338 ANNUAL REPORT SMITHSONIAN INSTITUTION, 195 



northwest and southeast corners. (The slightly hardier whelk, 

 Buccinum, still occurs all round the island.) 



To come down to the present, the last few decades have seen drastic 

 changes in the fish which are Iceland's prime economic support. 

 Herring, haddock, halibut, and especially cod have extended their 

 range northward in Greenland (the cod at the rate of about 24 miles 

 a year for close on 30 years) ; and cod and herring are moving north 

 from Iceland, so that anxiety is beginning to be felt about the future 

 of the fisheries. 



Meanwhile, there have been extraordinary changes in the bird 

 population of the island. No less than six species — nearly 10 percent 

 of the previous list of breeders — have only started to breed in Iceland 

 during the present century. There is the tufted duck, which arrived 

 in 1908, and has spread so fast that now it is the second commonest 

 species on My vatn ; three gulls — the blackheaded, herring, and lesser 

 blackback; the coot and the starling, both only after 1940, the latter 

 still confined to cliflfs near its presumed landfall in the southeast. 



Further, the oystercatcher, previously confined to the southwest, 

 has shown a spectacular spread northward. The blacktailed godwit 

 and the gannet have also pushed up the northern limit of their range, 

 the latter having established three new colonies on the north and east 

 coasts. 



Meanwhile, the little auk, the only true high Arctic species in Ice- 

 land, has entirely deserted one of its two breeding colonies in the 

 northeast, and the other has dwindled to almost nothing ; apparently 

 Iceland is no longer cold enough for it. Finally, some plants are 

 moving north — ^notably the bilberry {Vaccinium myrtillus) which 

 has colonized areas previously reserved to dwarf willows ; and there 

 have been similar shifts in some of Iceland's insects. 



All these changes have become much more pronounced within the 

 last 10 to 15 years. 



We in Britain have had numerous examples of bird species spread- 

 ing northward in the present century, including some birds which 

 have been doing the same thing in Iceland, like the tufted duck, and 

 others like the black redstart which are quite recent invaders of 

 these islands. 



All such observations take on new interest when it is realized that 

 they can contribute to our understanding of a world-wide and secular 

 change of immense significance for our human future ; and one which 

 is unique, since, in Ahlmann's words, "It is the first fluctuation in the 

 endless series of past and future climatic variations in the history 

 of the earth which we can measure, investigate, and possibly explain." 



I have certainly returned from my Iceland trip with a new aware- 

 ness of the importarHce (in addition to the interest) of field natural 

 histoiy, . -' . . ':■■■• .. . . ..-.- - - 



