Publications Archive

Conspicuousness of terrestrial birds from a distribution study using 100 ha squares based on the New Zealand map grid was investigated. Logistic regression was used to determine the amount of time observers should spend in each square to have a 50% chance of detecting any given bird species if it was present. The analysis was conducted for 3 habitats. For 14 species of native and introduced birds, the length of time necessary to determine presence was 1 – 631 min. To ensure that most species are accounted for in future distribution studies using similar grids, it is recommended that observers spend 1 h in each square.

The population status of the Chatham Island tomtit (Petroica macrocephala chathamensis ) was determined for each island of the Chathams group, east of New Zealand. Also, the breeding biology of the population on Rangatira (South East Island), which is free of introduced mammalian pests, was determined from observations made during 8 breeding seasons, 1981/82 to 1988/89. The total population of the Chatham Island tomtit is estimated to be

North Island kokako (Callaeas cinerea wilsoni) appear sexually monomorphic. Females are, on average, slightly smaller than males in most body measurements. Mean tarsus length was significantly smaller among females at all sites and can be used to predict sex of unknown birds with up to 86% accuracy. A simple discriminant function, using tarsus and wing chord measurements, was derived which increased sex resolution to over 90% at some sites. This is sufficient accuracy to provide a useful field technique for kokako research and conservation management. Best discri- minant functions for different sites are presented and their geographical limitations are discussed. Flux, I.; Innes, J. 2001. A field technique for determining the sex of North Island kokako (Callaeas cinerea wilsoni).