WHOEVER notices what is going on in the natural world about him must be impressed with the fact that no two months in the year are alike so far as the bird population is concerned. In winter, bird life is at its minimum; in June, at its height; and between the two extremes there is constant fluctuation. Great flocks of migrants stream southward across the sky in autumn. Then, if we search the heavens with a telescope on moonlight nights, we find the vast procession stealing a march on its watchful enemies of the day, some detachments moving slowly, laboriously; others, like the wild ducks, at the rate of over a mile a minute. Hour after hour, both by day and by night, day after day, week after week, the procession passes; yet in the spring, doubtless, every one of these birds that has survived will reverse the tedious journey. With the coming of warm weather we waken every morning to find in our gardens birds that may have been a hundred miles away — yes, or even a thousand — only the day before. Chimney-swifts fly at almost incredible speed. Audubon picked up in Kentucky a dead wild pigeon in whose crop were berries that did not grow nearer than five hundred miles from his home, yet they were only partly digested! Why do so many birds attempt these wearisome journeys twice a year? What relentless impulse drives the little travelers back and forth, north and south, here to-day, away to-morrow?

Wherever you live you will find that some of the birds about you are more or less in evidence the year round. If you walk far enough you are likely to see a crow or a sparrow, for example, any month in the twelve. But other birds simply pass regularly through your locality on their spring and fall migrations, barely affording a glimpse of their feathers as they hurry by. With such disdain are we treated by the majority, but not all, of the warbler tribe, charmingly-colored, restless, dainty little sprites which flit among the spring blossoms for a day or two on their way to Canadian forests, where so many nest. These are the days when one grudges every moment that must be spent in the house; such rare guests do us the honor to pause awhile at our very doors, affording us, if not an opportunity for intimate acquaintance, at least the chance to know them again by sight. Within six months increased numbers of these warblers will stop again for a hasty lunch of insects, in the garden shrubbery and orchard, to refresh themselves on their journey back to the Gulf States, Central or South America or the West Indies. Clever little creatures, thus to live in perpetual summer! Some of the old birds having exchanged their wedding clothes for more quiet suits, and some of the young ones not yet wearing the feathers of maturity described in the books, the poor novice is often sadly bewildered in autumn, by not recognizing in its change of clothes a species he may have identified easily in spring. He misses, too, the characteristic songs and call-notes of the courting season; because the autumn travelers are mostly silent, they slip by unobserved.

"Crows, like the poor, are always with us"

The migrants, then, must be classed among one's fair-weather friends, and these, like human ones, alas! constitute the largest class. But no reproach on the birds is intended by this comparison: theirs is a motive compelling desertion when conditions of life become too hard for endurance in our neighborhood. Thus the robin and bluebird remain constant residents in some favored parts of the United States, while, in others, conditions make of them summer residents only. You may know the wood-thrush as a migrant, while to me he may be a near neighbor from May to October; for the bird population differs in different localities, though they may be not more than ten miles apart, just as surely as it differs from month to month everywhere. Why, you see different birds at different hours of the same day! That is one of the reasons why bird study is of perennial interest; there is about it always the charm of variety and the unexpected.

"Where Chickadees delight to dangle"

No sooner have the summer residents and the more tender migrants deserted us in the fall than certain hardy birds regularly appear; some, like the chickadees, merely from deep woods where they have nested; others, like the sea-gulls in our harbors and the Great Lakes, from inaccessible nesting islands off the northern coast; still others from the region of the north pole. But whether the so-called winter birds come from the next county or from the arctic regions, they are in evidence about our homes only at the most inclement season. With the return of the sun, bringing joy and abundance in its train, away go chickadees, nuthatches, kinglets, winter wrens, longspurs, juncos, snow-buntings, crossbills, redpolls, shrikes and gulls, — not to be seen again until the frost or snowfalls of next autumn.

