72 EDWARD A. WILSON. 



wanders out of reach and is sooner or later snapped up by a hungry neighbour. It 

 is a 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 Nov. 3 ... Oct. 25 



Birds obviously pairing ... ... ... ... Nov. 25 



First egg discovered Dec. 9 ... Dec. 2 



First chicken hatched ... ... ... ... ... Jan. 1 



Young are first able to fly Mar. 5 ... Feb. 24 



The majority have gone north ... ... Mar. 25 ... Mar. 20 



Last bird seen in McMurdo Sound Mar. 30 ... 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. 



