ON OUR FIRST DAY at camp, I sat in a small screened dining room, poking at the fly larvae wriggling through my fish. Next, a chicken foot appeared in the ricea choice piece of meat if you like that kind of thing. Later, the screams of our guide would yank us from our rooms: He had been stung by eight wasps, now holding him captive 20 feet up a tower. Clearly, the rough edges of Parque Nacional Noel Kempff Mercado had yet to be smoothed.
Lying along Brazil's western flank, this 3.8-million-acre, Connecticut-size park sees fewer than 250 people a year. Low visitation means the place feels only marginally more explored today than when Colonel Percy Fawcett, the British naturalist, first explored it nearly 100 years ago. To get here, my companionsa tour operator from Seattle and a writer from Boulderand I had opted against a 12-hour bus ride and sprung for a two-and-a-half-hour flight from the Bolivian city of Santa Cruz. During this flight, one gazes downin wonder or horror, depending on one's cultural referencesat hundreds of miles of unbroken rainforest canopy, a view that magnifies the unsettling feeling of having slipped, irretrievably, behind the back of beyond.
Hiking in such an undervisited park appealed to my misanthropic side: There'd be no enthusiasts on the trail asking if I'd spotted the razor-billed curassow. Wandering among some of the richest animal and plant diversity in the hemisphere appealed to my biophilic side. Last December, UNESCO designated the park a World Heritage Site, a seal of approval that puts itin terms of scientific valuein the same league as the Great Barrier Reef, the Galapagos Islands, and 135 other sites worldwide. South America has 17 such sites, but in none of them, Tim Miller, our American guide who runs Neblina Forest Birding and Natural History Tours in Bolivia, assured us, can visitors see so much wildlife with so little effort. By day, we'd move by plane, boat, and truck; by night, we'd sleep at rustic camps. Backpackers are welcome at Noel Kempff, but their options are limited: The park has only 28 miles of marked trails and only 43 miles of dirt roads. Like most visitors, we planned to day hike from an interior camp, then fly north, go by boat to another camp, and then hike to the park's feature attractionthe 250-foot-high Arco Iris waterfall.
At camp one, Los Fierros, which consisted of a few screened dorms, a kitchen, and a dining room, we dumped our gear and hopped into a truck bed for a drive through the rainforest. The landscape obliterated any notion of Bolivia as the Tibet of South America. This was unadulterated Amazonian jungle, replete with high heat, high humidity, and high hymenopteraants, bees, and wasps that covered our clothing and packs at every static moment. We walked ahead of the truck to examine purple dragonflies of paleolithic proportions and the tracks of a maned wolf, a rare nocturnal creature. It was so hot, a white-tailed hawk was panting.
Several miles to the east loomed the park's defining physical feature, the imposing Huanchaca Plateau. Like a vast shoebox, it rises 1,800 feet above the surrounding plain. The 93-mile-long escarpment, comprised of steep-sided Precambrian sandstone, was first explored in 1910 by Percy Fawcett, whose accounts inspired Sir Arthur Conan Doyle's The Lost World in 1912.
Sixty-nine years after Fawcett's wanderings, the Bolivian government named the region a national park. It was expanded in 1988 and renamed for Noel Kempff Mercado, a Bolivian conservationist who was murdered in 1986 while exploring the Huanchaca Plateau. He had landed on a covert airstrip where Brazilians tended the world's largest cocaine factory. The coca processors gunned him down on the spot.
Protecting the unique fauna of the plateau and its surrounding forest and grasslands is crucial to the park's mission. The Brazilian state of Rondonia, notorious for clear-cutting and for slash-and-burn agriculture, flanks the park's northeastern edge: an 80-mile border with environmental disaster. Brazil's inability to enforce environmental law has made Noel Kempffwhere poaching and logging are fairly well controlleda last refuge for many species driven to extinction just a mile or two away.
Would we see any of those species? Tim had given us fair warning that the rainy season wasn't ideal for mammal sightings, yet we'd spot black spider monkeys and a tropical rodent called an agouti in the forest, and giant river otters, pink dolphins, capybaras, and brown capuchin monkeys along the waterways. Pastór, our local guide, would claim that a puma streaked in front of our truck, but the group decided he was hallucinating.
