THE DIVERS 



[ORDER: Colymbiformes. SUBORDER: Colymbi. FAMILY: Colymbidce] 

 PRELIMINARY CLASSIFIED NOTES 



[F. C. R. JOURDAIN. W. P. PYCRAFT. A. L. THOMSON] 



GREAT NORTHERN-DIVER [Gdvia immer (Brunnich); Coltfm- 

 bus glacidlis Linnaeus. Loon, herring-loon, cobble ; herring-bar (Kent); nauk 

 (Northumberland) ; ember, imber, or immer-goose (Scotland). French, 

 plongeon imbrim ; German, Eis-Seetaucher ; Italian, strolaga maggiore]. 



I. Description. The great-northern may readily be distinguished from the 

 blackthroated-diver in its nuptial dress by the median throat patch of white marked 

 by vertical lines of black, and a similar but much larger patch lower down the neck 

 and on each side. In its winter dress the upper parts are of a dark ash-brown, 

 and each feather has an ash-coloured margin, while the wing-coverts are unspotted. 

 The sexes are alike. (PI. 177.) Length 30 in. [762 mm.]. In the nuptial dress the 

 head and neck are black, glossed with purple and green. At the base of the throat 

 is a median band of white marked with vertical lines of black, and lower down, on 

 each side of the neck, is a similar but much larger patch forming a half collar. The 

 back and wing-coverts are glossy black, the scapular feathers sharply truncated, 

 and ornamented with quadrangular pairs of spots of large size. The interscapular 

 feathers are similarly shaped and marked, but the spots are smaller. The rump, 

 flanks, and wing-coverts are also black, and speckled with small round white spots. 

 The breast and abdomen are white. Beak black, cutting edges bluish horn ; iris 

 red. Legs and toes blackish, lighter on their inner surfaces. After the autumn 

 moult the plumage assumes a dark brownish grey, each feather of the back being 

 margined with light ash-grey ; the head and neck brown glossed with green, save 

 the throat and fore-neck, which are white, like the breast and abdomen. The 

 flanks are coloured like the back. This dress, in fully adult birds, is speedily 



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