, as if mocking you, the old bird give, in a laughing voice, the Tremble Song:

If you had tried again a few days later, the young loon would have been able to dive and swim by himself out of sight under water, the old ones giving him warning of danger and telling him what to do.

But no child chased the two Olairs and no lawbreaker fired a shot at Gavia or Father Loon. They had frights and narrow escapes in plenty without that; but those were of the sorts that loons get used to century after century, and not modern disasters, like guns, that people have recently brought into wild places. For the only man who dwelt on the shore of Immer Lake was a minister.

Because he loved his fellow men, this minister of Immer Lake spent part of his days among them, doing such service to the weak of spirit as only a minister can do, who has faith that there is some good in every person. At such times he was a sort of servant to all who needed him.

Because he loved, also, his fellow creatures who had lived in the beautiful wild places of this land much longer than any man whatsoever, he spent part of his days among them. At such times he was a sort of hermit.

Then no handy trolley rumbled by to take him on his near way. No train shrieked its departure to distant places where he might go. There was no interesting roar of mill or factory making things to use. There was no sociable tread of feet upon the pavement, to give him a feeling of human companionship.

But, for all that, it was not a silent world the minister found at Immer Lake. On sunny days the waves, touching the rocks on the shore, sang gently, "Bippo-bappo, bippo-bappo." The trees clapped their leaves together as the breezes bade them. The woodpeckers tapped tunes to each other on their hollow wooden drums. The squirrels chattered among the branches. At dawn and at dusk the thrushes made melodies everywhere about.

On stormy nights the waves slapped loudly upon the rocks. The branches whacked against one another at the mighty will of the wind. The thunder roared applause at the fireworks the lightning made. And best of all, like the very spirit of the wild event, there rang the strange, sweet moaning Storm Song of the Loon:—

The minister of Immer Lake liked that song, and he liked the other music that they made. So it was that he sat before his door through many a summer twilight, and played on his violin until the loons answered with the Tremble Song:—

Then they would swim up and up, until they floated close to his cottage, feeding unafraid near by, while he played softly.

Often, when Gavia and her mate were resting there or farther up the lake, some other loon would fly over; and then Father Loon would throw his head way forward and give another sort of song. "Oh-a-lee'!" he would begin, with his bill wide open; and then, nearly closing his mouth, he would sing, "Cleo´-pe´´-a-rit´." The "Oh" starts low and then rises in a long, drawn way. Perhaps in all the music of Immer Lake there is nothing queerer than the Silly Song of Father Loon:—

Such were the songs the two Olairs heard often and again, while they were growing up; and they must have added much to the interest of their first summer.

Altogether they had endless pleasures, and were as much at ease in the water as if there were no more land near them than there had been near those other young birds that had teeth and no wings, four million years or so ago. Their own wings were still small and flipper-like when, about the first of August, they were spending the day, as they often did, in a small cove. They were now about two-thirds grown, and their feathers were white beneath and soft bright brown above, with bars of white spots at their shoulders. They had funny stiff little tails, which they stuck up out of the water or poked out of sight, as they wished. They swam about in circles, and preened their feathers with their bills, which were still small and gray, and not black like those of the old birds.

After a time Gavia came swimming toward them, all under water except her head. Suddenly Father Loon joined her, and they both began diving and catching little fishes for the two Olairs. For the vegetable part of their dinner they had shreds of some waterplant, which Gavia brought them, dangling from her bill. Surely never a fresher meal was served than fish just caught and greens just pulled! No wonder it was that the young loons grew fast, and were well and strong. After the twins were fed, Gavia and Father Loon sank from sight under the water, heads and all, and the Olairs saw no more of them for two hours or so, though they heard them now and then singing, sometimes the Tremble Song and sometimes the Silly Song.

They were good children, and did not try to tag along or sulk because they were left behind. First they dabbled about and helped themselves, for dessert, to some plant growing under water, gulping down rather large mouthfuls of it. Then they grew drowsy; and what could have been pleasanter than going to sleep floating, with the whole cove for a cradle?

You could never guess how those youngsters got ready for their nap. Just like a grown-up! Each Olair rolled over on one side, till the white under-part of his body showed above water. Then he waved the exposed leg in the air, and tucked it away, with a quick flip, under the feathers of his flank. Thus one foot was left in the water, for the bird to paddle with gently while he slept, so that he would not be drifted away by the wind. But that day one of the tired water-babies went so sound asleep that he didn't paddle enough, and the wind played a joke on him by shoving him along to the snaggy edge of the cove and bumping him against a log. That was a surprise, and he woke with a start and swam quickly back to the middle of the cove, where the other Olair was resting in the open water.

