CHAPTER XII 



THE MIGRATION Ol' lllkliS 



The Li^lithc 



HeligulaiiJ (after Seebohni). 



Scanty knowledje of the subicct — Summary of obsen-ations by 

 Mr. W. Eagle Clarke — Giitke's observations in Heligoland — 

 Migration in the Mississippi Valley — IMigration in the North Sea 

 — Mr. A.bel Chapman's remarks on the flight of birds. 



There is no subject in the ornithological world about 

 which people speak and write so glibly as on the " Migration 

 of Birds," and yet there is no branch of Natural Historj' of 

 which less is really understood. Those who have laboured 



