Kakapo became isolated from the remaining parrot species when New Zealand broke off from Gondwana, around 82 million years ago. Around 30 million years ago, the kakapo diverged from the genus "Nestor". Earlier ornithologists felt that the kakapo might be related to the ground parrots and night parrot of Australia due to their similar coloration, but this is contradicted by recent studies; rather, the cryptic colour seems to be adaptation to terrestrial habits that evolved twice convergently. The kakapo is a large, rotund parrot; the adult can measure from in length, and weight can vary from at maturity. Males are larger
Flightless bird requirement for flightlessness. The kiwi does not exhibit gigantism, along with tinamous, even though they coexisted with the moa and rhea that both exhibit gigantism. This could be the result of different ancestral flighted birds arrival or because of competitive exclusion. The first flightless bird to arrive in each environment utilized the large flightless herbivore or omnivore niche, forcing the later arrivals to remain smaller. In environments where flightless birds are not present, it is possible that after the K/T Boundary there were no niches for them to fill. They were pushed out by other herbivorous mammals. New Zealand had