Part 7
The latter experience is common enough among hunters of big game, who are often at a loss to explain the sudden flight of animals that a moment ago, under precisely the same outward influences, were feeding or resting without suspicion. Thus, you may be stalking a big herd of elk, or wapiti, which are spread out loosely over half a mountainside. You are keen for the master bull with the noble antlers; nothing else interests you, more’s the pity; but you soon learn that the cunning old brute is hidden somewhere in the midst of the herd, depending on the screen of cow-elk to warn him of danger to his precious skin. Waiting impatiently till this vanguard has moved aside, you attempt to worm your way nearer to the hidden bull. You are succeeding beautifully, you think, when a single cow that you overlooked begins to act uneasily. She has not seen or heard you, certainly, and the wind is still in your favor; but there she stands, like an image of suspicion, head up, looking, listening, testing the air, till she makes up her mind she would as lief be somewhere else, when without cry or grunt or warning of any kind that ears can hear she turns and glides rapidly away.
Now if you value animal lore above stuffed skins, or experience above the babble of hunting naturalists, forget the big bull and his greed-stirring antlers; scramble quickly to the highest outlook at hand, and use your eyes. No alarm has been sounded; the vast silence is unbroken; yet for some mysterious reason the whole herd is suddenly on the move. To your right, to your left, near at hand or far away, bushes quiver or jump; alert brown forms appear or vanish like shadows, all silent and all heading in the direction taken by the first sentinel. One moment there are scores of elk in sight, feeding or resting quietly; the next they are gone and the great hillside is lifeless. The thrill of that silent, moving drama has more wisdom in it, yes, and more pleasure, than the crash of your barbarous rifle or the convulsive kicking of a stricken beast that knows not why you should kill him.
Such is the experience, known to almost every elk-hunter who has learned that life is more interesting than death; and I know nothing of deer nature to explain it save this—that the whole herd has suddenly felt and understood the silent impulse to go, and has obeyed it without a question, as the young wolf or fox cub obeys the silent return call of his watchful mother.
Such impulses seem to be more common and more dependable among the whales, which have rudimentary or imperfect sense-organs, but which are nevertheless delicately sensitive to external impressions, to the approach of unseen danger, to the movements of the tiny creatures on which they feed, to changes of wind or tide and to a falling barometer, as if nature had given them a first-class feeling apparatus of some kind to make up for their poor eyes and ears. Repeatedly have I been struck by this extraordinary sensitiveness when watching the monstrous creatures feeding with the tide in one of the great bays of the Newfoundland or the Labrador coast. If I lowered a boat to approach one of them, he would disappear silently before I could ever get near enough to see clearly what he was doing. That seemed odd to me; but presently I began to notice a more puzzling thing: at the instant my whale took alarm every other whale of the same species seemed to be moved by the same impulse, sounding when the first sounded, or else turning with him to head for the open sea.
A score of times I tried the experiment, and commonly, but not invariably, with the same result. I would sight a few leviathans playing or feeding, shooting up from the deep, breaching half their length out of water to fall back with a tremendous souse; and through my glasses I would pick up others here or there in the same bay. Selecting a certain whale, I would glide rapidly toward him, crouching low in the dory and sculling silently by means of an oar over the stern. By some odd channel of perception (not by sight, certainly, for I kept out of the narrow range of his eye, and a whale is not supposed to smell or hear) he would invariably get wind of me and go down; and then, jumping to my feet, I would see other whales in the distance catch the instant alarm, some upending as they plunged to the deeps, others whirling seaward and forging full speed ahead.
This observation of mine is not unique, as I supposed, for later I heard it echoed as a matter of course by the whalemen. Thus, when I talked with my friend, Captain Rule, about the ways of the great creatures he had followed in the old whaling-days, he said, “The queerest habit of a whale, or of any other critter I ever fell foul of, was this: when I got my boat close enough to a sperm-whale to put an iron into him, every other sperm-whale within ten miles would turn flukes, as if he had been harpooned, too.” But he added that he had not noticed the same contagion of alarm, not in the same striking or instantaneous way, when hunting the right or Greenland whale—perhaps because the latter is, as a rule, more solitary in its habits.
