The Kōkako has a beautiful, clear, organ-like song. Its call can carry for kilometres. Breeding pairs sing together in a bell-like duet for up to an hour in the early morning. Different populations in different parts of the North Island (if any populations of the South Island Kōkako remain they are at present unknown) have distinctly different songs which many people consider analogous with human "dialects" of a given language.
The Kōkako is a poor flier and seldom flies more than 100 metres.
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