"This species was a unique part of Earth's history," said Eric VanderWerf, the Fish and Wildlife Service's Hawaiian bird recovery coordinator. "We'll never have another one like it if it disappears. I kind of liken it in some way to the loss of the Mona Lisa or the Sistine Chapel. If we lost that, we could never get it back. We can never get another one."

The rare Hawaiian honeycreeper had been kept at the Maui Bird Conservation Center in Olinda since it was captured for breeding on Sept. 9. Biologists failed to capture a mate for the aging bird, which was found in the Hanawi Natural Area Reserve.

The remaining two po'ouli, believed to be a male and a female, haven't been seen for nearly a year. They might have died, moved to another area or been missed by wildlife officials.

Even if the two birds are located, they still must be caught and successfully bred. It is also uncertain if the birds are male and female.

But biologists aren't giving up hope.

The state, the Fish and Wildlife Service and the Zoological Society of San Diego, which operates the Maui conservation center, launched a search yesterday to find the remaining two po'ouli in the remote rainforests of Maui.

"There's so many things going against this effort that (the death) makes it all very much more desperate, but no one is giving up on it," said Alan Lieberman, the Zoological Society's avian conservation coordinator. "As long as there's a chance that there are two, a male and female, no one is willing to throw in the towel."

The po'ouli is part of the Hawaiian honeycreeper family and is so unique is has its own genus. It was not discovered until 1973, when a group of University of Hawai'i students conducting research on the east slope of Haleakala volcano sighted a bird they had never seen before.

It is the only Hawaiian forest bird to rely heavily on native tree snails as its food. The small, stocky, brown bird has a partial black face described as a bandit's mask.

It is possible the po'ouli that died Friday was the last one, making it one of the rare opportunities where scientists were able to document the moment a species became extinct.

"This unfortunately is an opportunity for people to say, 'I know the hour, the day, the hour, the minute, the second, it went extinct,' " Lieberman said. "That is a sobering moment."

Tissue samples from the bird were saved for cryogenic preservation for possible cloning in the future.

"Someday, when technology catches up with our fantasies, we may be able to resurrect the po'ouli because we saved these cells," Lieberman said.

The po'ouli's numbers have dwindled from a rough estimate of 150 because of habitat loss and introduced predators like rats, cats and mongooses. Nonnative diseases carried by mosquitos, such as avian malaria, have also taken a toll on the Hawaiian birds.

The po'ouli that recently died contracted avian malaria, but the exact cause of death won't be known until tests from the necropsy are completed.