The Guam rail was extinct in the wild for nearly 40 years. Now it's back.

(CNN)Almost four decades after completely disappearing from the wild, a bird that had survived only in captivity now roams freely on two tropical islands.

The Guam rail's native home is a remote, 212-square-mile island in the Pacific Ocean, half way between Australia and Japan.
Known locally as the ko'ko', the rail, which had been classified as "extinct in the wild," was promoted to "critically endangered" by the International Union for the Conservation of Nature's (IUCN) 2019 red li