 <unk> feeding not only increases kakapo breeding frequency , but also affects the sex ratio of kakapo offspring , as maternal conditions influence this ratio . ( See section " Reproduction " . ) This finding was subsequently used to increase the number of female chicks by deliberately manipulating maternal conditions . During the winter of 1981 , only females lighter than 1 @.@ 5 kg ( 3 @.@ 3 lb ) 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 . 
