DEEPER PROBLEMS OF MIGRATION. 



THE first of the deeper problems is as to the position 

 of migrational movements on the inclined plane of 

 animal activities. Do they imply intelligent control at 

 every, or at any step ; is there anything habitual about 

 them, or have they an entirely instinctive basis, that is to 

 say, is the brain endowed by inheritance with ready-made 

 preparedness of a very definite kind for the great annual 

 effort of migration ? If we take this last view, there is no 

 reason to increase the puzzle by raising the wider question 

 of how instinctive activities arise at all, for that has no 

 special relevancy to this particular case. Every one knows 

 that the animal world is rich in examples of instinctive 

 activities, for the performance of which, without education 

 or experience, the brain is hereditarily endowed by the 

 establishment of definite nerve-paths or otherwise. Our 

 question is, whether birds have a specific hereditary pre- 

 paredness for their migratory movements, analogous to 

 that which bees have for burglaring the blossoms and 

 building a honeycomb, or that which spiders have for 

 spinning a complex web ? 



That the migratory movement has an instinctive basis, 

 is suggested by a number of facts which have a cumulative 

 force, though they are not individually very convincing. 

 Migration shows a regularity and orderliness, without 

 much individuality and with little hint of caprice, which 

 is suggestive of the instinctive ; preparations are made 



for the journey before often long before there is any 



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