The effect of surrounding land use on the distribution of Southern Crested Grebes (Podiceps cristatus australis) on Lake Forsyth, Banks Peninsula, New Zealand

Abstract

The Southern Crested Grebe (Podiceps cristatus australis) is a vulnerable Australasian subspecies of diving bird inhabiting lakes and lagoons across the South Island, New Zealand. Little research has occurred on Southern Crested Grebes in lowland habitats such as Lake Forsyth, as it was previously assumed that grebes remained in their high country habitats during winter (Sagar & O'Donnell, 1982). The population of grebes on Lake Forsyth is continuing to increase (S. Petch, pers. comm.), and with some 20% of the estimated New Zealand population wintering on this lake, the importance of Lake Forsyth to this vulnerable subspecies is high. Farming and roads occur very close to the lake margin, and this study suggests that proximity of these land uses affects the utilisation of some parts of Lake Forsyth by grebes. This may limit the number of grebes the lake can support in the future, or at least slow the current rate of increase.