NATURE NOTES.

New Zealand Herald, Volume LXII, Issue 19061, 4 July 1925, Page 1 (Supplement)

NATURE NOTES.

GREATER NEW ZEALAND.

BY J. DIIUIIMOND, F.L.S., If.Z.S.

Pigs have roamed on the southern island I of the Poor Knights group, off the east coast of North Auckland, for more than a hundred years. Their capacity as agents of destruction is" evidenced by a report by Mr. W. R. 8.. Oliver, a member of the staff of the Dominion Museum, Wellington, who visited the islands in December last. He found that pigs have almost extirpated plants of the forest floor, including seedlings of trees; some species, notably a beautiful fern, Asplenium lticidum, abundant on the northern islands, where pigs have not had an opportunity to destroy, are almost extinct on the southern island. The most serious damage is in respect to the seediings of trees, as "the whole physiognomy of the forest may be altered and its power of regeneration greatly impaired." As *-> animal life on the southern island, pigs have destroyed the breeding-grounds of petrels that make burrows in the soil. This must involve the death of many petrels. The result is that a, rare petrel, known as Puller's shearwater, and other petrels are almost extinct on the southern island, although they are abundant on other islands in the group. Gannets, gulls and terns are prevented from breeding on islands infested by pigs. A large snail, peculiar to the northern part of the Dominion, Placostylus liongii, has been exterminated in all places to which pigs have access. By the efforts of Mr. W. M. Fraser, of Whangarei, the Poor Knights have been declared a scenic reserve, and all native plants and all the native animals on them are in sanctuary. Many species of trees, plentiful on them, are nearing extinction on the mainland. Mr. Oliver describes them as a natural museum for the whau, the parapara, the tawapou, the broad-leaved maire and some shrubs and herbs. Mr. Oliver and Mr. H. H. Hamilton, of Wellington, who was with him, made an important record on the islands. It is the presence there of a large plant, about the same size as a moderate flax bush, with leaves like the leaves of the iris and bright red flowers in heads up to a foot long. The conspicuous parts of the flower, as in the ratas, are the stamens and pistil. The plant's appearance is not more remarkable than its relationship. Its nearest connection, as far as its known, is on the mountains of New Caledonia. The Poor Knights species is larger than the New Caledonian species. The presence of the remarkable plant on the islands was known to Mr. Fraser, who is honorary curator of the group, but irs identity was not known until Mr. Oliver identified it as Xeronema. It has bloomed there unrecorded because the Poor Knights are seldom visited by naturalists. They are not of the tracks of vessels, and no naturalist botanised on them until 1905. The presence of these two related species in widely separated places has led Mr. Oliver into the realm of biological speculation. Biologists and geologists find an explanation of many New Zealand problems in the theory that in past ages a greater New Zealand stretched north-west as far as New Caledonia. In this landconnection, Mr. Oliver finds sufficient explanation of the plant's present distribution. The theory is supported by relatives of the kauri, the karaka, the snail mentioned above and other plants and animals. Toward the close of the Cretaceous Period, New Zealand was a small group of islands, with a scanty vegetation and a meagre population of animal life. Later, very early in the Tertiary Era, it was gradually elevated, until it was almost a continent, stretching through New Caledonia and Fiji, and joining the mainland at New Guinea. Mr. Oliver asks why Xeronema should be found on the Poor Knights and on New Caledonia and not on the mainland of New Zealand or on Lord Howe Island and Norfolk Island, which intervene. He suggests that it should be numbered among plants that can survive only in places like isolated islands or mountain tops where competition is not as intense as in other places, and where species of waning vitality have a better chance than, in more desirable abodes. " But nothing can be said definitely," he concludes; "the biologist must admit frankly that he cannot say why one species increases and another decreases and is wiped out." "The watershed of the Roaring Lion River, north and west of Nelson, cuts probably one of the deepest gashes in the formation of New Zealand," Mr. H. F. Chaffey wrote from Asbestos Cottage, Pokororo, on June 7. "It occupies about 250 square miles, mostly covered by unpenetratcd forests, the heme of many native birds. On lower parts and extensive flats near the river, the South Island bush-robin is the most noticeable bird. I prospected part of the watershed all last summer, and have just returned from closing down for the winter, bringing away jny camera, bedding and clothing, but leaving tent, tools and cooking utensils. I had no knowledge previously of the robin's wonderful vocal powers. ] believe that it rivals the far-famed nightingale. It begins as the sun tips the mountains. Some of its notes are like the lark's, some like the songjthrush's. All are poured forth with great joyousness and abandon for twenty minutes or more, with short intervals, while the songster flits from tree to tree. It was my pleasureable lot to listen to this song morning after morning. The same pleasure was experienced if 1 was back in camp in time. The songster then descended to iriy tent, investigated all my belongings and fed on crumbs or anything else available. Wherever I went in the valley, robins abounded. If I stopped for only a few minutes one, two, or three were with me." Mr. W. Baucke, Otorohanga, King Country, who lived on the Chatham Islands for many years, and applied to the natural history and ethnology of those interesting islands the keen observation of a genuine naturalist, states that two more items must bo added to the record of places in this Dominion at which ribbon-fish Jiave been found. One was cast uf> on the northern shore of the Chathams in 1374, and another in 1881. He writes: "I found stranded specimens of the shapo and colour you describe. My 1874 ribbon-fish was so like a bushman's nine-loot crosscut in shape that a younger brother of mine said: 'Fix a handle at each end, and there you are.'' The 1881 ribbon-fish was larger"; measured by heel-and-toe feet pacings, 13J,- were used to cover its length. What, added to its singular bizarre appearance, but did not detract from its beauty, was the fanshape and the size of its lower plumes. Their ribs, like brilliant scarlet rods, projected ten or eleven inches from the web and ended in miniature Maori paddles. The web, when spread and held between the eye and sun, was seen to have a palo lavender iridescence, the iridescence more conspicuous than the colour. As the strange fish lay on tho flat, sandy, beach, with its silver sheen and brilliant colours, all was in elegant proportions, perfect in harmony in every line." New Zealand's native bees have attracted tho attention of Professor T. I). A. Cockerel, Colorado University, who has sorted out their classification and their entomological names. The bee fauna of this Dominion is strangely small, and little is known of tho habits of its members. Each species is smaller than the honey-bee, none of them, as far as is known, hordes up honey, and all seem to live in holes in the ground. A species collected on Mount Egmont by Mr. G. V. Hudson, Karori, Wellington, who is better known for his work among the moths and butterflies, is tho first mountain bee .recorded in New Zealand.