The bird inhabited the subtropical forests of Kauai. After 1987, there have been no reliable records of its presence. Its extinction resulted from predation by black rats and wild pigs, the spread of mosquito-borne diseases, and habitat destruction. On September 29, 2021, the U.S. Fish and Wildlife Service confirmed its extinction. The mating call of the last known individual was recorded in 1983 by conservationist John Sincock. Its mate died in Hurricane Iwa, leading to failed reproduction.

The lonely final call of the world's last Kauaʻi ʻōʻō is deeply sorrowful... Yet thousands of species have vanished silently, without even leaving such a farewell. It would be nice if Slowly could add a stamp of the Kauaʻi ʻōʻō to raise awareness about wildlife and nature conservation.