Kakapo than females. Twenty-eight males were found to average in one study, and 39 males were found to average in another. In the same studies, 28 females were found to average and 18 females were found to average , respectively. Kakapo are the heaviest living species of parrot and on average weigh about more than the largest flying parrot, the hyacinth macaw. The kakapo cannot fly, having relatively short wings for its size and lacking the keel on the sternum (breastbone), where the flight muscles of other birds attach. It uses its wings for balance and to break its fall when
Kakapo supplementary feeding of females. Kakapo breed only once every two to five years, when certain plant species, primarily "Dacrydium cupressinum" (rimu), produce protein-rich fruit and seeds. During breeding years when rimu masts supplementary food is provided to kakapo to increase the likelihood of individuals successfully breeding. In 1989, six preferred foods (apples, sweet potatoes, almonds, Brazil nuts, sunflower seeds and walnuts) were supplied "ad libitum" each night to 12 feeding stations. Males and females ate the supplied foods, and females nested on Little Barrier Island in the summers of 1989–91 for the first time since 1982, although nesting success was