320 



NUMENIUS. 



east coast of Greenland, where it is still found, and whence it has gradually spread to East 

 Siberia. In the latter locality its ramp is considerably streaked, leading to the supposition 

 that when its range first touched that of its dark-rumped allies the species had not become 

 quite so completely differentiated as they appear to be now, and that consequently some 

 interbreeding took place between them, which has left its permanent mark on the Eastern 

 form of the Common Whimbrel. 



The birds comprised in the third group, the Dai'k-rumped Barred-winged Whimbrels, 

 have the rump nearly the same colour as the mantle and lower back, the crown uniform 

 dark brown, with an obscure pale mesial line, and more or less distinct bars across the 



Whimbrel (Numenius plueopus). 



primaries and secondaries. They appear to represent the birds which emigrated down 

 Baffin's Bay and the chains of American lakes. After the retreat of the ice they seem 

 to have spread westwards to Alaska. Neither of the two species belonging to this group 

 breed in the Old World, but the Hndsonian Whimbrel has occurred in Greenland and 

 once in Iceland. The Pacific Island Whimbrel breeds in Alaska, but appears to be 

 unacquainted with the coasts of China. 



The birds comprised in the fourth group may be called Plain-winged Whimbrels, and 

 are easily distinguished from all their allies by the absence of bars on their primaries and 

 secondaries. They appear to represent the birds which escaped from the Polar ice through 

 Behring Straits, and afterwards followed the Siberian coast. Of the two species with dark 

 rumps and plain primaries, one breeds in East Arctic Siberia and the other in Arctic 

 America. As the latter is unknown on the Pacific coast, it is most probable that it did 

 not emigrate along the American shores of the Pacific, but is the result of a later emigration 

 across Behring Straits to Arctic America. 



The fifth and last group consists of the Dark-rumped Curlews. They may be 

 diagnosed as having the rump pale brown, streaked with dark brown, like the mantle and 

 lower back ; and the crown pale brown, each feather having a dark centre. They appear 

 to represent the birds which passed through Behring Straits, and followed the American 



