not all take one line of migration for their winter quarters, but some go east, others come west. Take for instance the case of the Snow and Lapland Buntings; great flocks of both these species make for the American Continent, whilst other flocks come to us. What one species of bird will do, others will also; and is there anything unreasonable in suggesting that some flocks of A. gambeli make for the American Continent, while others come to our shores? It will, I think, be but reasonable to look for more American bird visitors in the future.
When we can obtain the services of some competent field naturalist who thoroughly understands the differences in the notes of birds, and who will have an opportunity of studying both A. albifrons and A. gambeli at their breeding haunts, we shall probably find that the habits and the notes of the two species are distinct. I quite understand the difficulties of studying the breeding habits of these birds, in consequence of the high northern districts selected by them for nidification being almost inaccessible to most naturalists, but I will urge that anyone whose good fortune it may be to pass a season in these regions can render a great service to ornithology by paying particular attention to this subject.
Before concluding this paper, I ought perhaps to say a few words of explanation upon two subjects I have touched upon during the progress of my arguments, viz. the power possessed by birds of extracting from and transmitting to their feathers colouring matter. The latter—colour change independent of a moult—has been dealt with by several writers latterly, but, in my judgment, not thoroughly. It will be seen that my views are very strong on the point—they have been so for a good many years past—and I have accumulated a mass of evidence which appears to me to place the matter beyond doubt; nevertheless, an intelligent study of the case of the White-fronted Geese alone ought to be sufficient to satisfy even our American friends. The former case—extracting the colouring matter from the feathers—is, I think, new. This point also I have not broached without due consideration, and during many years' study have amassed evidence of a most conclusive character. I formulated my views in a paper as far back as 1896, but for certain reasons did not allow it to be published at the time, and have since been too much occupied with other matters to revert to it.