In spite of this constant shifting of the feathered population, there is astonishing system and punctuality of appearance and disappearance of the greater part of it, one discovers on keeping a bird diary, which, by the way, is even more interesting than Pepys's. For thirty years the purple martins reached a certain home set up for their benefit in a New Jersey garden, on the 26th, 27th, or 28th of April, leaving it as regularly on one of four dates early in September. Sportsmen know almost to a day when ducks, plover and snipe may be found in the marshes. There are late springs and early springs; a belated blizzard may freeze back the budding fruit trees, raging storms may retard the progress of many a north-bound flock, but the going and coming of nearly all birds may be reckoned just as certainly as the coming of apple blossoms. One confidently listens for the first bluebird's song in March, when poking about in the leafless woods for the first hepatica. When shad ascend the rivers from the sea, and the shadbush stretches out fleecy white blossoms from the woodland borders with wild, irregular grace, then the Indians taught us to expect the first night-hawk's uncanny, mournful, jarring sound.

"A cold exposure" - Redpoll on a cedar tree

All birds, however, are not so punctual in their goings and comings as a railroad express, by any means. Some few species habitually lead a gypsy-like existence, roving hither and yonder, not as fancy dictates altogether, although their movements certainly appear erratic. Flocks of lisping, twittering, amiable cedar-waxwings, clad like Quakers but having a rather frivolous crest, may visit you for a week if there are plenty of choke-cherry and juniper trees about, yet one may not come again for a year. In addition to the more or less familiar visitors whose habits are known to be roving, occasionally, rarely, a total stranger to your neighborhood appears. Some extraordinary natural phenomenon in one part of the world often affects the bird population in a place very far distant, as when a sooty tern belonging on the Florida Keys got caught in a tornado and was blown northward until it had lost its reckonings. Finally, it was picked up exhausted in a Hudson river village. On some winter walk, that rare apparition, a great, blinking, snowy owl, from the arctic regions, may startle you, like a ghost among the evergreens. Quantities of red crossbills came far over the Canadian border a few winters ago. Bird lovers wrote each other excited letters in their joy at finding these charming, friendly little strangers pecking at the seeds in the cones of their pine trees. Cameras didn't frighten them. It may be a decade, perhaps a lifetime, before the severity of the cold at the north or a driving storm sends such numbers to us again. Doubtless the warm reception of hot-shot they received in some places had much to do with their sudden disappearance. One zealous ornithologist — of all men! — calmly told of killing eighty crossbills to learn what kind of food they had in their stomachs! These are the little birds which, legend says, dyed their breasts crimson and twisted their bills awry in their struggle to pull the nails from our crucified Saviour's hands and feet.

"Erratic winter visitors" - White-winged Crossbills

As permanent residents, summer residents, winter residents, migrants and visitors, whether regular way in life without either parent or guardian. Probably birds are influenced by similar considerations or uncertain, we may, then, classify the birds; but, however their habits may differ, one chief motive impels the going and coming of them all — the finding of adequate food. Perhaps, in the spring migration, this is more for the sake of the young than for the parents themselves. Fish migrate to spawn, running into harbors and rivers from the sea, leaping cataracts and mill-dams, if need be, to reach quiet, shallow, warmer waters, where there is greater hope of protection from foes and more suitable food for small fry left to make their own when they migrate.

Of course the food question incites the greater part of the activities in our own world; and be it observed that birds and other wild creatures seek those places where the food on which life itself depends is abundant just as unerringly, with just as much intelligence and forethought, as men do. When conditions prove too hard in Russia, Italy or Ireland, a great stream of human immigrants pours into America — greater in our prosperous years than in the lean periods of financial depression. When the birds are starved out of frozen Canada and the northern states, they go south, where the proverbial hospitality of that genial land will be extended to them by nature. Those which can live on pine seeds, insect eggs, larvæ, and grubs hidden in the bark of trees, the dry, seedy weed-stalks that rear themselves above the snow, the fish and refuse in the open waters of our larger streams, lakes and harbors, may safely remain at the north all winter, and they do. But we shall never find a flycatcher north then. To escape competition from the horde of contestants that pours out of the south in spring, the winter residents beat a retreat on their approach. Plenty of birds do not find it necessary to shift their residence farther than the next state in order to live in a land of plenty. Robins from Ohio may find Kentucky perfectly satisfactory as a winter resort. Robins, crows, and wild geese often sleep in one state and eat in another, going and coming daily as regularly as sunrise and sunset from one to the other. Geese, which prefer to sleep a-float, fly early to inland feeding grounds to spend the day — that is, if hunters are not waiting in ambush to receive them.

