Haast's Eagle was the largest eagle known to have existed, preying on large flightless birds called moa in New Zealand until its extinction in the 15th century due to overhunting of its main food source and habitat loss. The Huia, with its highly sexually dimorphic beak sizes, went extinct in the early 20th century due to habitat clearance, introduced predators, and overhunting for its attractive feathers. The tiny Bush Wren, last sighted in 1972, is believed extinct due to introduced predators like ferrets and rats, though some hope remains that individuals may still survive unknown.