Page:The Zoologist, 4th series, vol 6 (1902).djvu/181

Rh perhaps) intelligent, to have originated in nervous and non-purposive movements, is removed. My note, taken on the spot and at the time of occurrence, is as follows:—

"Instead of fighting, however, which both the champions seem to be chary of, one of them again runs into a hollow—this time a very shallow one—and begins to dance, but in a manner slightly different. He now hardly rises from the ground, over which he seems more to spin in a strange sort of way, than to fly—to buzz, as it were—in a confined area and with a tendency to go round and round. Having done this a little, he runs quickly from the hollow, plucks a few little bits of grass, returns with them into it, drops them there, comes out again, hops about as before, flies up into the air, descends and again dances about."

Now here a bird brings to a certain spot, not unlike such a one as the nest is usually built in—approaching to it, at any rate—some of the actual material of which that nest is composed, and I ask if, under the circumstances, it can possibly be supposed that such bird really is building its nest when it does so, in the ordinary purpose-implying sense of the term. As well suppose—so it seems to me—that a man, in the pauses of a fierce sword-and-dagger fight with a rival suitor, should set seriously to work house-hunting or furniture-collecting. Such peckings and pluckings seem to me to partake of the general frenzied character of the bird's whole actions. Yet when once the object had been seized, associations might be aroused by it.

Supposing the habit of nest-building to have originated in the way here suggested, it need not surprise us that natural selection, seizing hold of such a prime opportunity, should have entirely altered its original character, so that, now, such pairing on the nest as does take place may be looked upon as a survival of a past state of things. In one particular group of birds—the Bower-Birds of Australia—such survival may have been more than usually pertinacious, and there—on the principle of specialization being always an advantage—the thalamum, or pairing-place, may have become, gradually, quite distinct from the true nest. The habit of building more than one nest would (as I suggest)