The Guam rail is a tiny, virtually flightless bird that once thrived on the Micronesian island of Guam. But that all changed sometime in the mid-1900s when brown tree snakes made their way onto the island, likely stowed away in cargo delivered by a U.S. Navy supply ship. And once these lithe, narrow-necked serpents made landfall, they started gobbling up every native species insight.
Prior to the snakes’ arrival, Guam had no large predators that would eat eggs or chicks. So it took just a few decades before 9 of Guam’s 11 native species of forest-dwelling birds disappeared for good down the snakes’ gullets. In 1987, the Guam rail was added to the International Union for Conservation of Nature’s (IUCN) ignoble list of species considered extinct in the wild. But there is some good news.
Just before the species left this world entirely, scientists managed to capture 21 rails and create a captive breeding program on Guam and at several mainland American institutions, including the National Aviary in Pittsburgh. The breeding program has performed so well that new populations of Guam rails have been reintroduced to the nearby islands of Cocos and Rota. These islands never had rails, but they also don’t have any snakes, which makes them ideal sanctuaries for Guam rails. And with just 60 birds on Cocos and 200 on Rota, there are no indications that the birds are becoming an invasive species themselves.
The Guam rail went from functionally extinct to alive and kicking: that’s something only one other species of bird can claim.
