Kakapo low. Supplementary feeding affects the sex ratio of kakapo offspring, and can be used to increase the number of female chicks by deliberately manipulating maternal condition. During the winter of 1981, only females lighter than were given supplementary feeding to avoid raising their body condition, and the sex ratio results in 1982 were close to parity, eliminating the male-biased sex ratios in the unrestricted feeding. Today commercial parrot food is supplied to all individuals of breeding age on Whenua Hou and Anchor. The amount eaten and individual weights are carefully monitored to ensure that optimum body condition is maintained. Kakapo
Geography of New Zealand isolation, and this has resulted in a dynamic evolutionary ecology with examples of very distinctive plants and animals as well as populations of widespread species. Evergreens such as the giant kauri and southern beech dominate the forests. It also has a diverse range of birds, several of which are flightless such as the kiwi (a national icon), the kakapo, the takahē and the weka, and several species of penguins. Around 30 bird species are currently listed as endangered or critically endangered. Conservationists recognised that threatened bird populations could be saved on offshore islands, where, once predators were exterminated, bird life