414 BRITISH BIRDS. 



" Last night I had an excellent opportunity of watching a Red-tliroated 

 Diver gradually sinking its body in the water before diving. I saw by the 

 kind of quick shaking motion of the bird^s body that it was pulling itself 

 down in the water by a rapid action of the feet, till very little more than 

 the top of the back and the neck and head were visible, when it bent its 

 head forward and shot below/^ 



The Black-throated Diver is a smaller bird than the Great Northern 

 Diver, and weighs about a third less. The female is similar in colour to 

 the male, but is slightly smaller. In nuptial plumage the general colour of 

 the upper parts is brownish black, faintly glossed with green, each feather 

 ha^-ing an obscure paler margin, and those of the nape, hind neck, and the 

 sides of the lower neck broadly margined with white, and there are a few 

 scattered white spots on the u])per back, scapulars, and wing-coverts ; the 

 head and neck are slate-grey, spotted on the crown with black, and the 

 centre of the lower throat is reddish chestnut ; the rest of the underparts 

 are silky white, streaked with dark grey on the flanks, axillaries, and under 

 tail-coverts. Bill black ; legs and feet greenish black ; irides hazel. After 

 the autumn moult the chin and throat are white, and the crown and hind 

 neck are slate-grey, sprinkled Avith brown and white ; the rest of the upper 

 parts, except the quills and tail-feathers, which are not moulted in the 

 spring''^, are greyish brown, spotted with white. Young in first plumage 

 differ from autumn plumage of adults in having the white spots on the 

 upper parts, especially on the scapulars and wing-coverts, elongated into 

 streaks, and the ear-coverts, chin, and throat are mottled with brownish 

 grey. After the first spring moult the adult plumage is assumed, except 

 that the slate-grey of the head and neck is slightly suftused with brown, 

 the chestnut on the throat is paler and duller in colour, and the white 

 feathers on the lower throat, below the chestnut, have brown centres like 

 those on the sides of the lower neck. Young in down have the upper 

 parts brownish black, and the underparts greyish brown. 



* Adamson (' Some more Scraps about Birds,' p. 199) asserts that the nearly plain back 

 of the summer plumage of this species is acquired, not by a moult, but by the abrasion of 

 the white spots. This is undoubtedly an error. The Red-throated Diver is not excep- 

 tional in this respect. Examples obtained in the valley of the Yenesay early in June are 

 in splendid plumage, and show little or no signs of abrasion. 



^^ ,. 3'j^m^.^^ 



