Order I. DIVING BIRDS. 



PYGOPODES. 



Family 1. GREBES. Podicipid^. 6 species. 



Family 2. LOONS. Gaviid/E. 5 species. 



Family 3. AUKS, MURRES, and PUFFINS. Alcid^. 21 spe- 

 cies, 3 subspecies. 



Grebes are at home in reed-grown ponds or sloughs where their nests 

 are made on raffs or islets of water-soaked vegetation. Their eggs 

 number from four to eight, are dull white in color, and are usually 

 covered by the bird with a portion of the nesting material when it 

 leaves its home. Grebes occasionally rest on the shore, but are rarely 

 found far from the water. When on land they may lie flat on their 

 breasts or sit erect on their tails and entire foot, or tarsus. Their 

 progress on land, as a rule, is awkward and they may use their wings 

 as fore feet to assist them. In diving, Grebes sometimes spring part- 

 ly from the water and then plunge downward head first, or they may 

 quietly sink with scarce a ripple to mark the place of their disap- 

 pearance. 



Loons generally pass the summer on some large lake, and in the 

 winter many of them live at sea. They nest, as a rule, on the shore, 

 but so near the water that the parent bird may slide off its two dark 

 brown, mottled eggs into its favorite element. Like the Grebes, Loons 

 are expert divers, and birds of both families so often seek safety under 

 the water rather than in the air that it is frequently difficult to make 

 them fly. The young of both Grebes and Loons are born covered with 

 feathers and take to the water shortly after birth, often using the back 

 of the parent bird as an ever present island on which they may rest 

 at will. 



The Auks, Murres, and Puffins are sea birds which nest usually in 

 large colonies on isolated islets or rocky, inaccessible shores of the 

 northern part of the northern hemisphere. They lay one or two eggs, 

 sometimes in an exposed position among the rocks with no attempt 

 at nest-building, sometimes at the end of a burrow excavated by the 

 birds. In the latter case, the young are reared in the nest; in the for- 

 mer, they sometimes enter the water at an early age. 



The one egg laid by Murres is remarkable both in color and in shape. 

 In color it varies from bluish green to buff, and is usually heavily 

 scrawled with black. In outline it is pyriform or pear-shaped. When 

 moved it does not roll away as would a hen's egg but revolves about 

 its own tip. In this manner it retains its place on the narrow 

 ledges often chosen by Murres for nesting-sites. 



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