506 COLYMBID^E 



glossed with green ; sides of the upper breast, streaked with 

 black and white and glossed with green ; breast and 

 abdomen, white; under tail-coverts, chiefly brownish. 



Adult female nuptial. Similar in plumage to the male. 



Adult winter, male and female. The neck-bands dis- 

 appear and the ground-colour of the head and neck 

 becomes brownish-black ; the spots on the back, scapulars, 

 and wings, are ash-grey on a dark brown ground-colour 

 not so pure as in the nuptial plumage ; throat, fore-neck, 

 breast, and abdomen, white. 



Immature, male and female. Eesembles the adult 

 winter-plumage except that the back, scapulars, wings, 

 and hind-neck, are dark greyish-black ; breast and abdomen, 

 impure white. 



BEAK. Blackish-brown, tip lighter ; powerful and 

 dagger-like. 



FEET. Greenish-black. 



IEIDES. Crimson. 



AVERAGE MEASUREMENTS. 



TOTAL LENGTH 31 in. Female smaller. 



WING 14 



BEAK 3'5 ,, 



TAKSOMETATAUSUS ... 3*6 ,, 



EGG 3-5 x 2*5 in. 



WHITE-BILLED NORTHERN DIYER. Colymbm adamsi 

 (G. E. Gray). 



Coloured Figures. Dresser, 'Birds of Europe,' vol. ix, pi. 722; 

 Lilford, 'Coloured Figures,' vol. vi, pi. 45; 'Ibis,' 1894, 

 pi. 8. 



This species, the Arctic form of the Great Northern 

 Diver, is a very rare visitor to British waters. An example 

 was shot at Pakefield, near Lowestoft, in the spring of 

 1852 ; it is now in the collection of Mr. J. H. Gurney. An 

 immature specimen, supposed to have been taken in Suffolk 

 at a later date, is figured by Babington ('Birds of Suffolk'). 

 Another was obtained on the coast of Northumberland, and 



