Bird Watching

by Edmund Selous

"The one bird stands still and upright, whilst the other, holding the neck constrainedly down, but with the head raised as far as is compatible with this, keeps moving round and round it. After revolving thus several times, keeping, always, very close to and, sometimes, actually touching the standing bird, this one also stands still, always in the same attitude, and opens his beak. The other one, standing as before, now raises the head and opens the beak also, upon which the satellite bird, assuming, at last, his proper height, delivers into it, from his own, something which he appears to bring up, and this, as it seems to me, is swallowed by the bird receiving it. The morsel is small, but the actions of giving and taking, and, afterwards, the movements of the beak and throat of the bird that has parted with it, are unmistakable. This would appear, therefore, to be a little friendly act, or, perhaps, an act of courtship—a love-token between the male and female bird—and I take the bird who delivers the morsel, and who is cream-marked, to be the male, and the other, who is uniformly dark, the female."

Skuas, as is well known, attack one if one comes at all near to their nest, and gulls—at any rate the two black-backed kinds—will sometimes, though much more rarely, come very near to doing so too. For instance, the greater black-backed gull swoops at one backwards and forwards, in the same way (though more clumsily) as do the skuas, except that he neither touches you nor comes so near. Every time he passes he gives a loud, harsh, tuneless cry, and drops down his legs as though intending to strike with them. When he does this, he may be some five or six feet above one's head—a little more, perhaps, or a little less—and presents an odd, uncouth appearance. The skuas swoop in silence, though the great one continually says "ik, ik" (or words to that effect), whilst circling between the swoops. "On another occasion two of the lesser black-backed gulls acted in this way, though one of them continued to do so for a much longer time. These two seemed to be angry with each other, making little motions and opening their bills in the air as though each thought it was the other's fault." This little trait, which would seem to raise them nearer humanity, I particularly noted. The mode of attack, when thus aerially delivered, is the same in all these birds, and, as it seems to me, curiously ineffective. The beak, a powerful weapon, is not employed, nor is a blow—which, if it were, might be of real force—delivered with one of the wings. Instead, the webbed feet, which would seem to be weak in comparison, and have no talons or grasping power, are made use of in the way I have already described in the case of the two gulls fighting, when, after the tussle on the ground, the one was swooped at by the other.

The following account of the attack of the smaller or Arctic skua, will apply almost equally to the great one. "The bird comes swooping down in a slanting direction, with great speed and impetus, and as it passes over one's head, makes a slight drop with the feet hanging down, so that they administer a flick just on the top of it, as it shoots by. Having made its demonstration, it shoots on and upwards, and turning in a wide sweep, again comes rushing down to repeat it, and so forwards and backwards for perhaps some half-a-dozen times, after which the intervals will become longer, the circling sweeps which fill them up wider and more numerous, till the attacks cease, and the bird flies away." (The great skua, however, will attack almost indefinitely.) "The force of the downward rush is in all cases very great, and the 'swirr' which accompanies it quite startling, suggesting a larger bird, or something of a more portentous nature altogether. In striking, the bird shoots the feet forward as they dangle, so that they hit one with the anterior surface, and there is not the slightest attempt to scratch or grasp with them. The force that can be put into such a blow is but slight, and, even in appearance, there is something trivial and inadequate about it that takes away from the effect of the bold sweep, which, in the case of the great skua especially, strikes the imagination, and is, indeed, a fine sight. A terrific blow with the wing, or a seizing and tearing with beak and claw, as with an eagle, would seem the fitting sequel to such power and fierceness."

This failure of the sublime, and falling almost into the ridiculous, cannot be observed when one is oneself the object of attack, and, moreover, the buffets that one is constantly receiving, though quite out of proportion to the size and fury of the birds, are often so stinging and disagreeable as to spoil one for looking at the matter from such a point of view. A ruse, however, may be adopted, and the scales then fall from one's eyes. For instance: "To-day I sat down by the almost fledged chick of a pair of great skuas, and, drawing my plaid over my head, numbered the attacks of the parent birds. When I began to count it was 3.13 P.M., and at 3.30 they had made between them—turn and turn about—136 swoops at me. Of these, 67 were hits and 69 misses. Some of the hits were very—indeed, extremely—violent, so that without the plaid I could not have stood it, and even as it was, it was unpleasant. The blow is always delivered with the feet, though sometimes (and pretty often as it seemed to me) a portion of the bird's body touches one at the same time, thus giving more weight and force to it. The force of the swoop is tremendous, and did the bird strike one full with its whole bulk, it would, I believe, knock one over, as a hare, it is said, has sometimes done by accident, in leaping over a hedge. After this heroism, I stuck my umbrella (staff, or even stick, would sound better, but it was an umbrella) into the ground, arranged my plaid upon it, and walked to a little distance. The birds, one after another, swooped at the plaid but never hit it. As they got just above it they stretched down their legs, but at the last moment seemed to think something was wrong, and rose, so as just to clear it. 'But out upon this half-faced fellowship!' This dangling down of the legs, in which the speed is checked and the grand appearance lost, is quite pitiful. Why cannot the birds fell you with a blow, or tear you with the hooked beak? This would be 'Ercle's vein, a tyrant's vein,' but a flick with the feet merely—it is a tame conclusion!"

