Haast's eagles (Hieraaetus moorei) are an extinct species of eagle and the largest eagle known to have existed, they once lived in the South Island of New Zealand. Its massive size evolved to cope with the increasing size of its prey, the flightless moa (animal). Haast's eagle became extinct after the moa were hunted to extinction by the first Māori. Knowledge of Haast's eagle survives in Māori legend in the form of the "poukai".