That it may have the entire field to itself and escape the keen competition of hosts of tropical relatives for the nectar and minute insects in the deep-tubed, brilliant flowers that please him best we have seen that the ruby-throated humming-bird travels from Central America, or beyond, to Labrador and back again every summer of its incessantly active little life. Think what the journey from Yucatan even to New England must meal, for a creature so tiny that its outstretched wings measure barely two inches across! It is the smallest bird we have. Then what must be the size of the body itself beneath its dress of feathers? Wherein lodges the force that propels it through the sky at a speed and a height which take it instantly beyond the range of human vision?

Leaving our grassy meadows in August, the joyous, rollicking bobolinks go to feed on the wild rice in our southern states, en route for Brazil; and some may count themselves fortunate if they do not end their journey suddenly as reedbirds, which, plucked and broiled, are served at the epicure's table.

As near the north pole as Grinnell Land, General Greeley found ring-neck plovers nesting in July; yet the young birds, hatched at this late day, were ready by the end of August to journey toward the Amazon country, their winter resort. Many birds must divide their residence between the upper and the lower half of the globe to secure a living. Sandpipers travel between Alaska or Greenland and Patagonia twice a year as a matter of course. Man does not appear to be only a little lower than the angels when he is willing to take advantage of the tameness of these birds, which, because they have been reared in out-of-the-way corners of the earth where he is practically unknown, allow him to approach with his gun, when their autumn flocks are resting awhile among us, near enough to rake the last innocent.

In spring some happy couples, already mated, travel northward together; or, all the males may come in one flock, a sort of bachelor's club, ungallantly leaving the females to find their way alone. Then, how these same bachelors sing to advertise their locality when possible mates are expected to arrive!

Different species have different traveling methods, and even the same species does not always about near last year's nest very early in spring, calling repeatedly to a mate that may be many miles follow the same method in spring and fall. Some of the wild ducks, for instance, which go southward in large family parties, return in mated couples, very tenderly attached to each other one might think who had never observed the dandified drake calmly desert his partner just as soon as nursery duties threaten to interfere with his leisure and pleasure. The devoted phoebe, in his somber drab suit, sits away; but in a few days how unerringly she finds the old home, and the faithful lover waiting at the trysting-place beside the bridge to welcome her! The joy of such reunited lovers puts a song into the heart of all beholders.

Permanent residents without the flocking habit - young screech owls

When the cares of a young family beset them, and when old feathers must be replaced by new ones during July and August, birds are seldom sociable. The males of only a few species, that sleep in club-like roosts even at the nesting season, must be excepted. Indeed, so silent and moping are the vast majority when molting that they seem to have entirely disappeared. In the course of a walk through the midsummer woods we may neither see nor hear one. But with the proud consciousness of new clothes and the return of energy with the cooler weather, out they come from their rest-cure retreats, refreshed and even tuneful again, ready to welcome as friend any bird of the same feather, to collect into family parties, or join any passing band of good fellows which receives not only individuals but small roving flocks, one after another, day after day, until, perhaps, many thousands so assemble. Now the meadows and marshes are alive with swallows, and the telegraph wires, strung with them, look like bars of printed music-scrolls stretched across the sky. Now, robins, chewinks, and thrushes congregate along woodland borders, to feast on dogwood or whatever bright berries cling to the trees and bushes waiting for just such distributing agents as they. (For how much of the earth's beauty are not birds, the seed-carriers, responsible!) Mr. William Brewster declares that he has found as many as twenty-five thousand robins sleeping together in one roost. It is well known that crows, likewise, roost in enormous numbers. At the approach of cool weather even the English sparrow, although at no time a shy recluse exactly, becomes intensely gregarious. Great numbers of sparrows — sometimes a sprinkling of the rarer cousins in the flock — settling on the lawn, speedily clean off the seeds of whatever grasses may have got ahead of the mowing machine. Large companies of feeders must necessarily be rovers. Now, flocks of slate-colored juncos appear among the late asters and goldenrod by the waysides. Hosts of old friends come back to us every day; some new acquaintances may turn up at any hour.

