Whenua Hou diving petrel.
Photo: DOC
There are just 200 of the birds left at a single breeding colony in the dunes on Whenua Hou, near Rakiura / Stewart Island.
The birds - known as kuaka in Ngāi Tahu dialect - were once widely found in coastal dunes across southern New Zealand, but it wasn't until 2018 that it was discovered they were a distinct species of petrel.
However, invasive predators destroyed all breeding colonies except one.
Although Whenua Hou has been predator-free since 2000, other threats remain, including storms, climate change, and competition with common diving petrels.
The research by Victoria University of Wellington, the Department of Conservation and the University of California has been trying to piece together more information about the threats the little-known birds face.