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196 eaten at all, I cannot say; but I have noticed that the guillemot, also, sometimes brings in a sand-eel to the ledges, that has been neatly decapitated. I can quite understand that the head of a herring, if swallowed by a greedy young chick, might have a bad effect on it, but that the old birds, through some process of natural selection—for we cannot suppose that they are impelled by ordinary foresight—should have acquired the habit of first decapitating the herrings and thus removing the risk, seems very unlikely. On the other hand, that they should eat one particular part, and no other, of each fish that they bring to their young, is almost as difficult to believe. I have elsewhere suggested another explanation, but this too I find it difficult to adopt, and the only remaining one I can think of is that the gulls who catch these herrings, and who are robbed of them by the skua, either bite off their heads in order to kill them, or eat the head separately. Whatever the reason of it may be, I once more draw attention to the fact.

At the tail, so to speak, of this track of herrings, I find another young great skua, and sit down by him to make my entry. He is a big chick, but the fluff still remains upon his head, neck, and under surface, springing from the ends of the true feathers, which have thus gradually pushed it out. On the back it is almost gone, thin patches of it only appearing above a thick brown panoply of the mature plumage. This chick is of milder mood than either of the other two.