Captive Mariana crows released on Rota

For the first time in CNMI history, two captive Mariana crows under the watch and care of the Rota Avian Behavioral Ecology Program were released into the wild eight months ago.

The last release of captive Mariana crows from Rota took place in Guam back in the mid-’90s. However, the crow population experienced a sharp decline and later became extinct in Guam.

Two-year-old Mariana crow “Guy” gathers sticks as he builds his nest. (Contributed Photo)

According to Captive Care coordinator Phil Hannon, there are 130 Mariana crows left on Rota. This is a decrease in numbers compared to the 160 recorded in 2008.

The biologists under the Rota Avian Behavioral Ecology Program are working with the University of Washington and implements plans partnered with the Division of Lands and Natural Resources and Department of Fish and Wildlife on Saipan and the federal Fish and Wildlife Service in Honolulu.

Hannon said their theory for the main cause of the bird’s population decline is due to cat predation.

“We think that the decline is because of the feral cats. There are a lot of other untested theories. We don’t think this is the only cause,” he added.

One of the crows, named by the biologists on the island as “Groucho,” is 3 years old and was taken in by the organization two years ago due to feather damage caused by parasites. The second crow, “Guy,” is 2 years old and was cared for by his parents for six months before sustaining injuries to his wings. Guy then was taken into captivity by biologists for 15 months.

Both birds are monitored daily by radio tracking devices, which allows the biologist to locate their exact location.

“When we find them we first look to see that their health is OK and watch them for 20 to 30 minutes each day. We observe how well they are finding food for themselves. We track and watch them every day,” Hannon said. 

The technology also monitors body temperatures that give biologists information on whether or not the crow is still alive.

Just two weeks ago, Guy was found building a nest with a wild Mariana crow.

“This is our biggest measure of whether or not the releases are successful. We can see if the bird can actually reproduce in the wild and increase the number of crows on the island,” Hannon told Saipan Tribune. “Guy and Groucho were released eight months ago. So it is considered a success. The fact that they are alive shows us that there is a potential to rear them in captivity and release them. It at least shows that that is an option for us and it has the potential.”

Both Guy and Groucho were raised and fed in captivity by “Latte,” the oldest captive crow, who died last year.

The program has four captive birds left in its aviary in the southern island. Two of the birds are expected to be released next year.

Hannon leads the program on the island along with Sarah Faegre, a University of Washington Ph.D. student, and Field Crew Supervisor Andria Kroner.

The team is expecting four more biologists to join them next month when the breeding season begins.