Art. VII.—Notes on Phalacrocorax colensoi, of the Auckland Islands, and on Phalacrocorax onslowi, of the Chatham Islands.
[Read before the Wellington Philosophical Society, 5th September, 1894.]
Mr. H. O. Forbes, in his paper “On the Birds inhabiting the Chatham Islands,” which appeared in the Ibis for October, 1893, describes, under the name of Phalacrocorax rothschildi, a Shag found at the Chatham Islands and in the
south of New Zealand, separating it from Phalacrocorax colensoi, and saying, “This species is distinguished at once by the approximation of the dark plumage of the head beneath the throat, leaving a comparatively narrow white stripe between them.” He also makes the possession of both the white alar bar and the white dorsal spot characteristic of his new species.
In my opinion we have a good deal more to learn about the Shags inhabiting New Zealand and the adjacent islands; and I think Mr. Forbes was somewhat rash in characterizing this as a new species without further investigation.
The type of my Phalacrocorax colensoi was from the Auckland Islands, but (like all the other specimens collected there by Mr. Burton at a wrong season of the year) it was in old and faded plumage, with dingy colours. Quite recently, however, I have had an opportunity of examining a large number of skins in good plumage, collected by Mr. Henry Travers at the Auckland Islands and on Campbell Island during the last cruise of the Government gunboat “Hinemoa.” The examination of this collection has satisfied me that Mr. Forbes's “characters” are of very little value. The form and width of the white stripe down the foreneck, the presence or absence of the alar bar, and the dorsal patch of white, are inconstant features, due apparently to age or season. It will probably be found, when we become better acquainted with the species, that the bird is carunculated at one season of the year and not at another, for all the specimens brought by Mr. Travers (killed in May) are without caruncles on the face. They include adult birds of both sexes, but presenting very different phases of plumage. In three of them there is a slight coronal crest, the feathers being acuminate, and produced beyond the ordinary plumage of the head.—In some the alar bar is very conspicuous, occupying the whole of the median wing-coverts, in others it is broken and irregular; in one of the birds it is wholly absent, whilst in another the only indications of it are a few scattered white feathers among the dark wing-coverts. Of the whole series only one presents the white dorsal spot. The white throat-stripe is very uncertain in character: in some of the specimens it widens gradually from the chin to the breast, whilst in one of them it is narrow and of even width in its whole extent; in some it is constricted in the middle; and in one of them the dark plumage of the sides of the neck almost meets above the breast, the white stripe being interrupted and broken. Out of the whole lot only one gives the wing – measurement of my type—namely, 10.5in. In all the others the wing, from the flexure, measures 11in. It will be seen therefore that, even in this respect, the species is variable. The fact is that this Shag, like many others,
varies with age and season, and the only thing to be done, so far as I can see, is to make the characters of Phalacrocorax colensoi somewhat wider.
In a specimen which I have since had an opportunity of examining the dark plumage actually meets about the foreneck, there being only a few minute white feathers along the line of junction. There is a single lengthened coronal feather, evidently the vestige of a crest that had recently been shed. There is a broad alar bar of white, but no dorsal spot. This bird, which presents old and faded, or out-of-season, plumage, was obtained by Mr. Henry Travers on a former visit to the Auckland Islands, about the year 1890.
With regard, however, to another species of Shag Mr. Forbes has, I think, been more fortunate. He is probably right in considering Phalacrocorax imperialis, with which I had united the Chatham Island Shag, as being confined to the Straits of Magellan, from whence the type came. I am perfectly sure that the Chatham Island bird is distinct from Phalacrocorax carunculatus of New Zealand, and if it cannot properly be united with P. imperialis it requires a distinctive name; and in providing this Mr. Forbes could not, in my opinion, have made a better selection than he did in dedicating this handsome species to our late Governor. Lord Onslow not only took an active interest in our native birds and their preservation, but he was the first to send to Europe living specimens of Phalacrocorax carunculatus, one of which, I believe, still survives in the Zoological Society's Gardens at Regent's Park.
The beautiful example of Phalacrocorax onslowi which I have the pleasure of exhibiting to you to-night came, I presume, from the Chatham Islands, although I have no information of locality with it. The specimen is in brilliant plumage, and if you will handle it you will find the feathers of the neck as soft and yielding to the touch as the finest silk-velvet. It is a male bird in full breeding plumage, and has a superb coronal crest, the feathers composing which are from one to three inches in length, of narrow even breadth, and of the same brilliant metallic blue as the surrounding plumage. Mr. Forbes, in diagnosing the character of this species, includes “an alar bar and doubtfully a dorsal spot of white as it is absent in the specimens, though mature and crested, described and figured by Sir W. Buller.” On examining the specimen now before the meeting, you will observe that, although apparently in the most matured plumage, the neck being adorned with white hair-like filaments an inch long and the alar bar being very conspicuous, there is not the slightest indication of the dorsal spot of white. I think we may conclude that its absence is characteristic of the species.
P.S.—Since the above was written I have had an opportunity of examining some further specimens of Phalacrocorax carunculatus from the White Rocks, Queen Charlotte Sound, the only locality in New Zealand, so far as we are aware, in which this species is to be found. Captain Fairchild informs me that there is still a small colony of these birds, numbering from fifteen to twenty, breeding on the rocks. On the occasion of his visit last week he found the young hatched out, but still occupying the nests. Four of these, of different sizes, clothed in thick down, he brought over with him in the “Hinemoa,” and I have sent them up to the Papaitonga Lake, where I trust they will thrive and ultimately breed. Two old birds, both females, were shot by the crew and the skins preserved. I had an opportunity of examining one of these. The pad of orange caruncles on the brow, on each side of the head, is very prominent, and as it is entirely absent in some examples I take it to be a feature peculiar to the breeding-season. There is no appearance whatever of a crest, or even an elongation of the coronal feathers. The white alar bar is very conspicuous; so is the dorsal double patch of white. The naked space around and in front of the eyes is entirely dark-blue; and the feet are flesh-coloured.
Nestling.—Covered with sooty down. Fore part of head, face, and throat, perfectly bare; the skin, which is jet-black, presenting a granulated surface, and having the appearance of kid-leather. Upper mandible brownish-black; the under mandible, except at the tip, as well as the skin at its base, in a straight line from the angle of the mouth, bluish-white, the black colouring of the skin beyond, however, being continued, in a tapering streak, to a point within the rami. Under each eye there is a minute round spot of white. Legs and feet dark-grey, the webs lighter.—W.L.B. Wellington, 25th September, 1894.