330 Wonders of the Bird World 



formed the esplanade in Heligoland, when a gentleman 

 accosted me and hoped that I had got the Crows quite 

 safely. " I sent them up by one of my servants," he ex- 

 plained, and I afterwards found out that he was one of the 

 Chief Government Officials of the island. Well ! it is not 

 given to everybody to offer a Colonial Secretary sixpence 

 in bad German from the top of a cliff! 



The Hooded Crows afterwards appeared in small parties 

 of from six to twenty, all migrating from east to west. 

 They were never out of sight during the day-time, for as 

 fast as one party disappeared, another was seen approaching 

 over the sea. Even during the night this stream of 

 migration went on. 



Heligoland, certainly, is the place on which to study 

 migration, and Gatke is its prophet. Any one who wishes 

 to take up the subject must read this author's work on 

 1 Heligoland as an Ornithological Observatory.' It is the 

 one book in which the observations of fifty years have been 

 steadily summarized, and it will ever remain a classic. 

 Other popular books have been written on the subject of 

 migration, but they present only the general ideas which 

 occur to the mind of every ornithologist, and the conclusion 

 must be that we know at present very little about the 

 phenomena of migration, and furthermore, that we shall 

 not be able to generalize until we have more reliable 

 statistics to work upon. Mere theory and guess-work will 

 not help us. 



There are, however, certain facts on which we may 

 ground an opinion, but they are very few. The specimens 

 of our British migrants which have been shot and preserved 

 in their winter homes, enable us to judge of some of the 

 routes by which the birds travel, but even here some diffi- 

 culty intervenes. Africa is evidently the continent which 

 receives most of our migratory species, and the specimens 

 in the British Museum prove their occurrence in Africa 



