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
Kakapo approximately every five years, with the ripening of the rimu fruit. In mating years, males making "booming" calls for 6–8 hours every night for more than four months. Each court consists of one or more saucer-shaped depressions or "bowls" dug in the ground by the male, up to deep and long enough to fit the half-metre length of the bird. The kakapo is one of only a handful of birds in the world which actually constructs its leks. Bowls are often created next to rock faces, banks, or tree trunks to help reflect sound: the bowls themselves function as amplifiers