xiv MIGRATION 349 



fifty years watching the might)- stream of migrants 

 that passes to and fro. All the Heligolanders have 

 helped him, bringing ever)- specimen they could obtain 

 that was rare enough to be worth looking at. And 

 every one in the island turns out for the battue, with 

 a far too slaughterous zeal, when the flocks of migrants 

 descend upon it. Sometimes such clouds of birds 

 appear that they cover every square foot of ground 

 upon the island. The most striking of the recorded 

 flights took place in October 1882, when for three 

 successive nights there were thick masses of migrating 

 Goldcrests, beating thick as snowflakes against the 

 lighthouse. But these represented only a small frac_ 

 tion of their numbers, for the front of the advancing 

 host extended from the Shetlands to Guernsey, and 

 probably even further south. Living thus on his islet, 

 the ways of migrants as familiar to him as the beat of 

 the waves, Herr Gatke has been able to give a 

 life and interest to his book that no writer on the 

 subject who has gained his knowledge only by reading, 

 or who has caught only occasional glimpses of the 

 great movement, can possibly rival. And though he 

 has seen so much, he has never failed to realise the fact 

 that what he has seen is much less than what has 

 passed beyond his ken, or been only dimly descried, 

 that the birds which have flown over Heligoland, often 

 far too high for the reach of the human eye, are far 

 more numerous than those which stress of weather, or 

 whatever circumstance, has led to settle on the island. 

 Unfortunately Herr Gatke's work has not been trans- 

 lated into English, but it should be read by every 

 lover of birds who is tolerably familiar with German, 



