MOUTHS WITH MEANINGS
T
THE young kittiwake differs in appearance from the parent birds in a quite uncommon manner, for, being prettily and saliently marked, it looks like a mature gull of another species, whereas the young of other gulls, being plain brown things, suggest their juvenility on the analogy of pheasants or birds of paradise. The general colour is mauvy grey, but black, falling here and there upon it, seems striving to blot it out. Half of the wings are thus darkened, and a broad half-moon of sooty black nearly encircles the neck, looking like black velvet on the back of it, where it is by much the broadest. There is a clouded black mark, too, on either side of the head, with some nuances of black between, black tips the tail, and the beak is all black. The tout ensemble of all this is very pretty, and the young kittiwake is a pretty bird. Mauve and black velvet is the dress it comes out in, and it looks like a soft little dove. Many might admire it beyond the grown bird, but, personally, I prefer the latter.
One of these well-grown young kittiwakes has just been fed by the mother, or father—but call it the mother, it always sounds better. Being importuned by sundry little peckings at her beak, she opened it, and the young one, thrusting in its own, helped himself as though her throat were a platter. It was much the same as with the fulmar petrels. Numbers of the young have left their nests, and keep all together, standing on the rocks or floating on the sea. Others remain, and I notice that these keep flapping their wings. This must strengthen them, and have the effect of preparing Dædalus for his first flight—for it seems probable that these particular ones have not made it. But they have, though, and bang goes a provisional hypothesis! Every moment, to laugh at me, one or other of them is flying out from the ledges, whilst others are returning to them.
When one of these young kittiwakes opens its bill, it is at once apparent that the inside of its mouth is much less brilliantly coloured than it is in the parent bird, being of a pale pinkish, merely, with, perhaps, a tinge of light yellow. As for the grown bird's mouth, one can hardly exaggerate the lurid brightness of it. The whole buccal cavity, including, as I think is usual, the tongue, is of a fine rich red, or orange-red colour, carrying on that of the naked skin adjoining the mandibles outside, with which, indeed, it is continuous. It is just the same in the case of the old and young shag. The mouth of the former presents a uniform surface of splendid gamboge, whilst that of the latter is almost the natural pink, only just beginning to pass into yellow. In the young guillemot, also, the interior of the mouth is pinkish merely, whilst in the grown bird it is of a pleasing lemon or gamboge. With the fulmar petrel again, we have much the same thing, though here—and this is significant—the difference, as well as the actual colour, is less striking. These varying degrees of brilliancy of colouring in this particular region, as between the mature and immature form, must surely have some meaning, and as it goes hand-in-hand with a similar, if not, as I believe, an identical difference in the hue of the naked facial integument, as well as with the pattern and shade of the plumage, I feel persuaded that all three are governed by the same general law.
As explained by Darwin—and nothing better, that I can see, than opposition has ever been opposed to his views—the beauty of certain birds has been acquired through the principle of sexual selection, and the lesser degree of it, which we notice in the young, represents the earlier and less-finished beauty of the adult in times gone by. Of all the elements which go to make up the beauty thus acquired, colour, on the whole, plays the most conspicuous part, and nothing can be more brilliant and striking than some of the colours that I am here speaking of. The only reason, therefore, why, in their use, and the laws that have governed their acquirement, they should be thought to differ from the hues and tintings of the plumage, or of the naked outer skin—the cere or the labial region—would be their habitual, necessary concealment. If, then, it can be shown that, far from their being always concealed, they are prominently displayed during the breeding season by certain birds which possess them in a marked degree, then, as far as these birds are concerned, there ceases to be a reason for thus, in idea, separating them. Let us see, now, how far this is the case. To begin with these kittiwakes, in their courting, or rather connubial actions on the ledges—as may be seen now, but much more earlier in the year—both sexes open their bills widely, and crane about, with their heads turned toward each other, whilst at the same time uttering their shrieking, clamorous cry. The motion, however, is often continued after the cry has ceased, and this we might expect if the birds took any pleasure in the brilliant gleam of colour which each presents to, and, as it were, flashes about in front of the other. The effect of this it is not easy to exaggerate, and if it is extremely noticeable to an onlooker at some little distance, what must it be to the bird itself, who looks right into the almost scarlet cavity? We have only to think of the inside of some shells, or of a large, highly-coloured flower-cup, to understand the kind of æsthetic pleasure that may be derived from such a sight.
Similar, but much more striking, is the nuptial behaviour of the fulmar petrel. A pair of these birds lying near together, on some ledge or cranny of the rock, will, every few minutes, open their bills to the very widest extent, at the same time blowing and swelling out the skin of the throat, including that which lies between the two sides of the lower mandible, until it has a very inflated appearance. In this state they stretch their heads towards each other, and then, with languishing gestures and expression, keep moving them about from side to side, uttering whilst they do so, but by no means always, a hoarse, unlovely sort of note, like a series of hoarse coughs or grunts, as though in anger—and indeed, it is uttered in anger, too. But though these motions, with the distension of the jaws, always, as far as I have seen, accompany the note when it is uttered, yet they are often continued afterwards, and sometimes commence and end in silence, so that one has to conclude that they are themselves of importance, and may have as much, or even more, to do with the expression of the bird's feelings as the vocal utterance has.