Starlings, again, furnish striking examples of the same phenomenon. Their aerial evolutions before roosting are sufficiently remarkable, but, perhaps, still more so from this point of view is the manner in which they leave the roosting-place in the morning. This is not in one great body, as might have been expected, but in successive flights at intervals of some three or four to ten or twelve minutes, each flight comprising, sometimes, hundreds of thousands of birds—the numbers, of course, will vary in different localities—and the whole exodus occupying about half-an-hour. Each of these great flights or uprushes from the dense brake of bush and undergrowth where the birds are congregated, takes place with startling suddenness, and it seems as though every individual bird composing it were linked to every other by some invisible material, as are knots on the meshes of a net by the visible twine connecting them. There is no preliminary,[17] nor does it seem as though a certain number of more restless individuals gradually affected others, but at once a huge mass roars up from the still more immense multitude, as does a wave from the sea, or as a sudden cloud of dust is puffed by the wind from a dust-heap. I am speaking here of the great main flights, which are, in most cases, of this character. The fact that quite small bands of birds will sometimes fly off between the intervals of these, does not detract from the more striking phenomenon or lessen the difficulty of explaining it. For, surely, there is a difficulty in explaining how the example of one vast body of birds, soaring forth on the morning flight, should not affect every individual of the still vaster body of which they form a part—the whole occupying, it must be remembered, a small and densely packed area—and why the impulse of the flying birds to fly should, apparently, become uncontrollable in each individual of them at the same instant of time. If we saw soldiers issuing in this manner from an encampment, or performing all sorts of collective movements and evolutions before entering it in the evening (as do the starlings before descending on their roosting place), and yet satisfied ourselves that there were neither captains nor officers, signals nor words of command amongst them, we should probably wonder, and might think the phenomenon sufficiently curious to make it worth study and investigation.
[17] As far, at least, as observable from just outside the plantation, and to judge from the sound. But previous movements within the plantation—unless we assume a quite human organisation—would not explain what is here assumed to require explanation.
I will take one more example from my notes on wood-pigeons before returning to the flocks of small birds at the stacks.
"A number of wood-pigeons" (this was early on a very cold winter's morning) "have now settled on the elms near me. I am quite still, and they have sat there quietly for some little time. All at once the whole band fly out, to all appearance at one and the same moment, and in a peculiar way, with sudden sweeps and rushes through the air in a downward direction, shooting and zig-zagging across each other with a whizzing whirr of the wings, in much the same manner as do rooks. On account of this peculiar flight, which seems to be joyous and sportive, I do not believe they have seen me. But whether they have or not, the absolutely simultaneous flight of the whole body is, to me, equally hard to account for. Supposing—what would be most likely—that only one bird has seen me, how has this knowledge been communicated, instantaneously, to all the rest? There was no note uttered of any kind. I must have heard it, I think, if it had been, so near as I was, nor are pigeons supposed to have an alarm-note. It may be said that the sudden abrupt flight of one alarmed the rest, but all cannot have been looking at this one at the same time, and it is difficult to suppose that there was anything to discriminate in the actual sound of the wings—for one or more than one bird may, at any time, fly eagerly off without affecting the others. Moreover, if this were the explanation, there would have been an appreciable interval of time between the flight of the alarmed bird and the others, which, to my sense, there was not. But, as I say, I do not believe that the birds saw me, and, if not, the collective, instantaneous impulse of flight seems still harder to account for on ordinary known principles. It is, of course, easy to give a plausible explanation of a thing and take for granted that all the facts are in accordance. But the facts, when one watches them, are apt to discredit the theory. Observation and difficulties begin, often, at the same time."
