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 metabolic demands in comparison to flighted birds. It is able to survive easily on very little or on very low quality food sources. Unlike most other bird species, the kakapo is entirely herbivorous, feeding on fruits, seeds, leaves, stems, and rhizomes. When foraging, kakapo tend to leave crescent-shaped wads of fiber in the vegetation behind them, called "browse signs". Having lost the ability to fly, it has developed strong legs. Locomotion is often by way of a rapid "jog-like" gait by which it can move several kilometres. A female has been observed making two return trips each night during nesting