THE OLDER STAGES 129 



As these thirteen species alone represent a very substantial part of the huge oceanic bird population 

 of Antarctica it is probable that the quantity of krill they devour is second only in magnitude to that 

 consumed by the whales, seals and penguins themselves. Their diet as already said is a catholic one 

 and during the whaling season they are often to be seen in vast numbers gorging on the scraps and 

 garbage arising from the slaughter, at times it would seem to the virtual exclusion of their natural diet. 

 Bennett (i 931) who spent a number of years with the early whalers and saw the rise of the southern 

 industry to its present dimensions, records the following passage : 



When the day comes which sounds the death-knell of Antarctic whaling, it will also see the doom of millions of birds 

 that at present prey on the waste produced by this industry. For whaHng artificially produces an abundance of food 

 that has enabled all sorts of birds to increase enormously in numbers. When an end comes to it, the natural food 



supply will only be able to support a tithe of the present bird population At present the birds, thanks to the 



whaling trade, get plenty of food, and get it easily. But the withdrawal of this source of nourishment can only spell 

 disaster on a gigantic scale. 



'No one', he continues, 'can doubt this who has seen the myriads of petrels of all kinds '^ that 

 gather at the whaling stations and round the floating factories to gorge upon the waste. Whether in 

 fact such a holocaust would ensue seems doubtful, for the chief predators of the krill, the whales 

 themselves, now supposedly so reduced in numbers as to make whaling uneconomic, would be taking 

 less from the plankton and leaving more for the birds. Even so there can I think be little doubt that 

 as a result of whaling the numbers of Antarctic oceanic birds have increased, and possibly increased 

 enormously, and so it could well be that the mortality among the krill for which they are responsible 

 is even heavier today than in the years before the advent of the modern whalers upon the Antarctic 

 field. 



Mawson (19406) refers to the impact of sealing on the bird population of Macquarie Island, 

 stating that round about 1911-14 carrion birds such as skua gulls and giant petrels had 'increased 

 greatly in numbers, owing to the abundant food supply available in the flensed carcases of the seals 

 left on the beaches '. A similar increase, as a result of whaling, seems to have occurred too in the Brown 

 Skua population of the South Shetlands and Graham Land (Hamilton, 19346). Falla (1952) also 

 calls attention to the steady increase in numbers of scavenging or turned-scavenging birds that has 

 accompanied the growth of the summer whale fishery, adding that since the luinter food supply is also 

 of concern to this artificially swollen and ravening population some species in order to survive have 

 evidently been compelled to increase their winter range, the Cape Pigeon and Giant Petrel even as 

 far north as Tory Channel in New Zealand. 



The extensive circumpolar journeys of young first year Giant Petrels, recently demonstrated by 

 Antarctic banding (Carrick, 1959), could also it is suggested spring from a growing necessity in this 

 species to increase its winter range. 



Other bird populations are known to have increased enormously both in numbers and range as a 

 result of human activity, the fulmar providing a striking example. Originally a high Arctic bird and 

 a plankton feeder, as a result of the easy food supply provided in former times by whaling and more 

 recently by trawling, it has multiplied and gradually spread southwards far into temperate waters 

 (Crisp, 1959). 



Quantities of krill have been reported in the stomachs of the Giant Petrel or Stinker, Macronectes 

 giganteus (Gmelin), but in this case it comes as a rule to the Stinker third-hand, being derived not 

 directly from the plankton but from the stomachs of the nestling penguins it is known to attack and 

 devour (Matthews, 1929; Murphy, 1936; Ardley, 1936). It seems possible, however, that even this 



1 A remarkable photograph of Bennett's myriads, 'Birds preying on refuse', is given in his book facing page 189. It is the 

 most striking of the many such congregations I have seen. 



13 DM 



