BIRDS OF THE SOUTH ORKNEY ISLANDS 359 



An excellent account of the habits of this species is given by L. H. Matthews (1929), 

 and nothing further remains to be said in that respect. 



In the South Orkneys, laying takes place about the middle of November, and on 

 January 4 hatching had just commenced in the colony in EUefsen Harbour. This gives 

 an incubation period of about seven weeks. On this date about one in four of the nests 

 contained newly hatched chicks and the majority of the remaining eggs were cracking. 

 By January 14 all the eggs were hatched. 



The colony at Borge Bay is very straggling, but in their choice of nesting sites the 

 birds are gregarious, and usually from six to twenty nests are associated in groups. On 

 January 17 all the nests here contained chicks. A single parent bird only was usually 

 present at each nest, but sometimes the mate would appear, usually with food for the 

 chick. As usual, when their nests were approached the birds vomited the contents of 

 their stomachs. In the Borge Bay district the contents were found to consist mainly of 

 Euphausians, while in the EUefsen Harbour colony, which adjoins the Adelie rookery, 

 remains of young penguins, and in one case half a large fish, were among the Eu- 

 phausians. The plankton probably came from the stomachs of young penguins. 



No whalers were working near the South Orkneys in January 1933, and it is probable 

 that the birds found more difficulty than usual in obtaining food. Certainly they kept a 

 very sharp eye on the penguin rookeries, and were ready to attack any dead or ailing 

 chick, advancing upon such an unfortunate at a clumsy waddle, wings half spread and 

 neck outstretched. 



With regard to colour phases, it was found that at EUefsen Harbour the average 

 proportion of white birds was 10 per cent, and at Borge Bay 9-5 per cent. The average 

 of birds seen about the remainder of the islands was also 10 per cent. This agrees well 

 with the observations of Bennett in the South Shetlands a few years ago, where he found 

 an average of i2| per cent of white birds. The Scotia Expedition, however, found an 

 average of only 2 per cent of white birds in the South Orkneys (Eagle Clarke, 1906). 

 It would be interesting to know if only absolutely white birds were included in this 

 count, for in a number of the birds included in the Discovery percentage, a few feathers 

 were very faintly flecked with grey — a common feature in "white" birds. Eagle Clarke 

 also mentions a number of very dark brown birds seen in the Orkneys. On the present 

 visit, no dark-phase birds at all were seen anywhere in the group. All were in either the 

 white or intermediate phase (Plate XII, fig. 2), and the observations suggest a pro- 

 gressive lightening of the plumage of the South Orkney birds in the last thirty years. 



L. H. Matthews, in his account of the birds of South Georgia (1929), recognizes three 

 main phases in the plumage of the Giant Petrel — dark, light, and intermediate. Bennett 

 refers to four — " all-browns ", " grey-necks ", " white-necks ", and whites. These phases 

 are referred to by Lowe and Kinnear (1930, pp. 151-4). In my opinion, a better 

 nomenclature would be: (i) dark — uniformly dark brown or brown, (ii) dark inter- 

 mediate — plumage mainly grey-brown, flecked here and there with dirty whitish, grey 

 neck, (iii) light intermediate, generally lighter grey and with more dirty whitish about 

 the plumage than (ii), and with white head and neck, and (iv) white. The gradations of 



