THE CANADIAN FIELD-NATURALIST 



VOL. XXXIV. 



MARCH, 1920. 



No. 3 



THE SCOTERS AND EIDERS. 



By p. a. Taverner. 



(Published by permission of the Geological Survey of Canada.) 



The scoters and eiders are often regarded by swellings, protuberances and extended processes, 



the amateur ornithologist and the general sportsman In the females these bill characters are reduced; 



as confusing groups. Whilst the males are well but, except in the American Scoter, they retain 



marked by color and bill characters some females enough peculiarity of shape for ready generic recog- 



bear close general resemblance to each other. The nition. Generally juvenile males are similar to the 



following diagnosis and plates may therefore be of females but soon show sufficient traces of the com- 



interest to those who have occasion to identify these ing adult plumage to indicate their sex. 



MALE 

 A/VALE 



SCOTERS-GENUS Oidemia 



-^AMACRLU5t:s-Genre Oidemia 



^1 



FEAAALE, 

 FEMELLL, 



lu 

 O.americana 



2b 



O.de^laodi 



O.per^picUlata 



C.l.JQHNS>ON 



species. Two species of eider, Steller's and the 

 Spectacled, are rather different from the others, but 

 as they only are to be expected in the extreme north- 

 west, Alaska and the Yukon, they need rarely be 

 considered in connection with eastern material. 



Except these two species, the scoters and eiders 

 are ducks of the largest and sturdiest build. As the 

 accompanying plates show, the males are char- 

 acterized by unusually heavy bills often with strange 



THE SCOTERS. 



The adult males of all the scoters are practically 

 solidly black birds or with only restricted and sharp- 

 ly defined patches of pure white on head or wing. 

 The females are without variegation, dark brown 

 gradually lightening below or on breast and face, 

 and show no indication of bars or streaks. The 

 bills of all plumages except that of the female 

 American Scoter are characteristic. 



