334 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1950 



But there are other faunas represented in Iceland. An important 

 one is the North Atlantic fauna, mainly of course of marine creatures, 

 but emerging into the air in the form of a number of sea birds which 

 exist on both east and west coasts of the North Atlantic, and on 

 suitable islands in between, Gannets, guillemots, razorbills, and 

 puffins are examples. This North Atlantic bird fauna seems to have 

 differentiated comparatively recently — perhaps as a result of the 

 drifting apart of northern America and northern Europe — and con- 

 sists of immigrant types from other regions — from the Arctic, from 

 the Pacific round Cape Horn, and from the Indian Ocean. 



Finally — believe it or not ! — the Antarctic fauna is represented in 

 Iceland. The bonxie or great skua is merely a subspecies of a domi- 

 nant species widespread in the Antarctic and sub-Antarctic regions. 

 Many high-latitude birds migrate to the other hemisphere after 

 breeding, thus perpetually avoiding winter. Our bonxies must be 

 descended from some Southern Hemisphere migrants which stayed 

 to breed in their off-season area — one cannot say "in their winter 

 quarters." 



Thus we have in this one island representatives of five faunas — 

 North Hemisphere Old World, North Hemisphere New World, 

 North Atlantic, circumpolar South Hemisphere, and circumpolar 

 North Hemisphere. 



This last includes two subdivisions — the true Arctic fauna, with 

 such Iceland birds as little auk and glaucous gull, and the sub-Arctic 

 and north-temperate forms shared by New and Old Worlds, such 

 as wheatear, raven, mallard, and Slavonian grebe. 



One of the interesting things that came to our attention was the 

 frequent distinctiveness of the local Iceland race or subspecies of 

 various species of birds. For instance the Iceland wren is both larger 

 and darker than ours in Britain, and the Iceland redpoll is also larger 

 than our British subspecies, the so-called lesser redpoll, as well as 

 having a recognizably different call note. The redpoll, by the way, 

 is an example of an Iceland bird which is small in size but yet is found 

 in Greenland and North America, as well as in the Old World, so 

 that it, like the wheatear, is Holarctic. But, unlike the widely spread- 

 ing ducks, both these small birds break up into numerous well-marked 

 subspecies. 



The wren is curious in this respect. Although it has produced 

 separate and distinctive subspecies in Iceland, Faeroe, St. Kilda, and 

 Shetland, it is uniform over the whole of western and central con- 

 tinental Europe. The separation of Britain from the Continent has 

 not resulted in the evolution of a British subspecies, though this has 

 happened with many other birds, of which our pied wagtail, so easily 

 distinguishable from the continental white wagtail, is an example. 

 Why this is so, is a real puzzle. 



