THE DIVERS. 195 
muscle in this and other diving birds has an unusually large develop- 
ment to give further strength. Their plumage is smooth and silky, 
and impervious to water from its oily nature. They live chiefly on 
the sea, coming on land in the breeding season. 
The Divers (Colymbus) are distinguished from other Brachypteres 
by their beak being longer than the head, straight, robust, and nearly 
cylindrical, slightly compressed on the sides, acute, the upper man- 
dible longer than the lower; their toes, in place of being each 
furnished with marginal membranes, have the three united by a single 
membrane ; their feet being placed far backward and on the same 
perpendicular line with the tibia—an arrangement very unfavourable 
for walking, compelling the birds to take a vertical position, render- 
ing their movements on land both painful and difficult. 
They are, however, intrepid swimmers, and they dive with such 
alertness that it requires a quick eye and hand to shootthem. ‘They 
are inhabitants of northern seas; there they build their nests in 
some solitary islet or desert promontory, where they lay two eggs, 
oblong in shape, and more or less in colour of an Isabella white. 
Fish, particularly the herring, form their principal food ; crustaceans 
and marine vegetables are also eaten by them. Their flesh is tough 
and leathery, and has a disagreeable taste. In the winter they migrate 
to temperate countries, where they frequent rivers and lakes, re- 
turning to the northern regions when the ice has broken up. 
There are three species described: the Great Northern Diver, 
the Arctic Diver, and the Imber Diver. But there is considerable 
doubt on this subject, the young cf C. géacialis of the first and 
second year being so unlike the parent bird as to have been long 
supposed a distinct species. 
THE GREAT NorTHERN DIVER (Colymbus glacialis, Fig. 78). 
The Great Northern Diver is one of those birds which seek their 
food on the bosom of the great deep. It is not numerous in British 
waters, and can scarcely be called gregarious, although adults some- 
times, and the young more frequently, fish in small parties of five or 
six. A wanderer on the ocean, it not only frequents the margins of 
the sea, fishing in the bays and estuaries, but it is also met with 
many miles from the shore. Narrow channels, firths, coves, sea- 
lochs, and sandy bays are, however, its favourite resorts; there it 
floats, the body deeply submerged in the water. But though swim- 
ming deep in the water, it can overtake and shoot ahead of all its 
more buoyant congeners. But let us watch the actions of a pair of 
