DIVERS — G UILLEMO TS 281 



mountains, with low banks, or flat grassy islands, on which the nest can be placed 



so as to permit the parent birds to slide straight into the water. If the sheet of 



water be small, only a single pair of divers will nest, but on larger lakes each 



pair has its own defined area, from which all intruders are chased away. The 



members of a couple are devoted to one another, and always dive, swim, and 



fly in company, each being careless of its own safety when its mate is killed or 



injured. The young are able to dive long and perse veringly almost as soon as they 



leave the egg, and thereby escape many dangers. When in want of rest they 



climb on the backs of their parents, where they nestle close and hide among the 



feathers. A few days after leaving the shell they begin to catch their own food, 



which consists chiefly of fish. Small fish are swallowed whole, but larger ones 



are brought to the surface, where they are gradually pecked to pieces, the birds 



diving to recover the carcass as it from time to time sinks. By far the commonest 



of the four kinds is the red-throated Colymbus septentrionalis, a circumpolar 



species, breeding within the Arctic Circle and southwards as far as Scotland in the 



Atlantic, and somewhat lower still in the Pacific. On the winter migration it 



travels to the Gulf of Mexico in the one hemisphere and to the Mediterranean and 



Formosa in the other. The dark brown back, grey head, red throat, and black beak 



are characteristic features of this diver. Much larger is the great northern diver 



(C. glacialis), which attains some 33 inches in length, and is about as large as a 



goose. The back is ornamented with a kind of chessboard pattern of black and 



white squarish patches, while the throat is marked by two black and as many 



black and white rings streaked vertically. This stately bird inhabits the northern 



parts of Europe and America, but does not breed farther south than the Shetlands 



in European waters, or than Maine on the western side of the Atlantic. A third 



species, the black-throated G. arcticus, distinguished by its black throat and beak, 



is circumpolar, breeding in the north of Scotland and the Orkneys, though at 



present unknown in Iceland and Greenland. It also breeds in Scandinavia 



Russia, north-eastern Germany, and right across Siberia to Kamchatka. 



Very characteristic of the shores of the colder portions of the 

 Guillemots. J . r 



Northern Hemisphere are the guillemots, whose movements on land 



are nearly as awkward and ungainly as those of the divers. Owing, however, to 

 their powerful claws, guillemots are excellent climbers. The flight is recognisable 

 by the quick, short movement of the wings, being low and in long downward or 

 upward spirals especially when ascending or descending high cliffs. These birds 

 are powerful swimmers and divers, sitting high on the water with the tail slightly 

 raised, and the neck depressed between the shoulders. They dive noiselessly, 

 opening the wings as they descend and using them as paddles. The length of the 

 dive is sometimes as much as 10 fathoms, or even more, and when undisturbed 

 the birds generally reappear close to where they went down. The common species, 

 Uria troile, breeds as far south as the mouth of the Tagus, in Portugal, and is 

 particularly numerous in the Faroes and Iceland, while northwards its breeding- 

 range is known to extend to Bear Island, half-way between the North Cape and 

 Spitzbergen. On the American side these birds breed as far down as Massachusetts. 

 On the Pacific coast of the New World the typical form is replaced by the somewhat 

 larger U. troile californica. At their breeding-places guillemots may be seen in 



