STRUCTURE AND SEA-BIRDS OF THE N. ATLANTIC 27 



inland), and ranges the Pacific as well as the Atlantic; its Atlantic population is low 

 compared with that of the other southern shearwater. Unlike the Tristan great shear- 

 water, it probably makes its way into the North Sea by the Channel; and it is regular 

 in small numbers in the Western approaches. At Rockall on 17 May 1949 J. F. 

 saw none, but from 18 to 27 June 1948 R.M.L. found them always present there, 

 singly and up to eight together, that is in the proportion of about one to a hundred 

 hagdons. On the Newfoundland Banks, where it is in the same proportion, the 

 fishermen called it the haglet. It reaches Greenland and Icelandic waters, and 

 has been seen once as far north as Bear Island. 



The storm-petrel from the south is Wilson's petrel Oceanites oceanicus, which 

 nests in vast numbers in the antarctic continent and on the southern islands of 

 South Shetland, South Orkney, South Georgia, Falkland, Tierra del Fuego and 

 Kerguelen. It disperses into, and across, the Equator in the Atlantic, Indian and 

 Pacific Oceans. Wilson's petrel has been the subject of an exhaustive monograph by 

 Brian Roberts (1940), who mapped the dispersal in the Atlantic month by month 

 (Fig. 29, p. 1 68). Records north of the Equator are only irregular and sporadic between 

 November and March, but in April the species is spread widely over the western 

 half of the North Atlantic as far as Cape Cod. In May the petrels spread eastwards 

 reaching from Cape Cod across the Atlantic towards Portugal and the Bay of Biscay, 

 off which there is quite a concentration in June. By July there is a band of Wilson's 

 petrels across the whole North Atlantic with its northern border at about 40 °N., 

 but not reaching Britain. In August the eastern Atlantic petrels disappear, though 

 on the west a concentration remains with its nucleus near Long Island Sound; and 

 this persists in reduced population in September, by which time most Wilson's 

 petrels are making their way home. In September they reappear again off Portugal, 

 and the homeward stream in October runs south along the north-west coast of 

 Africa, continues its line across the Atlantic to the corner of Brazil, and carries 

 on mainly down the east coast of South America; in November and December the 

 concentration is at its greatest in the triangle Rio de Janeiro-South Georgia-Cape Horn. 



There are only about ten records for this abundant and successful species, in 

 Britain. It does not normally reach our islands, though elements cannot be within 

 much more than a few hundred miles of Cornwall in June and July. Most of the 

 British records are between October and December — suggesting young non-breeding 

 birds, inexperienced in the ways of wind and wave. 



Among the two dozen casual sea-bird visitors to the North Atlantic undoubtedly 

 the most exciting are the kings of the tubenoses — the albatrosses, whose occurences 

 in the North-Atlantic-Arctic are really monuments not so much to the fact that from 

 time to time the best-adapted birds make mistakes and get right out of their range, 

 as to the extraordinary powers of endurance and flight of the world's greatest oceanic 

 birds. Five albatrosses have strayed into the North Atlantic, four of the genus 

 Diomedea, which includes the largest kinds, and one Phoebetria. All breed in the 

 southern regions of the southern hemisphere. 



The most frequent in occurrence has been the black-browed albatross D. 

 melanophris, of which we can trace nine records. The first of these is astonishing; 

 on 15 June 1878, north-west of Spitsbergen and north of latitude 8o°N., the whaler- 

 skipper David Gray shot one that is now in the Peterhead Museum; it was farther 

 north than the species ever gets south, even though it nests to latitude 55°S. Another 

 northerly record is from West Greenland, and others have been shot south-west 



