358 DISCOVERY REPORTS 



Thus it is evident that the more rigorous the chmate the later the hatching date, and 

 this rule applies to nearly all Antarctic birds which have a breeding range embracing 

 considerable differences of latitude. 



In April the Gentoos, like the other penguins, leave the South Orkneys and become 

 pelagic, but occasional stragglers are seen from time to time during the v^^inter. The bird 

 is not a creature of the pack-ice, and is very rarely seen on floes. Probably when 

 approaching the islands the birds wait until the ice is either temporarily clear, or suf- 

 ficiently open for them to make the approach by water. 



Eudyptes chrysolophus (Brandt), Macaroni Penguin. 



The Scotia Expedition found five single specimens of E. chrysolophus among penguin 

 rookeries on Laurie Island, and suspected that the bird probably bred in the South 

 Orkneys (Eagle Clarke, 1906). Bennett (1926, p. 312) states that it breeds in all the 

 Dependencies of the Falkland Islands, but there appears to be no record of any rookeries 

 having been found in the Orkneys. 



During the visit of the ' Discovery II ' a sharp look-out was kept for the bird all round 

 the group, but no sign of a rookery was found. One adult male was captured in the 

 Ringed Penguin rookery at the south end of Fredriksen Island ; this was the only bird 

 seen. 



Although in view of the diligent search I think it improbable that this species breeds 

 in the Orkneys, it is possible that a small rookery might be established on one of the 

 off-lying islets between the two largest islands, where it might easily be overlooked. 

 As an instance, there is a small rookery of macaronis established right in the middle of 

 the great Pygoscelis antarctica rookery on Deception Island, which has often escaped the 

 observation of people who have visited the Ringed Penguin rookery. 



In the Scotia Report, Eagle Clarke points to the probability of a breeding ground in 

 the South Orkneys, since the birds captured were young and could hardly have 

 accomplished the rough sea passage of 600 miles from South Georgia. Since this report 

 was published, however, it has been discovered that there are several rookeries of 

 Eudyptes chrysolophus in the South Shetlands. This fact reduces the sea passage to 200 

 miles, with wind and sea conditions favourable, and it is no longer necessary to assume 

 the existence of a South Orkney rookery. It is unlikely that the bird visits the group 

 during the winter, for it dislikes ice and is never seen when pack-ice is in the vicinity. 



Macronectes giganteus (Gmelin), Giant Petrel. (Plate XII, figs, i, 2.) 



The Giant Petrel breeds in considerable numbers on the South Orkneys. On the 

 northern coasts of Laurie Island there are several colonies, and the Scotia Expedition 

 estimated the number of birds at about 5000. On the islets surrounding EUefsen 

 Harbour there is a large colony containing about 600 nests, but the main stronghold of 

 the species is on Signy Island, where their nests are established all along the western 

 coast. A large colony is also present on the slopes above Borge Bay. The nests are all 

 built on low foothills and gently rising slopes near the sea. 



