It is to be observed here that these two birds, though they were in active and excited rivalry for the greater part of an afternoon, and though they made many feints and, as it were, endeavours to fight, yet only really fought twice, seeming, indeed, to have a considerable respect for each other's prowess, and "letting I dare not wait upon I will" during most of the time. Perhaps they were brave, but the idea given me by the whole thing was that of two cowards trying to work themselves up into a sufficient degree of fury to overcome, for a moment or two, their natural timidity. "Willing to wound, but yet afraid to strike," seemed to me to describe their mental attitude.
Much has been said as to the pugnacity of birds, but I think that a large amount of timidity often mingles with this pugnacity, even in the most pugnacious kinds. I have seen, for instance, two pheasants sit, first, face to face, pecking timidly at, or rather towards, each other, and then, on rising, make various little half-hearted feints and runs, one at another, as though trying to fight and not being able to, and this for quite a long time. At last one of them ran to some distance away, and then, turning, made a most tremendous, fiery rush down upon the other one, like a knight in the tilt-yard. Nothing could have looked bolder, more spirited, more full of fire and fury, but—just like these wheatears—at the very moment that he should have hurled himself upon his foe he swerved timidly aside, and all his brave carriage was gone in a moment. And what struck me (and, indeed, as humorous) was that this other bird—the one thus charged down upon—who had been just as timid, and had seemed to find fighting equally difficult, did not retreat, as one might have expected, before this great show, but sat quietly, as knowing it to be "indeed but show," and that there was nothing really to fear. In fact, it was like the drawing of swords between Nym and Pistol in Henry V., each being afraid to use his, and knowing the other to be so too. Black-cocks, again, are often very ready to avoid a conflict, and dance much more fiercely than they fight. A bird, indeed, which is a very demon in the "spiel" or "lek-platz" may, as I have seen, become meek and retreat from it upon the entry of another, which other is then, of course, ipso facto, the boldest bird in existence. Blackbirds are considered to be quarrelsome,[10] and I know that even the hens—or, perhaps, they especially—will sometimes fight in the most vindictive manner. But, as with these wheatears, I have seen in the case of rival cock blackbirds a great deal of chariness of real fighting mingle with much ostentation of being ready to fight.
[10] Whereas the thrush (it is usually added) is peaceable. But this is one of those passed-on things with which natural history is burdened. From my own experience, I know it to be otherwise. I have watched thrushes fighting furiously, not only with one another but with the blackbird also.
I am not, of course, disputing the pugnacity of birds during the breeding season and often at other times. That is quite beyond doubt, and proofs or instances of it are altogether superfluous. But the pugnacity is all the greater if, in order for it to assert itself, a greater or less degree of timidity, varying, of course, in different species and individuals, must first be overcome. Assuming that this is sometimes the case (and I know not how else such instances as I have given are to be explained), is it so unlikely that rival birds, wishing to fight yet half afraid to, and being thus in a state of great nervous tension, should fall into certain violent or frenzied movements, into little paroxysms of fury, as when a man is popularly said to "dance with rage"? Anything that excites highly tends to exalt the courage and conquer fear, as we know with our own martial music, to say nothing of the "pyrrhic" and other dances. It seems possible, therefore, that such violent movements as are here imagined might have this effect, and thus, though excited originally by rage—or some high state of emotion—only, might be persisted in and increased through experience of their efficacy. But if this does ever happen, may we not have here the origin—or one of the origins—of those undoubted displays made by the male bird to the female, on which the theory of sexual selection is chiefly based? That the male birds should, in the beginning, have consciously displayed their plumage, in however slight a manner, to the females, with an idea of it striking them, seems improbable, and, even if we might assume the intelligence requisite for this, the theory of sexual selection supposes the beauty of the plumage to have been gained by the display of it, not that the display has been founded upon the beauty. Then what should first lead a bird of dull plumage consciously to display this plumage before the female? A mere habit of the male, increased and perfected by the selective agency of the female (as this is explained by Darwin), has hitherto—as far as I know—been considered a sufficient explanation of the origin and early stages of such displays as are now made by the great bustard, the various birds of paradise, or the argus pheasant. But if we can show a likelihood as to how this habit has arisen we are, at least, a step farther forward, even if a slight difficulty has not thereby been removed.
Now, with regard to these wheatears, it will, I think, be admitted that the little frenzies of the male birds—as I have described them—were of a very marked, and, indeed, extraordinary nature, and also, perhaps, that it is more easy to look upon them as sudden bursts of excitement—nerve-storms or emotional whirlwinds, so to speak—than as displays intended to attract the attention of the female bird. Certainly there was nothing like a set display of the plumage; and, with regard to the female, the question arises, Where was she, at least during the greater part of the time? The two male birds in the course of their drama got over a considerable amount of ground, and constantly flew from one part to another, so that, in order to have had anything like a good view, the female must have accompanied them, and I must then, perforce, have seen her, which I did not, except on the occasions related. She was, therefore, not with them, and, if watching them at all, could only have been doing so from such a distance that the dancings of the male birds would have been very much thrown away. Yet that she took some interest in what was going on appears likely from her flying up twice into the willow tree during its continuance, and being with the two rivals at the end of the day. She might, too, have been listening to the song and observing the flights up into the air, which would have been much more noticeable from a distance.
One might expect a female bird to take some interest in two male ones fighting for her merely, without any adjunct, and if they added to the fighting peculiar violent movements, such as those here described, that interest would tend to become increased. Now I can imagine that with this material of violent motions on the one side and some amount of interested curiosity on the other, the former might gradually come to be a display made entirely for the female, and the latter a greater or lesser degree of pleasurable excitement raised by it with a choice in accordance, which is sexual selection. And that the display would come at last to be made intelligently, and with a view to a proposed end—as in the case supposed of the female wild duck (or other bird) diverting attention from its young—I can also understand. In both instances mere nervous movements due to a high state of excitement would have been directed into a certain channel and then perfected by the agency either of natural or sexual selection.
On this view the curiosity (passing insensibly into interest and satisfaction) of the female bird would have been directed, at first, not to the plumage but to the frenzied actions—the antics—of the male, and he, on his part, would have first consciously displayed only these. From this to the more refined appreciation of colours and patterns may have been a very gradual process, but one can understand the one growing out of the other, for waving plumes and fluttering wings would still be action, and action is emphasised by colour.
Where, however, such movements had not been seized upon and controlled by the latter of these two powers—i.e. sexual selection—(and there is no necessity that they should be), we should have antics not in the nature of sexual display properly speaking, but which might yet bear a greater or less resemblance to such. That this is, in fact, the case has been pointed out by the opponents of sexual selection, and often as if it were evidence against it (though no one, unfortunately, can point to men as a ground for disbelief in armies). Mr Hudson, for instance, in his very interesting work, "The Naturalist in La Plata," after bringing forward a number of cases of curious dance-movements (or of song), performed by birds, and which are, in his opinion, not to be explained on the theory of sexual selection, says, in regard to other cases brought forward by Darwin in support of that theory:
"How unfair the argument is, based on these carefully selected cases gathered from all regions of the globe, and often not properly reported, is seen when we turn from the book[11] to nature, and closely consider the habits and actions of all the species inhabiting any one district!"
[11] But from which "book"? Not, I suppose, from Darwin's alone.