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The distribution, speciation and probable evolution of New Zealand parakeets are outlined. Specific ecological adaptations keep closely related sympatric species separate. Examples are given of such ecological isolating mechanisms in Antipodes and Chatham Island parakeets. Occasionally, where man has drastically modified the environment, these barriers break down and widespread hybridisation occurs, as on Mangere Island, Chatham Islands. The existence of the very rare Chatham Island yellow-crowned parakeet (Cyanoramphus auriceps forbesi) is endangered by habitat changes and hybridisation.