508 COLYMBID^ 



AVERAGE MEASUREMENTS. 



TOTAL LENGTH 33 in. 



WING 14-9 



BEAK 3*7 



TARSO-METATARSUS 3'4 ,, 



EGG 3*65 X 2'3 in. 



BLACK-THROATED DIYER. Colymbus arcticus (Linnaeus). 



Coloured Figures. Gould, ' Birds of Great Britain,' vol. v, pi. 

 44 ; Dresser, ' Birds of Europe,' vol. viii, pi. 627 ; Lilford, 

 ' Coloured Figures,' vol. vi, pi. 46. 



Though this Diver may be regarded as an annual winter- 

 visitor, it is much rarer than either the Great Northern or 

 the succeeding species. Old males with their handsome 

 velvety-black throats and richly variegated upper-plumage 

 are not often seen. 1 It is not improbable that immature 

 individuals of this and the next species are often con- 

 founded, as they resemble each other in plumage ; the Black- 

 throated Diver is, however, the larger bird. Exceptionally, 

 it wanders southward along the English coast visiting the 

 Channel. In the ' Zoologist ' for 1903, p. 277, Mr. Gordon 

 Dalgliesh states that on May 10th, 1903, an emaciated 

 immature male was picked up dead on the beach near 

 Cobo, in Guernsey, this being the second specimen recorded 

 from that locality. 



Along parts of the Scottish coast it occurs all the year 

 round, nesting in several counties of the mainland as well as 

 in the Orkneys and Hebrides. It has increased in North 

 Uist of late years, since the practice of robbing the eggs has 

 been checked (Ilarvie-Brown, ' Avifauna Of The Outer 

 Hebrides/ 1888-1902; Ann. Scot. Nat. Hist., 1903, p. 21). 



The Black-throated Diver has been recorded from the 

 greater part of the Irish coast ; while it has been taken 



1 In the ' Zoologist ' for 1877, p. 329, Mr. Warren records seeing this 

 bird in full nuptial dress at the mouth of the Eiver Moy, Mayo coast ; 

 the late Dr. Cox observed it on the Dublin coast in nuptial plumage in 

 May. It has also been noted in nuptial plumage about Belfast Bay 

 by the late Sir R LI. Patterson 



