BIRDS OF THE SOUTH ORKNEY ISLANDS 363 



out from the sides, and facing round to the intruder. In either case they kept up a 

 harsh scolding chatter. The regurgitations were always found to consist of an oily mess 

 almost entirely composed of Euphausians. 



In the Borge Bay colonies, where the nests were clustered fairly thickly, it was found 

 that about one in four of the nests was unoccupied. These were apparently used as 

 resting grounds by the mates of the sitting birds in the nests near by. The vacant nests 

 seem to indicate that fewer birds than usual were breeding in this locality, owing 

 probably, as with the local Giant Petrels, to the absence of whalers. 



The proportion of rotten eggs was found to vary in the different colonies, but it 

 averaged about 15 per cent. This is almost certainly due rather to the rigours of the 

 climate than to infertility. 



The Cape Pigeon is one of the few species which rarely visit the South Orkneys 

 during the winter. In April the birds leave the group and become pelagic. In the South 

 Atlantic their oceanic range in the winter lies some degrees farther north than their 

 summer range, though probably a few birds would be seen almost down to the ice-edge 

 in the winter. They rarely venture over the ice, and it is to this that their absence during 

 the winter at the South Orkneys is in part due. 



Pagodroma nivea (Forster), Snowy Petrel. 



The Snowy Petrel breeds in considerable numbers on all the islands in the South 

 Orkneys. It is also one of the commonest winter visitors, for in its oceanic range the 

 bird prefers the vicinity of pack-ice. 



The nests were usually found in the same localities as those of Daption capensis, and 

 in similar situations, except that the Snowy Petrels often used more sheltered sites on 

 the cliffs. Most of their nests were to some degree protected, either by an overhanging 

 portion of rock, or by being placed in a cranny or corner on the rocky ledges. In several 

 places it was found that favourable nesting sites were provided where the rock face was 

 fissured with diagonal cleavage planes and sheltered ledges were formed. 



The nest consists of a few small flat stones and scraps of rock debris, and is not usually 

 so neat as the nest of D. capensis. The birds, in nesting, were found to be less sociable 

 than the others of their order, and although in every favourable locality a number of 

 nests were established, the individual nests were usually placed singly and well apart 

 from each other. However, two or three nests were often to be seen on the same ledge. 



The single eggs are laid in the last few days of November and in early December. 

 On January 4, all the nests examined in the vicinity of EUefsen Harbour contained 

 chicks, ranging from a day or two to perhaps a week old. The chicks are clad in uniform 

 pale pearl-grey down dorsally, and their under surfaces are dull white. Like the young 

 of D. capensis they are proficient in ejecting their stomach contents. One parent bird 

 was present on each of the nests visited here. When approached the birds raised the 

 feathers on the crown, forming quite a noticeable crest, and kept up a harsh chatter 

 similar to the defensive note of D. capensis. When drivenfrom their nests they some- 

 times took wing and wheeled round in the vicinity, uttering a harsh call rather like the 



