GREAT NORTHERN DIVER. 



179 



Adult Male. — General colour above glossy blnck, spotted 

 with white, the feathers being square at the tip, and orna- 

 mented with twin sub-terminal spots of white, larger and 

 more cons[)icuous on the scai)ulars ; wing-coverts like the 

 back, but more feebly spotted with white, the spots being 

 rounder and sometimes two in number near the end of the 

 outer web ; lower back and rump more distinctly greenish- 

 black, minutely spotted with white; bastard-wing, primary- 

 coverts and quills black, browner on the inner webs; upper 

 tail - coverts and tail-feathers black ; head black, with a 

 purplish shade on the crown, changing to dull green on 

 the sides of the head and neck ; the sides of the hind-neck 

 more distinctly purplish-blue ; sides of face and throat black, 

 with a purple gloss on the chin, and the throat itself decidedly 

 more green till it reaches an abrupt line, where it changes to a 

 beautiful purple like the sides of the neck ; across the middle 

 of the throat a band of white feathers striped with black ; a 

 similar, but larger, band on each side of the neck ; remainder 

 of under surface, from the fore-neck downwards, white, the 

 sides of the fore-neck and chest streaked with black, the sides 

 of body and flanks black, with small white spots ; across the 

 line of the vent a narrow band of black ; under tail-coverts 

 black tipped with white spots ; under wing-coverts and 

 axillaries white, the latter narrowly streaked with black ; the 

 lower primary-coverts produced for half the length of the 

 wings, white, broadly streaked with ashy-brown down the 

 middle ; quill-lining ashy-grey ; bill black ; legs and feet 

 greenish-black; iris crimson. Total length, 28*0 inches; 

 culmen, 3-2; wing, i4'o ; tail, 2*5 ; tarsus, 3.35. 



Winter Plumage.— Brown above, with a slight greenish gloss, 

 the feathers sub-terminally dark in the centre and margined 

 with ashy-grey, less distinctly on the lower back and rump, 

 which are consequently more uniform ; wing-coverts like the 

 back, as also the inner secondaries ; quills and tail blackish- 

 brown ; head and neck brown with a slight greenish gloss ; the 

 lores and sides of face brown ; cheeks and under surface of 

 body white, shaded with brown on the lower throat ; sides of 

 the neck brown with white edges to the feathers, producing a 

 streaked appearance, the centre of the feathers darker brown ; 



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