THE GREY WARBLER.

Forest and Bird, Issue 26, 1 March 1932, Page 6

THE GREY WARBLER.

(By L. W. McCaskill, in Dunedin Evening Star.)

“In the warm sunlight of advancing summer, when the manuka is covered with its snow-white bloom and the air is laden with the fragrance of forest flowers, amidst the hum of happy insect life a soft trill of peculiar sweetness—like the chirp of a merry cricket—falls upon the ear, and presently a tiny bird appears for an instant on the topmost twigs of some low bush, hovers for a moment like a moth before a flower or turns a somersault in the air, and then drops out of sight again. This is the grey warbler, the well-known riroriro of Maori history and song.” The song, if not the bird itself, should be known to every New Zealander, because the warbler has adapted itself so admirably to the conditions of civilisation and settlement that in many places it is quite independent of the native bush. This adaptability is directly beneficial to man from the economic point of view, as it has greatly increased the value of the services of the riroriro to the farmer and gardener.

The plumage, a mixture of greys and browns, seems dull until we see the bird flitting at the tips of the branches, or perhaps crossing with jerky flight from one side of the road to the other, or from bush to bush. Then, with tail outspread, the white markings show to advantage and complete the identification. Although equipped with a fan-like tail, the riroriro does not catch its food in the air, as do the fantails, but rather explores a domain untouched by most of our birds, the tips of the branches. Often one may be seen, when searching inside the tree, to dart out into the sunlight after some insect it has disturbed. As the latter alight on the tips of the twigs, “snap, snap.” goes the bill, and the prey is secured. Few birds are so exclusively insectivorous. Honey, sugar and water, berries, jam, suet, so beloved of the wax-eye, leave the warbler cold. Its habit is not to sit still and accept the dole; it feels that every waking moment must be spent in honest toil, the eager pursuit of the children of the sun, the continuous hunt of the enemies of plants. Their efficiency as insect catchers must be increased by the fact that they hunt in pairs at all times of the year—rarely is a solitary bird met with —and what one misses, the other, perchance, will pick up.

Two broods are usually raised each season, one in September, the other in November. Rarely do we find such a perfect home for the young. So characteristic is it that it can be confused with the work of no other New Zealand bird. Built in manuka for preference, it is placed on the outer branches. It is a covered

structure, the hole is in the side, often shadowed by a porch, and provided with a ledge or rim. on which the birds alight in passing to and from the interior. The nest is suspended from the top and kept from swaying by light guys fastened to the surrounding twigs. A variety of materials is used—dry moss, grass, wool, cotton, rootlets, tree fern scales, and the fabric of which spiders’ nests are made. In obtaining this fabric, the warbler does not neglect to feed on the eggs exposed, “an economy of time and food very necessary to a bird that builds a nest ten to twelve times its own size.” The young, on emerging from the nest, follow the parents about for some time, uttering the while a scarcely audible piping note. Even after they have learnt to feed themselves they will still accept food from the parents, the whole family, happy, lively, and busy, forming in their last week of companionship an episode of exceeding charm.