74 EDWARD A. WILSON. 
Skuas are generally to be found in the neighbourhood of seals, in the hope of 
getting scraps of fish 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 cesophagus 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 and 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 
hirds. . 
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 
