A History of the Birds of New Zealand.
Anthornis Melanocephala. — (Chatham-Island Bell-Bird.)
Anthornis melanocephala, Gray, in Dieff. Trav. ii., App. p. 188 (1843).
Anthornis auriocula, Buller, Essay on the Orn. of N. Z. p. 8 (1865).
♂ similis A. melanurœ, sed conspicuè major: pileo undique chalybeo, indigotico vel purpureo nitente.
♀ juv. similis adulto, sed pallidior: abdomine imo cum crisso et hypochondriis imis fulvescentibus: fronte vix chalybeo nitente: filamentis pilei gulaeque chalybeo-nigris: fasciâ mystacali indistinctâ, pallidè flavâ: tectricibus alarum, remigibus et rectricibus brunnescenti-nigris, paullò chalybeo lavatis, extùs angustè flavicanti-olivaceo limbatis: rostro nigro: pedibus brunneis, plantis pallidioribus, unguibus saturatè brunneis: iride aureâ.
Adult male. The whole of the plumage olive-green, lighter on the sides of the body and lower part of abdomen; beneath dark plumbeous, this being observable only on raising the feathers; forehead and crown steel-blue, changing to a purplish-blue gloss on the sides of the head, nape, throat, and fore part of the breast, these parts appearing shot with purple and blue in certain lights; quills dusky brown, with yellowish-brown shafts, margined on the outer webs with yellow; the small wing-coverts steel-blue, margined with olivegreen; tail-feathers dusky black, with steel-black margins; the soft ventral feathers and under tail-coverts fulvous yellow, the latter with an olivaceous tinge. Irides golden yellow (?); bill black; tarsi, toes, and claws dark brown. Total length 10 inches; wing, from flexure, 4·25; tail 4·5; bill, along the ridge ·7, along the edge of lower mandible ·9; tarsus 1·5; middle toe and claw 1·05; hind toe and claw 1·15.
Female. Although, since the publication of my former edition, I have received four or five examples of this bird from the Chatham Islands, I have never yet had an opportunity of comparing the female. Prof. Hutton says that “it is similar to the female of A. melanura except as to size.”
Young. An examination of the type of Anthornis melanocephala in the British Museum satisfied me that the bird named by me (I. c.) was only the young of this species. The following is a description of this specimen, which is now in the Colonial Museum at Wellington:—The whole of the plumage yellowish olive, paler on the underparts, and tinged with fulvous on the abdomen, flanks, and under tail-coverts; faint steel gloss on the forehead; produced filaments on the crown, sides of the head, and throat steel-black; from the angle of the mouth a narrow indistinct streak of pale yellow; wing-feathers and their coverts, also tail-feathers, blackish brown, with a faint steel gloss, their outer webs narrowly margined with yellowish olive; inner lining of wings pale yellow. Irides golden yellow; bill black; tarsi and toes brown, with paler soles; claws umber-brown. Total length 9·5 inches; wing, from flexure, 4·4; tail 4·5; tarsus 1·5. (On a close inspection of this specimen two minute feathers of steel-blue on the side of the head give indication of a change of plumage.)
Obs. Gray’s type was obtained by Dr. Dieffenbach, the naturalist to the New-Zealand Company, who visited the Chatham Islands in 1839. I may mention that it is not in the fully-matured plumage. Three of the tailfeathers on one side are dusky black, deepening to glossy steel-black on the outer webs; the rest are, like the wing-feathers, dusky brown, margined with olivaceous green. In the adult male the primaries and secondaries, as well as the tail, assume the dark colour.
This species, which is a native of the Chatham Islands, is very similar to the well-known Anthornis melanura; but, as will be seen on referring to the measurements given above, it is considerably page 93 larger. It differs, moreover, in having the whole of the head and neck brightly glossed with purplish or steel-blue.
During a visit to the Chatham Islands in 1855, I observed this Anthornis in the woods near Waitangi, and procured a specimen, although, as already mentioned, I was unable at the time to identify it. In giving it a provisional name, I selected the beautiful golden irides as presenting a good distinguishable feature, those of A. melanura being bright cherry-red. I observed that its habits were precisely similar to those of the common Bell-bird, but that its notes appeared to be louder and somewhat less musical. Its gregarious instincts are the same; for, on imitating the alarm-cry, I was immediately surrounded by a number of these birds in a high state of excitement.
Mr. Henry Travers, from whom I have received several specimens, states that he found it in great numbers on Mangare, less frequent on the main island, and rare on Pitt Island. It had commenced to breed in October, and its nest, which he describes as being “composed of grass and feathers, large and coarsely constructed,” contained as a rule three eggs. He considers its song richer and fuller than that of its New-Zealand congener. It seemed to me very much the same, but louder.
It is said that of late years this bird has deserted the neighbourhood of the native villages and settlers’ homesteads, and retired to the southern portion of Wharekauri (as the main island is called), where the woods have not yet been destroyed*.
It is a remarkable fact that whereas the New-Zealand bird is common enough at the Chatham Islands, this larger form has never been found in any part of New Zealand. The two species subsist on the same kind of food; and it is difficult to account for this peculiarity of range on any principle of geographical distribution. Where species are representative of each other in neighbouring islands, as is the case with several birds inhabiting the North and South Islands respectively, this differentiation of character, with the necessary lapse of time, is intelligible enough; but the present case is entirely different. If the long-continued separation had affected the New-Zealand bird to any appreciable degree, the same result must presumably have happened to the same bird in the Chatham Islands, four hundred miles distant; we find, however, the same type common to both places, which in itself would occasion no surprise but for the singular fact that the larger and stronger form, associated with it, is confined strictly to the smaller area, and preserves its distinctive character.
It seems to me probable that in former times both species inhabited New Zealand, and that, as Anthornis melanura is now rapidly disappearing from the mainland, so in like manner the other species may have died out before we became acquainted with the country. In that case, however, it would be necessary to discover some other factor than the Norwegian rat, which, as explained on a former page, is suspected of the principal mischief now. The survival of the extirpated race in the Chatham Islands is consistent with this supposition, because it is an observed law of nature that expiring races of animals and plants linger to the last in such insular areas.
The nest of this species is very much larger than that of the Anthornis melanura. A specimen in the Canterbury Museum measures in its largest diameter about 8 inches by 7 inches. It is composed chiefly of dry narrow flags or grasses bent in a circular form, the outer wall being strengthened with an admixture of fibrous twigs. The cavity, which is rather loosely formed, as compared with that of the latter, is roughly lined with sheep’s wool, with a few small feathers intermixed. It contained two eggs, which differ somewhat from each other, both in form and colour. One of them is of a warm salmon-pink, thickly blotched at the larger end, and spotted at irregular intervals on the general surface with reddish brown, ovoido-elliptical in form, and measuring 1·05 inch by ·75 inch. The other egg is more oval in form, paler in colour, and less marked with reddish brown, the spots being much smaller and more scattered over the surface.
* Zoologist, 1885, vol. xliii. p. 422.