THE GOLDEN ORIOLE 155 



and even these appear to be mostly immature birds. 1 It may be that 

 the adult birds from the most southerly part of the breeding range 

 are the first to leave, and that their places are then taken for a time 

 by birds which have bred further north, so that no increase in 

 numbers is apparent there. These old birds, being strong on the 

 wing, are able to travel long distances without resting, and do not 

 find it necessary to make a stop at islands like Sicily or Malta, which 

 lie on their southward line of migration. 



1 Whitaker, Birds of Tunisia, i. p. 165. 



