146 SEA-BIRDS 



a maze of rivers, of which many short ones lie between it and the sea, 

 flowing erratically, depending on the temperature and melting 

 (sometimes also on volcanic eruptions), through great, flat, wide aprons 

 of morainic lava-sand, in places ten miles wide. These aprons of sand 

 are the chief breeding-habitat of the bonxie in Iceland; its headquarters 

 is on the sand- waste BreiQamerkursandur, and there are many on 

 the larger Skei6ararsandur, and some on the little waste of Steina- 

 sandur. Other parts of Iceland have a few breeding great skuas, but 

 not many nest on moorland resembling their typical habitat in Shet- 

 land. In the Faeroes and Britain the present situation is that annually 

 there are just over a hundred nests in the Faeroes, distributed over 

 eight islands, the vast majority being on Streymoy: about a thousand 

 nests in Shetland, distributed over nine islands, the vast majority 

 being on Foula, Unst, Yell, Hascosay and Noss: and over twenty 

 nests on Hoy in Orkney. It seems unlikely that there are over ten 

 thousand living northern bonxies in the world; yet the bird is so 

 conspicuous that it features very frequently in at-sea observations and 

 transects of the North Atlantic. 



The pomarine skua (we prefer this name to pomatorhine skua), 

 Stercorarius pomarinus, has the most restricted distribution (Fig. 24, 

 p. 145) of the three smaller species. Its breeding-range is typically 

 arctic, and confined to tundra countries, and it is quite absent from 

 the arctic sector between West Greenland and Novaya Zemlya, 

 except for what appear to be casual breeding-records from the Mur- 

 mansk coast and Kanin Peninsula in European Siberia, and Franz 

 Josef Land. It is doubtful whether it breeds anywhere in Labrador; 

 it is probably only irregular in Alaska south of the Arctic Circle, and 

 nobody seems to know anything about its status in Kamchatka (a 

 part of the Palearctic from which little information about birds seems 

 to be available). 



It is now possible to derive an indication of the ofl'-season distri- 

 bution of pomarine skuas from a plot of recorded observations of 

 birds on land at sea. What must clearly be quite a considerable 

 proportion of the world population enters the North Atlantic via the 

 Norwegian Sea, and migrates along the shores of Britain (particularly 

 the eastern shores), as well as more directly to mid-ocean. Pomarines 

 reach the Nova Scotia and U.S. seaboard; and pass along the western 

 North Atlantic shore as far as Florida, the Bahamas and North Cuba; 

 and there are records from the Sargasso Sea, and one from Dutch 

 Guiana. On the eastern side there seems to be a small, but fairly 



