348 THE STRUCTURE AND LIFE OF BIRDS cuap. 
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, Herr Giitke has been busy for 