Wolves and caribou and whales are far from the observation of most folk; but the winter birds in your own yard may some time give you a hint, at least, of the same mysterious transference of an impulse over wide distances. When you scatter food for them during a cold snap or after a storm (it is better not to feed them regularly, I think, especially in mild weather when their proper food is not covered with snow) your bounty is at first neglected except by the house sparrows and starlings. Unlike our native birds, these imported foreigners are easily “pauperized,” seeking no food for themselves so long as you take care of them. They keep tabs on you, also, waiting patiently about the house, and soon learn what it means when you emerge from your back door on a snowy morning with a broom in one hand and a pan in the other. They are feeding greedily the moment your back is turned, and for a time they are the only birds at the table. When they have gorged themselves, for they have no manners, a few tree-sparrows and juncos flit in to eat daintily. Then suddenly the wilder birds appear—jays, chickadees, siskins, kinglets and, oh, welcome! a flock of bob-whites—coming from you know not where, in obedience to a summons which you have not heard. Some of these may have visited the yard in time past, and are returning to it now, hunger driven; but others you have never before met within the city limits, and a few have their accustomed dwelling in the pine woods, which are miles away. How did these hungry hermits suddenly learn that food was here?
The answer to that question is simple, and entirely “sensible” if you think only of birds that live or habitually glean in your neighborhood. Some of them saw you scatter the food, or else found it by searching, while others spied these lucky ones feeding and came quickly to join the feast. For birds that live wider afield there is also an explanation that your senses can approve, though it is probably wrong or only half right: from a distance they chanced to see wings speeding in the direction of your yard, and followed them expectantly because wings may be as eloquent as voices, the flight of a bird when he is heading for food being very different from the flight of the same bird when he is merely looking for food. But these most rare visitors, kinglets or pine-finches or grosbeaks or bob-whites, that never before entered your yard, and that would not be here now had you not thought to scatter food this morning,—at these you shake your head, calling it chance or Providence or mystery, according to your mood or disposition. To me, after observing the matter closely many times, the reasonable explanation of these rare visitors is that either wild birds know how to send forth a silent food-call or, more likely, that the excitement of feeding birds spreads powerfully outward, and is felt by other starving birds, alert and sensitive, at a distance beyond all possible range of sight or hearing. By no other hypothesis can I account for the fact that certain wild birds make their appearance in my yard at a moment when a number of other birds are eagerly feeding, and at no other time, though I watch for them from one year’s end to another.
Like every other explanation, whether of stars or starlings, this also leads to a greater mystery. The distance at which such a summoning call can be felt by others must be straitly limited, else would all the starving birds of a state be flocking to my yard on certain mornings; and the force by which the silent call is projected is as unknown as the rare mental ether which bears its waves or vibrations in all directions. Yet the problem need not greatly trouble us, since the answer, when it comes, will be as natural as breathing. If silent or telepathic communication exists in nature, and I think it surely does, the mystery before us is no greater than that which daily confronts the astronomer or the wireless operator. One measures the speed of light from Orion; the other projects his finger-touch across an ocean; but neither can tell or even guess the quality of the medium by which the light or the electric wave is carried to its destination.
V
THE SWARM SPIRIT
This is a chapter on the wing drill of birds, the swarming of bees, the panics and unseasonal migrations of larger or smaller beasts, and other curious phenomena in which the wild creatures of a flock or herd all act in unison, doing the same thing at the same time, as if governed by a single will rather than by individual motives. If it should turn out that the single will were expressed in a voice or cry, or even in a projected impulse, then are we again face to face with our problem of animal communication.
Of the fact of collective action there is no doubt, many naturalists having witnessed it; and there is also a strictly orthodox explanation. Thus, when you see a large flock of crows “drilling” in the spring or autumn, rising or falling or wheeling all together with marvelous precision, the ornithologists resolve the matter by saying that the many crows act as one crow because they follow a “collective impulse”; that is, because the same impulse to rise or fall or wheel seizes upon them all at precisely the same moment. And this they tell you quite simply, as if pointing out an obvious fact of natural history, when in reality they are showing you the rarest chimera that ever looked out of a vacuum.
