Bird Life on Island and Shore
VI. The North Island Robin
VI. The North Island Robin.
The Robin of the North and the Robin of the South differ little from one another. Both, when standing expectant of grub or insect, indulge in that curious palsied shake or shiver of the foot—a rapid stamp or twitch; both are tame and trustful; both make choice of the same type of building site; yet as there are dissimilarities, real, though not perhaps specially conspicuous between the plumage of the one and other, so there are contrasts of a minor kind in the habits of the species.
The North Island Robin, dark above and greyish-white below, in size slightly larger than the Robin Redbreast of the Old Country, haunts in a rather greater degree the interior of woodland areas, the heart of the bush where the biggest heaviest timber grows—the mighty puriri, the magnificent tarairi. He does not eschew its page 64 filtered light, its green gloom. Unlike his relative of the south, he seems to have a less marked preference for the fringes of the bush, where luxuriance of growth often deteriorates at sea-level into scrub, jungle, and fern, and on the high tops into alpine flora, rooted in peat and sheltered by naked rock. The North Island bird, too, seems to be rather less tame. Certainly it does not trust its nest and young quite so generously and unreservedly into the keeping of mankind. Huts and disused outhouses well adapted for building purposes, which in the south would undoubtedly have been utilised, are neglected. Crumbs, too, are not, I think, picked up quite unhesitatingly—without at least a due degree of inspection. The egg of the North Island bird is in my experience rather less elongated. The male bird in the north sings from a greater height; the female is a little more shy, her habits a little more furtive.
Nests of the North Island Robin were, in Poverty Bay, built in situations not normal, the type of site most desired by the birds being unobtainable. One which I got in October was in the heart of a shrubby low-growing carpodetus. Its architects, failing the propitious shelf, had used as substitute the sound mud foundation of an ancient English Thrush's nest. Three perfectly fresh eggs had just been destroyed by rats or weasels. The sitting bird, too, had probably been killed, for abundant dark feathers lay scattered beneath. Alas! that exquisite music now is mute, the green woods are no more, the birds are gone. There are a few more sheep in the world, a few more cattle—surely God must wonder at the relative values we put upon his creatures. The generations to come have been despoiled of something precious and irreplaceable.page 68
The first of these ill-fated nests was arranged on, rather than secured to, a flat projecting kohe-kohe bole, deeply shaded by fronds of the silver-backed tree-fern. The second was established on the surface of a considerable limb—also a kohe-kohe,—broken but not wholly wrenched from the parent tree, and still green-leaved and full of sap. On the broadest portion of this split, the nest was seated rather than built, the space of several inches betwixt its inmost edge and the main trunk being blocked and wedged with stiff brown leaves gathered from the ground. There they stood close-packed like upright shingles or layers of paling one against another, making the nest appear large and cumbrous. The third nest built by this unfortunate pair was likewise page 71 placed on a sort of shelf formed by an accumulation of the midribs of tree-fern fronds consolidated by decay and rain. A fourth nest belonging to another pair was planted on a similar site, a gentle incline caused by the break of a huge limb from a puriri. In its fall away nearly two feet of its substance had been torn out, leaving a dry ledge at right angles to the magnificent trunk. Upon this the nest was deposited like a tart on a plate, so detachable that in order the more easily to observe the parent birds in attendance on their brood we were in the habit of moving it to the ground and up again as required. Any flat surface, or shelf, or gently inclined plane with a back to it is favourably considered by the Robin; always on such sites nests may be looked for.
In the disintegration of many deserted and old nests the inner parts came out almost whole, as wooden Japanese bowls fitted one within the other can be detached separately. The outer layer was composed of fresh-pulled fibre, small twigs, skeleton and dry leaves, bark, scraps of aerial roots of tree-fern, sere fragments of fronds, lichen, moss, and living trails of polypod, arranged so that the green ovoid fronds lay flat as if clinging naturally. The second nest within a nest was a wrapping of soft green moss; the innermost cup of all, a mass of the dark-brown hair page 72 gathered from uncoiling tree-fern fronds. In one instance one or two seedling plants of another kind of small polypod had been utilised in the structure of the exterior cup; the innermost lining, instead of the usual tree-fern hair only, had that substance intermixed with layers of soft frayed grass and carex. The edges of all Robins' nests are, as already described, beaten hard by the outstretched wings of the female, and firmly netted with spider-web. The hen sits closely; only the impudent obtrusion of a Pied Tit or the inadvertent approach of a Whitehead rousing her to anger and brief chase of the offender. Two or three times an hour during the progress of incubation the hen is called off into some convenient greenery, there to receive the offerings of the male, who, after feeding her, mounts high on a neighbouring tree and sings delightfully.
1 Although the above is an extreme case, there is nothing remarkable in the variation of song in different localities. The notes, for instance, of the Tui of the west coast of Stewart Island differ from the notes of the Tui of Hawkes Bay. I have listened in vain for that “organ note of surpassing richness “credited to the New Zealand Crow by one observer; for that “flute-like note” attributed by another to the Saddleback. As in song, so in degree of shyness are there great variations in races of the same breed. The Banded Rail, for instance, is in the north an exceedingly shy and wary species, yet I have reason to believe it to be quite the reverse, strangely and remarkably tame indeed, on at least one very limited area.