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Renee Ha’s work to save Mariana crows was featured in UW News

Researchers release endangered crows into the forests of Pacific island


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.

In 2016, researchers began collecting eggs from wild Aga nests to be reared in captivity as part of a program to raise the birds until they pass the critical period of highest mortality and then release them into the wild.

“Today, there are many species in decline all over the world, and we are really proud to be part of an effort to bring a species back from extinction,” said Renee Robinette Ha, the UW research associate professor of psychology who has led the university’s Aga research efforts since 2005. “Our research has determined some causes of mortality in Mariana crows, and by working collaboratively with our partners, we have been able to start turning that around.”

Aga nestlings are reared in captivity by San Diego Zoo Global. Photo of young bird with its mouth open, facing camera.

Aga nestlings are reared in captivity by San Diego Zoo Global.San Diego Zoo Global

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