Fate of Rare Species Hinges on Pair of Lovebirds

In a tangled Maui rain forest, a team of biologists is stalking the last male po’ouli left on the planet, in hopes of making a match for the stocky little bird with the “lone ranger” black mask.

The shy Hawaiian honeycreeper has been living a bachelor’s life on the rugged northeast slope of Haleakala, dining on tree snails, unaware that the last two female po’ouli live not far away. Their home ranges don’t overlap, and the soft-spoken species will die out if the birds don’t find each other.

“Without some sort of intervention, extinction is pretty much guaranteed,” said Eric VanderWerf, a U.S. Fish and Wildlife Service biologist, who is taking part in the matchmaking mission by the state’s Maui Forest Bird Recovery Project. “It may well be the rarest bird on Earth.”

The crew plans to outfit the male po’ouli with a tiny radio transmitter to help track him, then capture and carry a female into his terrain, releasing her near enough that they meet. The effort to get a pair of po’ouli to breed in the wild is considered a longshot. It’s tough just finding the black-faced, beige-and-brown birds, each weighing just an ounce.

“We’re looking for a needle in a haystack,” said Jim Groombridge, project coordinator. “The po’ouli (po-oh-oo-lee) is a very, very elusive, secretive bird that lives mainly in the lower canopy. It’s not a loud, gregarious, top-of-the-tree type with crazy-colored plumage you can spot from a distance.”

But in a state that has been called the endangered species capital of the country--where more than 40 native bird species have already gone extinct and 30 more are endangered--people aren’t willing to let this one go without a fight. The crew spent a year preparing for the translocation effort, practicing with a model species, the Maui creeper, in the same forest.

The po’ouli inhabit one of the more inaccessible spots in the islands: the Hanawi Natural Area Reserve, a steep mountainside above Hana that is sliced by deep gulches and drenched by 300 inches of rain a year. Moss overhangs ohia and olapa trees; ferns and dense foliage impede hikers.

Field workers use helicopters to get to Hanawi, then drape large “mist nets” of fine, soft nylon between trees in hopes that the birds fly into them. On their first expedition, the crew located the male, but he avoided their nets. More than 200 other birds were caught, banded and released.

Even if naturalists manage to capture two po’ouli and introduce them, there are no guarantees that the matchmaking will succeed. Ultimately, it’s up to the birds.

“After being moved, the female may immediately fly back to her home range or may decide she doesn’t like the male at all--or maybe he won’t like her,” Groombridge said. “There is no denying the fact that this is going to be very difficult.”

The scientists considered bringing two po’ouli into captivity for breeding but decided that working with them in the wild “involves less risk to the birds and probably has just as big a chance of success,” VanderWerf said. If the pair mates, the crew will protect the nest and could eventually collect eggs for a captive-breeding program.

Captive breeding has helped replenish the population of other endangered Hawaiian birds, including a Kauai thrush known as the puaiohi and the Hawaiian crow, or alala, but there have been setbacks. Many alala raised in captivity have died when released.

Although some observers argue that it’s too late to save the po’ouli, Groombridge points to other birds that have been pulled back from the brink.

“The Mauritius kestrel went down to four in 1974,” he said, “and today there are between 500 and 600 birds. New Zealand’s Chatham Island black robin recovered from a single pair.”

The po’ouli is so rare it was not even discovered until 1973, the year the Endangered Species Act was signed into law. A group of University of Hawaii students ventured to that remote section of Haleakala and discovered one of the most intact native ecosystems left in the state, with indigenous bird and plant species found nowhere else.

The po’ouli was so unusual that a new genus was created for it within the Hawaiian honeycreeper family, which is already renowned for its diversity. It is the only native forest bird to eat tree snails, and its stout prominent bill and black mask also set it apart.

“There’s nothing like it anywhere,” said Betsy H. Gagne, who was the first to spot the “mystery bird” as a college student and today is executive secretary of the Natural Area Reserves System Commission. “Are we going to just let these birds go quietly into the night, when we ourselves are the ones who’ve pushed them along?”

Much of Hawaii’s native forest has succumbed over the years to clearing for ranching, agriculture and urban development. The wild areas that are left remain vulnerable because Hawaiian plants and animals evolved in isolation and never developed natural defenses against foreign predators and disease. Hawaii accounts for less than 0.2% of the land mass of the United States, but it holds a quarter of the nation’s threatened and endangered species.

The 7,500-acre Hanawi rain forest was set aside as a reserve in 1986 in hopes of protecting the entire ecosystem--not just the birds but also the plants, insects and organisms interwoven in its network of life. In the last decade, the state has overseen aggressive efforts to remove alien threats, including the wild pigs that tear up the forest understory, tree-climbing rats that eat eggs and birds, and invasive plants that crowd out native species.

“Habitat management is hugely important,” Groombridge said. “If you save a forest, you save the birds.”

It seems to have made a difference for the endangered Maui parrotbill, so-called for its heavy, hooked beak, which has made a comeback in Hanawi over the last decade. The po’ouli population, however, has continued to drop. Its numbers were projected at roughly 150 in 1981, but many consider that an overestimate. By 1996, only six black-faced honeycreepers were sighted, and that number dwindled to three a year later.

“We may not be able to save the po’ouli, but we’re going to give it our best shot,” Gagne said. “In any case, we’ll learn from the work we do, and other species will benefit.”