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
