Haast's eagle

Haast's eagle ("Harpagornis moorei") was the largest known eagle. It is the only eagle in the world known to have been the top predator in its ecosystem. It lived on the South Island of New Zealand, where there were no other large predators.
Fossil evidence shows that the areas where the Haast’s eagle lived were covered in forest and shrublands, as well as in the grasslands on river floodplains. 
The arrival of people in New Zealand had unfortunate consequences for the eagle. By 1400 AD, most of the forest habitat it used had been cleared by fire, and most of the large flightless moas that it ate had been hunted to extinction. Not surprisingly, Haarst's eagle also became extinct.