Conservation report
This month, biologist Laura Barnhart Duenas shines a spotlight on a recovering rail species.
Guam rail
How did this flightless species become extinct in the wild?
A lot of shipments were coming to Guam, a US island territory in the western Pacific, in an effort to rebuild the island after World War II, and the brown tree snake was accidentally introduced. The island’s birds had never encountered a predator like this before and, consequently, both the Guam rail and Guam kingfisher became extinct in the wild.
How was the Guam rail saved from extinction?
Once the threat of the snake had been identified, staff at the Guam Department of Agriculture, Division of Aquatic and Wildlife Resources tried to capture as many native birds on Guam, including the rail, as possible. They brought in anything they could find, from adults to chicks and even eggs from the nest. Though they were able to catch a few individuals from every species, only the hardier birds were able to survive in captivity.
Why has the rail been reclassified as Critically Endangered?
Between 2010 and 2012, 26 Guam rails were released onto Cocos, a tiny island just off the southern tip of Guam where snakes are not present. On Rota, part of the Mariana Islands, Guam Rails have also been steadily introduced since the 1990s, involving, at times, as many as 100 birds per year. Though there aren’t any Guam rails in the wild on Guam, they have been breeding on Rota and Cocos, and their population has been stable for the past five years – approximately 260 rails exist here, more than in captivity. It is only the second bird species to come back from being classified as extinct in the wild.
What happens next?
Work is being done by our partners in the US Government to research methods of snake control and to ensure they don’t spread to other locations. We are looking at using their techniques to help prepare areas on Guam to be able to release the rail into the wild, using the populations on Rota and Cocos Island as source populations, in addition to captive-bred birds.
Megan Shersby
LAURA BARNHART DUENAS is a wildlife biologist working with the Guam Department of Agriculture.
FIND OUT MORE
How the Guam rail came back from extinction: birdlife.org/guam-rail