inherited instinct of self-preservation, they do not appear to have much fear of one. Therefore it seems likely that in their early flying days they might still be inclined to act in this way, and if so, any encouragement to fly which they received from their elders would be of assistance to them. It is noteworthy that the younger birds which I caught were not thus encouraged to run. The public attention, in this case, seemed concentrated on myself.
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
