248 NATURAL SCIENCE. April, 



immigrants, while passing northward along the eastern seaboard, 

 actually cross the movement of the coasting emigrants proceeding 

 southward. It is also found that the west coast does not receive any 

 immigrants direct from the continent. 



The spring movements on the west coast of England and the east 

 coast of Ireland are trifling in comparison with those on the east, and 

 it seems probable that those birds which pass to the Faroes and 

 Iceland pursue the former route. The return autumn journey is by 

 no means so simple on the west coast as on the east ; for Ireland, the 

 Isle of Man, the Hebrides, and the extremely irregular coast Hne 

 exercise their varied influences. Mr. Clarke thus describes the 

 course taken : — " The general route followed by these departing birds 

 has its north-western source in the Outer Hebrides, and after leaving 

 Barra Head it joins an important stream from the Inner Hebrides at 

 Skerryvore. The course then followed is via Duheartach, Islay, the 

 Wigtonshire coast, the Isle of Man, Anglesey, and the South Bishop 

 (off Pembrokeshire). Finally the south-western coast of England is 

 reached (possibly in part by an overland route across Devonshire 

 and Cornwall) between the Scilly Islands and Start Point." In its 

 course south it receives several tributary streams at various points, 

 and " at the Bristol Channel others from Western England and 

 Wales, and often from the south-eastern coast of Ireland." The 

 coasts of Ireland are not in themselves a main highway, and " the 

 majority of the birds on the shores of the sister isle are probably the 

 migratory members of her own avifauna." 



Astonishment has often been aroused by the wonderful migratory 

 flights to be witnessed at the proper season on the little island of 

 Heligoland, so graphically described by the late Mr. Gatke, and it 

 could not fail to be of interest to ornithologists, especially those 

 residing on the east coast, to learn whether and to what extent these 

 migratory hosts affected the arrivals on their o^n shore. With no 

 little disappointment, therefore, we learn that " a study of the 

 phenomena of migrations at the stations on the east and west sides of 

 the North Sea compels the investigator to come to the conclusion that 

 Heligoland and Britain draw their migratory hosts from different 

 sources," and that although " it is not impossible or improbable that 

 birds may occasionally cross the German Ocean by an east to west 

 flight in the latitude of Heligoland, our data lead us to believe that 

 such cases are the rare exception and not the rule." There is no 

 more astonishing feature in the whole range of this wonderful 

 subject than the arrival on our east coast of birds whose natural 

 habitat is Eastern Asia, and which must have crossed the whole 

 of Europe, finishing with the passage of the North Sea. Some 

 of these, too, are delicate warblers of the smallest size, and arrive here 

 after the British representatives of their kind have left us for the 

 south. The past autumn has been remarkable for these strange 

 occurrences. 



