Art. VIII.—Note on Œstrelata neglecta; with an Exhibition of Specimens.

Transactions and Proceedings of the Royal Society of New Zealand, Volume 27, 1894, Page 132

Art. VIII.—Note on Œstrelata neglecta; with an Exhibition of Specimens. By Sir Walter L. Buller, K.C.M.G., D.Sc., F.R.S. [Read before the Wellington Philosophical Society, 5th September, 1894.] When I had the privilege of placing before you on the 25th July last a budget of ornithological notes I took occasion to refer to Professor Hutton's supposed new species of Petrel from the Kermadec Islands, to which he had given the name

of Œstrelata leucophrys, and, following Mr. Salvin, I then stated my belief that, instead of being a distinct species, it was only a form of Œ. neglecta. We have not had to wait long for confirmation of this view. I have the pleasure of exhibiting to-night a pair of birds kindly lent to me for that purpose by Mr. Bethune, the second engineer of the “Hinemoa.” The male bird is in the plumage of Professor Hutton's CEstrelata leucophrys, whilst the female is in the ordinary plumage of Œstrelata neglecta. They were taken by Mr. Bethune himself from their breeding-burrow on Sunday Island. Indeed, Mr. Bethune assures me that on every occasion he can remember—and he has collected many of these birds in the breeding-season—he has found the two kinds mated and breeding together. From this it might be inferred that the difference of plumage is sexual. As against this view, however, I have to exhibit a specimen in an intermediate state of plumage, the sides of the head and neck being very prettily rayed with dusky grey; also an example with a still whiter head than Mr. Bethune's male bird presents. All this goes to prove the correctness of Mr. Salvin's contention as to the variability of this species in regard to plumage. It is perfectly clear, therefore, that Œstrelata leucophrys will not stand as a species. At the same time that I submitted my specimens of Œ. neglecta to Mr. Salvin (as stated in my former paper, page 123) I showed him also a pair in entirely dark plumage, which seemed to me to be distinct, and which, in that case, I proposed to dedicate to Captain Fairchild, who has done so much to increase our knowledge of the birds inhabiting the outlying islands. Mr. Salvin expressed a strong belief that these were referable to the same species in a dark phase of plumage, and said that nothing would satisfy him to the contrary short of finding the dark-coloured birds nesting together apart from the lighter-coloured birds, and breeding true. I felt bound to defer to the opinion of a naturalist who has made the Petrel family his special study, so I abstained from recording this supposed new form. The two specimens which I exhibit to-night seem to prove that in this case also Mr. Salvin was right in referring the bird to Œstrelata neglecta. In one of them the entire plumage is brownish-grey, darker on the upper surface, changing to brownish-black on the wings and tail; the primaries, secondaries, and tail-feathers being white in their basal portion, with white shafts, darkening towards the tip. In the other specimen the under surface is much lighter, whilst on the throat there are indications of a change to the pale-grey characteristic of ordinary specimens of Œ. neglecta. I think, therefore, we may pretty safely assume that this is the young state of that species.

In Mr. Bethune's two specimens now exhibited the wing measures, from the flexure, exactly 11.75in.; in my intermediate example it measures 12in., and in the more matured one only 10.5in. In the two entirely dark birds the wing, as in the first-named, measures 11.75in. The dark birds have brownish-black legs and feet, whereas in all the others the tarsi are yellowish, and the toes “sandalled” with black; but this difference is no doubt due to the immaturity of the former.