We had rain covers tightly drawn about our packs, to give the clawing ferns and vines fewer places to grasp, though they occasionally threw us to the crumbling lava anyway. With my two one-gallon canteens tied inside the rain cover, I couldn't simply stop and drink. I had to either unwrap the whole pack or bend like a supplicant beside it and suck from the mouth of a canteen. Thus when I reached camp on the fifth day of our trek, I slung down my burden and greedily knelt. A shadow passed across the pack. The forest filled with a chilling screech, soon followed by the calls of excited biologists.
"An io!" said Dr. Mike Scott of the U.S. Fish and Wildlife Service, pointing upward. "A Hawaiian hawk."
"There are two!" said Tim Burr of the Hawaii State Fish and Game Department. We watched the broad-winged birds about the size of red-tailed hawks glide in tight curves above the broken canopy of 60-foot ohia trees. One calmly landed on a snag while the other flew on. Then the first rose and headed in a different direction.
The biologists conferred. We were 4,000 feet up the western slope of Mauna Loa on the island of Hawaii, the only place in the world where the io is found. "We know practically nothing about them," said Scott. "Even a count of how many eggs they lay would be an addition to present knowledge." In 1972 University of Hawaii ornithologist Andrew J. Berger wrote in Hawaiian Birdlife, "The total population is estimated in the low hundreds, [and] very few nests of this species have been found."
Because we had seen a pair of birds, it was possible a nest was in the vicinity. Our camp was a scattered affair of tents and hammocks on a soft grassy pasture. Above us rose steep ridges. Scott and Burr set off to search the higher ground. That left photographer Heinz Kluetmeier and me. "Let's take a walk down the transect," he suggested. "We might see a hawk, and we might finally get a look at the dreaded ie ie."
We were near no road or trail. The transect of which Kluetmeier spoke was a 16-mile-long straight line running from the dry lava of Mauna Loa, through the rain forest, almost to the Kona Coast near Kealakekua Bay, where the Hawaiian Islands' European discoverer, Captain James Cook, was killed. Our transect, marked by blue plastic ribbons tied to branches or rocks every 100 feet or less, was No. 57 of 75 surveyed by the Fish and Wildlife Service through all the forests on the island of Hawaii. Since 1976, teams of biologists, botanists and highly trained graduate students have scrambled down them, conducting the first exhaustive survey in Hawaii of forest bird populations and habitats. No more sensible place for such a count exists. Of the 58 kinds of birds indigenous to the Hawaiian forest, 24 are classed as endangered, 19 are believed extinct. Since 1800, more birds have been extirpated in Hawaii than in any other biological province on earth.
Kluetmeier and I had followed Scott, the director of the survey, and Burr over much of No. 57, pestering them with questions, gradually learning something of the sad, complex story of the islands' vanishing birds, and struggling in amazement with the ever-thickening forest. Of this, the ie ie was the ultimate test, always waiting before us, a specter vine, described by Burr and Scott as wiry, unyielding and virtually impenetrable. It was to sneak a look at it that Kluetmeier and I walked downhill through the afternoon mists.
The pasture ended against an ancient lava flow, great unstable rocks covered with moss and fern. We crawled over this for a few hundred yards, falling as the moss slipped off the lava beneath our boots, dead masses of fern closing over us with a final switch. There had been drought on this side of the island for three years. It was wet now, but the damage was clear. Stakes of saplings were leafless. The brown fern—called eluhe—broke at a touch. There is no running water on the west side of Hawaii. It rains 250 inches a year at some elevations but the porous lava gathers it all in and sends it on to the sea underground. It must rain almost daily for the forest to persevere. Now, after the drought, it seemed there was nothing to hold on to. Once, falling, I grabbed a tree three inches in diameter and it fell with me. Examining the break, I saw hundreds of white termites squeezing back into their tunnels.
We returned to camp having found nothing more than sour ohelo berries. But Burr had found a hawk. Aptly named Buteo solitarius, the io is Hawaii's only hawk. "Where is this photographer?" said Burr, and led Kluetmeier to the tree. As they approached, the bird flew to another tree, and another, always looking away from the camera. Then it settled into the mid-branches of a 40-foot kolea, and suddenly it was on a nest, a deep bowl of sticks.
The naturalists' eyes were shining. "It's only the second nest found this year...." Scott began, excitedly. Then another io picked its way down from the branches on the opposite side of the tree, and the two hawks exchanged places, beautiful, vigilant parents; their behavior seemed proof, in the failing light, of there being eggs in the nest.