IMPRESSIONIST SKETCH 245 



cloak about us shiveringly, as we wish the last migrants 

 " Bon voyage ! " 



The history of this remarkable habit is wrapped up 

 with the evolution of climates ; thus many see in the 

 autumnal retreat a reminiscence of the Ages of Horror 

 which made whole faunas shudder the Glacial Epochs. 

 The impulse to migrate perhaps expressed originally 

 what we have called a constitutional responsiveness to 

 seasonal change ; it seems now to be inborn or instinctive, 

 though it may still require the stimulus of the outer world 

 to pull the trigger. Moreover, after we have allowed all 

 we dare allow to the experience of successive years, to 

 the education of juniors by seniors, to a kind of social 

 tradition in the case of those that migrate in great squadrons, 

 we have still to fall back on the theory that a sense of 

 direction, developed in many animals, not yet wholly lost 

 in Man, has been brought to perfection in birds. 



Of all pilgrimages and there are many animals who 

 travel, such as reindeer and lemmings, whales and seals, 

 salmon and herring this of birds is certainly the most 

 marvellous. Picture the rush of the feathered tide, spread- 

 ing sometimes for many square miles in the heavens, con 

 tinuing day after day without interruption 



" Who can recount what transmigrations there 

 Are annual made ? What nations come and go ? 

 And how the living clouds on clouds arise ? 

 Infinite wings! till all the plume-dark air, 

 And rude resounding shore, are one wild cry." 



Think of the velocity of the flight, an exaltation of 

 the bird's usual powers, perhaps reaching a hundred miles 

 an hour. Consider the extent of the flight, the dot- 

 terel passing from the North African steppes to the Arctic 

 tundra, the Virginian plover passing from Labrador to 

 North Brazil. Notice the breadth of the flying phalanx ; 



