Now, had Darwin been of opinion that antics performed by a bird which could not, or could not easily, be explained by his theory, were fatal to it in other cases—if he had thought that the one was inconsistent with the other—then, no doubt, it would have been unfair on his part to have marshalled the affirmative evidence without concerning himself with the negative. But why should he have held that view, or on what good grounds can such a view be maintained? As well might it be argued—so it appears to me—that woollen or other goods could only have been produced through the action of the loom, or some such special machinery. But let the wool be there, and it can be worked up in various ways. Mr Hudson would account for all such displays or exhibitions by "a universal joyous instinct" present throughout nature, but to which birds are more subject than mammals. I do not dispute the instinct—or rather, perhaps, the emotion—or that some of the displays in question may be due to it simply and solely: but I cannot believe that all are. Why should this be the case, or how can movements which are often of a complex and elaborate nature be explained solely by reference to some large general factor, such as joy or vital energy? These may lie at the root of all; but something else, some more special process is, I think, in many cases required. One would not be content to explain all the phenomena of history by a reference to human nature, and though it may be true, as the Kaffirs say, that in a cattle-kraal there can only be one bull, yet nature is a good deal larger than a cattle-kraal. I believe myself that various antics which are performed by birds have grown out of various nervous, excited, or automatic movements arising under the influence of various special causes. Two such possible causes—viz. (1) sudden alarm whilst incubating, and (2) paroxysms of rage or nervous excitement during rivalry for the female I have already indicated. Two other possible ones have also been suggested to me by some of my observations, and I will now, by the aid of these, make an attempt—I daresay a lame one—to throw light on the possible origin of a very extraordinary case of bird-antics, described by Mr Hudson in the work I have mentioned, and which is believed by him to be unique.
The bird in question is the spur-winged lapwing, and the following is Mr Hudson's account of its performances:—
"If a person watches any two birds for some time—for they live in pairs—he will see another lapwing, one of a neighbouring couple, rise up and fly to them, leaving his own mate to guard their chosen ground; and instead of resenting this visit as an unwarranted intrusion on their domain, as they would certainly resent the approach of almost any other bird, they welcome it with notes and signs of pleasure. Advancing to the visitor, they place themselves behind it; then all three keeping step begin a rapid march, uttering resonant drumming notes in time with their movements, the notes of the pair behind being emitted in a stream, like a drum-roll, while the leader utters loud single notes at regular intervals. The march ceases; the leader elevates his wings and stands erect and motionless, still uttering loud notes; while the other two, with puffed-out plumage, and standing exactly abreast, stoop forward and downward until the tips of their beaks touch the ground, and, sinking their rhythmical voices to a murmur, remain for some time in this position. The performance is then over, and the visitor goes back to his own ground and mate, to receive a visitor himself later on."
Now the most curious point in this remarkable performance, so well described, is that three birds—a pair (male and female), and one other, whether male or female is not stated—take part in it, and how is this fundamental peculiarity to be explained better on the theory of "a universal joyous instinct" than on that of sexual selection, if, indeed, the former one helps us so well? Joy, no doubt, is there, but something else—some shaping force—is surely required to account for the particular form in which it finds expression. Now with regard to the peculiarity pointed out—the odd bird (though all act oddly)—I have, whilst watching birds in the early spring, been struck by the frequency with which three of the same species will be seen in each other's company, usually chasing one another about, and, as with the spur-winged lapwing, these three are almost always made up of a pair (a male and female) and another bird, a male, as I believe. It may be said that here there can be no analogy, for that it is either merely a case of two males courting one female, or that the odd male is both a rival and intruder, endeavouring to come between the married happiness of two who have made their choice. This latter explanation is the one that has generally seemed to me to meet the case, but what I have frequently noticed with surprise is that the state of anger, or, indeed, fury, which one might imagine would obtain under such circumstances between the two male birds, is either wholly absent, or very much subdued. Now it is in the case of our own peewit, more than with any other species, that I have noticed this quite amicable association of three birds, two of which would often seem to be a paired couple, and as my notes, made whilst I had the birds under observation, both illustrate the point and contain the explanation of it which I have to offer, I will here quote from them:
"February 25th.—Three peewits in company with each other. Two are flying close together, as though they were a paired couple, whilst one follows them at a short interval.
