The extinction rate on Earth today is more than 100 times what it would be without humans by the most conservative estimates and hasn’t been higher since the Cretaceous-Paleogene (K-Pg) extinction event that wiped out about 80% of animal species, including the nonavian dinosaurs, 66 million years ago, Live Science previously reported. In other words, humans hit this planet like an asteroid, and the dust is still settling as wildlife continues to decline.

“My great, great grandfather was able to observe flocks of thousands of parakeets in the natural landscapes, my grandfather saw flocks of a hundred, my father saw a few and I’m lucky if I can see two in the forests,” Worthy said.

The human-led decline of nature indicates that Earth would be a much wilder place without us, with some lost giants, such as moas, sticking out more than others. This group of ostrich-like birds, some of which stretched up to 11.8 feet (3.6 meters) tall, evolved in New Zealand over millions of years. Within 200 years of humans’ arrival on these birds’ lands 750 years ago, all nine species of moa were gone, along with at least 25 other vertebrate species, including the giant Haast’s eagles (Hieraaetus moorei) that hunted the moas, according to Worthy.