New research published in a scientific journal suggests that the declining number of most native Hawai'i birds, including the endangered 'akepa, is due to the Japanese white-eye bird eating much of their food, basically starving or stunting their growth.

If the findings are confirmed, the development would be a significant step in efforts to save Hawai'i's endangered birds, according to two Mainland scientists who have lived or worked in Hawai'i and are familiar with the 'akepa research.

But a long-simmering dispute between the lead scientist behind the research and the federal agency that oversees the Big Island wildlife refuge where the field work has been done could impede further attempts to confirm the findings.

"This dispute is one where the important loser is Hawai'i's biodiversity itself," said Stuart Pimm, a Yale University professor of conservation biology who worked in Hawai'i for more than 20 years before leaving in 1992. "This is a terrible tragedy for Hawai'i."

University of Hawai'i zoologist Leonard Freed, the lead author of the paper published last week in Current Biology, says the research done by him and his wife, Rebecca Cann, UH professor of cell and molecular biology, indicates that the population of all but one species of native birds in the midlevel elevations of Hakalau Forest National Wildlife Refuge began declining as the numbers of white-eye birds started swelling around 2000.

The two scientists concluded that the white-eyes' hearty appetite for the same foods that the 'akepa and other native birds eat accounted for the stunted growth of juvenile members and their premature deaths. In another area of the refuge that had substantially fewer white-eyes, the native birds grew normally, Freed said.

"It shows the middle elevation stratum has become a killing field for native birds," said Freed, who is advocating that the white-eye numbers be curtailed in the refuge to enable the 'akepa and other species to recover.

But the pair's research has been met with skepticism by scientists at the U.S. Fish and Wildlife Service, which oversees the refuge and issues the permits allowing scientists to study endangered species there. For the past few years, the federal agency has questioned the methods used by Freed to reach his conclusions and has found him in violation of the conditions of his permit, suspending his research privileges in the refuge. Freed has not been allowed to do research there since 2006 — even though he is director of the Hakalau Forest Biological Field Station, a million-dollar facility where much of the work is done.

Freed, who has done research in the refuge for 20 years, has accused the agency of retaliating against him for past criticisms related to the ongoing dispute. "The refuge, in my opinion, has been fascist in dealing with us," he said.

In a written response to Advertiser questions, Fish and Wildlife spokesman Kenneth Foote defended the agency's actions and said it does not believe the Japanese white-eye, a songbird native to much of East Asia, is hurting the 'akepa population in the refuge. He pointed out that a January 2009 UH report indicated the 'akepa numbers are stable or increasing. In addition, Foote added, the issue has been extensively examined by staff and independent experts over the years.

"Our (refuge) management is based on the advice from this group of highly respected experts," he wrote.

Freed said his Hakalau work has held up under several rigorous peer reviews that are required before papers are published in scientific journals, and one such paper on avian malaria in birds recently won a prestigious award.

The Japanese white-eye was introduced to Hawai'i in the late 1920s as a way to control the insect population on agricultural lands and in gardens. Being from a bird family famous for expanding its range and diet of prey, the white-eye spread to all islands and now proliferates.

If refuge managers hope to save the 'akepa and other native birds, measures need to be taken to pare the white-eye population to a level that allows the others to recover, Freed said. Otherwise, he added, the 'akepa effectively could become extinct in about six years.

But UH zoologist Sheila Conant said even if Freed's findings are correct, the number of white-eyes in the refuge is so large — more than 200,000, by one estimate — that trying to make a meaningful dent in that population would be too costly and impractical.

"It's like saying let's get rid of all the rats on the Big Island," said Conant, who agrees with the Fish and Wildlife position in the Freed dispute.

Conant said Fish and Wildlife already is taking effective steps to improve the Hakalau habitat for native birds by planting thousands of koa trees and removing feral pigs.

To scientists who study endangered species, Haka-lau is considered one of the most important wildlife refuges in the country.

That's what makes this ongoing dispute particularly troublesome and very risky if Freed's research is not pursued to verify whether he's correct, according to Steve Stearns, Yale University professor of ecology and evolutionary biology.

"If Lenny is right, there's a big downside (by ignoring his findings)," said Stearns, who was born and raised on the Big Island. "If he's wrong, everything is hunky dory."

Stearns agreed that the birds ultimately may be the big losers.

"When the survival of species is in danger, it is essential that humans be able to set aside their differences and work together to achieve solutions that are transparent and based on objective results," he wrote in an e-mail. "Vanishing species should not get caught in the crossfire of conflicts among humans, all of whom are ostensibly interested in saving them."