The Bird Watcher in the Shetlands/Chapter 7
CHAPTER VII
BIRD SYMPATHY
TO-DAY—which is my third here upon the island—I was actually assaulted by the terns. I saw a young one, now well advanced, that flew for a little and then went down on the grass. Walking towards it, a bird—presumably one of the parents—descended upon me twice in succession, and, with that angry and piercing cry that I have spoken or ought to have spoken of—it sounds very like a shrill "bah!"—delivered a fierce peck at my head, so that I felt it each time, quite unpleasantly, through the thin cloth of my cap. The difference is to be noted in this form of attack, to that employed by gulls and skuas, the former in battles inter se only, and the latter as against man in defence of their eggs or young. Both of them, when they thus "swoop to their revenge," use the feet only, and the superiority of the tern's method is so great that it makes this small bird almost as redoubtable—if this exaggerated word may be pardoned—as even the largest of the others. The Great Skua, especially, were it to use its powerful beak, would be really formidable, even to a man. In fighting with its fellows, it no doubt does so, and gulls, under these circumstances, make the greatest use of theirs. This, however, is when they struggle together on the ground; but when one fights on the ground and the other in the air, the latter uses its feet only, with effects that are irritating rather than to be feared. Now why is this, and what causes the difference in this respect as between gull and tern? From my own observation I think I can explain it. So long as two contending gulls fight with any equality, they do so upon the ground, but when one of them can no longer hold his own there, he rises into the air and, sweeping backwards and forwards over the other, who stays where he was, annoys him in this particular way. The bird, therefore, by whom these tactics are resorted to has already got the worst of it, and the last thing he wishes is again to close with a rival who has defeated him. This, however, is exactly what would happen were he to use his hooked beak in the manner proper to it, for it is adapted for seizing and tearing, and to these uses it has hitherto been put. To peck or stab with it would be like making a thrust with a sickle, and though possibly as against a weaker antagonist it might be made effectual in some other than the normal way, yet here there is always the fear of detention, to check any experiment of the sort. Let the hooked tip but pierce the skin to any extent, and the swoop would be checked sufficiently to allow of the flying bird's being seized. The feet, therefore, though without efficient claws and quite unadapted to anything except swimming, are employed by preference, and in the manner in which they are used we see the same principle at work, for instead of making any attempt at grasping or scratching, the flying gull, as it sweeps by, just gives a flick with the back of them, which the other revenges or parries with a blow of the wing.
The tern, however, having a straight and sharply pointed bill, adapted for pecking, and nothing else, can use it in this manner when flying also, though in other respects it delivers its attack in exactly the same manner as the gull does, allowing for the difference in bulk and aerial grace and mastery, between the two birds. Here, as it appears to me, we see structure affecting habit. As a rule, I think, it is rather the other way, for it is wonderful to how many uses, other than the primary one for the performance of which it has been specially adapted, almost any part of an animal's anatomy may be put. And indeed, if we look at it in another way, this truth is as strikingly illustrated by what we have just been considering as by almost anything, for the webbed foot of a gull or any swimming bird is extremely unadapted for fighting, and yet we here see it thus employed. But it is owing to the structure of the beak, in my opinion, that this has come about. That is the bird's real weapon, which I am convinced it would always use if it could or if it dared. Not even in their rough-and-tumbles, where they close and roll over and over together, have I seen gulls fight with their feet, upon the ground.
I had not gone far, after this episode with the terns, when I was pecked at, twice again, by another one, under similar circumstances. Each time, I believe, the sharp point of the beak went through the slight stuff of my cap, or I should hardly have felt it so sharply. It is not only the skuas, then, that attack you in defence of their young. These terns, though so much smaller, do so too, and, as appears by the story, they have more than one weapon in their armoury. But a more interesting experience was in store for me, which brought still more forcibly to my mind that incident with the wounded tern to which I have before alluded. Walking on, I noticed a bird which, though a young one, looked almost in its full plumage, and which kept flying for a little, and then going down again at some distance in front of me. Every time it alighted, a cloud of terns hovered excitedly over it, and first one, and then another of them kept swooping down, so as just or almost to touch it, until at last it flew up again, so that I could never approach it more nearly. It certainly seemed to me as though the grown community were trying to get this young one to fly, so as to be out of danger, and this they always succeeded in doing. I do not think they really prevented me from catching the bird, for, no doubt, it would have flown of itself before very long; but what interest and sympathy shown! Moreover, had I been pursuing it with a gun it might have made all the difference.
