Which parrot is the world's only flightless parrot?

The world’s only flightless parrot is the kākāpō.

Native to New Zealand, the kākāpō is also called the owl parrot because of its facial disc and nocturnal habits. It is a large, moss-green, ground-dwelling bird that climbs trees and uses its wings for balance or to parachute short distances, but cannot achieve powered flight. Its flightlessness evolved in an island environment where native land predators were historically scarce.

The kākāpō is not merely unusual among parrots: it is the heaviest living parrot and one of the longest-lived birds, with reported lifespans approaching a century. It is herbivorous and has a distinctive lek breeding system, in which males gather and call to attract females.

A common mix-up is with the kākā, kea, and other New Zealand parrots. Those birds can fly; the kākāpō is the sole parrot species recognized as flightless. Introduced predators such as cats, rats, and stoats caused a severe population collapse, so conservation teams now manage the remaining birds on predator-free islands and protected mainland sites.