354 DISCOVERY REPORTS 



was the progressive state of filth, confusion, and smell in the rookeries. In the early 

 days of January the colonies were still comparatively orderly, individual nests were well 

 marked, and the chicks, still fairly small, seemed to be more under the control of the 

 parent birds, who were well able to protect them from the depredations of the many 

 skuas which frequent the rookeries. The young birds grew at an astonishing rate, and 

 by January 5, the "creche" system, whereby parties of from ten to twenty chicks are 

 herded together under the supervision of a few old birds, was beginning to become 

 necessary. The rookeries henceforward lost all semblance of order, becoming pro- 

 gressively filthier and more untidy. The nests were scattered and trampled out, and 

 as the chicks grew larger and individuals wandered from the flocks, the death-rate 

 mounted. Every day more dismembered remains and flattened, trampled corpses of 

 youngsters which had fallen in the race were to be seen. The skuas had growing and 

 ravenous young of their own to feed, and were increasingly vigilant and bold in their 

 attentions. Giant petrels and sheathbills were always in evidence about the rookeries. 

 These birds were never seen to attack a strong and healthy chick ; always they waited until 

 an ailing youngster was almost at the point of death. It is safe to say that no weakly 

 penguin chick has the smallest chance of surviving in an Adelie rookery. If it were 

 lucky enough to escape its natural enemies, it would soon starve from being unable to 

 pester and attract the attention of an old bird and induce it to provide food, or would be 

 trampled beneath the heedless feet of its stronger contemporaries. 



By January 13 the chicks in the large rookery surrounding EUefsen Harbour in 

 Powell Island were beginning to lose their nestling down. These were reckoned to be 

 from 5^ to 6| weeks old. The chicks at this time assisted one another to pluck the 

 down, with the occasional attention of an old bird, which was given in an absent- 

 minded manner. After January 21 the birds were not watched ashore in the rookeries, 

 but by that date most of the young birds were in their normal first-year plumage, 

 though none were seen to enter the water. 



In all the nests examined during the early days of January, two chicks were found. 

 No eggs were seen, and addled eggs appear to be a rarity. In this respect P. adeliae 

 differs from some other penguins. Many bones were seen in the nests and the nesting 

 birds probably collect the skeletons of the previous year's dead to add to their usual 

 pile of stones. 



Adelie Penguins in their choice of nesting sites undoubtedly prefer low, rocky shores, 

 and they were never found on steep rocky slopes and scarps in such positions as might 

 be occupied by Ringed Penguins. With a little practice it is easy to distinguish from 

 seaward the species inhabiting a rookery, even when individual birds cannot be identi- 

 fied. Adelie rookeries have a brick-red appearance, while rookeries of Ringed Penguins 

 are paler and yellowish in colour. This colouring is due to the profusion of excrement 

 about the rookeries, and the difference must result from some small divergence in the 

 general diet of the two species. Another good indication in identification is the character 

 of the site, for a rookery established in a steep and difficult situation is almost certain 

 to contain Ringed Penguins. 



