230 THE MIGRATION OF BRITISH BIRDS 



Species that at one time bred in our area, and whose 

 range extended northwards with the changing chmate 

 across it, until Britain was entirely (or nearly) deserted 

 in summer, as the breeding range more or less com- 

 pletely passed on to the north. I sa)- " nearh* " in some 

 cases, because a few individuals of such species for 

 instance as the Wigeon, the Greenshank, etc, [coiif. 

 table, p. 151), still continue to breed in our islands, 

 but more dominantl}' to winter in them or to pass them 

 as coasting migrants. None of the birds whose breed- 

 ing and winter range overlap in the British Area are 

 Inter-polar or Inter-hemisphere. Some of these birds, 

 as for instance the Little Stint, the Sanderling, and the 

 Ringed Plover, were never resident in our area (no more 

 than the Swallow is), although their breeding range once 

 unquestionably extended over it, and as far to the south 

 of it as the winter quarters once extended north from 

 south Polar latitudes during the time Antarctica was 

 occupied. They are dominant Inter-polar species that 

 must always have passed far to the south or south-east 

 to winter, and which may be regarded as our earliest 

 Post-Glacial summer migrants, whose breeding range 

 now only begins far to the north of us. 



During this period the British Area was practically 

 unbroken and compact, not only far south towards the 

 Bay of Biscay, but far north in the direction of Iceland, 

 Greenland, and Scandinavia. The vast submergence 

 that has taken place has broken much of the continuity 

 of these Routes of Migration, but they are still followed, 

 as we have found to be the universal rule. The North 

 Sea between Scandinavia and Scotland is still swept b}- 

 these miufrant hosts each season : the wider waters are 