So, too, it must be considered how lethargic these young terns are before they can fly, and how easily they then let themselves be caught, though able to run quickly. When noticed, or approached closely, they crouch, but though this is probably due to an 
BIRD SYMPATHY
Terns vary much in the degree of resistance, or rather of evasion, which they offer to the attacks of the skuas—always I am speaking of the smaller of the two species. I have often seen them get off scot-free, without losing their fish, and, as before said, this has always seemed to me to be because of their persistency in holding out, and not at all on account of their superior speed. I have advanced a theory as to why the skuas should not actually attack the terns on these occasions, as they do not seem to me to do, and if there is any truth in it, we here see a road along which a certain number of the latter might become free of the tyranny under which they now suffer. It is doubtful, however, whether these more obstinate birds would gain, in this way, a sufficient advantage over the others to allow of natural selection coming into play. They could carry, no doubt, more fish to their young, but here, at least, the skuas seem hardly in sufficient numbers to make the difference a working one. With many birds, however, a similarly acquired change of habit would mean the difference between life and death. I remember once passing unusually close to a cock pheasant, which remained crouching all the while, though nineteen out of twenty birds would, I feel sure, have gone up. It struck me, then, that as all such pheasants as acted in this way would have a greater chance of not being shot than the others that rose more easily, whilst these latter were constantly being killed off, therefore, in course of time, the habit of crouching close ought to become more and more developed, and pheasants, in consequence, more and more difficult to shoot. Some time afterwards I met with some independent evidence that this was the case, for a gentleman who shot much in Norfolk, remarked, without any previous conversation on the subject, that the pheasants there had taken to refusing to rise, and that this unsportsmanlike conduct on their part was giving great trouble and causing general dissatisfaction. That was his statement. He spoke of it as something that had lately become more noticeable, but only, as far as his knowledge went, in Norfolk, which, I believe, is an extremely murderous county.
Beyond this I have no knowledge on the subject, but I feel sure that a gradual process of change and differentiation is every day going on amongst numbers of our British birds. I believe that I have myself, here and there, seen some traces of it, and my idea is that greater pains ought to be taken to collect evidence in this and similar directions. Along all those lines where fluctuation has been observed, or where modification might, in course of time, be expected, the present truth should be most carefully made out, and having been accurately recorded and published, observation, after a certain length of time, should again be focussed on the same points, and this being renewed every ten, twenty, fifty, or a hundred years, the results could be compared. For instance, our green woodpecker feeds now largely upon ants in their nests, whilst it both fights and copulates upon the ground. How interesting would it be if we had a continuous record of observations of this bird's habits, dating, say, from William the Conqueror or the days of the Saxon Heptarchy, and if we found that no mention was made of these peculiarities, by the field naturalists of those times, but that they first began to be doubtfully recorded in the reign of Henry the Fifth, or Richard the Third. No doubt a connected chain of evidence of this kind will gradually grow up, owing to the accumulation of works of natural history, but it would, I think, be a great deal more satisfactory if the object were kept steadily in view, and I am quite sure that observations made in this spirit would produce much more interesting matter than that which is to be found in the ordinary bird or beast book. For the great idea would then be to compare the present with the past habits of any creature, in order to see whether, or in what degree, they have changed, and this could only be done by continual re-observation, which would assuredly lead to novelty of some sort, instead of mere repetition, which is what we have now; and not only so, but the thing that is so constantly repeated seems often to be founded either on nothing, or nothing that one can get at. Take, for instance—but no, that would lead to twenty more pages at the least, and I want them for something better.