Now the wonderful wing drill of certain birds has something in it which I cannot quite fathom or understand, not even with a miracle of collective impulse to help me; yet I have observed two characteristics of the ordered flight which may help to dispel the fog of assumption that now envelops it. The first is, that the drill is seen only when an uncommonly large number of birds of the same kind are gathered together, on a sunny day of early spring, as a rule, or in the perfection of autumn weather.
The starlings [3] furnish us an excellent example of this peculiarity. For months at a stretch you see them about the house, first in pairs, next in family groups, then in larger companies, made up, I think, of birds raised in the same neighborhood and probably all more or less related; but though you watch these companies attentively from dawn to dusk, you shall never see them going through any unusual wing drill. Then comes an hour when flocks of starlings appear on all sides, heading to a common center. They gather in trees here or there about the edges of a great field or a strip of open beach, all jabbering like the blackbirds, which they imitate in their cries, flitting about in ceaseless commotion, but apparently keeping their family or tribal organization intact. Suddenly, as at a signal, they all launch themselves toward the center of the field; the hundred companies unite in one immense flock, and presto! the drill is on. The birds are no longer individuals, but a single-minded myriad, which wheels or veers with such precision that the ash of their ten-thousand wings when they turn is like the flicker of a signal-glass in the sun.
The same characteristic of uncommon numbers holds true of the crows and, indeed, of all other species of birds, save one, that ever practise the wing drill. Wild geese when in small companies, each a family unit, have a regular and beautiful flight in harrow-shaped formation; but I have never witnessed anything like a wing drill among them save on one occasion, when a thousand or more of the birds were gathered together for a few days of frolic before beginning the southern migration. Nor have I ever seen the drill among thrushes or warblers or sparrows or terns or seagulls, which sometimes gather in uncounted numbers, but which do not, apparently, have the same motive that leads crows or starlings to unite in a kind of rhythmic air-dance on periodic occasions.
A second marked characteristic of the wing drill is that it is invariably a manifestation of play or sport, and that the individual birds, though they keep the order of the play marvelously well, show in their looks and voices a suppressed emotional excitement. The drill is never seen when birds are migrating or feeding or fleeing from danger, though thousands of them may be together at such a time, but only when they assemble in a spirit of fun or exercise, and their bodily needs are satisfied, and the weather or the barometer is just right, and no enemy is near to trouble them. Whatever their motive or impulse, therefore, it is certainly not universal or even widespread among the birds, since most of them do not practise the drill; nor is it in the least like that mysterious impulse which suddenly sets all the squirrels of a region in migration, or calls the lemmings to hurry over plain and forest and mountain till they all drown themselves in the distant sea; for no sooner is the brief drill over than the companies scatter quietly, each to its own place, and the individual birds are again alert, inquisitive, well balanced, precisely as they were before.
The drill is seen at its best among the plover, I think; and, curiously enough, these are the only birds I know that practise it frequently, in small or large numbers and in all weathers. I have often watched a flock come sweeping in to my decoys, gurgling like a thousand fifes with bubbles in them; and never have I met these perfectly drilled birds, which stay with us but a few hours on their rapid journey from the far north to the far south, without renewed wonder at their wildness, their tameness, their incomprehensible ways. That you may visualize our problem before I venture an explanation, here is what you may see if you can forget your gun to observe nature with a deeper interest:
You have risen soon after midnight, called by the storm and the shrilling of passing plover, and long before daylight you are waiting for the birds on the burnt-over plain. Your “stand” is a hole in the earth, hidden by a few berry-bushes; and before you, at right angles with the course of the storm (for plover always wheel to head into the wind when they take the ground), are some scores of rudely painted decoys. As the day breaks you see against the east a motion as of wings, and your call rings out wild and clear, to be echoed on the instant. In response to your whistle the distant motion grows wildly fantastic; it begins to whirl and eddy, as if a wisp of fog were rolling swiftly down-wind; only in some mysterious fashion the fog holds together, and in it are curious flickerings. Those are plover, certainly; no other birds have that perfect unity of movement; and now, since they are looking for the source of the call they have just heard, you throw your cap in the air or wave a handkerchief to attract attention. There is an answering flash of white from the under side of their wings as the plover catch your signal and turn all at once to meet it. Here they come, driving in at terrific speed straight at you!
