74 BRITISH BIRDS. 



fact which seems to have escaped the majority of writers 

 is that all our adult drakes have a yellow base to the bill. 

 Anyone who has shot and examined freshly killed birds 

 will confirm this. 



As regards the very falcate tertials, I have examined 

 many drakes possessing- these feathers quite as fully 

 developed as in the Oldham specimen. 



Besides the three above mentioned, I know of two other 

 specimens of 8. moUissima showing a V-mark, namely : — 



1. A drake obtained by Mr. Abel Chapman off Holy Isle, 



in January, 1898. 



2. A specimen shot by Sutherland, of Graemsay, in 1906, 



and sent to Mr. Clarke, of Scarborough, who can 

 perhaps furnish further details as to exact date. 



It would be interesting if owners of Eider skins would 

 look over their collections and give full particulars of any 

 drakes they may find showing this indistinct V-mark. 



The fact that our Common Eider occasionally exhibits 

 an indistinct Y-mark is to me far more interesting than 

 the occurrence of a true S. v-nigrum in British waters 

 could possibly have been, for it opens up a new field of 

 thought and research for those interested in our avifauna. 



I believe I am correct in stating that in no work on the 

 Common Eider [S. moUissima) is there any mention made 

 of the occurrence of a Y-mark in some of the males, yet 

 on the other hand, if we consult the works of American 

 authors, we find that in the American Eider (S. dresseri) 

 there is sometimes a trace of a black Y-mark on the chin 

 indicating an approach to S. v-nigrum, {see Elliot Coues' 

 "Key to North American Birds," Yol. II., p. 940, oth 

 edition), and again in the so-called Noi-thern Eider 

 {S. moUissima horealis) which, as I have previously stated, 

 is identical with our owu S. moUissima, " a black Y is 

 sometimes found on the throat " {see " The Wildfowl 

 Family," by L. C. Sanford, p. 167). I can therefore see 

 no valid reason why we should not expect to find a similar 

 mark sometimes appearing in our own 8. m,oUissim,a. 



It seems to me that this Y-mark is simply a case of 



