[8] But I have not been able to find the passage, so may be mistaken.
But may we not think that an act, which in its origin has been of a nervous and, as it were, pathological character, has become, in time, blended with intelligence, and that natural selection has not only picked out those birds who best performed a mechanical action—which, though it sprung merely from mental disturbance, was yet of a beneficial nature—but also those whose intelligence began after a time to enable them to see whereto such action tended, and thus consciously to guide and improve it? There is evidence, I believe—though neither space nor the nature of this slight work will allow me to go into it—that such abnormal mental states as of old inspired "the pale-eyed priest from the prophetic cell," and to-day influence priests or medicine-men amongst savages (to go no farther), can be, and are, combined with ordinary shrewd intelligence; nor does it seem too much to suppose that a bird that was always seeing the effect of what it did when it, as it were, fell into hysterics, should have come in time to reckon upon the hysterics, to know what they were good for, and even to some extent to direct them—as a great actor in an emotional scene must govern himself in the main, though, probably, a great deal of the gesture, action, and facial expression is unconsciously and spontaneously performed.
Now, if we assume that these ruses employed by birds for the protection of their young—as in the case of the wild-duck—have commenced in purely involuntary movements, without any proposed object, the instance here given of the snipe may perhaps throw some light upon their origin. A bird, whilst incubating, and thus, hour after hour, doing violence to its active and energetic disposition, is under the influence of a strong force in opposition to and overcoming the forces which usually govern it. Its mental state may be supposed to be a highly-wrought and tense one, and it therefore does not seem surprising that some sudden surprise and startle at such a time, by rousing a force opposite to that under the control of which it then is, and producing thereby a violent conflict, should throw it off its mental balance and so produce something in the nature of hysteria or convulsions. But let this once take place with anything like frequency in the case of any bird, and natural selection will begin to act. As the eggs of a bird are stationary, and do not run away or seek shelter whilst the parent bird is thus behaving in their neighbourhood, it would, on the whole, be better for it to sit close or to fly away in an ordinary and non-betraying manner. Allowing this, then, as the eggs of a bird would be less exposed to danger the less often the sitting bird went off them in this way, might not natural selection keep throwing the impulse to do so farther and farther backwards till after the incubatory process was completed? Then the tendency would be encouraged—at least in the case of birds whose young can early get about—for, as a rule, such antics would shield them better than sitting still. The young would generally be in several places—giving as many chances of discovery—and, on account of the suddenness of the surprise, would often be running or otherwise exposing themselves. Take, for instance, the case of the wild-duck, where I have always found the brood a most conspicuous object at first, and taking some time, even on reedy rivers, to get into concealment.
And I can see no reason why an aiding intelligence in the performance of such movements should not be selected pari passu with the movements themselves, though of a nervous and, originally, purely automatic character. Natural selection would, in this way, develop a special intelligence in the performance of some special actions, out of proportion to the general intelligence of the creature performing them, though, no doubt, this also would tend to be thereby enlarged. And this is what, in fact, we often do see or seem to see.
I may add that when, a few days afterwards, I again approached this same nest the bird went off it without any performance of the sort. This, if we could be sure that it was the same bird, would seem to show that the habit was in an unfixed and fluctuating condition. On the other hand, a bird that acts thus in the case of its young, would, I think, always act so.
Perhaps it may be wondered why I have not included the peewit in the list of birds which employ, or appear to employ, a ruse in favour of their young ones, since this bird is always given as the stock instance of it. The reason is, that whilst the birds I mentioned have always, in my experience, gone off, so to speak, like clock-work, when the occasion for it arrived, I have never known a peewit to do so, though I have probably disturbed as many scores—perhaps hundreds—of them, under the requisite conditions, as I have units of the others. I have also inquired of keepers and warreners, and found their experience to tally with mine. They have spoken of the cock bird "leading you astray" aerially, whilst the hen sits on the nest, and of both of them flying, with screams, close about your head when the young are out, which statements I have often verified. But they have never professed to have seen a peewit flapping over the ground as with a broken wing, in the way it is so constantly said to do. I cannot, therefore, but think that, by some chance or other, an action common to many birds has been particularly, and yet wrongly, ascribed to the peewit. As it seems to me, this is just one of those cases where negative evidence is almost as strong as affirmative, and though, of course, quite ready to accept any properly witnessed instance of the peewit's acting in this way, I cannot but conclude that it does so very rarely indeed.
