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 meat as a food source and for its feathers, which were used to make highly valued pieces of clothing. Kakapo were also occasionally kept as pets. The kakapo is critically endangered; as of August 2018, the total known adult population was living individuals, all of which are named. Because of the introduction of predators such as cats, rats, ferrets, and stoats during European colonisation, the kakapo was almost wiped out. Conservation efforts began in the 1890s, but they were not very successful until the implementation of the Kakapo Recovery Programme in 1995. Most kakapo are kept on two predator-free islands,