246 BRITAIN^S BIRDS AND THEIR NESTS. 



unknown till well on in the latter half of last century. 

 Since then it has become so abundant in nearly all districts 

 that from its very numbers it threatens to become a pest, 

 although its habits are in the main beneficial to man. 



This is one of the best and most striking examples of 

 the extension of the range of a species to within oui' own 

 area and our own times. The study of the question is 

 suggestive of many very interesting points in connection 

 with the problems of geogi'aphical distribution. In- 

 directly, also, it affects migration. What relation, if any, 

 do the migratory habits of the birds recently settled in 

 an area bear to those of the original stock in the area 

 from which the extension of range has taken place ? 

 This is an interesting ' side problem,' the elucidation of 

 which might throw light on the vexed question of the 

 inheritance of certain migratory habits. The point is 

 rather a difficult one to study, because observations are 

 difficult to obtain. 



Although the Starling is found to some extent 

 throughout the year in most districts, the fact that it is 

 a migratory bird is obvious fi'om the seasonal variations 

 in its numbers. In some districts it becomes compara- 

 tively scarce in winter, while in mild regions like the 

 south of Ireland its numbers are at that season greatly 

 augmented by refugees from the severer weather of other 

 parts. The British Isles as a whole, moreover, receive 

 reinforcements from northern Europe on the approach of 

 the cold season. A bird marked in Denmark has been 

 recovered near Edinburgh. 



For nesting purposes the Starling usually selects a hole 

 or other sheltered situation, although the nest is not 

 infrequently placed in a tree open to the sky. The more 

 normal site is a hole in a tree, in a cliff or bank, or 

 in a wall or building. Chimneys, pipes, and so on, are. 