While their children were napping, Gavia and Father Loon went to a party. On the way, they stopped for a bit of fishing by themselves. Gavia began by suddenly flapping around in a big circle, slapping the water with wing-tips and feet, and making much noise as she spattered the spray all about. Then she quickly poked her head under water, as if looking for fish. Father Loon, who had waited a little way off, dived a number of times, as if to see what Gavia had scared in his direction.

Then they both dove deep, and swam under water until they came near the four Neighbor Loons, who had left their two families of young dozing, and had also come out for a good time.

When Father Loon caught sight of his four neighbors, he sang the Silly Song, after which the six birds ran races on the water. They all started about the same time and went pell-mell in one direction, their feet and wings going as if they hardly knew whether to swim or fly, and ending by doing both at once. Then they would all stop, as suddenly as if one of them had given a signal, and turning, would dash in the opposite direction, racing to and fro again and again and again. Oh! it was a grand race, and there is no knowing how long they would have kept it up, had not something startled them so that they all stopped and sang the Tremble Song, which sounds like strange laughter. They opened their mouths quite wide and, wagging the lower jaw up and down with every "ha," they sang "O, ha-ha-ha, ho!" so many times that it seemed as if they would never get through. And, indeed, how could they tell when the song was ended, for every verse was like the one before?

Then all at once they stopped singing and began some flying stunts. A stiff breeze was blowing, and, facing this, they pattered along, working busily with wings and feet, until they could get up speed enough to leave the water and take to flight. Though it was rather a hard matter to get started, when they were once under way they flew wonderfully well, and the different pairs seemed to enjoy setting their wings and sailing close together around a large curve. They went so fast part of the time that, when they came down to the surface of the water again, they plunged along with a splash and ploughed a furrow in the water before they could come to a stop.

Of course, by that time they were hungry enough for refreshments! So Gavia went off to one side and stirred the water up as if she were trying to scare fish toward the others, who waited quietly. Then they all dived, and what their black sharp-pointed bills found under water tasted good to those hungry birds.

After that the loon party broke up, and each pair went to their own home cove, where they had left their young. It had been a pleasant way to spend the time sociably together; and loons like society very much, if they can select their own friends and have their parties in a wilderness lake. But gay and happy as they had been at their merrymaking, Gavia and her mate were not sorry to return to the two Olairs, who had long since wakened from their naps and were glad to see their handsome father and mother again.

By the time the two Olairs were full grown, Gavia had molted many of her prettiest feathers and was looking rather odd, as she had on part of her summer suit and part of her winter one. Father Loon had much the same appearance; for, of course, birds that live in the water cannot shed their feathers as many at a time as Corbie could, but must change their feather-wear gradually, so that they may always have enough on to keep their bodies dry. And summer and winter, you may be sure that a loon takes good care of his clothes, oiling them well to keep them waterproof.

Fall grew into winter, and the nest where Gavia had brooded the spring before now held a mound of snow in its lap. The stranded log against which the little Olair had been bumped while he was napping, months ago, was glazed over with a sparkling crust. The water where Gavia and Father Loon had fished for their children, and had played games and run races with Neighbor Loons, was sealed tight with a heavy cover of ice.

And it may be, if you should sail the seas this winter, that you will see the two Olairs far, far out upon the water. What made them leave the pleasures of Immer Lake just when they did, I cannot explain. I do not understand it well enough. I never felt quite sure why Peter Piper left the shore where the cardinal flowers glowed, for far Brazil. All I can tell you about it is that a feeling came over the loons that is called a migration instinct, and, almost before they knew what was happening to them, they were laughing weirdly through the ocean storms.

If you see them, you will know that they are strange birds whose ancestors reach back and back through the ages, maybe a million years. You will think—as who would not?—that a loon is a wonderful gift that Nature has brought down through all the centuries; a living relic of a time of which we know very little except from fossils men find and guess about.

It is small wonder their songs sound strange to our ears, for their voices have echoed through a world too old for us to know. It makes us a bit timid to think about all this, as it does the minister of Immer Lake, who sits before his door through many a summer twilight, playing on his violin until the loons answer him with their Tremble Song:—