COLYMBUS. 295 



Colymbus immer. GREAT NORTHERN DIVER. 



Colymbus immer Briinnich, On. Bor. 1764, p 38 : 

 Faeroe Islands. 



Colymbus glacialis Linn. ; B. O. U. List, 1st ed. 1883, p. 201 ; 

 Ogilvie-Grant, Cat. Birds B. M. xxvi. 1898, p. 496 ; Saun- 

 ders, Manual, 2nd ed. 1899, p. 709. 



Immer, from the Norwegian name of this bird. 



Distribution in the British Islands. A Winter Visitor, gene- 

 rally distributed along the coasts o Great Britain and Ireland 

 between October and May, but most numerous towards the 

 north. Individuals usually remain about the Outer Hebrides 

 and the Shetland Islands throughout the summer, and may 

 even have nested in the latter group. On migration it is 

 not uncommon on inland waters. 



General Distribution. The Great Northern Diver breeds 

 in the northern parts of North America, ranging eastwards 

 to Greenland and Iceland and westwards to the Asiatic 

 shores of Bering Straits. It moves southwards in winter to 

 the Azores, Madeira, the Mediterranean and Black seas, 

 Lower California, and the Gulf of Mexico. In Siberia it is 

 represented by the next species, C. adamsi. 



Colymbus adamsi. WHITE- BILLED 

 NORTHERN DIVER. 



Colymbus adamsii G. R. Gray, Proc. Zool. Soc. 1859, 

 p. 167 : Alaska. 



Colymbus adamsi Gray ; B. O. U. List, 1st ed. 1883, p. 201 ; 

 Ogilvie-Grant, Cat. Birds B. M. xxvi. 1898, p. 500; Soun- 

 ders, Manual, 2nd ed. 1899, p. 711. 



Adamsi, in honour of Surgeon C. B. Adams, who discovered the bird. 

 Distribution in the British Islands. A Eare Visitor in 

 winter. About five examples have been recorded from the 

 east and south coasts of Great Britain between Northumber- 

 land and Hampshire : also one from Argyllshire. 



