The Haast's Eagle was once the largest known eagle species, native to the South Island of New Zealand. It preyed primarily on large, flightless birds like the Moa, which could reach up to 3.6 meters in height.
YOUTUBE yTU76_gQeQc Pouākai or the Haast's Eagle - The World’s Largest Eagle
The eagle itself had an estimated wingspan of up to three meters and talons as large as a modern tiger’s claws, making it a true apex predator.
- Te Ara Encyclopedia - govt.nz 
Fossil evidence shows that Haast's Eagle evolved rapidly after its ancestors arrived in New Zealand, adapting to a prey-rich but mammal-poor environment.
Without large terrestrial predators competing for food, it specialized in ambushing enormous prey in forested valleys. This ecological role makes it an extraordinary example of Island Gigantism, where species evolve larger body sizes in isolated ecosystems - britannica.com
YOUTUBE UgYo_KtRvGw The giant Haast's eagle has competition!
Unfortunately, the extinction of the Moa due to overhunting by early Māori settlers also led to the disappearance of Haast's Eagle around 1400 CE. With its primary food source gone, the eagle could not survive, leaving only fossils and cultural memory behind. Legends of the Pouakai in Māori mythology may reflect encounters with this bird, remembered as a giant man-eating eagle - nzgeo.com
YOUTUBE sRED7pWHbPQ How the Haast's Eagle Ruled Over New Zealand