The grey-backed storm petrel, one of New Zealand's smallest seabirds, are found around the Southern Ocean in sub-antantarctic waters.
While they tend to stay close to colonies after breeding, there have long been rumours of a breeding colony in Fiordland.
A clue to where the storm petrels might breed within Fiordland was revealed in March 2019, when a passive acoustic recording device used to monitor kiwi calls picked up several mystery bird calls.
Bird expert Colin Miskelly gave a presentation on Sunday about how they were found, and the suprising role Morning Report's daily bird calls had to play in their discovery.
He spoke to Ingrid Hipkiss.