"February 27th.—Three peewits flying together in the same way as before—that is to say two, which may be paired birds, are close together, whilst there is commonly a short space between them and the third one. This arrangement may be temporarily suspended or reversed by the bird that has been separated getting up to the other two, when one of these will often fall behind, so that now the bird which was the follower makes one of the two advanced ones, whilst one of these has taken its place. As there is no sexual distinction in the plumage of peewits,[12] it is impossible to be quite sure to what sex each of these birds belongs, but I believe that two of them are male and female, and the third a male, either of the two males being alternately in the close company of the female. This, indeed, may be in the nature of the matter. The pairing off of the birds, we will suppose—as is likely at this time—is not yet completed, and, assuming two of the three to be of one sex, it may not be quite settled with which of them the third will pair. It is not, indeed, necessary to suppose that either of the three will eventually pair with one of the others, though this may be probable. But what appears to me to obtain is this, that the association of two birds (male and female) together has a tendency to bring up a third, presumably a male, who envies this arrangement, and would fain itself make one of the two. But how, then, is the amicableness—or, at any rate, the absence of any marked evidence of hostility—to be accounted for? I believe that at this early season the sexual feelings have not yet become fully developed, or so strong as to produce jealousy to any active extent. Things are only beginning, the emotions are, as yet, in their infancy, and thus, I believe, the curious, not fully defined nature of the actions of the three birds—their seeming to be half unconscious of what they really want or mean—may be accounted for. As the season advances, the tendency will be more and more for the two birds (but I here speak of birds generally) to avoid, or actively to drive away, the third, and for the third to find another bird for a partner, the whole being tempered by the character both of the species of bird and the individual birds belonging to it. The three birds being thus brought together, without the feelings being of a very strong or defined character, and the feelings of animals generally being, as I believe they are, of a very plastic nature (by which I mean that they pass easily from one channel into another), I can understand a sort of sport or game of three birds together arising, at first almost imperceptible, till, by the fundamental laws of evolution—variation and inheritance—it might pass into something highly peculiar, as in the case of the spur-winged lapwing—for though such sport might commence in the air, there would be no reason why it should not pass from thence on to the ground. And that the number should be three, and not more, is thus also explained, for whilst the sight of a paired male and female bird would be likely to excite the sexual feelings—even though, as here supposed, somewhat languid—of another male, so as to make it join them, three together would hardly have this effect in an equal degree, and, moreover, more than three would tend to become a flock, when other feelings would come into play. However this may be, I have, as a matter of fact, been struck with the frequency with which, in the early spring, three birds will keep together, as and in the manner before stated."
[12] For ordinary field observation at least.
This, it will be observed, was written at a time of year when peewits are only beginning their nuptial antics, though, as to their having begun them, there is no doubt, as I had carefully noted this at a still earlier date. But long subsequent to this, and when the theory of a not fully developed state of the sexual feelings could no longer be tenable as an explanation of non-combativeness, I noticed, or thought I noticed, a more than usual tendency in this species for a single bird to project itself, so to speak, into the midst of a married pair, and for its presence not to be resented, but rather otherwise. If this be really so—for, of course, I may be deceived—it is interesting, and perhaps assists the suggestion which I have offered as to the origin of the astonishing conduct of the spur-winged lapwing, the two being such near relations. When the habit had once commenced, it might continue and become fixed, irrespective of season.
But it may be said that all the evidence which I here bring forward is of three birds being together, and that there is none as to any sport or antic, of however incipient or rudimentary a nature. I have, however, often seen peewits sport and wanton in the air in threes, but I admit that more evidence in this direction is wanted. The little that I have, and will here give, relates, not to the peewit, but to two birds very different both to it and to each other. The first of these is that attractive and delightful little creature, the dabchick or little grebe (Podiceps fluviatilis), a bird whose society I have always cultivated to the best of my ability. My first note, taken on 14th December, I give merely by way of showing that sexual feelings in birds may not always lie entirely dormant, even in the depth of winter; for, from having long watched the same birds in the same little reedy creek, I feel sure that the two I here chronicle were male and female.
These were "pursuing each other, first over the water—fly-flapping along the surface in their peculiar way—then on and under it, ducking, coming up close together, ducking again, and so on, flapping, ducking, and swimming, each in turn. It is very sustained and animated, suggesting an amorous pursuit of the female by the male, even at this time of year. They make a great noise and splashing, they are obstreperous, and a hen moor-hen standing staidly on some bent reeds gives a look as though doubtful of the strict propriety of such conduct,—in the winter,—then with an 'Ah, well! dabchicks will be dabchicks, I suppose, at all times,' resigns herself to the inevitable, and takes to preening her feathers." In the other case, which is the one that bears more directly on the question under discussion, three dabchicks pursued each other in this manner, one behind the other, and following the course of the stream. The last bird was particularly energetic, and seemed determined to interfere with the pursuit of the foremost by the one just in front of him. "When quite near me they all three pitch down and instantly dive. The first to come up stops dead still on the water, looking keenly and expectantly over it, his neck stretched rigidly out, his head darting forward from it at a right angle, as rigid as the neck. The instant another one appears, he dives again with a suddenness as of the lid of a box going down with a snap, and this other one has seen him at the same time, and dives still more quickly, if that were possible—so quickly that there is just a swirl on the water, the appearance seems part of the disappearance, 'and nothing is but what is not.' And this, as I think, continues, but owing to the rapid progress of the birds under the water, and their getting amongst flags and weeds, I never have an equally 'convincing' sight of it."