12 The Irish Naturalist. [Jan., 



quarters. Our shores form a main highway and convenient 

 resting-places for these migrants. Our islands have a vast 

 bird population of their own, and the majority of these birds 

 belong to migratory species. Many species which are migra- 

 tory are only partially so in our islands. Our variable climate 

 causes much internal migration within Great Britain, and 

 with Ireland. This occurs in winter. Migrations of a varied 

 nature thus occurring, often through a combination of 

 meteorological conditions, two or more distinct migratory 

 movements are sometimes observed in progress simul- 

 taneously. 



Although in passing from summer to winter haunts birds 

 go from a northern to a more southerly clime, it does not 

 follow that these haunts are reached by a simple movement 

 from north to south. This is especially the case in Western 

 Europe, where, with its irregular coast-line, more or less 

 devious routes are followed. The situation of the British 

 Isles is an important factor in this deviation. The distribu- 

 tion of birds on our coasts during migration, and the routes 

 traversed, naturally depend on the nature of the particular 

 movement. The principal movements are the intermigra- 

 tions between our islands and the Continent. 



Between Britain and the Continent pass hosts of migrants, 

 which are either birds of passage on, or winter visitors to, our 

 shores. The former visit our east coast in spring when 

 passing to their northern summer haunts to the north-east of 

 Britain, and again in autumn when going to their winter 

 haunts in the south. The wdnter visitors are chiefly indivi- 

 duals from the ranks of migrator}^ species which spend the 

 winter in the British area, and go to the north-east of .Europe 

 for the summer. In autumn these numerous migrants arrive 

 from the north-east on the eastern shores of Britain, from the 

 Shetland Isles to the northern coast of Norfolk. During 

 these movements the more southern portion of the east coast 

 of England is reached after the arrival of the birds on the 

 more northern portion. It is noteworthy that all the British 

 birds of passage to northern Europe are either summer 

 visitors to Scandinavia, or are regular migrants along the 

 western shores of that peninsula ; and that they all occur 

 during migration in the Orkney and Shetland Isles, but not 



