THE GLACIAL RANGE CONTRACTION, ETC. 107 



part of Europe. There can be little doubt that had the 

 same facilities for Emigration existed between Labrador 

 and Greenland as between the British Isles and Ice- 

 land, the latter island would have possessed a much 

 more heterogeneous avifauna, and that it would have 

 been an area in which the ranges of many Palsearctic 

 and Nearctic species would have coalesced. I cannot 

 find that a single species (excluding the Wheatear) 

 breeds in South Greenland and in Iceland that does not 

 go further south in the Nearctic Region to winter — 

 proof that some portion of the species had a range base 

 there from which it emigrated northwards. It is a curious 

 fact that the Wheatear is a comparatively common 

 summer visitor to the extreme south of Greenland. The 

 individuals that breed in Greenland, say south of lat. 

 65^, most certainly do not reach their summer area by 

 way of Iceland, but must enter the country either from 

 the south-east, south-west, or west. It is most im- 

 probable that the Wheatears breeding in South Green- 

 land cross the Atlantic from North-west Ireland to Cape 

 Farewell ; it is even more improbable that they reach 

 their breeding area by way of the coast of Labrador ; 

 not only because, so far as we can ascertain, the species 

 had no base in the Nearctic region during the Glacial 

 Epoch, but because the individuals that have been ob- 

 served in Labrador are extremely few, and can only be 

 classed as abnormal migrants there. We are therefore 

 forced to the conclusion that the Wheatears breeding in 

 the extreme south of Greenland are the descendants of 

 individuals that have extended their area from Eastern 

 Asia across Behring Sea — when dry land — into the Ne- 

 arctic region. These individuals fly nearly due west 



