THE INSURGENCE OF LIFE 163 



heavens knoweth her appointed time, and the turtle and 

 the crane and the swallow observe the time of their coming ' ; 

 and Homer made telling use of the familiar picture of the 

 migrating cranes. We know much more about migration 

 than did these early observers, but it can hardly be said 

 that the wonder is less. 



Sometimes the migratory movement is seen with almost 

 startling vividness, so that even the careless are impressed ; 

 at other times the annual tide flows and ebbs without 

 calling for much remark. On an island like Heligoland, 

 which lies on a favourite migratory route and is without 

 any resident birds of its own (save sparrows), it is very 

 impressive to see wave after wave of migrants strike the 

 rocky shore in the autumnal westward and south-westward 

 movement. The birds used to light in thousands on the 

 small fields now given over to batteries, and rest for a 

 few hours before continuing their journey. Observers 

 on the Isles of Scilly sometimes see hundreds of thousands 

 of birds of the same kind flying from the English coast ; 

 and taking many hours to pass. And many who have 

 travelled on a steam-ship up the West Coast of Africa in 

 autumn have had the good fortune to see enormous numbers 

 of birds making their way south, looking from a distance 

 like dense clouds of smoke swirling rapidly close to the 

 water. Some of the migrants often rest on the ship for 

 a while, until they feel that they are being carried the 

 wrong way. Then they rise into the air and make for the 

 south again. 



Not less interesting is it to watch the actual arrival of 

 the summer visitors, especially when they come in after a 

 long sea- voyage, and sink to the ground as if welcoming 

 a rest. When one sees swallows and the like arriving on 



