An Apex Predator in Isolation
Before the arrival of humans, New Zealand's ecosystems were dominated by birds. With almost no land mammals, a unique predator-prey dynamic evolved. At the top of this food web was the Haast's eagle, Harpagornis moorei. It was the largest and heaviest eagle species known to have existed. Females, which were larger than males, weighed up to 15 kilograms (33 pounds), while males were around 9 to 12 kilograms. The eagle's wingspan reached up to 3 meters, but its wings were relatively short and broad for its body size—an adaptation for moving through the dense forests and scrublands of New Zealand's South Island.
The eagle's primary prey was the moa, a group of large, flightless birds. There were nine species of moa, with the largest, Dinornis robustus, standing up to 3.6 meters (12 feet) tall and weighing as much as 230 kilograms (510 pounds). The Haast's eagle was a specialized hunter of these giants. Its legs and talons were immensely powerful, with claws as large as a modern tiger's. The rear hallux-claw could be up to 11 centimeters long. The eagle would perch in high trees or on rocky outcrops, diving at speeds of up to 80 kilometers per hour to strike a moa's pelvis or neck with incredible force.