124 THE MIGRATION OP BIRDS 



Some writers affirm that birds only migrate on 

 the wing, but the journey by sea of many species 

 is varied in method. Those very regular migrants, 

 the puffins and guillemots, which the light keepers 

 assure us leave and return to their stations almost 

 at fixed dates, move by slow nautical stages, 

 swimming and feeding as they go. On May 2nd, 

 1911, 1 watched a red- throated diver slowly travelling 

 north ; it actually travelled farther beneath the 

 surface than either by swimming or flying, so long 

 as I had it in view. The penguin's migrations 

 cannot possibly be on the wing. Dr Brooks rightly 

 contended that the periodic assemblage of wander- 

 ing sea-birds at their " rookeries " is true migration, 

 regular as the almanack, although the feeding area 

 is immense and the birds do not reach home by 

 any single path. Seebohm tells us of young bean 

 geese migrating in full moult, marching in an 

 army to the interior of the Tundra, and Mr W. H. 

 Hudson, in " Birds and Man/' relates a pathetic 

 story of a pair of upland geese in southern Buenos 

 Ayres. His brother saw them in August, the early 

 spring of South America, leaving the plains where 

 they had wintered to breed in Magellanic islands. 

 The main flocks had departed, but these two birds, 

 the female with a broken wing, were steadily 

 moving south, the male taking short flights and 

 waiting for her, as if to urge her on, and the female 



