72 EDWARD A. WILSON. 
wanders out of reach and is sooner or later snapped up by a hungry neighbour. It 
isa fact, at any rate, that though two young ones are almost always hatched, one is 
invariably missing after a few days or a week. This point we noticed at Cape Adare 
in 1902, and proved conclusively when we had better opportunities for watching at 
Cape Royds in 1904. That the chicks are eaten in every case by their own kind is 
probable, though this was actually seen but once; the fact remains that one of the two 
mysteriously disappears out of every brood, and the corpse is very seldom found. 
From the end of October to the beginning of April may be considered the six 
summer months given up by this bird to the business of reproduction. It inhabits 
during this period the most southerly part of the globe that can by any bird or beast, 
including man, be looked upon as habitable at all. No bird goes farther south than 
this, and very few so far. When the young were well feathered and fully capable of 
looking after themselves, they appeared with their elders round the ship in search of 
scraps and refuse. They are easily known by their very dark and uniform plumage. 
They have not got the bleached and whitened feathers that give their elders at the end 
of summer a characteristic hoary look, nor have they the straw-coloured ring round the 
back of the neck that becomes prominent in the second year and increases then with 
each year. The changes in plumage from the slate grey downy nestling to the 
adult are much as follows. The first thing noticeable before the feathers of the 
wing are properly developed, is a gradual blackening of the pale blue feet from 
the claws upwards, a blackening which gradually creeps up the toes and webs with 
a definite line of demarcation, extending by degrees till the feet and legs are black to 
the feathers at the tibio-metatarsal joint. Here, in the young just about to take 
the wing, there is still a bright blue patch of skin, but by March the legs and feet are 
black all over. The down has by this time been exchanged for a uniformly dark and 
soft mouse-grey plumage, which gradually becomes more brown by the removal 
apparently of the soft loose ends of the barbs by wear and tear. The bird now in its 
first year’s plumage has no trace whatever of the golden straw-coloured band upon the 
neck ; this begins to appear at about the age of ten or eleven months. 
The following table gives at a glance the general movements of McCormick’s Skua 
throughout the year in McMurdo Sound. 
1902. 1903. 
The first bird arrived ... a Si ae Nov. 3 a6 Oct. 25 
Birds obviously pairing vis a ia — “a Nov. 25 
First egg discovered... er oe aS Dec. 9 ae Dec. 2 
First chicken hatched ... 2 es a — ne Jan. 1 
Young are first able to fly... fe os Mar. 5 se Feb. 24 
The majority have gone north fs et Mar. 25 _ Mar. 20 
Last bird seen in McMurdo Sound __... ws Mar. 30 6 Apr. 7 
The food of the McCormick’s Skua consists of a variety of things, most of which 
have already been mentioned incidentally. 
In the early days of November when Weddell’s Seals are giving birth to their 
young, the Skuas are ready scavengers, and make short work of the placental refuse. 
