560 THE BIRDS OF HELIGOLAND 



Swans were observed swimming about near the island or travelling 

 past on migration. Iceland Gulls, old as well as young birds, were 

 seen and frequently shot, and a young Arctic Gull occurred on the 

 3rd of the month, all of which occurrences indicated that, owing to 

 climatic changes of an unfavourable nature, the homes of these 

 birds in the far north had ceased to be habitable. A gull of 

 perfectly pure white plumage had been seen on a previous 

 occasion, but in this case the person who reported its occurrence 

 was not a professional shooter, and consequently not so reliable as 

 the observer in the first-mentioned instance, whose statement 

 admits of no doubt. On the coasts of Great Britain, especially 

 those of the north of Scotland, and on the Orkney and Shetland 

 Islands, old and young birds of this species have been shot in more 

 than twenty instances. 



The nesting stations of this gull rank among the northernmost 

 of all birds, being found in Spitzbergen, Franz-Joseph Land, and 

 Grinnell Land. According to Seebohm, only four eggs of this species 

 are to be found in collections, three of which were discovered by 

 Malmgren on Spitzbergen, in latitude 80 N., while the fourth was 

 brought home by McClintock from Prince Patrick Island, 77 25 ' 

 N. latitude. 



Tern Sterna. The present, like the preceding related genus, 

 contains about fifty species. These are distributed over all the 

 oceans of the world ; but only one of them belongs to the Arctic 

 north. Only eight of the European species are met with in 

 Heligoland. 



363. Sandwich Tern [BKANDSEESCHWALBE]. 

 STERNA CANTIACA, Gmelin. 



Heligolandish : Kerr. Name formed after the call-note. 



Sterna cantiaca. Naumann, x. 50. 



Sandwich Tern. Dresser, viii. 301. 



Hirondelle de mer Gauyek. Temminck, Manuel, ii. 735, iv. 454. 



These birds make their appearance in Heligoland during the 

 second half of April and until the middle of May, when they may 

 be seen chasing one another about in pairs in the bright sunshine, 

 at heights of from five hundred to a thousand feet, amid frequent 

 utterance of their loud shrill cries ; often, indeed, their calls alone 

 are audible from heights to which the eye vainly endeavours to 

 penetrate. These are undoubtedly breeding pairs from the coasts 



