[[111]]
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 [[112]]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[1] furnish us an excellent example [[113]]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.