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Volume 6, 1873
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Art. XXVIII.—Remarks on Captain Hutton's Notes on Certain Species of New Zealand Birds.—

[Received by the Wellington Philosophical Society, March, 1874.] *

Gerygone Flaviventris, Gray.

In a paper which I had the honour of reading before the Society in November, 1870 (Trans. N.Z. Inst., Vol. III., pp. 37–56), I referred at some length to the nest-building habits of Gerygone flaviventris, and in the course of my observations I made the following remark:—

“Among the substances used as building materials by this bird, spiders' nests are always conspicuous; indeed, in some specimens the whole exterior surface is covered with them. The particular web chosen for this purpose is an adhesive cocoon of loose texture, and of a dull green colour. These

[Footnote] * Dated at London 26th December, 1873.

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spiders' nests contain a cluster of flesh-coloured eggs, or young, and in tearing them off the bird necessarily exposes the contents, which it eagerly devours. Thus, while engaged in collecting the necessary building material, it finds also a plentiful supply of food—an economy of time and labor very necessary to a bird that requires to build a nest fully ten times its own size, and to rear a foster-brood of hungry cuckoos in addition to its own” (l.c., p. 42).

This statement appearing, I suppose, fanciful to Captain Hutton, he ventured, in the “Critical Notes” appended to his Catalogue of New Zealand Birds (p. 73), to pronounce these spiders' webs nothing but fresh-water Algæ! Captain Hutton afterwards wrote to me, admitting his error, but I cannot find that he has made any avowal of it in his numerous communications to the Institute. This omission is, I think, to be regretted; for while it is perfectly well understood that the “opinions” of a writer on any question of science are a fair subject of criticism and discussion, one naturalist has no right to impugn the accuracy of another in matters of fact, or to throw doubt on his habits of observation, unless in doing so he can adduce something better that mere conjecture.

Rallus modestus, Hutton.

The October number of “The Ibis” contains a communication from Captain Hutton in defence of this species. He combats my judgment in referring his type specimen to Rallus dieffenbachii, juv. (“Birds of New Zealand,” p. 180), and enters upon a long argument to prove that not only are they distinct species, but that they belong to different sub-genera. Inasmuch, however, as there is a fatal mistake in Captain Hutton's premises, his conclusions go for nothing.

“I labour under the difficulty of never having seen the specimen of Rallus dieffenbachii” is the admission with which he starts, and he immediately falls into the error of supposing that it is scarcely distinguishable from Rallus philippensis, “in fact [to quote his own words] so similar are they that it appears to me doubtful whether R. dieffenbachii should be retained as a distinct species.” Starting, therefore, with the assumption that Rallus diffenbachii and R. philippensis are the same—in which he is entirely wrong—he proceeds to prove that Rallus modestus “belongs to a different sub-genus from Rallus philippensis.” He gives a figure to show that “the bill of R. modestus is much more slender and longer in proportion to the size of the bird than in R. philippensis,” and indicates other points of difference.

Granting the whole of his argument as regards Rallus philippensis, that is quite beside the question of Rallus modestus and R. dieffenbachii being the same, which is the only point in issue.

Let the reader glance at the subjoined figures (by Keulemans) of the heads

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of Rallus philippensis and Rallus dieffenbachii, and then compare them with the figure Captain Hutton has given of the head of Rallus modestus.

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Fig. 1.—R. philippensis.
Fig. 2.—R. dieffenbachii.

It will, I think, be at once manifest that what Captain Hutton says of the bill of Rallus modestus, as compared with R. philippensis, applies with equal force to that of R. dieffenbachii.

No two species of Rail, I should say, are more readily distinguishable than Rallus philippensis and R. dieffenbachii. I have rejected sub-generic distinctions altogether in my work, or I would willingly have referred these forms to different sub-genera, as was originally proposed by the late Mr. G. R. Gray. No naturalist who had actually seen the birds would attempt to unite them as a species.

The fallacy of Captain Hutton's case is, that he labours to disprove a proposition of his own making, for no one ever asserted that Rallus philippensis and Rallus modestus were the same.

Captain Hutton is in error in stating that “R. philippensis has no claw at the end of the thumb.” The claw is well developed and very sharp. [The specimen submitted measures .25 of an inch in length.]

Tribonyx mortieri, Du Bus.

The introduction to my “Birds of New Zealand” contains a notice of the occurrence in Otago of a living example of Tribonyx mortieri. But from Captain Hutton's letter to “The Ibis” of 1st July last, it would seem that the bird brought home by Mr. Bills was obtained at Hobart Town, and kept for

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a time in the Otago Acclimatization Society's Gardens, and that (as is too often the case) a wilful deception was practised by the dealer for the sake of obtaining a higher price.

The bird in question was purchased from Mr. Bills by the Zoological Society as a New Zealand bird, and I received a letter from Dr. Sclater apprising me of the fact, and kindly placing it at my service. Mr. Bills, whom I saw personally on the subject, declared that it had been obtained on the shores of Lake Waihora, in the interior of the Otago Province, and gave me a circumstantial account of its capture! As there was nothing improbable in the occurrence of such a form in New Zealand, or rather (as I have pointed out in my Introduction, p. xviii.) as such a form might naturally be looked for there, I did not, of course, discredit the story, and was only too glad to accept Dr. Sclater's offer to make use of the Society's wood-cut in my notice of the species.