McCORMICK'S SKUA. 67 



attacking one another or the smaller petrels on the wing till the weaker disgorges 

 what he has eaten. 



Again, in Granite Harbour, on the west coast of McMurdo Sound, w^e found them 

 nesting, with young and even eggs, though it was so late as January 20th. We then 

 crossed over to Cape Crozier, where many Skuas nest, and practically live on the 

 Adelie penguins of the enormous rookery there, and here we saw the bird settle 

 deliberately on a healthy penguin chick and peck its eyes out. 



On January 31st we were at the extreme eastern end of the Great Ice 

 Barrier of Eoss, and off the new land, now called King Edward VII.'s Land, we 

 procured three Skuas, which on the same day provided us with examples of the two 

 extremes of colour variation and an intermediate form. One bird was uniformly dark 

 all over, another was weathered and bleached, with an almost white head and breast 

 and white splashes on the back and mantle, while the third was a stage between the 

 two. This variability has nothing whatever to do with sex, but much to do with 

 age and moult. The moult which replaces the bleached and whitened feathers is 

 apparently more complete and rapid in the young than it is in the older birds. 



Returnino- alono- the Barrier we saw that the Skuas were almost as constant 

 in their attendance on the seals as they were upon the penguins. So late as 

 February 9th they still had nestlings in down, and on this day we reached our winter 

 quarters in McMurdo Sound. We then had bad weather for some days, and on the 

 nth we found that these young ones had succumbed. Probably this is the fate of 

 the majority of late broods. I believe there would be no late eggs or second 

 broods at all were it not that so many of the first are destroyed and eaten by their 

 neighbours. 



The number of Skuas increased largely day by day as we killed seals round the 

 ship for food, and there were at no time less than twenty or thirty flying over the 

 dog-kennels on Hut Point. At the end of March they began their migration north- 

 ward, and finally disappeared on the 30th, to be seen no more till the following spring. 

 This Skua is of a social )le disposition, notwithstanding its cannibal tendencies, feeding, 

 nesting, and basking in the sun in groups. It is, moreover, a very cleanly bird, and 

 repeated search failed to reveal an external parasite of any kind. It is particularly 

 fond of bathing in the thaw-water pools among the hills where the snow is melted by 

 the heat absorbed from the sun's rays by the adjacent rocks. Round and in these 

 pools a group of Skuas might always be found, and the abundance of their feathers at 

 the edge testifies to the habit {see fig. 42, p. 68). In the adjacent snow their 

 tracks are found, and here and there a pattern in the hardened surface that might 

 puzzle anyone who had not watched them there {see fig. 40, p. 5G). Just ahead of 

 two footmarks is a fan-shaped series of linear scoop-marks, made by the bird's beak 

 as it squats comfortably on the snow and proceeds to satisfy its thirst by eating it. 



The Skua has no doubt good sight, but its sense of smell must be little short of 

 marvellous. When on a sledge journey to the south with Captain Scott, on Ross' 



.^' 



