A Small Predator Removal Experiment to Protect North Island Weka (gallirallus Australis Greyi) and the Case for Single-subject Approaches in Determining Agents of Decline

North Island weka (Gallirallus australis greyi Buller) have declined in numbers and range this century (Marchant and Higgins, 1993). There are now probably less than 2 000 weka in the North Island of New Zealand and the population is scattered (D. King, pers. comm.; Department of Conservation, Gisborne, NZ) and appears to be still declining (A. Bassett, pers. comm.; Department of Conservation, Gisborne, NZ). The cause of small weka populations in the North Island is not known and hence there is a need to identify the cause before effective management to increase the population size can begin. Several factors have been suggested to account for the original decline in weka numbers including drought (Beauchamp, 1987), and disease (E. Jones, pers. comm.; Department of Conservation, Russell, NZ) but it is not clear why a bird that is omnivorous, prolific and capable of reaching high GARY N. BRAMLEY