PLATE V. 



Chart of North-Western Europe showing Typical Weather 

 Conditions, with South-Easterlv Winds, over the British 

 Isles 



A large Continental anticyclone lies to the east of the British Isles, and 

 extends to our shores. To the west the pressure decreases, especially off 

 the Atlantic Coast of Ireland and over Iceland. Wind, a south-easterly 

 current over the United Kingdom. 



The south-easterly type of weather is the most favourable of all for inter- 

 migration between Great Britain and the Continent of Europe in both spring 

 and autumn. During its prevalence the great migratory movements, termed 

 "rushes," are performed. 



Fine weather is then in the ascendant over the countries whence the 

 great majority of our bird-visitors come to us in the autumn, and to which 

 they return on leaving us in the spring. The North Sea is spanned, at both 

 seasons, by weather which is most promising for the voyagers. 



On the other hand, the western low-pressure area, with its unsettled 

 conditions, extends to Iceland, and is against intermigration between the 

 British Isles and that great north-western island. (See also p. 173.) 



