200 ANIMALS AT WORK AND PLA Y 



the Seine Valley, and across to Selsey Bill. The 

 most northerly route is that of the birds that are 

 coming from the Danube Valley. These pass 

 through Zurich on to Rheims, and reach the 

 channel coast near Boulogne and Calais, whence 

 they cross the channel at the Straits of Dover. In 

 these journeys, the land-routes are preferred, and 

 the straits are as a rule chosen for sea passage ; but 

 some birds fly straight across the Mediterranean at 

 its widest part, from Algeria to Marseilles ; while 

 birds making for Ireland, though mainly crossing via 

 England and that part of the Irish Channel which lies 

 opposite Milford Haven, often cross directly from 

 Brest to Cape Clear. 



Next to the success and persistence of the 

 birds in making good their point across unknown 

 continent and seas, the most striking features of 

 the migration is the enormous number of the birds 

 which sometimes journey together. The ' locus 

 classicus ' on this subject is the late Mr Seebohm's 

 description of a ' migration night ' on Heligoland, 

 where he had been in 1870 to visit Dr Gatke, the 

 results of whose observations have recently been 

 published and translated. This is Mr Seebohm's 

 account of the scene by the lighthouse. 



He was awakened at ten o'clock to find that 

 the whole population was moving towards the 



