142 STUDIES IN BIRD-MIGRATION 



rearing of their families (or have perhaps been unfortu- 

 nate in their efforts to do so), begin to leave their nesting 

 areas and to appear in other localities more or less 

 removed. Some of them find their way to the coast and 

 take leave of our shores. In addition, there are the 

 wanderings and migrations of young birds only a few 

 weeks old. It seems to me highly probable that the 

 broods of many of our birds leave the place of their 

 birth and go off on their own account as soon as they 

 are fit to take care of themselves ; while in the case of 

 species which are double-brooded, the first families are 

 often driven away by their parents. Numbers of these 

 roving youngsters are the offspring of migratory parents, 

 and they form a considerable portion of the early 

 emigrants ; hence it is that a number of young birds 

 migrate in advance of their parents. 



The British migratory birds are earliest of all to 

 leave their summer haunts. This is to be accounted for 

 by the fact that nesting in our areas takes place at an 

 earlier period than in corresponding latitudes on the 

 Continent, and much earlier, of course, than in those 

 further north. The late nesting season in Northern 

 Europe explains the appearance of many birds of 

 passage and winter visitors on our shores at dates 

 considerably after the British summer visitors of the 

 same species have quitted our islands. 



The autumn retreat towards winter quarters is a 

 leisurely performance in marked contrast to the 

 feverish rush to nesting haunts in the spring. In the 

 early autumn there is no necessity for the migrants 

 to hurry southwards, for food is still abundant in many 

 places along the routes of flight. Consequently, many 

 migratory visitors tarry for a considerable time, some of 



