ROUTES 35 



sky ? Indeed he again and again declares that 

 migration passes unseen yet calculates the numbers 

 observed on the darkest nights ; the illumination 

 of the lighthouse could not be sufficient to enable 

 him to even guess at the numbers he mentions. 

 After stating that ' the whole vault of heaven was 

 literally filled to a height of several thousand feet 

 with these visitors from the regions of the far North/' 

 and that a certain east to west passage extended 

 from the Faroes to Hanover, he concludes that 

 ' the view that migrants follow the direction of 

 ocean coasts, the drainage areas of rivers, or de- 

 pressions of valleys as fixed routes of migration can 

 hardly be maintained/' 



As emphatically he maintains that most observ- 

 able migration over Heligoland is due east to west 

 or west to east, though the birds tuffer Aeuckens, 

 who supplied him with much of his information, 

 told Seebohm that it w^as north-east in spring and 

 south-west in autumn (45). Is it not perfectly 

 evident that the geographical position of Heligoland 

 makes it a convenient resting place for large numbers 

 of migrants, for it is certainly true that large 

 numbers are observed there, which pass southward 

 and westward along the Baltic, crossing Schleswig- 

 Holstein and the mouth of the Elbe, or coast south 

 along Denmark, and cross the Elbe diagonally, 

 en route for the Dutch and French coasts and 



