(Gallirallus owstoni)

FUN FACT

When the first innocuous brown stow-away slipped off a Navy supply ship and disappeared into the island night, Guam was home to 11 native species of forest-dwelling birds, with populations estimated in the hundreds of thousands. 

Less than forty years later, nine of those eleven species had disappeared entirely, and the last two (the Guam Rail and the Micronesian Kingfisher) were down to only about fifty individuals combined.  Biologists on Guam realized that drastic action was necessary if there was going to be any hope of saving what was left of the small island’s native birds.

The Guam Rail seems an unlikely poster-child for successful captive management.  Small (only about ten inches, nose to tail), flightless, and the shade of cinnamon brown that fades into the background of a dark forest floor, the Guam Rail is hard glimpse, even when you know what you’re looking for.  It’s a generalist, preferring small lizards and bugs over vegetation, and can slip through dense undergrowth with remarkable speed and silence.  It was found nowhere but Guam, and evolved without snake predators.  The ground-nesting Guam Rail was thus defenseless when the Brown Tree Snake was accidentally introduced into its habitat.

In 1984, biologists at the Guam Department of Agriculture initiated an unprecedented intervention.  The last of the wild Guam Rails were rounded up and transported to protected breeding areas on Guam, as well as to zoos in the United States such as the Philadelphia Zoo, the National Zoo in Washington, DC, and the National Aviary in Pittsburgh (then known as the Pittsburgh Conservatory and Aviary).  With these twenty-one small birds traveled whatever hope remained for the species’ survival. 

As of 2013, there are 115 Guam Rails in captivity – ninety-six in protected aviaries on Guam, and fifty-five in American zoos.  Careful management has resulted in an impressive 83%  genetic diversity in the captive population.  The National Aviary has hatched 57 Guam Rails since welcoming its first wild-caught pair in 1984, and returned 23 of those Pittsburgh-hatched offspring to Guam.  These chicks have been among the nearly 200 individuals released on Cocos and Rota, two neighboring islands that share almost identical habitats with Guam.  It’s hoped that, without the Brown Tree Snake to chase them toward extinction, the Guam Rails on Cocos and Rota will recover their pre-snake numbers.  If so, it will be from that genetic reservoir that the island of Guam is someday re-populated.

Distribution

Endemic to the island of Guam.

Habitat

Forests

Diet

Omnivorous, eating more small lizards and mammals than plants and fruits.

Breeding

Year-round ground nesters.

Status

Extinct in the Wild

At the Aviary

See the Guam Rails in our Tropical Rainforest exhibit.