Sex Ratio of North Island Kaka (nestor Meridionalis Septentrionalis), Waihaha Ecological Area, Pureora Forest Park

New Zealand Journal of Ecology (1998) 22(1): 11-16 ©New Zealand Ecological Society The apparent imbalance in the sex ratio may have been a reflection of methods used to capture birds, but if it is real, it suggests that female kaka might suffer much higher mortality, possibly associated with nesting behaviours, than do males. The long-term effects on this population will be serious. Disproportionate losses of breeding females (or males) from any population over a prolonged period of time will inevitably lead to a decline in overall numbers. Assessment of a population’s sex ratio is a fundamental element in the conservation of any threatened species (Elliott, 1996; Elliott, Dilks and O’Donnell, 1996). The detection of such an imbalance, however, can be problematic particularly if, like kaka, the sexes are difficult to distinguish in the field (Murray, 1994; Moorhouse et al., in press). To test whether the sex ratio of captured kaka reflected the true sex ratio, an independent sampling method was required. Field observations of physical and behavioural characteristics were chosen as the only practical means of comparison. This paper presents results from field observations of kaka in the Waihaha Ecological Area, Pureora Forest Park during mid October 1994 to December 1994.