NEW ZEALAND GIANT PETREL. 
The whole distance covered in the Southern Oceans was thus about 22,000 miles, 
and we were much struck by the way in which the several phases appeared and dis- 
appeared from time to time. In the open ocean, and in the more temperate regions 
throughout September and October, we saw only the largest and blackest birds, in good 
condition and with clear lemon-yeUow biUs. On approaching the ocean islands of 
Macquarie and the Aucklands in November we came into a region frequented almost 
wholly by the smaller and greyer phase or variety, sometimes in great numbers, and 
these all apparently in full moult, but although we must have seen in all many hundreds, 
we had met with as yet one only that was whoUy white, and that in the rather higher 
ranges of the temperate latitudes. Between New Zealand and the ice we again saw the 
grey birds moulting off Campbell Island on December 26th and 27th, and somewhat 
darker birds on Decembei 29th. In the pack-ice we saw one or two of the darker birds, 
and they became more numerous as we neared the coast at Cape Adare, and one might 
there constantly see two or three upon the floes, running along with wide ungainly 
straddling legs, unable to rise after feeding on some dead Adelie Penguin. 
On January 9th when we came to Cape Adare, we were surprised to see a collection 
of Giant Petrels standing on the shore, about a dozen of which were wholly white. 
In all there must have been two or three dozen birds, the majority of which were black, 
dark grey and brown, though some had paler heads, and some had heads quite white, 
with darker bodies . . . We obtained three of the white birds, and also one of the 
darkest brown ... In connection with the frequency of the white phase within the 
Antarctic Circle ... I have put in a tabular form an estimate of the various phases, 
necessarily a very rough one ... It shows that whereas the white phase is a variety 
in the sub- Antarctic region, it is by no means so rare in the region of the ice. In the 
sub-Antarctic region, moreover, Ossifraga is almost always of a uniform colour, either 
imiformly dark, blackish-brown, or blackish-grey, when viewed on the wing at a short 
distance, or else uniformly white. But within the circle one sees not only these unicolor 
phases, but a very considerable number of birds which vary between the white and 
dark. Some birds are dark all over, with white head and neck, and some are mottled 
grey, brown, and white. 
Between 33° S. and 66° 7' S. we observed, in a voyage of 140 days covering many 
thousands of miles : 
Dark birds. At least 500. Intermediate 4. White 1. 
Whereas between 66° 7' S. and 78° S. we observed in half as many days : Dark 
birds about 60. Intermediate 14. White 18. 
Then he notes that the percentage of white birds around Graham’s Land, 
according to Mr. Burn Murdoch, is about 5 per cent., and quotes Eagle Clarke’s 
South Orkney estimate of less than 2 per cent., and then points out that his 
observations were made 13° farther south than Graham’s Land, and 17° farther 
south than the South Orkneys, and writes : — 
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 region 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 SLirmise 
that in the above facts we are looking upon a very early step on the road i^o the 
formation of a distinet Antarctic species. 
From this it will be gathered that there appear to be two almost distinct 
zonal forms, both circumpolar, one being Subantarctic, the other strictly 
Antarctic. Wilson was mostly concerned in showing that the Antarctic form 
was becoming pure white, while the Subantarctic form was a dark one ; he also 
VOL. n. 
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