New Zealand Geographic, July/August 2017

For generations, Rakiura Māori told stories of a terrifying spirit bird they heard calling at night from a great height, when they visited the tītī islands during the muttonbirding season. The call—‘hakwai, hakwai, hakwai’—was followed by a screaming roar, like a jet engine passing over, or an anchor chain dropped into a boat. The sound was so hair-raising that some listeners reported falling to the ground in fright.