The Takahe - a Relict of the Pleistocene Grassland Avifauna of New Zealand

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. We conclude that the takahe is a specialised tussock grassland feeder adapted to the alpine region and that it is unlikely to have changed these feeding adaptations since the last glacial period of the Pleistocene; that the widespread sub-fossil distribution occurred in the glacial periods of the Pleistocene when alpine and sub-alpine grassland covered most of New Zealand; and that replacement of grassland and scrubland by forest when the climate ameliorated in the late Pleistocene-Holocene would have reduced takahe habitat restricting the bird to certain localities where it was vulnerable to hunting by Polynesians when they colonised New Zealand.