CHAPTER VII 



Migration — ^An anciently observed phenomenon still imperfectly 

 understood — ^Reasons for it — Methods as far as is known — 

 Difference between migratory species and the homing Pigeon 

 — Widespread tendency to migration, contrasted with con- 

 tradictory tendency to form localized non-migratory races, 

 ending in some cases in flightlessness, as in some birds of 

 remote islands 



Migration has always been a conspicuous pheno- 

 menon in the lives of certain birds, and often, as in 

 the case of Wildfowl and Quails, intimately bound 

 up with the question of human food-supplies, so 

 that it is a very familiar fact ; but in spite of this 

 familiarity, it is still far from being properly under- 

 stood. The old idea of the hibernation of some 

 birds is indeed definitely done away with, and 

 nowadays no one seems to believe that small birds 

 ever ride on big ones ; yet Bee-eaters in Africa 

 have been found riding on Storks or Bustards when 

 these were searchiiig for prey on the ground, and 

 taking their share of the insects driven up ; so 

 where is the difficulty of a weary Wren or Warbler 

 taking refuge on a Swan or Gannet, which certainly 

 could not dislodge it in mid-air i I mention this 

 because there; is no physical impossibility involved, 



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