West Coast kiwis subject of classification doubts

Press, 2 July 1979, Page 24

West Coast kiwis subject of classification doubts

Greymouth reporter Doubts remain about the assification of kiwis ound in the South Oka:ito forest the existence of which may halt plans to log the area. The Wildlife Service 1 of the Department of Internal Affairs, in a letter to West Coast Futures, said that concern for the Okarito kiwis was “further increased because we are unaware of their precise taxonomic status.” The service said that investigations were continuing but it was evident that many of the early classifications of kiwis were wrong. It seemed probable that the Okarito race of brown kiwi, which had developed differently from that found in Fiordland, could well be “a strong contender for the status of one of New Zealand’s rarest birds.”

William Docherty said in 1872 that the South Island brown kiwi inhabited certain districts, the well defined boundaries of

which it did not attempt to pass. Charles Douglas wrote that it could be found only between the

Okarito River and the Waiho, and between the Waiatoto and the Arawata, said the Wildlife Service.

The service had catalogued the distribution of the three species of South Island kiwis, and had

started an extensive field Investigation programme late in 1976 to assess the kiwis’ present status.

It had become evident that the status and distribution of the three South Island kiwis was

different from tliat originally believed, and that many old records were doubtful, or wrongly identified the species. “Birds in museum collections have been mislabelled, many field sightings misidentified, and the port of dispatch has, in many cases, been given as the locality of recovery. “Thus all three species have been accepted as occuring in the low-lying forest lands adjacent to Okarito when, in fact, many birds were obtained from other localities serviced by that port.” The service said that although the little spotted kiwis had been erroneously reported from the Okarito forest as recently as October, 1976, when “12 birds" were heard calling, the results of four surveys by the Wildlife Service during 1976, 1977, 1978 showed only the brown kiwi to be present in the

Okarito forest — “and never more than three or four birds were heard from any one listening station.”

Since 1974, the service’s distribution maps of South Island kiwis had been amended five times.

The little spotted kiw’i has been deleted from the Paparoa Ranges, brown kiwis from the Nelson

back country, and both species of spotted kiwi from the tract of land now included in Okarito.

Last century, the little spotted was the most abundant kiwi in the South Island, with a dis-

tribution from Nelson to Preservation Inlet and surrounding the brown kiwi enclaves. The vacant

habitat resulting from their disappearance this certury had not been subsequently coionised by brown kiwis.

This suggests that either the two West Coast remanent populations, at best, are static and lack the reproductive capacity to exploit additional habitat; or the adjacent areas are ecologically deficient for brown kiwis, or a combination of both. “Thus, it seems that the survival of the West Coast members of the members of the brown brown kiwi family depends on two habitats — Okariti and the Waia-oto-Arawata block. "Concern for the Okarito kiwis is further increased because we are unaware of their precise taxonomic status.” Workers last century recognised up to 10 different species of kiwi, but in a bid to rationalise nomenclature, the family merged to three species of which the brown kiwi was sub-di-vided into three subspecies — one in each of the three main islands. It now seems that this may have been incorrect. “The Okarito ‘colony’ is the most northern of the South Island brown kiwi populations. The colony is small and, by its static performance over recent decades,. precariously balanced. It is isolated by I2okm from the small (and presummably similarly precarious) Waiatoto-Arawata enclave. It is believed that Okarito has been separated from the more southern populations over a great many centuries and

observations made in Dusky Sound iu Marcn, 1579, suggest isolation at OKarito is resulting in a different kiwi from the Fiordland "parent stock. The Okarito race of the brown kiwi could well be f strong contender for the status of one of New Zealand’s rarest birds, said tne service At Okarito, brown kiwis had been seen adjacent to the logging access road, | but none had been found in north Okarito where felling had occurred. The most important undis- j turbed colony was probsbly that inhabiting Com- I p ny Creek in south Oka- , rito, said the Wildlife Ser- I vice. West Coast Futures, in its reply, has asked the I extent of the sampling of j the various habitats, and whether it included areas being logged, cut-over j areas, farmlands, and I other forests. It has also asked te, what extent the incidence . of natural enemies, such i as ferrets, had been I i lotted and compared with the distribution of birds. West Coast Futures wants to know the deciding factor in the present I Okarito brown kiwis’ ' “weak postion,” and in its survival.

If transplanting was j used to protect the little I spotted kiwi, they ask I why the brown kiwi has been said to be more likely to disappear if its ! habitat was altered. It has also asked the number of actual handled birds required for a subspecies, and the number of 1 birds needed to separate individual variations.