238 



GREBKS AND DIVERS 



Black-throated 



Diver 



(Colymbus 



arcticus). 



The black-throated diver is a decidedly smaller bird 

 than the last, measurinL,^ only 27 inches in total 

 length ; but has the same general type of colouring, 

 although lacking the distinct white band with black 

 lines on the back and sides of the neck in the 

 summer-dress, and with the white spangling of the upper-parts divided 

 into separate areas. Among the distinctive features of the summer- 

 plumage may be mentioned the smoky grey hue of the head and neck. 



and the purplish- 

 black patch extend- 

 ing from the throat 

 down the front of 

 the neck to terminate 

 in a V-shaped patch, 

 broken on each side 

 of the throat by a 

 much smaller patch 

 of white \crticall\' 

 streaked with black. 

 Behind and below 

 the dark area the 

 sides and base of the 

 neck arc streaked 

 with narrow black 

 and white lines ; the 

 hack and wings are 

 glossy black speckled 

 between the shoulders 

 with quadrangular 

 white spots arranged 

 in ladder-fashion, and 

 on the scapulars with transverse rows of larger spots ; the wings are 

 marked by white flecks ; and the flanks are black, and the rest of the 

 under-parts white. In winter the upper-parts become ashy brown, while 

 the throat and front of the neck assume the same pure white hue as 

 that of the lower surface of the body. With the exception that the 

 feathers of the back and wing-coverts have grey edges, the plumage of 

 the birds of the year resembles the winter-dress of the adults. The 

 long down of the chick, as in the case of the larger species, is smoky 

 brown above and white below. From 5 to 7 lbs., or not much more 

 than half that of its larger relative, is the weight of this species. In 



BI,ACK-TIIK<).\Ti;i) DIVICK. 



