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
Geography of New Zealand isolation, and this has resulted in a dynamic evolutionary ecology with examples of very distinctive plants and animals as well as populations of widespread species. Evergreens such as the giant kauri and southern beech dominate the forests. It also has a diverse range of birds, several of which are flightless such as the kiwi (a national icon), the kakapo, the takahē and the weka, and several species of penguins. Around 30 bird species are currently listed as endangered or critically endangered. Conservationists recognised that threatened bird populations could be saved on offshore islands, where, once predators were exterminated, bird life