368 DISCOVERY REPORTS 



search was carried out in the locaUty during the following three days, but no more nests 

 were found or birds seen. 



The Blue Petrel is fairly frequently met with at sea in the South Atlantic, and is 

 common in the Weddell Sea. In November 1931 three were seen about 300 miles north- 

 west of the Orkneys. The Scotia Expedition captured two about 300 miles south-east of 

 the group. On January i, 1933, twelve were seen between twenty and a hundred miles 

 north of Laurie Island, with Prions. On this day the number of Prions was estimated 

 at 1500, so that if the Blue Petrel nests on Signy Island in numbers proportionate with 

 the numbers of the two species seen at sea, it is not surprising that only two nests were 

 found. On other occasions a few birds were seen between the South Orkneys and 

 Elephant Island, and again north of Elephant Island. 



Oceanites oceanicus (Kuhl), Wilson's Storm-Petrel. 



Wilson's Petrels are extremely abundant at the South Orkneys in the summer, being 

 probably even more numerous than the Cape Pigeons. They breed round the coasts of 

 all the islands. The nests, hidden in crannies among the rocks of the cliffs and screes, 

 are difficult to find, and it would be easy to underestimate the population, particularly 

 as the birds are mainly nocturnal. 



Eagle Clarke, in his account of the birds of the Scotia Expedition, comments on the 

 remarkable regularity of the dates at which this species makes its annual appearance at 

 the South Orkneys. November 11 and 12 were the dates on which the Scotia Expedi- 

 tion saw the first birds. This regularity has been remarked in the South Shetlands also. 

 Usually, in the summer, Bransfield Strait literally teems with birds, but on November 

 6, 1932, not a single bird was seen there. The next day several were observed north of 

 Elephant Island, and in the following days increasing numbers were seen in the Scotia 

 Sea. On November 20 birds were present in numbers near the South Orkneys. The 

 second week in November is evidently the regular time of the species' annual arrival in 

 this locality. 



The egg-laying dates appear to be subject to no such regularity. The Scotia Expedi- 

 tion found the first egg on December 1 1 . This must have been a very early laying, for 

 Eagle Clarke states that no chicks had hatched by February 21 of that year. Possibly 

 the egg was unfertile. We found the first egg on January 4, in EUefsen Harbour, but 

 several nests in this locality had not yet been laid in, though sitting birds were present 

 at nightfall. In Sandefjord Harbour, where the birds are very numerous, twenty-four 

 nests were examined, but none of them were laid in on January 10. Between January 

 17 and 20 two hundred nests were examined on Signy Island, and in about fifty of 

 these freshly laid eggs were found. This lateness in breeding imposes an enormous 

 disadvantage on the birds, and in view of their arrival at the islands a full two months 

 earlier, it is difficult to account for it. That a heavy toll is exacted is proved by the fact 

 that nearly half of the nests contained either rotten eggs from a previous season, or 

 remains of dead young. These old eggs were usually turned out of the actual nest 

 hollow, and lay near by in the cranny. 



