Researchers release endangered crows into the forests of Pacific island

September 28, 2018

Kim Eckart

UW News

For more than 2 million years, the native forests on the Pacific islands of Guam and Rota were home to several thousand crows, members of a species found nowhere else on Earth. But over the last 60 years, the Mariana crow — called the Aga in the Chamorro language — has completely disappeared from the island of Guam and rapidly declined on neighboring Rota. Today there are only about 175 Aga left in the wild.

To ensure the survival of the species, scientists from the University of Washington and San Diego Zoo Global are partnering with the Northern Mariana Islands Department of Lands and Natural Resources and the U. S. Fish and Wildlife Service on a bold new project that they hope will stabilize the population of Aga on Rota.

The population got a new start on Sept. 28, when the first cohort of five captive-reared Aga were released on public lands on Rota.

 “Aga are a critical strand in the ecological and cultural web that make up the forests of Guam and Rota. Without drastic measures, we could lose this part of our natural and cultural heritage forever,” said Anthony Benavente, secretary of the Northern Mariana Islands Department of Lands and Natural Resources, or CNMI-DLNR.

An additional five birds will be released into the same area later this year. Researchers will continue to monitor and support the birds for approximately one year after the release to ensure their continued success in the wild.

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How can forests regenerate without birds?

April 30, 2018, University of Guam

Human activity continues to shape environmental systems around the world creating novel ecosystems that are increasingly prevalent in what some scientists call the Anthropocene (the age of humans). The island of Guam is well known as a textbook case for the devastating effects of invasive species on island ecosystems with the extirpation of most of the forest dwelling birds due to brown tree snake predation. The loss of native birds has resulted in a loss of forest seed dispersers. Recent research conducted by lead author Ann Marie Gawel, based on her University of Guam master's thesis, has found an unlikely forest ally, feral pigs.

With the loss of birds in the limestone forests on Guam, seed dispersal for native plants has become problematic. The damage caused by ungulates, introduced deer and pigs, has been documented in tropical forests worldwide. Less documented is the effect of these animals on seed dispersal of native and nonnative forest plant species.

Gawel's study examined scat from deer and pigs foraging in the limestone karst forests of northern Guam. Her findings indicate that pigs, featherless and flightless, might be one of the last seed dispersers left on the island to assist in forest regeneration. Particular to limestone forests, where pigs would be hard pressed to find places to wallow and root, this study found negative impacts from the presence of deer but did not detect negative impacts from pigs.

Read more at: 

Bird-slaying snakes ravage island forests too: study

March 8, 2017 by Marlowe Hood 

The venomous brown treesnake can grow up to three metres in length 

A non-native snake species that has already wiped out most of Guam's tree-dwelling birds is also decimating the Pacific island's forests, researchers said Wednesday. 

Growth of new trees on the US island territory may have dropped by as much as 92 percent due to the snake's presence, they reported in the journal Nature Communications.

The findings show that the devastation wrought worldwide on island wildlife by invasive species—especially snakes, rodents and mosquitoes—may be far greater than previously suspected, the authors warned.

"The full impact of the brown treesnake invasion, and the loss of birds, is still unfolding," said Joshua Tewksbury, a professor at the University of Colorado and senior author of the study.

"But our results clearly suggest that the indirect effects are going to be large, potentially affecting forest composition and structure."

Birds play a critical role by eating and spreading seeds from tropical trees.

Probably arriving on Guam via a cargo ship just after World War II, the venomous, brown treesnake—scientific name Boiga irregularis—hunts at night and can grow up to three metres in length.

By the mid-1980s, the snake had eliminated 10 of 12 forest bird species native to the island, including the Guam kingfisher and the Guam flycatcher.

The flycatcher is now extinct globally.

One doesn't have to be a scientist or a bird watcher to notice that something is awry, said the study's lead author, Haldre Rogers, an ecologist at Iowa State University.

Rewired ecosystems

"When you're on Saipan"—a neighbouring island where the treesnakes have so far been held at bay—"there is constant bird chatter," she said.

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New children's book helps endangered Guam bird

By Isa Baza

A longtime science teacher and licensed minister is doing his part to bring back Guam's endangered territorial bird. Jose Gallego is the author of Guam's newest children's book,Little Lola Ko'ko'.

"My books are to try to give the koko (the Guam Rail) help by developing that awareness, and by telling people say hey to write about it, sing about it, write more books about it," Gallego told KUAM News.

Little Lola Ko'ko is also translated to Chamorro by Harry S. Truman Elementary School teacher Ceferino Nededog Sucaldito and illustrated by Michelle Moyer. The book sales for just under $8 at the New Faith Book Store location in Maite.

For more information, visit GuamKokoBook.com.

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