Takahe

Little is known about the movement of stoats in alpine grassland, where several species of native birds, reptiles and invertebrates are potentially at risk from predation. Radio-tracking, live trapping and tracking tunnel techniques were used to sample stoats in two adjacent habitats to determine whether the home range of stoats in beech forest valley floors extends into neighbouring alpine grasslands in the Ettrick Burn Valley, Fiordland.

New Zealand's avifauna is characterised by a variety of endemic, often flightless, birds most of which are critically endangered. One of these, the takahe, is a large flightless rail which has been reduced to one population of 115 birds in its natural alpine habitat plus 52 others introduced on four small offshore islands. By contrast the takahe's closest extant relative, the pukeko, has been highly successful since its invasion of New Zealand within the past 800 years.

In late 1986 an official deer hunting regime in the Murchison Mountains, Fiordland, was compared with two commerical aerial hunting regimes in the adjacent Stuart Mountains by measuring the density of deer faecal pellet groups. Overall densities in the Stuart Mountains were twice those in the Murchison Mountains. Official hunting appeared to be more effective than commercial hunting at reducing and controlling deer densities in heavily forested catchments, but not in catchments with less extensive forest cover.

A significant recovery of food plants preferred by introduced deer (Cervus elaphus) occurred between 1969 and 1984 on 57 permanent plots in the alpine grasslands of northern Fiordland. During this period the deer population was reduced markedly by hunters operating from helicopters.

The takahe (Notornis mantelli), an endangered rail once widely distributed through New Zealand, had become restricted to Fiordland, and possibly Nelson and the Ruahine Ranges, by European times. Two contentious viewpoints have been advanced to explain the decline: climate and vegetational changes in the late Pleistocene and Holocene; and ecological changes induced by early Polynesians. These theories are examined in relation to the habitat requirements of takahe in its present restricted range, the historical and sub-fossil record, and the possible age of the sub-fossils.