348 THE STRUCTURE AND LIFE OF BIRDS chap. 



rid himself of the then popular notion, that they 

 hibernated in holes, or mud or water. Even now some 

 people are credulous enough to hold this belief, though 

 the fresh evidence adduced diminishes to the vanishing 

 point when subjected to investigation, and the evi- 

 dence from past times is valueless, since it is as 

 strong for the hibernation of Swallows in water, 

 which is clearly impossible, as it is for their hiberna- 

 tion in holes. But Gilbert White's book should be 

 studied as the work of a man who took care to see 

 with his own eyes what he chronicled, instead of 

 repeating the myths that are handed down from writer 

 to writer. And his remarks on migration are a first- 

 rate landmark that shows how our knowledge of the 

 subject has advanced. Even now, however, there is 

 an atmosphere of mystery about it, which can only be 

 dissipated, if it ever is, by the co-operation of hosts of 

 patient investigators. When the necessary facts have 

 been thus accumulated, keen penetration will be 

 necessary in dealing with them if the meaning is to 

 be discerned. The progress already made is, indeed, 

 very great. Modern facilities of travel have helped 

 forward our knowledge. The nesting places of all 

 the British migrants except one, the Curlew Sandpiper, 

 have been found, thanks chiefly to the energy of 

 English ornithologists. Our summer visitors have 

 been seen and recognised in their South African winter 

 resorts by English travellers. But when we think of 

 bird migration, the mind more naturally turns to 

 Heligoland than to any other one spot upon the 

 globe. There, in his tiny rock island, hardly over a 

 hundred acres in extent, ITcrr Gatke has been busy for 



