KUNGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 40. NIO 5. 61 



It is ready at every opportunity to try to procure a meal. If somebody begins to 

 dig up the burrows of Prion or Pelecanoides the Great Skua puts instantly in ap- 

 pearance to divide the spoils. If a bird is shot or disabled and not immediately 

 secured, the Great Skua snatches it away. The same is the case if a young bird 

 looses the maternal defense. Mr. Sörling shot for instance a duck on one of the 

 small lakes and intended also to secure its only young, but before he could get hold 

 of it a Skua had caught it and swallowed it. 



The carcasses of seals and whales gave of course plentiful food to the Great 

 Skua and it fed on them together with Daption, Larus dominicanus and Chionis. Sör- 

 ling did not observe that these speoies of birds, nor their young were ever molested 

 by the Skua. 



The Skuas and Chionis visited mostly such remains of whales that lay on dry 

 ground, while the others prefered to get their food from carcasses, or remains of such 

 in the water. In. swallowing large pieces the Skuas give perfectly wonderful per- 

 formances, Sörling says. 



On the behaviour of the Great Skuas on the South Orkneys W. Eagle Clarke 

 writes (21) »These birds were to be seen incessantly hovering över the Penguin 

 rookeries, and swooping down ever and anon at the sitting birds to snatch their 

 eggs or young.» 



»If one approaches a nest of the Great Skua», Sörling continues, »it is soon 

 to be observed if they have eggs or yonngs. In such a case they stånd with the 

 wings stretched straight upwards and the head bent to the ground, and scream as 

 loudly as possible. They do not fly before one has come quite near to them, but 

 when well on the wing, they are ready to attack. They swoop down on the intrader, 

 only just missing to strike his head with their wings, rise again in the air and repeat 

 the attacks till the f oe has retired from the neighbourhood of the nest. » Von den 

 SteinEn (12) has also related about »eine intensive Elternliebe der Raubmöwen als 

 schönster Zug in ihrem Charakter. » Only the female Skua sits on the eggs, Sör- 

 ling thinks. The male bird lies on the ground quite near the nest or reconnoitres 

 in the surroundings without leaving the nest ont of sight. When the female is off 

 feeding, both sexes make company and then they make rather long excursions so 

 that the eggs may be unprotected for hours at a time. The Great Skua is a hardy 

 bird against snow and cold weather. Even during its breeding season violent storms 

 with snow are not uncommon and the ground may be covered by a 15 — 20 cm. 

 deep layer of snow. The Skua, nevertheless, remains sitting on her eggs. 



In spite of this it migrates and is absent from South Georgia during the win- 

 ter. This is, no doubt, originally caused by the difficulty to obtain sufficient supply 

 of food at that time. According to Sörling's observations the Skuas began to mi- 

 grate from South Georgia at the end of April. This migration must be an inveter- 

 ated instinct, because, as Sorling observes, in the autumn 1905 there was no lack 

 of food in Cumberland Bay and its surroundings as carcasses of whales, blubber and 

 other refuse was quite plentiful. But on the other hand it was very much snow the 

 year mentioned, and snowdrifts even to a depth of 3—4 m. occurred. In the begin- 