I doubt now, if the bird ever does strike you with the body even lightly. It feels as if there must be more than the feet at the time, but, probably, this is not the case.

Both the male and female of the great skua defend the nest—and especially the young—in this manner, but the swoopings of one of them, probably of the female, are generally fiercer than those of the other. In my limited experience this dual attack was almost invariable, but in one instance the nest was guarded by one bird alone. This bird, as though to make up for the deficiency, was even more than usually fierce, making long rushing swoops from a great height and distance, which would, I believe, have been effective each time had I not bobbed. The other bird circled at a still greater height, and never once joined in the attack. The height, I may say, from which the birds swoop is not, as a rule, very considerable. The above does not apply equally to the Arctic skua—at least in my own experience—for though often the two birds would attack, yet in the greater number of cases only one of them did so. Now the Arctic skua, as I have mentioned elsewhere, is one of those birds which employs strategy (begging here the question for the sake of brevity) as well as force to defend its young, and it occurred to me that here might be a case of co-operation, the male bird most probably attacking, and the female employing the ruse. I satisfied myself, however, that the same bird sometimes does both one and the other. How often this is so, and whether there is a tendency on the part of either sex to resort by preference to one or the other method, it might be difficult to find out. Yet I cannot help thinking that this is the case, and that a process of differentiation is in course of taking place. The facts are—or appeared to me to be—these. In the case of the great skua, both sexes—almost, but not quite, always—attack, and there is no ruse. In that of the Arctic skua both sexes sometimes attack, but far more frequently (that, at least, was my own experience) one alone does so, and here a ruse is employed. In the former case we just see occasionally, as an exception, the raw material (the non-attacking of the one bird) that might conceivably be utilised by nature for the elaboration of another form of defence. In the latter we may see this other form being elaborated.

Questions of this nature might be settled in the future on facts observed now, as easily as a reference to an iron ring where boats were once moored settles the question as to whether the coast has risen or the sea encroached. The coast and the sea, however, remain. Birds, slaughtered by millions each year, must cease almost as a class before any great period has gone by. Of what use then the ring, the record when what it speaks of is no more?

Another interesting point in the Arctic skua (which it shares with at least one other species of the genus) is its dimorphism—or rather, to describe it more properly, its polymorphism. To me it seems to offer a case of a species in course of variation from one form into another. In the two extreme forms the plumage is, respectively, either entirely sombre both above and below, or the whole throat, breast and under surface, with a ring round the neck, and more or less of the sides of the head, is of a fine cream colour. Between these extremes there are various gradations, the cream being sometimes on the breast only, whilst the throat is of a lighter or deeper grey, more or less mottled with the still darker shade, or the lighter colour is hardly or not at all discernible on these parts, whilst lower down it becomes less and less salient till it is merely a not so dusky duskiness. The cream-coloured birds, though numerous, are in the minority, and both this and their being much handsomer suggests that the process of change is in this direction, whilst the intermediate tintings may represent the steps in this process. To what form of selection (if to any) are we to attribute the change? As the cream colouring makes the bird more conspicuous, natural selection (as distinct from sexual) seems excluded, unless it could be shown that the change of colour is correlated with some still greater advantage, and this is neither apparent nor likely. There remains sexual selection, which to my mind is strongly suggested. The modified colouring is, it is true, shared by the two sexes, but this is quite compatible with the theory, which supposes the tintings of the male kingfisher and numerous other brilliant birds to have been thus acquired and transmitted in each stage of progress to the female. It would, therefore, be interesting, though, no doubt, difficult, to determine by observation whether the creamy-coloured male birds were on an average more attractive to the females than the other kind, and also whether the more handsome form was increasing. In regard to the last point, this was the opinion of a man guiltless of theories, but with a large amount of experience of the birds.

Of these two species of skua, the great and the lesser or Arctic one, the latter appears to me to be the boldest and most aggressive. It will chase not only gulls, but occasionally the great skua also, this last, as it would seem, for sport or pleasure rather than for any particular object. In the same way they often chase each other. A too near approach to the nest may, perhaps, be the reason in either case, but having watched them attentively I do not think that the pursuing bird is often under any real apprehension. Gulls are persecuted by them in the manner I have described, and sometimes, I think, also in mere wantonness. The larger ones seem never to resist, but the kittiwake will sometimes go down upon the water, turn to bay, and drive the robber off. Gulls seem to fear the great skua less than the Arctic one, and will sometimes mob and molest it. A single pair that had nested on the outskirts of a gullery were a good deal subject to this annoyance. One and then another gull would pursue them when they flew near, and sometimes even swoop at them from side to side as they stood upon the heather. But I never saw them annoy the Arctic skuas in this manner. The latter, however, were much more numerous.