THE GLACIAL RANGE CONTRACTION, ETC. 149 



As will be seen from the table above given these 

 number 6^ species, but two of these, however (the 

 Osprey and the Dotterel), have now ceased to breed 

 in England, although they did so say within the last 

 hundred years, and three others (the Red-necked 

 Phalarope, the Whimbrel and Richardson's Skua) now 

 only pass that country on migration, but there is no 

 doubt that in earlier ages, when the climate was 

 sufficiently Arctic, they bred there. Four of these 

 species also pass Ireland on migration, which is a 

 safe indication that they formerly occupied that area 

 as breeding species when extending their range north- 

 wards after the Glacial Epoch had passed. Exclusive 

 of these species, but including the three that have 

 become extinct purely through man's interference, we 

 find that out of the 58 Summer Migrants to the British 

 Islands no less than 26, or nearly one-half, have either 



