Guam Rail / Ko'ko'
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Guam Rail / Ko'ko'
Rallus owstonii
Endemic to Guam. Endangered species
The Guam Rail is a special bird. Locally known as the "ko'ko' ", it is endemic to Guam, which means it is found only on Guam and nowhere else in the world. This bird is dark brown with white stripes on its stomach.
A Chamoru legend tells how the ko'ko' got its stripes. One day a monitor lizard, or "hilitai", and a ko'ko' decided they looked too plain, so the ko'ko' began painting the hilitai. When it was the ko'ko's turn to be painted, the hilitai painted a few strokes then decided he was tired and left all but the ko'ko's stomach unpainted. The ko'ko' became so angry that he bit the hilitai's tongue in two. This is why, according to the legend, hilitai have forked tongues and cannot make noise.
The ko'ko' came to our island thousands of years ago. At that time it was able to fly. However, since there were no predators on Guam, it slowly lost the ability to fly. But then people arrived on the island and brought dogs, cats, rats and monitor lizards with them. Sometime after World War II, the predatory brown tree snake also found its way to our island. Since the ko'ko' is flightless and builds its shallow nest on the ground, it was easy for these predators to catch the ko'ko' and its babies.
Ko'ko' lay up to four large, freckled eggs. Young ko'ko' leave the nest when they are only one day old. Their parents then eat the egg shell. Adult ko'ko' eat insects as well as snails, skinks and geckos. They like to live in brushy areas mixed with grassland or forest. They also like to bathe in the rain. When their numbers were high, they could often be found along the roadside in tall grass early in the morning.
The ko'ko' was so common that local hunters were able to hunt and eat all the ko'ko' they wanted. Now it is against local and federal law to capture, harass or kill a ko'ko'. Due to snake predation, the ko'ko' population has become extinct in the wild.
In 1983, a captive breeding program was established to ensure that the ko'ko' does not become extinct. The captive ko'ko' population, as of early 1994, stands at over 200 birds on Guam and in various zoos throughout the continental United States. An experimental population of rails was begun in 1990 in nearby Rota where environmental conditions are similar to Guam's and there are no kulepbla (brown tree snakes). Over 50 ko'ko' were released on Rota in 1990 and 1991, but it is not known if any of the birds survived. More releases are planned for the future.
Hopefully, when Guam's kulepbla population is controlled or eradicated, the Rota population will have flourished enough so that we will be able to bring the ko'ko' back to its native habitat.
Guam Comprehensive Wildlife Conservation Strategy, 9/27/2005