Returning now to the little winter collections of chaffinches, greenfinches, bramblings, etc., which come and feed at the corn-stacks during the winter, in general they whirr up every three or four minutes, but the intervals vary, and may be much longer. Sometimes only about half the flock flies off, the rest not appearing to care much about it; usually a much greater number does, and this often appears to be the whole number, but almost always—unless, of course, on the approach of a man or some other such alarming occurrence—some few, at least, remain. As with the starlings, these flights seem often to be absolutely instantaneous, the birds all rising together in a solid block, but this is not always the case, and the cloud may be preceded by a little half-hopping, half-chasséeing about of three or four individuals, whilst sometimes there is, for a second or two, a very quick following of one another. If this were always so, and if one bird could not fly off without others following it, there would be little or nothing to explain, but, as we have seen, this is very far from being the case. In nine cases out of ten the birds begin to come back almost as soon as they are gone; but, in spite of this, I came to the conclusion that the cause of flight was almost always a nervous apprehension, such as actuates schoolboys when they are doing something of a forbidden nature and half expect to see the master appear at any moment round the corner. Though there might be no discernible ground for apprehension, yet after some three or four minutes it seemed to strike the assembly that it could not be quite safe to remain any longer, and presto! they were gone. Afterwards it was recognised that there had been no real reason for alarm, and they came back, but this seemed to strike them individually rather than collectively. Now it was by stacks in the open fields under no more cover, as a rule, than the neighbouring hedgerow, that I had noticed these phenomena, and, coming one day upon such a heap of chaff or draff—though without any stack—in the centre of a small plantation of fir and pine trees, I determined to watch here, a number of small birds having flown up as I approached. I was able to conceal myself very well amidst some bushes that grew quite near, and very shortly the birds—chaffinches, bramblings, hedge and tree-sparrows, etc., but not greenfinches—were down again. I stayed a considerable while, but, except once or twice when I moved a little so as to alarm them, they remained feeding all or most of the time. Sometimes, indeed, some or other of them would fly into the surrounding trees or bushes, but this they did at their leisure, without alarm or hurry, and only as desiring a change. The simultaneousness was wanting—there were none of those nervous flights at short intervals that I had observed when watching at the open corn-stacks. Here, amongst the pines, and protected on every side, the birds felt, apparently, quite secure, though whether it was altogether a rational security may be questioned. This observation strengthened me in my conclusion as to these flights being caused by a feeling of nervous apprehension or alarm, but I am bound to add (another case of the mouse) that I subsequently watched by stacks in the open, where, also, a considerable sense of security seemed to prevail. Temperature may perhaps have something to do with the explanation, but I have as yet taken no steps to test this theory.
But whatever may be the motive (which, of course, may vary) of such sudden flights—and here I am thinking of all the examples which I have brought forward, as well as others, in fact, the whole range of the phenomena—how are we to account for their simultaneousness, and the other special features belonging to them?
It would seem as though either one and the same idea were flashed suddenly into the minds of a number of birds in close proximity to each other at one and the same instant of time, or that this same idea, having originated or attained a certain degree of vehemence, at some one point or points—representing some individual bird or birds—spread from thence, as from one or more centres, with inconceivable rapidity, so as to embrace either the whole group or a portion of it, according to the strength of the original outleap. In other words, I suppose (or, at least, I suggest it) that birds when gathered together in large numbers think and act, not individually, but collectively; or, rather, that they do both the one and the other, for that individual birds are capable of withstanding the collective influence of the flock of which they form a part, I have ample evidence. The old Athenians—though slave-holders, wherein they may be compared to the Americans at one period—were a very democratic people, and lived a more public life than any other civilised community either before or after them, of which we have any record. They were also of a very emotional temperament, and it is curious to find amongst them the idea (at any rate) of the φημη—a sudden wave or current of thought which swept through an assembly, causing it to think and act as one man.