52 E. LÖNNBERG, CONTRIBUTIONS TO THE FAUNA OF SOUTH GEORGIA. 



The avifauna of the South Shetlands and Graham land resembles that of the 

 South Orkneys. Priocella glacialoides is added (8) as breeder, the stately Emperor 

 penguin is also to be seen there, but Fregetta melanogaster is to be subtracted, from 

 the list. Otherwise the conditions are, on the whole, similar. 



Kerguelen land has only cireumpolar species in common with South Georgia. 

 Its fauna is richer, and it has also its own endemic species. 



In the following the birds of South Georgia are enumerated and notes on their 

 habits are communicated from Sörling's observations with references to other authors. 

 But before this is done, it is too tempting to be avoided to make with a few words 

 a comparison between the bird-life at the northern and southern extremes of the At- 

 lantic hemisphere, the Pacific being entirely left out not to complicate matters. It 

 is axiomatic that the analogies in climatic and other conditions that exist between 

 the Arctic and Antarctic shall produce and offer to some extent similar conditions 

 of life for sea-birds at the opposite poles. Broadly speaking there are also two, and 

 biologically the same, types which have found the best opportunity to develop in 

 these icy regions of the North and the South, and these are that of the longwinged 

 bird with great flying capacities and that of the shortwinged diving bird which uses 

 his wings as öars when swimming below the surface. The place of the former type 

 is in the Arctic chiefly occupied by the Laridce (+ Fulmarus) and in the Antarctic 

 by the Tubinares ( + a gull and a few terns). The place of the latter type or that 

 of the short-winged diver is in the South taken in possession by the penguins, which 

 have become so extremely specialised for this mode of life that their wings were 

 transformed to flippers and they entirely löst the flying-capacity. — The reason why 

 this could happen without risk was of course the complete absence of terrestrial foes, 

 land mammals, such as polar foxes etc. — In the Arctic the auks turned to an 

 analogous mode of life, but although they certainly became specialised as divers they 

 could not be Avithout their flying capacity, for this was well needed because they had 

 terrestrial enemies which threatened them and their eggs and offspring with de- 

 struction and forced them to breed on inaccessible ledges of cliffs and rocks, and in 

 such localities the wings were absolutely needed to carry the birds to and fro the 

 nest. But when the flying capacity of the wings must be retained the birds could 

 not increase in bulk so much as was the case with some penguins. The correspon- 

 dence between bulk and flying-capacity is clearly demonstrated by the now ex- 

 tinct Great Auk, which at the same time proA 7 es that the Alcidce were able of 

 developing large and bulk}' birds like penguins, but then at the cost of the power 

 of flight. 



The avifaunas of the arctic and antarctic parts of the Atlantic hemisphere have 

 hardly anything in common with each other. In the north Laridce and Alcidce do- 

 minate in the south Tubinares and Aptenodytidce. Some terns and a gull extend 

 into the Antarctic region but they are not identical with those of the Arctic. One 

 only of the numerous Tubinares (Fulmarus' glacialis) has reached the far north, but 

 the same is differentiated from its southern allies. Alcidce and Aptenodytidce are 

 wholly confined each to its own polar centre. The difference makes itself sharply 



