This video says about itself:
21 November 2017
The Guam Rail (Hypotaenidia owstoni), locally known as ko’ko’, was endemic to Guam and is listed by BirdLife International as Extinct in the Wild on the IUCN Red List. Predation by the brown tree snake (a non-native invasive species introduced by the US military) caused dramatic declines in Guam Rail populations but before they disappeared, 21 birds were clutched from the jaws of extinction and taken to captive breeding facilities.
On Rota (part of the Mariana Islands, to USA, north of Guam), Guam Rails have been steadily introduced since the 1990s, involving as many 100 birds per year. This video, taken in 2017 shows one of these birds in the “wild” on Rota.
Is this Guam bird coming back from extinction in the wild? Here.
Scientists have discovered why brown tree snakes have become one of the most successful invasive species. The research team has been studying why a type of cat-eyed snake has been so effective at devastating native bird populations on the island of Guam: here.