24 The Bible of Nature 



level we marvel at an instinctive skill whose ex- 

 pression is unconscious art; finally, we are face to 

 face with a^ intelligent behavior which seems at 

 once a caricature and prototype of our own con- 

 duct. 



Let us recall, for a moment, just one of the 

 wonders of animal behavior — the wonder of mi- 

 gration. There is the migration of those birds 

 that "know no winter in their year," *'wild birds 

 that change their season in the night, and wail 

 their way from cloud to cloud down the long 

 wind." What journeys they take — the Arctic Tern 

 was found by the "Scotia" explorers in the Far 

 South! How swiftly they fly, how confidently 

 across the pathless sea, at night, at a great alti- 

 tude. How strange that the young birds usually 

 fly away first in the autumn, without waiting for 

 those who have made the journey before. How 

 striking the fact — proved for some birds — that 

 they may return from their winter-quarters to the 

 garden where they spent the summer. 



Or take as another instance of migration the 

 life-history of the common European eel. It be- 

 gins its life below the 500 fathom line on the floor 

 of the deep sea — in that dark, cold, calm, silent, 

 plantless world; it passes to the surface as a 

 flattened, transparent larva and lives an open-sea 

 life for over a year, not eating anything, and grow- 

 ing rather smaller as it grows older; it becomes a 