High up in the air, sometimes a mile or more above the earth, if the weather be clear, travel flocks of migrants where they can obtain a bird's-eye view of the country to be traversed. Geese have been detected four miles high. Rivers running like silver threads across the map, mountain ranges, valleys, and the seacoast line, must be far more familiar to the birds that follow them systematically than to Macaulay's schoolboy. Only large, strong, or courageous birds dare travel in broad daylight. A mellow honk, honk from the veteran leader of a wedge-shaped flock of wild geese will be answered all along the ranks by his lusty followers, lest any straggler should be lost; for sound as well as sight aids their flight. The twitterings and pipings of the birds that pass in the night float earthward to our listening ears from the dark vault overhead, where they move unseen by friend or foe.

Young Bluebird resting for refreshments after wing practice.  
A candidate for a personally conducted excursion next November

In autumn, great numbers of migrants dash to their death against the lighthouses along our coasts, partly because many are young, inexperienced, wayward travelers; partly because fog now often obscures their course, and chiefly, because they are irresistibly attracted toward the bright, cheerful beacons, much as moths are drawn to the flame. Young birds have learned to fly swiftly in a straight line before they can steer their bodies well. Once launched on a long flight, it is easier to keep going than to stop short. Immature cedar-waxwings, for example, do not lag behind their swift parents when they fly in a straight course above the tree-tops; but I have picked up in September the dead bodies of more young waxwings than I care to recall, simply because, in flying low between one choke-cherry tree on the lawn and another on the road, they couldn't turn out suddenly enough to escape the corner of the house that stood in a direct line between the trees, and so they broke their poor little necks by dashing at top speed against the piazza posts.

Opposing theories to account for the migratory instinct are advanced by scientists. By some it is contended that peculiar acuteness of the five senses, inherent in all animals, would account for the birds' faculty of finding their way from one region to another, even from one continent to another, with precise regularity, which birds alone possess in the highest degree. Other scientists insist that orientation, the instinct of determining direction or relative position in general, brings into play a sixth sense not dependent on the other five. Doubtless the descent and withdrawal of the ice in the glacial period had much to do with the origin of the migratory habit. Certain it is that only a bird which has once made a journey can find its way back to the starting point. Therefore, every young traveler must be "personally conducted" by a veteran. A bird will always return, if possible, to the region of its birth. It knows no other course to follow than the one once taken. A wounded young bird that is not able to leave with the south-bound flock in autumn and recovers strength too late to overtake it, must remain perforce at the north. If the food it requires fail, die it must, for by no possibility could it find its way alone to a land of plenty. The soaring lark, which "at heaven's gate sings," has been imported to this country from Europe, only to die, in most cases, because, at the approach of winter, it couldn't migrate over unknown territory, and couldn't find food enough in our snow-covered northern fields, where, however, it was perfectly content in summer.

In all probability the journeys undertaken by birds at first were short, roving excursions from home; gradually the routes traversed were lengthened of necessity, until, in generation after generation, the habit of traveling became hereditary; the "homing instinct" led little by little to fixed migratory habits. The entire subject stirs our imagination as no other phase of bird life does; for, after all has been said about migration by the scientists, the wonder and the mystery remain.

A clear highway for the migrants between fog and clouds