Historically on the island of Guam in the Pacific Ocean, now only on the island of Rota as an introduced population.


Forest, grassland, mixed woodland and scrub, and fern thickets

A rare bird, indeed!

The Guam rail is native to Guam in the western Pacific Ocean and is found nowhere else in the world. Most rails are somber and solid in color, but the Guam rail has dark brown and white stripes called bars beneath a plain mantel of light brown, shading to buff on the neck. A white eye stripe draws attention to the narrow, blackish bill. Its medium-length legs are strong, and the long toes help the bird to walk over grasses and soft marsh mud. Its narrow body is an adaptation for running through thick marsh grass, weeds, and underbrush.

Betcha can't find me!

Little is known about the secretive and territorial Guam rail. Why? Because there are so few of them in the wild! We do know that rails are very good at walking, or even running, without making any noise, even when moving through thick vegetation.

Guam rails can fly only about 3 to 10 feet (1 to 3 meters) at a time.
In their native Guam, Guam rails are called ko'ko'.

The San Diego Zoo received its first Guam rails in 1968 for the purpose of observation and scientific study. We then participated in a breeding program with the goal of providing birds for reintroduction or relocation to their native islands.

Today, the San Diego Zoo Safari Park has a small group of Guam rails in our off-exhibit Bird Breeding Complex.

Prior to the 1960s, there were probably around 10,000 Guam rails living on Guam, a South Pacific island. Sometime between 1944 and 1952, brown tree snakes Boiga irregularis arrived on Guam, most likely on cargo ships. The snakes’ population rapidly increased, because there was lots of prey (such as the Guam rails) and no natural predators. Prior to the tree snakes’ arrival, there were no snakes on Guam, so the rail, like other native animals there, had not developed natural defenses against this predator. The tree snakes wiped out the native animal populations, and by the 1970s, 9 of the 11 native bird species, including the Guam rail, had disappeared.

Trying to save the species, the last few birds were removed from the island in the 1980s. In 1989, reintroduction of these birds began on the island of Rota, near Guam, as part of the Association of Zoos and Aquarium’s Species Survival Plan for the species. It is hoped that controlling the feral cat population on this island will help with the Guam rail’s success there. San Diego Zoo Global is participating in both the breeding programs and current reintroduction programs on Guam and nearby Rota Island. Some of the rails now living in the wild were raised at our facilities.

You can help us bring Guam rails and other bird species back from the brink by supporting the San Diego Zoo Global Wildlife Conservancy. Together we can save and protect wildlife around the globe.