[18] When watching numbers of birds together, this φημη idea has constantly been brought to my mind, nor do I see how the whole of the facts are to be explained except upon some such hypothesis. If we suppose that the sudden flurryings away of a band of small birds from the chaff-heap where they have been quietly feeding, are caused by the apprehension of danger, we may well credit the birds with having sharper senses than our own, though that they are often mistaken is shown by their almost immediate return, and also by as many of them (sometimes) remaining as fly away. But it is impossible to imagine that every individual bird of a large number, crowded together and busily feeding, can at the same instant of time see the same object, or even hear the same sound of alarm, unless very loud or conspicuous, nor can it be supposed that the same thought, producing the same action, can flash independently into all their minds at once, by mere chance. But if we suppose thought to be like a wind, sweeping amongst them and producing, each time that it rises to a certain degree of strength, its appropriate act, then we can understand fifty, seventy, or a hundred birds rising in this thought-wind, like leaves or straws blown up in a sudden gust, and, in the same way as when a blizzard or tornado bursts on a town, some frail objects in a room through which it has torn may be left standing, whilst everything else is strewed about in ruin, so may the thought-wave (to use the more familiar term) moving with inconceivable rapidity amidst the flock, miss out some individuals, though right in the midst of those that are affected, in a manner which is hard to account for. Again, if we suppose two centres from which two opposite thought-waves or impulses spread, we can understand two groups of birds, which, together, have made one band, acting in different ways or going in different directions (as one may constantly see with rooks and starlings), whilst, by supposing that the wave, or energy, tends to exhaust itself after spreading to a certain distance around any point or centre where it may have originated or become focussed, we account for such facts as many thousands of starlings, say, rising from, perhaps, a million without the others being affected. But, no doubt, even in an Athenian assembly there were some men capable of withstanding the force of the φημη, and if we give to birds, even when thus assembled together, a power of individual as well as collective action, varying in each unit so that the one power is now more and now less under the control of the other—but with, on the whole, a preponderance in favour of the latter—we then, as it appears to me, come near to explaining what I must regard as the often very puzzling problem of the movements of such assembled bodies.
[18] In the wilderness of Grote's twelve volumes I cannot, now, find the passage which I seem to remember so well, nor can anyone (including the whole of the Psychical Research Society) help me to. My Greek word, I am told, too, is wrong. But let it stand till someone can give me the right one.
This, of course, is the theory of thought-transference, and if this power does really exist in the case of any one species we might expect it to exist also in the case of others. With the evidence of its existence amongst ourselves I am not unacquainted, but I need say nothing of this or of my humble opinion concerning it, here. I have suggested it as a possible explanation of some of the actions of birds, because I have found it difficult to account for them in any other way. If it could be made out that animals did really, in some degree, possess this power, it might throw a new light upon many things, and, possibly, explain some difficulties of a larger kind than those which I have called it in to do. To me, at least, it has always seemed a little curious that language of a more perfect kind than animals use has been so late in developing itself; but animals would feel less the want of a language if thought-transference existed amongst them to any appreciable extent.
Assuming its existence, it is amongst gregarious animals that we might expect to find it most developed, and gregariousness has, probably, preceded any great mental advance. Therefore, before an animal reached a grade of intelligence such as might render the growth of a language possible, it would have become gregarious; and, assuming it then to have a certain power of feeling, and being influenced by the thought of its fellows, without the aid of sound or gesture, it is obvious that here would be a power tending to dull and weaken that struggle to express thought by sound, which may be supposed to have slowly and unconsciously led to the formation of a language. Here, then, would be a retarding influence. Still, as ideas communicated in this way would probably be of a general and simple kind, corresponding, perhaps, more to emotions and sensations than definite ideas, the need for more precise impartment would gradually, as mental power became more and more developed, become more and more felt. Then would come language (as spoken), and spoken language, once established, would tend to weaken the old primitive power, as an improvement on which it had arisen. Thus if thought-transference exist in man, it may, perhaps, represent a reversion to a more primitive and generalised means of mental intercommunion, or the older power may exist, and still occasionally act, or even do so habitually to some extent; in fact, it may not yet have entirely died out. Possibly, also, it might tend to survive, and even to some extent increase, as being, in certain ways and directions, superior to the more precise medium. But if so, it would become—unless specially cultivated—more and more limited to these directions. Certain it is that people seem often to approach each other mentally much more by feeling than by words, and in a wonderfully short space of time. We call this insight, intuitive perception, affinity, etc.,—but such words do not explain the process.