ANSER GAMBELI AS A BRITISH BIRD. 351 



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, 

 i V. 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. 



