78 EGGS OF BRITISH BIRDS. 



THE BLACK-THEOATED DIVER. 



(Colymbus arcticits.) 

 Plate 21. Fig. 1. 



The Black-throated Diver is known to breed in the north of 

 Scotland, and in some of the lochs in the Outer Hebrides. Its 

 breeding-range extends from Scandinavia, as far east as Kamts- 

 chatka, and throughout North America from Alaska to Hudson's 

 Bay. The nests found by my son in North Uist were substantial 

 structures, about a foot in diameter, and two or three inches high. 

 The foundation was composed of dead stalks and roots, upon which 

 was a lining of fresh green grass and herbs, the whole forming a 

 bona-fide nest, as different as possible from the slovenly debris on 

 which its Red-throated cousin lays its eggs. Two is the usual 

 number of eggs, but sometimes one only is laid. The ground- 

 colour is dark or light russet-brown, sometimes with a slight shade 

 of olive. The spots are nearly black, sparingly distributed over 

 the surface, rather more profusely at the larger end, and seldom 

 as big as a pea. The underlying spots are few and indistinct. 

 The eggs vary in length from 3'5 to 2"9 inches, and in breadth 

 from 2'2 to 1*9 inch. 



THE RED-THROATED DIVER, 



{Colymbus septentrionalis.) 

 Plate 21, Fig. 2. 



The present species nests commonly in the Hebrides, as well as 

 in many localities in the west and north of Scotland, from Argyle- 

 shire northward, and in the Orkneys and Shetland Isles. It also 

 nests in the lakes of Donegal, in Ireland. Its breeding-range 

 elsewhere is circumpolar. 



The Red-throated Diver very rarely makes a nest. The eggs 

 are often laid on the bare turf, often in a depression in the grass 

 or moss, but a scanty lining of weeds or sedge is frequently found. 

 The eggs are somewhat more variable in colour than those of its 

 allies, being more commonly of a brownish-olive than of a russet- 

 brown ground-colour. The spotting is also occasionally somewhat 

 bolder. They vary in length from 3*1 to 2*5 inches, and in breadth 

 from 1"9 to 1"7 inch 



