i7° British Birds, with their Nests and Eggs. 



assumed which could scarcely be distinguished from that of the Black- throated 

 Diver at the same season ; that is to say, the upper parts almost uniform blackish- 

 brown ; under parts, except the flanks, but including the sides of the face below 

 the eye, white. But " Mr. Gatcombe once examined an adult Northern Diver in 

 the middle of winter, the markings on the back and scapulars of which formed 

 spots similar to those of summer, but were rather obscure and of an ash-grey 

 instead of white, and not wavy like those of an immature bird, which fact leads 

 him to suppose that it may be the true adult winter plumage of this species " 

 (" Yarrell," 4th Ed.) From Professor Collett's observations on the plumage of 

 C. adamsi, this view is probably a correct one. 



Young birds have the feathers of the back with rounded or semi-pointed ends, 

 and the face and throat minutely marked with brown. "Young in down are 

 blackish-brown on the upper parts, paler brown on the under parts" (Seebohm). 



The weight varies from 7 lbs. to 16 lbs. 



Family- COL YMBIDAL. 



The White-Billed Northern Diver. 



Colymbus adamsi, G. R. Gray. 



THE White-billed Diver is known to have occurred in Great Britain on 

 several occasions ; one shot was at Pakefield, near Lowestoft, in 1852 ; another 

 on Hickliug Broad, in December, 1872 ; a third off the coast of Northumberland ; 

 a fourth in Suffolk, and another on Loch Fyne. The White-Billed Diver inhabits 

 Arctic America, west of Hudson Bay, and its range extends across Siberia and 

 probably across Arctic Russia. It has been observed in Novaya Zemlya, and is 

 probably found on Jan May en Island and Spitsbergen. In winter it migrates 

 southward, and it visits the coast of Norway annually. 