It is better to stop calling now, because the plover will soon see your decoys; and these birds when on the ground make no sound except a low, pulsating whistle of welcome or recall. This is uttered but seldom, and unless you can imitate it, which is not likely, your whistling will do no good. Besides, it could not possibly be heard. Listen to that musical babel, and let your nerves dance to it! In all nature there is nothing to compare for utter wildness with the fluting of incoming plover.
On they come, hundreds of quivering lines, which are the thin edges of wings, moving as one to a definite goal. Their keen eyes caught the first wave of your handkerchief in the distance; and now they see their own kind on the ground, as they think, and their babel changes as they begin to talk to them. Suddenly, and so instantaneously that it makes you blink, there is a change of some kind in every quivering pair of wings. At first, in the soft light of dawn, you are sure that the plover are still coming, for you did not see them turn; but the lines grow smaller, dimmer, and you know that every bird in the flock has whirled, as if at command, and is now heading straight away. You put your fingers to your lips and send out the eery plover call again and again; but it goes unheeded in that tumult of better whistling. The quivering lines are now all blurred in one; with a final flicker they disappear below a rise of ground; the birds are gone, and you cease your vain calling. Then, when you are thinking you will never see that flock again, a cloud of wings shoot up from the plain against the horizon; they fall, wheel, rise again in marvelous flight, not as a thousand individuals but as a unit, and the lines grow larger, clearer, as the plover come sweeping back to your decoys once more.
Such is the phenomenon as I witnessed it repeatedly on the Nantucket moors, many years ago. The only way I can explain the instantaneous change of flight is by the assumption, no longer strange or untested, that from some alarmed plover on the fringe or at the center of the flock a warning impulse is sent out, and the birds all feel and obey it as one bird. That the warning is a silent one I am convinced, for it seems impossible that any peculiar whistle could be heard or understood in that wild clamor of whistling. Nor is it a satisfactory hypothesis that one bird sees the danger or suspects the quality of the decoys, and all the others copy his swift flight; for in that case there must be succession or delay or straggling in the turning, and the impression left on the eye is not of succession, but of almost perfect unity of movement.
The only other explanation of the plovers’ action is the one commonly found in the bird-books, to which I have already briefly referred, and which we must now examine more narrowly. It assumes that all the birds of a migrating flock are moved not by individual wills, but by a collective impulse or instinct, which affects them all alike at the same instant. In support of this favorite theory we are told to consider the bees, which are said to have no individual motives, and no need for them, since they blindly follow a swarm or hive instinct that makes them all precisely alike in their actions. The same swarm instinct appears often in the birds, but less strongly, because they are more highly developed creatures, with more need and therefore more capacity for individual incentive.
This illustration of the hive is offered so confidently and accepted so readily, as if it were an axiom of natural history, that one hesitates to disturb the ancient idol in its wonted seat. Yet one might argue that any living impulse, whether in bees or birds, must proceed from a living source, and, if that be granted, speculate on the absorbing business of a nature or a heaven that should be perpetually interfering in behalf of every earthly flock or swarm or herd by sending the appropriate impulse at precisely the right moment. And when our speculation is at an end, I submit the fact that, when I have broken open a honey-tree in the woods, one bee falls upon the sweets to gorge himself withal, while another from the same swarm falls angrily upon me and dies fighting; which seems to upset the collective-impulse idol completely.
I must confess here that I know very little about bees. They are still a mystery to me, and I would rather keep silence about them until I find one bee that I fancy I understand, or one man who offers something better than a very hazy or mystical explanation of a bee’s extraordinary action. Yet I have watched long hours at a hive, have handled a swarm without gloves or mask, and have performed a few experiments—enough to convince me that the collective-impulse theory does not always hold true to fact even among our honey-makers. Indeed, I doubt that it ever holds true, or that there is in nature any such mysterious thing as a swarm or flock or herd impulse.