THE ORIENTAL MIGRATION. 255 



borealis) are truly Arctic; and indeed, as almost all of 

 them pass the winter in southern latitudes, it may 

 be assumed that they are of southern and not of 

 northern origin. 



The Dippers (Cinclus) are practically unknown in 

 the Central European plain, but they occur in 

 Western Europe as far north as Scandinavia, also 

 in the Alps, Carpathians, and Southern Europe, in- 

 cluding Sicily and Sardinia. Some authorities dis- 

 tinguish three species, others only one. As a matter 

 of fact, the difference between the three forms is very 

 slight, and their nests and eggs are undistinguishable. 

 Eight other species have been recognised, and all 

 these are either Asiatic or American. As one of the 

 American forms is peculiar to Peru and another to 

 Ecuador and Columbia, and since the genus as a 

 whole is a mountain-genus, it probably is an ancient 

 one. Its European range alone, however, implies that 

 it has inhabited our continent for a considerable 

 time and is no new-comer. We may look upon it as 

 of Asiatic origin. The ancestors have spread east 

 and west, the European species having arrived with 

 the earlier Oriental migrants, and wandered along 

 the Mediterranean at a time when the geographical 

 conditions of that sea were vastly different from what 

 they are to-day. 



Not quite so ancient as the Dippers, but like- 

 wise Asiatic in their origin, are the Bullfinches 

 (Pyrrhida). The closely allied Pine-Grosbeak {Pint- 

 cola enucleator] has already been referred to (p. 191) 



