Holocene extinction may have put some pressure on other birds but at the time of early European contact (18th Century) and colonisation (19th Century) the bird life was prolific. With them, the Europeans brought ship rats, possums, cats and mustelids which decimated native bird life, some of which had adapted flightlessness and ground nesting habits and others had no defensive behavior as a result of having no extant endemic mammalian predators. The kakapo, the world's biggest parrot, which is flightless, now only exists in managed breeding sanctuaries. New Zealand's national emblem, the kiwi, is on the endangered bird list. There has been
Kakapo at approximately 10 to 12 weeks of age. As they gain greater independence, their mothers may feed the chicks sporadically for up to 6 months. Because the kakapo is long-lived, with an average life expectancy of 60 (plus or minus 20) years, it tends to have an adolescence before it starts breeding. Males start booming at about 5 years of age. It was thought that females reached sexual maturity at 9 years of age, but four five-year-old females have now been recorded reproducing. The kakapo does not breed every year and has one of the lowest rates of reproduction among