Endangered Mariana crow dies of rare liver cancer

Biologists at the Rota Avian Behavioral Ecology Program, a research program under the University of Washington, reported last month that one of their captive Mariana crows, which can only be found on Guam and Rota, has died of a rare liver cancer.

“I do not know of any other cases in which Mariana crows have been diagnosed with cancer,” said RABEP biologist Sarah Faegre.

The dead crow, which biologists on Rota had named “Latte,” was found at the Mochong Latte Village with a broken wing caused by a typhoon that passed close by the southern island in November 2009.

According to Faegre, Latte, at the time, was unable to feed herself or fly and the biologists eventually learned weeks later that her mate was catching food and bringing it back to her. When the biologists decided to assess her broken wing, Latte was transported to Guam for a wing amputation and was never released back into the wild.

After the amputation, Latte was brought back to Rota to be the first Mariana crow to live in captivity. RABEP eventually brought Latte to schools around the island to raise awareness about endangered species in the CNMI.

While Latte was in captivity, biologists put four different fledging Mariana crows under her care—two of which will be released into the wild this year.

“Because of Latte’s foster care the birds learned how to behave as normal, wild crows and are adjusting well to the wild,” Faegre said.

She said that cancer in young birds is extremely rare and that her research team thinks that Latte may have been an older bird and at least 6 years old when she died. Her mate—the one that helped keep her alive in 2009—was 11 years old when Latte was captured. The biologists believe that if Latte was the same age as her mate, she should be 15 years old. The oldest Mariana crow is 18 years old.

Researchers and biologists are unaware of how Latte got cancer, saying no other diseases have been identified in Mariana crows.

“It is not currently believed that disease is a cause of decline for the species,” Faegre noted.

The current crow population on Rota has declined by more than 50 percent since 1998. About 140 birds are estimated to be left on the island.

A variety of factors have affected the crow population in the past including introduced predators, habitat loss, and direct shooting. Data collected by RABEP in the past four years on radio-tagged crows has found that feral cat predation is a main cause of death for wild crows.

Faegre said the organization’s current work is to mitigate known threats to the population and continue monitoring whether there are other problems that need to be addressed.

“Another important goal is to work with the public, both to educate them about the Mariana crow and to help find solutions to problems that can be beneficial to local people as well as the crow.”

The RABEP program is run by Dr. Renee Ha at the University of Washington. There are currently seven biologists conducting research and studying the bird species on Rota.