74 EDWARD A. WILSON. 



Skuas are generally to be found in the neighbourhood of seals, in the hope of 

 getting scraps offish and offal. Round our ship they lived on ^ any refuse they could 

 find, gorging themselves mainly with seal's blubber, but swallowing everything that 

 was novel to their sight. On one occasion, the stomach and oesophagus of a bird that 

 was shot were completely occupied by two sheep's ribs, the bones of two very lengthy 

 chops from some of our frozen mutton. 



I have said above that the wide range of colour in McCormick's Skua depends 

 mainly on the bleaching of the feathers, which is excessive during the summer months, 

 and on the moult, which occurs irregularly during the summer, chiefly at the latter end 

 of January and in February. When the birds first came south to McMurdo Sound in 

 November, it was exceptional to see one in the bleached and weathered phase of 

 plumage. Most of them were then in the dark plumage which had been assumed 

 towards the end of the preceding summer, and the exposure undergone during the 

 darker months of winter had not left very much trace of wear and weathering. 



But amongst the number of dark birds which characterise the month of November 

 (of which No. 75 and No. 83 are typical examples), one is occasionally seen (No. 87, 

 for example) which carries the same plumage that it had during the previous winter, 

 and consequently appears very white and weathered on the head, breast and mantle. 



In December the birds are nesting, and one may note the light and the dark phases 

 paired together. One may also still see the exceptionally weathered birds in a plumage 

 now completing its second year, and these may be of either sex. But the more usual 

 phase is the darker one with slightly weathered plumage, since the summer sun rapidly 

 takes effect in bleaching the plumage which has already stood the winter's wear. 



In January all stages of weathering may be seen, and every intermediate phase as 

 well, produced by moult. Light, dark and mottled, can all be easily procured, though 

 by the end of the month the bleached birds predominate. Of the eight skins procured 

 this month six were much weathered, two were moulting, and one had already com- 

 pleted the moult. 



In February one has still a mixture of very white and dark birds, the dark phase 

 perhaps predominating, as the majority of birds have shed their whitened plumage, and 

 are now as dark as the young which may be seen occasionally on the wing. 



In March once more almost the same condition holds good that is to be seen 

 in October, though there is a greater freshness in the dark brown of the moulted 

 adults aud the young. Here and there, again, as in October, one may see a bird 

 which has not changed its plumage, showing pale and weathered amongst the moulted 

 birds. 



Even the oldest adults are dark when freshly moulted (as, for example, No. 76), 

 and apart from evidences of age in the beak and claws, there seem to be no definite 

 age characteristics except, possibly, in the straw-coloured collar, which has been con- 

 sidered of some value in the distinction of the species. The development of this golden 

 collar varies a good deal ; in some birds it is very marked, but in others absent, and 



