THE GIANT PETREL. 97 



I may quote here some remarks which have fallen from other observers upon the 

 same point, and which, indeed, first led me to take special note of the facts : Mr. Burn 

 Murdoch, for example, in his book, " From Edinburgh to the Antarctic," says, speaking 

 of Giant Petrels, " Some of them are partly white, and a few, of the same kind of bird, 

 I believe, perhaps one in twenty, are pure white, all but one or two brown feathers." 

 Thus giving the percentage proportion of white birds around Graham's Land, where 

 the Dundee whalers were at work, as 5 per cent. 



Mr. Eagle Clarke, on the other hand, in writing of the South Orkneys, says, 

 " The proportion of birds in white plumage in the rookeries was not more, perhaps less, 

 than 2 per cent.," going on, however, to say that the " colour of the birds ranged from 

 very dark brown through all shades of chocolate, and from grey through light grey 

 and mottled white to white." 



Although 2 per cent, and 5 per cent, are a great deal smaller than the 

 30 per cent, which our observations show for the Victoria Quadrant, nevertheless, 

 they uphold my main contention that the white form is very much more abundant in the 

 ice-covered regions than farther north. For even 2 per cent, in the South Orkney 

 Islands amounts to ten times as many as the highest percentage allowable on our 

 observations in the temperate seas, where we saw but one white bird to, at the very 

 least computation, five hundred dark ones. In South Victoria Land we saw a far 

 smaller total number of Giant Petrels than were met with by either of the above-quoted 

 observers ; and I may also draw attention to the fact that the area in which our 

 observations were chiefly made extended some 13 degrees (780 miles) farther south 

 than Graham's Land, and no less than 17 degrees (over 1,000 miles) farther south 

 than the South Orkneys. This very gradation in the percentage of white birds from 

 1 in 500 in the ice-free seas to 2 per cent, in the South Orkney Islands, then 5 per 

 cent, in the ice off Graham's Land, and about 30 per cent, in South Victoria Land, 

 so very much farther south, not only upholds but suggests that there are conditions 

 in the ice-covered regions which are more attractive to the whiter variations than to 

 the darker ; but until white birds can be shown to interbreed and to exhibit some 

 tendency to form nesting colonies apart from those of the darker birds, which at 

 present is not the case, one can but surmise that in the above facts we are looking 

 upon a very early step on the road to the formation of a distinct Antarctic species.* 



Not only do such figures as the above lead one to believe this, but certain 

 measurements of the bill and wing, taken first from a series of the darker phases 

 and then from a series of the white phases, tend also to the same conclusion. Thus, in 

 the ' Discovery ' and ' Morning ' collections we have nine examples, four of which are 



* Since writing the above I have been reminded by Mr. Eagle Clarke that data obtained at the breeding 

 grounds are of far greater value than those taken from birds that are merely wandering, and that the latter may 

 be very misleading. While I agree with this objection, I have allowed my observations to stand for what they 

 are worth, feeling that they may yet acquire some value, if breeding grounds are discovered farther south than the 

 farthest that are at present known, namely, those in the South Orkneys and South Shetlands. And this appears 

 to me to be possible, considering how small an area of the Antarctic has as yet been properly explored. E. A. W. 



