A History of the Birds of New Zealand.
Miro Albifrons. — (South-Island Robin.)
White-fronted Thrush, Lath. Gen. Syn. ii. pt. 1, p. 71 (1783).
Turdus albifrons, Gm. Syst. Nat. i. p. 822 (1788).
Miro albifrons, Gray, in Dieff. Trav. ii., App. p. 190 (1843).
Petroica albifrons, Gray, Voy. Ereb. and Terror, p. 7, pl. 6. fig. 2 (1844).
Turdus ochrotarsus, Forster, Descr. Anim. p. 82 (1844).
Muscicapa albifrons, Ellman, Zool. 1861, p. 7465.
♂ similis M. australi, sed multo major et magis fuliginosus, scapis plumarum minùs distinctè albis: sed præcipuè pectore et abdomine medio ochrascenti-albis distinguendus.
Adult male. Head, neck, sides of the body, and all the upper surface dark sooty grey, the base of the feathers plumbeous; at the root of the upper mandible a small spot of yellowish white; breast, abdomen, and vent yellowish white, tinged with lemon-yellow on the breast, and forming a tolerably well-defined line against the dark plumage of the fore neck; inner lining of wings, flanks, and under tail-coverts greyish white; quills and tail-feathers smoky black; an oblique bar of white on the inner face of the wings, as in M. australis. Irides black; bill brownish black; palate and soft parts of the mouth yellow; tarsi, toes, and claws brownish black; soles of the feet dull yellow. Total length 7·25 inches; extent of wings 10·5; wing, from flexure, 4; tail 3; bill, along the ridge ·65, along the edge of lower mandible ·85; tarsus 1·5; middle toe and claw 1·05; hind toe and claw ·9.
Female. Somewhat smaller than the male, and having the plumage of the upper parts tinged with brown; there is less yellow on the breast, and the grey of the underparts is lighter.
Obs. This species may readily be distinguished from M. australis by its appreciably larger size, its black legs and darker coloration, and the more defined patch of yellowish white on the under surface. The white shaft-lines are not so distinet on the crown and nape, but are far more so on the throat and fore neck, owing to the ground-colour of these parts being darker than in M. australis. The frontal spot is smaller and less conspicuous.
Dr. Finsch has expressed an opinion in favour of uniting M. australis and M. albifrons; but a glance at the Plate will show how decidedly the two species differ from each other in their external characters*.
Var. My collection contains a specimen received from Christchurch in which the whole plumage is suffused with brown, and the underparts are smoky grey instead of being white†.
Note. The figure of this species in the ‘Voyage of the Erebus and Terror’ is incorrect, on account of the exaggerated extent of white on the underparts; but the attitude is a very characteristic one.
The habits of this bird differ in no respect from those of its near congener Miro australis; and the account given in the foregoing pages may be considered equally applicable to both species.
* “These birds seem to be scarcely distinct” (Finsch, Trans. N.-Z. Inst. vol. v. p. 207).
† In the ‘Journal of Science,’ vol. ii. p. 170, a full description is given of a pied example, or partial albino, the white preponderating over the normal colour, and the breast being creamy yellow.
It has large lustrous eyes, and the feathered fringe to the eyelid imparts to them an unusually prominent appearance. When its attention is excited, it assumes a very erect position, and flips its wings and tail, often uttering a short chirp between each operation. It is popularly said to have the power of expanding and contracting the small white spot on its forehead, but the explanation is a simple one: when the bird is at rest, it habitually raises the frontal feathers, making the head look large and rounded and rendering the white spot almost invisible; when excited or alarmed the feathers are immediately depressed and the frontal spot is at once conspicuous.
Under the head of Eudynamis taitensis, mention will be made of its services as foster-parent to the young of that Cuckoo, of which we have at least one undoubted instance.
On comparing the eggs of this species with those of M. australis, there is a manifest difference. They are slightly larger and more ovoido-conical in form, measuring 1·05 inch in length by ·7 in breadth. They present also more individual variation than do those of the North-Island bird, which are all marked on the same pattern. In two eggs of M. albifrons in my son’s collection one has the entire surface minutely and indistinctly freckled with grey, whilst the other has the larger end splashed all over with confluent spots of purplish brown, with a few widely scattered specks over the rest of the surface. Another (taken from the nest in February) is somewhat pyriform in shape, measuring ·9 of an inch in length by ·7 in breadth; the obtuse end thickly smudged with dull brickred, washed over with brown, and a few sprinkles of the same colour on other portions of the shell.
Some doubts having existed as to the true position of the genera Miro and Myiomoira, I furnished Dr. Gadow with specimens in spirit of Miro albifrons and Myiomoira toitoi to enable him to study their internal characters, and he reports, as the result of his investigations, that both forms are true Singing-birds, and that the place I had already assigned them, in my former edition, among the Sylviidæ is undoubtedly the right one*. This fact is of some importance from a systematic point of view, because of the relation of this group to others about whose location in the system there is much difference of opinion.
In the British Museum Catalogue (Birds, vol. iv.) Mr. Sharpe places both these forms among the Muscicapidæ, associating M. toitoi and M. macrocephala with twelve other species in the genus Petrœca, with a range extending over Australia, New Zealand, and the Pacific Islands.
Professor Newton, in his able article on “Ornithology” (Encycl. Brit.), has the following remarks:—“There is no doubt whatever as to the intimate relationship of the Thrushes (Turdidæ) to the Chats (Saxicolinæ), for that is admitted by nearly every systematizer. Now most authorities on classification are agreed in associating with the latter group the Birds of the Australian genus Petrœca and its allies—the so-called ‘Robins’ of the English-speaking part of the great southern communities. But it so happens that, from the inferior type of the osteological characters of this very group of birds, Prof. Parker has called them (Trans. Zool. Society, v. p. 152), ‘Struthious Warblers’†. Now, if the Petrœca group be, as most allow, allied to the Saxicolinæ, they must also be allied, only rather more remotely, to the Turdidæ—for Thrushes and Chats are inseparable, and therefore this connexion must drag down the Thrushes in the scale. Let it be granted that the more highly developed Thrushes have got rid of the low Struthious features which characterize their Australian relatives, the unbroken series of connecting forms chains them to the inferior position, and of itself disqualifies them from the rank so fallaciously assigned to them.”
* “Miro albifrons (Passeres, Aeromyodi, Turdiformes).—Stands very well with the Sylviidæ, where you have already put it. Tail-feathers twelve. Primary remiges ten, the terminal one being long, more than half the length of the next. Secondary remiges nine. Pterylosis typically Sylviine and Turdine. Metatarsus completely encased by three long scutes or shields, one anterior and two lateral, the latter forming a sharp posterior prominent keel; truly Sylviine. Intestines agree with Sylviine birds likewise. Stomach contained insects. Nothing peculiar about Miro at all. The same applies to Myiomoira.”—H. Gadow.
† “Petrœca has been stated by Professor Parker to be a ‘Tracheophone’ (i. e. Mesomyodian), having ‘the muscles of lower larynx quite indistinct.’ In three specimens, however, of that genus examined by me I find a perfectly Oscinine syrinx with its muscles as well developed as in other birds of the same size” (Forbes, P. Z. S. 1882, p. 545).