Species' survival rests in last three members


HANAWI NATURAL AREA PRESERVE, Hawaii - On the slope of a volcano, in an almost impenetrable rain forest, a lone bird goes about his avian business, surely unaware that for his species he is that proverbial last man on Earth.

The fate of the po'ouli bird, a rare species found nowhere else but in this Maui rain forest, hinges on this sole male - and whether he can attract one of the two remaining females that are all of the rest of their critically diminished population.

But help is arriving in the matchmaking department, from a group of wildlife experts who have decided that if nature hasn't taken its course by now, it needs a little nudge.

"There will be low lights," jokes Alan Lieberman, a director of the Hawaii Endangered Bird Conservation Program, "and a little music."

Conservationists are trying to capture the birds one at a time and bring them to live in an aviary near here, where they'll be protected from predators and other distractions and thus might be able to concentrate on propagating their species.

It is a risky venture, fraught with potential for disaster and without much of a margin for error, but one that experts say is the last chance to save the po'ouli (pronounced poh-oh-ooh-lee) from extinction.

"We were still hoping they would breed on their own in the wild," says Eric VanderWerf, a biologist with the U.S. Fish and Wildlife Service who coordinates bird recovery efforts in Hawaii. "It's been long enough, and we feel they're not going to get together on their own."

VanderWerf was part of a team that helicoptered into the rain forest last month to try to capture one of the birds, which live in separate home ranges within about a mile of one another but apparently have never met.

The team spotted the bird, one of the females, but was unable to net it during the week they spent in the rain forest. Teams will continue to drop into the densely overgrown and rugged area - on the steep northeast slope of the monumental, 10,000-foot Haleakala volcano - for a week at a time until they retrieve all three birds.

The po'oulis are chubby little birds, averaging about 5 1/2 inches long and weighing less than an ounce. The name is Hawaiian for "black head," given to the mostly brown and gray bird for the bandit-style mask on its face.

Previous attempt

This is not the first time that humans have played matchmaker for the bird. Last year, a wildlife crew was able to capture one of the females, place a tiny radio transmitter on her and take her to the male's home range, where she was released.

But for some reason, the birds apparently passed like ships in the night.

Although the female po'ouli spent the night, researchers don't believe the two birds met. The next day, the female high-tailed it back home, the species no closer to increasing its numbers than before.

Still, the wildlife experts say the success in moving one of the po'oulis last year, however briefly, bodes well for the current project: The female bird apparently suffered no ill effects from being captured, caged and carried to another part of the forest.

Several state and federal agencies and private conservation groups have united in a massive effort to save the po'ouli, but say they know very little about the birds except that their numbers have fallen drastically over the years.

"They're fairly secretive birds. They're not brightly colored," VanderWerf says. "They don't make a lot of noise. Sometimes they call."

Recent discovery

The po'ouli was discovered only 20 years ago, the first new bird species found in the United States in about a century.

A University of Hawaii student, part of on an expedition into the remote northeast slope of Haleakala, spotted several unfamiliar birds. Further investigation determined that the bird was a previously undiscovered species.

Even then, the po'ouli was considered a rare bird, with fewer than 200 living in a fairly confined habitat. By 1996, the population was down to six.

Why their numbers dropped so precipitously is not entirely clear.

"There's probably no one factor," says Lieberman, whose program is part of the Zoological Society of San Diego, which operates the aviary in Maui where the po'oulis will be taken if captured.

A likely cause, he and others say, is the degradation of the bird's habitat. Over the years, much of Maui's forest has been cleared for farming, cattle ranching and timber operations. Additionally, invasive species such as feral pigs have also taken their toll - they tear up the forest floor, rooting about and damaging the habitat of the snails and insects that the po'ouli eat.

In addition, the water that collects in the ruts that the pigs create provides a breeding ground for mosquitoes, which could carry various avian diseases.

Many endangered

The story of the po'ouli, sadly, is far from unique in Hawaii, where the islands' exotic native animals and plants go extinct more frequently than in any other state in the nation.

Hawaii has lost a staggering 80 percent of its native birds, according to one estimate, and has more species on the federal endangered list than any other state.

As with the po'ouli, wildlife experts point to habitat damage by humans and the introduction of alien species.

Researchers are unsure why the three remaining po'oulis have never sought one another out.

"You would think it would push to the outer edge of its territory to look for other birds," Lieberman says.

Still, there is reason to believe that they're not simply confirmed singles or anti-social. The po'oulis have been seen flocking with other birds, and at least one of the females showed some maternal instincts, VanderWerf says.

"All three have strong associations, they've been seen with Maui parrotbills," he says of another native bird species. "One female was seen feeding fledglings, which shows displaced parental behavior."

Wildlife experts are usually reluctant to net birds because the stress of capture can damage or kill the creatures. With just three po'oulis to work with, the peril is great.

The teams are using mist nets, made of such fine mesh that they are almost invisible. If captured, the birds will be examined on site to assess their health and stress level, placed in small, lined cages and offered food. The plan is to move them into larger and larger cages as they acclimate to captivity and then place them in the aviary.

The researchers are not sure how old the po'oulis are, but estimate that they are about 6 or 7 years old. Their average life span is unknown.

Po'oulis are believed to be monogamous - which might well be a problem when there is only one male left in their world.

"Will the birds like each other?" VanderWerf muses, imagining one of the females pairing off with the male. "There's no other option if she doesn't like him."

Copyright © 2020, The Baltimore Sun, a Baltimore Sun Media Group publication | Place an Ad