372 DISCOVERY REPORTS 



November, 1904. During the visit of the 'Discovery 11' no birds were seen in the 

 group, and the normal hmit of range of McCormick's Skua Ues several degrees to the 

 southward. The species no doubt occurs from time to time as a straggler, and the most 

 likely times for its appearance would be during the spring and the autumn. 



Bennett states that he has seen a few birds in Graham Land, but during the periods 

 that the 'Discovery 11' was in this locality the bird was never definitely identified. 

 Hamilton (1934) states that he did not find the bird in the South Shetlands although 

 formerly it bred there. 



Larus dominicanus, Licht, Southern Black-backed Gull. 



This bird breeds in small numbers round most of the coasts of the South Orkneys, and 

 during the entire month we spent at the group a few birds were nearly always in sight 

 from the ship. In all the harbours and straits some were present, and at frequent intervals 

 round the coasts one or two birds would appear and remain in company for short periods. 

 The only area where they were comparatively scarce was along the north coast of Corona- 

 tion Island, where the steep cliffs of the shore allows of no suitable nesting grounds. 

 The Scotia Expedition estimated the summer population of Laurie Island at about three 

 hundred birds, and probably twice that number nest among the other islands of the group. 



The gulls are the earliest breeders of all the South Orkney birds, for their eggs are 

 laid in the latter half of November. In South Georgia breeding takes place at about the 

 same time. Bennett (1926, p. 318) states that in the South Shetlands the bird breeds 

 six weeks earlier than in the Falklands. This species is practically the only exception in 

 the south to the usual rule that birds with a wide latitudinal breeding range lay their 

 eggs progressively later the higher the latitude of their nesting places. 



Several nests were found round EUefsen Harbour, but the chicks had all left in early 

 January and none were seen. The brownish chicks are always difficult to see on stony 

 ground, and on the approach of an intruder they often remain quite still, rendering 

 themselves almost invisible. 



The nests consist of scraps of lichen, feathers and seaweed, and are easy to find even 

 after they have been vacated, on account of the number of limpet shells which always 

 lie scattered around them. All the nests found were on rather flat ground, usually on 

 the top of low slopes behind the beaches. A number of nests were present in the Borge 

 Bay district, and here two chicks were observed. In these birds almost all the down was 

 gone, and they were estimated to be at least six weeks old on January 18. 



Bennett is of the opinion that the South Shetland gulls are subspecifically different 

 from those of the other parts of the South Atlantic. No noticeable superficial difference 

 is to be observed in the South Orkney birds. 



The Scotia Expedition found that a few gulls remained throughout the winter. These 

 were possibly induced to stay by the presence of the ship, but the birds would no doubt 

 be able to sustain themselves through the winter. A principal article of their diet is the 

 limpets which are found on the rocks in many parts of the coasts, and these would 

 always be obtainable. 



