SEA-BIRD MOVEMENTS I47 



regular, overland passage to the Caspian, Black Sea and Mediter- 

 ranean; and along the east Atlantic shore, and some distance off it, 

 they travel in numbers to the tropical West African coast in the neigh- 

 bourhood of the Rio de Oro and Cape Verde. Here there is a significant 

 concentration of pomarine skuas, remarked upon by many different 

 observers; and some go farther, towards the Gulf of Guinea and even 

 beyond, for there are records from Walvis Bay in South Africa and 

 from St. Helena. 



In the Indian Ocean the pomarine skua has, as far as we can 

 find, only been recorded from Burma. In the Pacific it coasts along 

 the American side to Mexico, has reached the equator at the Galapagos 

 Islands and crossed it to Peru. On the Asiatic side it is found in the 

 Kuriles, off Japan and possibly off northern New Guinea; and it has 

 reached northern and eastern Australia; one straggler is recorded 

 from North Island, New Zealand. 



The arctic skua, Stercorarius parasiticus^ has much the widest 

 breeding-distribution of all skuas, extending from the High Arctic to 

 the moors of northern Scotland, and the forest zone of northern Europe, 

 Asia, and America. Comments on the map (Fig. 25, p. 148) can be 

 confined to particular areas; the arctic skua is probably the only 

 skua that breeds regularly in Labrador, though much has still to be 

 discovered about its exact distribution on that coast. In Greenland 

 it breeds on three well-defined coastal strips: the southern part of the 

 west coast; the Thule district at the entrance to Smith Sound; and 

 the east coast between Scoresby Sound and Hochstetter's Foreland; 

 not, apparently, elsewhere. It is the only skua which breeds regularly 

 on Jan Mayen. In Europe its southern limit was formerly Denmark; 

 it still breeds on the fells and coastal moors of Norway south to its 

 southern tip, Lindesnes, but is relatively rare in Sweden — even in 

 arctic Swedish Lapland, where the long-tailed skua is commoner. It 

 breeds, however, in western Finland and on the Aland islands in the 

 Baltic. It is abundant on the moors and sands of Iceland, and on all 

 the islands of the Faeroes. In Britain it now breeds regularly in Shet- 

 land, Orkney, Caithness, the Outer Hebrides and the Inner Hebridean 

 island of Coll. In Shetland it is widespread, nesting in at least three 

 parts of Mainland, and on Mousa, Noss, Yell, Fetlar, Hascosay, Unst, 

 Foula and the Fair Isle. In Orkney it breeds in Hoy, and has bred 

 in Papa Westray since about 1925; it formerly bred in Eday and 

 Sanday. The Caithness and Coll colonies are small and fluctuating, 

 and the Outer Hebridean birds are widely scattered over the maze 



