78 STUDIES IN BIRD-MIGRATION 



streams of birds on their passage northwards ; but the 

 travellers are composed of fewer species, and in most 

 cases of fewer individuals, than those proceeding via 

 the east coast route. The migrants travelling between 

 the British Islands and the Faroes, Iceland, and 

 Greenland, are, however, probably more numerously 

 represented on the western shores. 



The western passage movements are far more 

 complicated in their geographical aspects, and hence 

 more difficult to trace than those witnessed on the 

 eastern side of Great Britain. The migrants proceeding 

 northwards along this route, or series of routes, are part 

 of the great hosts which appear on the westernmost 

 section of the south coast of England and the Scilly 

 Isles in the spring. After arrival on our shores they 

 continue their journey northwards ; some skirting the 

 west coast of England and Wales, others traversing 

 the east coast of Ireland, and a number taking a middle 

 course, and visiting the Isle of Man. 



When the northern limit of the Irish Sea is reached, 

 the migratory streams which have flowed along its eastern 

 and western shores meet in the narrow waters between 

 the Mulls of Galloway and Cantyre on the one side, and 

 the coast of Antrim on the other. The Scottish coast 

 having been reached, complications await the would-be 

 investigator wishful to follow the further courses 

 pursued. Much migration is observed in the numerous 

 bays of the Solway Firth and on the Galloway coast ; but 

 on departing from the latter, the main stream travels via 

 the Mull of Cantyre, Islay, Dhu Hearteach Rock, Tiree, 

 and other inner islands. On reaching the importantly 

 situated rock of Skerryvore, a number of the migrants 

 which have not proceeded northwards by way of the 



