70 BRITISH BIRDS. [vol. vii. 



in his statements about the age when the male gets its 



full plumage. After Briinnich, Holboll (Ornith. Beitrag 



zur Fauna GrOnlands, pp. 69-73) seems to have been 



the next author who diagnosed the plumage-change 



of the Eider correctly. On page 72 he says that, 



having compared a great number of young birds of 



both species {S. mollissima and 8. spectahilis), he has 



come to the conclusion that both require two years 



to become full grown, so that young birds which were 



hatched in 1840 were full grown in the autumn of 1842 



and had attained a complete winter-plumage in October.* 



This period, he states, is alike for both sexes. During 



the first year the female bird is quite grey, without the 



white bands on the wings ; in the second year she attains 



almost the same colour as the old birds, only differing 



from these by the absence of the white bands on the 



wings. Professor Collett gives (Mindre Meddelelser ved. 



Norges Fuglefauna, 1881-1892, pp. 284-286) a detailed 



account of the plumage-change which seems to leave the 



reader in a state of some doubt, for he believes that the 



young males do not begin to turn white until the second 



winter. Most Enghsh authors, except Booth, say 



very little about the plumages of the Eider, and what 



they do is strictly of a non-committal order. By far 



the best account of the sequence of plumages of 



S. mollissima and its alUed races is to be found in Mr. 



E. Lehn Schioler's paper on the Eider Duck {Sotnateria 



mollissima L.) and some of its allied races, which was 



published in the Dansk ornithologisk Forenings Tidsskrift 



(Vol. III., June, 1908, pp. 109-149). This contains a 



very complete summary of Mr. Schioler's views on the 



plumage passage of the Eider, as well as notes on skeletons, 



breeding-habits, and the distribution of alhed races. 



In the following descriptions of the plumages of the 

 Common Eider, I have taken specimens whose plumage 

 is normal at the days mentioned. Sometimes there is a 



* Broadly speaking this is qviite correct, although many males do 

 not attain full plumage imtil December, owing to the delay in moulting. 



