CHATHAM ISLANDS, a small group in the Pacific Ocean, forming part of New Zealand, 536 m. due E. of Lyttelton in the South Island, about 44° S., 177° W. It consists of three islands, a large one called Whairikauri, or Chatham Island, a smaller one, Rangihaute, or Pitt Island, and a third, Rangatira, or South-east Island. There are also several small rocky islets. Whairikauri, whose highest point reaches about 1000 ft., is remarkable for the number of lakes and tarns it contains, and for the extensive bogs which cover the surface of nearly the whole of the uplands. It is of very irregular form, about 38 m. in length and 25 m. in extreme breadth, with an area of 321 sq. m.—a little larger than Middlesex. The geological formation is principally of volcanic rocks, with schists and tertiary limestone; and an early physical connexion of the islands with New Zealand is indicated by their geology and biology. The climate is colder than that of New Zealand. In the centre of Whairikauri is a large brackish lake called Tewanga, which at the southern end is separated from the sea by a sandbank only 150 yds. wide, which it occasionally bursts through. The southern part of the island has an undulating surface, and is covered either with an open forest or with high ferns. In general the soil is extremely fertile, and where it is naturally drained a rich vegetation of fern and flax occurs. On the north-west are several conical hills of basalt, which are surrounded by oases of fertile soil. On the south-western side is Petre Bay, on which, at the mouth of the river Mantagu, is Waitangi, the principal settlement.
The islands were discovered in 1791 by Lieutenant W. R. Broughton (1762–1821), who gave them the name of Chatham from the brig which he commanded. He described the natives as a bright, pleasure-loving people, dressed in sealskins or mats, and calling themselves Morioris or Maiorioris. In 1831 they were conquered by 800 Maoris who were landed from a European vessel. They were almost exterminated, and an epidemic of influenza in 1839 killed half of those left; ten years later there were only 90 survivors out of a total population of 1200. They subsequently decreased still further. Their language was allied to that of the Maoris of New Zealand, but they differed somewhat from them in physique, and they were probably a cross between an immigrating Polynesian group and a lower indigenous Melanesian stock. The population of the islands includes about 200 whites of various races and the same number of natives (chiefly Maoris). Cattle and sheep are bred, and a trade is carried on in them with the whalers which visit these seas. The chief export from the group is wool, grown upon runs farmed both by Europeans and Morioris. There is also a small export by the natives of the flesh of young albatrosses and other sea-birds, boiled down and cured, for the Maoris of New Zealand, by whom it is reckoned a delicacy. The imports consist of the usual commodities required by a population where little of the land is actually cultivated.
There are no indigenous mammals; the reptiles belong to New Zealand species. The birds—the largest factor in the fauna—have become very greatly reduced through the introduction of cats, dogs and pigs, as well as by the constant persecution of every sort of animal by the natives. The larger bell-bird (Anthornis melanocephala) has become quite scarce; the magnificent fruit-pigeon (Carpophaga chathamensis), and the two endemic rails (Nesolimnas dieffenbachii and Cabalus modestus), the one of which was confined to Whairikauri and the other to Mangare Island, are extinct. Several fossil or subfossil avian forms, very interesting from the point of view of geographical distribution, have been discovered by Dr H. O. Forbes, namely, a true species of raven (Palaeocorax moriorum), a remarkable rail (Diaphorapteryx), closely related to the extinct Aphanapteryx of Mauritius, and a large coot (Palaeolimnas chathamensis). There have also been discovered the remains of a species of swan belonging to the South American genus Chenopis, and of the tuatara (Hatteria) lizard, the unique species of an ancient family now surviving only in New Zealand. The swan is identical with an extinct species found in caves and kitchen-middens in New Zealand, which was contemporaneous with the prehistoric Maoris and was largely used by them for food. One of the finest of the endemic flowering plants of the group is the boraginaceous “Chatham Island lily” (Myositidium nobile), a gigantic forget-me-not, which grows on the shingly shore in a few places only, and always just on the high-water mark, where it is daily deluged by the waves; while dracophyllums, leucopogons and arborescent ragworts are characteristic forms in the vegetation.
See Bruno Weiss, Fünfzig Jahre auf Chatham Island (Berlin, 1900); H. O. Forbes, “The Chatham Islands and their Story,” Fortnightly Review (1893), vol. liii. p. 669, “The Chatham Islands, their relation to a former Southern Continent,” Supplementary Papers, R.G.S., vol. iii. (1893); J.H. Scott, “The Osteology of the Maori and the Moriori,” Trans. New Zealand Institute, vol. xxvi. (1893); C.W. Andrews, “The Extinct Birds of the Chatham Islands,” Novitates Zoologicae, vol. ii. p. 73 (1896).