GUAM RAILS

Smithsonian animal keeper Erica Royer holds a Guam rail during a 2017 visit to the island of Rota to release 49 birds into the wild. After being driven nearly to total extinction, the birds are making a comeback in the wild and have been raised in classification to critically endangered.

The Guam rail is making a comeback.

Declared extinct in the wild for nearly 40 years, the bird was, in late 2019, classified critically endangered, according to a news update by animal keeper Erica Royer posted at the Smithsonian Conservation Biology Institute website, nationalzoo.si.edu/conservation.

It’s only the second time in history a bird species has recovered from being extinct in the wild, the update states. The first was the California condor.

The rail used to be common in Guam, with about 60,000 to 80,000 birds there during the late 1960s and early ’70s.

“[T]he species was almost lost entirely due to predation by the invasive brown tree snake,” Royer wrote. It’s believed the snake was accidentally introduced to Guam by military cargo ships after World War II.

“There are no large snakes native to Guam,” she wrote. “In a relatively short time period, the snake spread across the island and wiped out 10 of the 12 species of forest birds.”

Biologists from Guam’s Department of Aquatic and Wildlife Resources began an effort to save the Guam rail in the early 1980s, capturing the last 17 birds to start a breeding and recovery program.

In 1985, 12 birds were brought to the SCBI in Front Royal, which over the years has served as a quarantine facility for Guam rails hatched on the mainland that were destined for Guam.

Because the birds are territorial and experience mate incompatibility and aggression, the Guam rail is difficult to breed, she wrote.

However, they had some success, and Guam’s Department of Agriculture, Division of Aquatic and Wildlife Resources started releasing birds into an experimental population on the island of Rota from 1989 to 1990.

There are now about 200 birds living and producing offspring on Rota.

In 2010, 16 Guam rails were released on Cocos Island, a small, uninhabited daytime resort island 1 mile south of Guam, and the population of 60 to 80 Guam rails there is flourishing and considered self-sustaining.

“Today, all of the chicks produced at SCBI are slated for repatriation to Guam and eventual release to the wild,” Royer wrote.

For more information, visit nationalzoo.si.edu/conservation.