THE MIGRATION OF BIRDS 



A CONSIDERATION OF HERB GATKE'S VIEWS. 



DIRECTION OF THE MIGRATION FLIGHT. 



H AFTER I., though interesting, is to all intents and 

 purposes a diary, and as a whole calls for no 

 special comment. Such items as it contains, 

 which are of exceptional value, can, therefore, 

 readily be referred to as occasion may demand. 

 In a detailed examination of the whole work it will be convenient 

 to follow the author in his arrangement of the various chapters 

 relating to the different phases of the migratory movement. His 

 theories on the direction of the migration flight expressed in 

 Chapter II., which next claims the attention of the reader; will be 

 found of especial interest as they, to a great extent, controvert 

 the general opinion held by the majority of naturalists. 



This chapter also contains his remarks on the character or 

 breadth of the migration front, in which the flight is performed. 

 As the two subjects are intimately connected, his observations on 

 both may be conveniently examined at the same time. 



It has been previously more or less generally assumed, that the 

 direction of the migratory flight in spring and autumn is approxi- 

 mately between the points of north and south. Whilst Herr Gatke 

 fully recognises a movement of this description it seems to him, as 

 may be gathered from his constant references, to be quite over- 

 shadowed in importance by an east to west flight or the reverse 

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