Tim tried to refocus my attention on birds, of which the park contains some 600 species. "Stand right here," he'd say, manhandling me into position and pointing toward far-off snags. "Follow that whitish branch to where it intersects at ninety degrees, go over two feet, and you've got a motmot."
He was right. And so I birded.
WE LEFT LOS FIERROS early the next morning for a 3.5-mile hike. Our goal: El Encanto waterfall. If the dry season lures visitors intent on spotting neotropical mammals, the wet season brings out the waterfall freaks. El Encanto leaped 262 feet off the plateau at the back of a winding, shaded canyon. Layers of billion-year-old red stone loomed overhead, and the wind bore curtains of cool spray. Acting as an enormous catchment, the plateau funnels precipitation into some of the most impressive waterfalls on the continent. These cataracts, in turn, form deep, churning poolsjust the thing for a sticky hiker.
Stepping off trail to struggle into my swimsuit brought a scary revelation. Choked with lianas and close-growing palms, the forest was nearly impenetrable. It took me five minutes to move 20 feet into this green hell.
The numbers mattered because my companions, for days, had delighted in telling jungle-survival epics: about the lost adventurer who wandered for three weeks without food until he was rescued, or the hapless soul devoured by swarming insects. By now I was phobic about getting into the Cessna waiting on the nearby runway. I obsessed over the park map; I memorized scant landmarks; I kept strict track of my lighter. In the event of a treetop landing, I asked Tim, how long would it take to carve a runway in the rainforest? "A year," he said soberly.
From the air we got a good sense of the five distinct ecosystems responsible for Noel Kempff Mercado's high biodiversity: its savanna wetlands, semideciduous forest, humid evergreen forest, riverine forest, and subtropical thorn scrub.
We touched down on the park's northern border at Flor de Oro, a scattering of screened dorms and a kitchen. After plates of rice and vegetables, we motored up the Iténez River. Alex, our man from Boulder, flopped overboard to commune with the pink river dolphins arcing off the bow.
In the morning, Fernandoa blond Brazilianmotored us down the Iténez, then made a hairpin turn up the Paucerna River. For hours, he whipped the skiff around oxbow turns, burying its gunwales in black water. Through a trick of sunlight and shadow, the water seemed to flow through the tree trunks and over the edge of the world. Going upriver, we counted close to 100 bird species.
AT AHFELD CAMP (one screened lodge and a rough kitchen), we mentally prepared ourselves for the next day's nine-mile hike to Arco Iris. Tim roused us before dawn. Coffee, instant oatmeal, headlamps. The trail ascended steeply up the plateau, and we hauled ourselves along fixed ropes. When the trail leveled, we stopped to poke at a few sap-sucking insects disguised as styrofoam flecks and pocket lint scuttling over plant stems. Such weird organisms are exactly what one hopes to see in this hothouse of evolution.
After a final scramble, we ledged out opposite the great Arco Iris. Cascading more than 15 stories from behind a Seussian spire of red rock and green hummocks, Iris easily fit the Platonic ideal of tropical waterfalls. It had taken us nearly five hours in a boat and three hours on foot, after four days of travel, to get here.
Was the trip worthwhile? I took measure of this place as I inhaled a sandwich. The waterfall was certainly stunning, but it seemed slightly unreal to me. The problem could have been a matter of scale. Arco Iris was more than a hundred feet across a deep chasm.
So after lunch, our intrepid guide led us over the side of a ledge. We slid down lianas, crashed through spiky bromeliads, and skidded down several hundred feet to the swiftly flowing Paucerna River. We scouted the swirling eddies, dived, and made for the opposite bank.
Stroking slowly upstream, we rounded a turn and clambered up the red boulders that formed Iris's spill cup. The noise was deafening, the water white. I shouted to Tim, who was grinning like a Cheshire cat a couple of rocks over.
"Have you brought many groups up here?"
"None," he said. "I didn't even know the river could be crossed during the rainy season; I didn't know if we could get up here."
Sitting inside Arco Iris, the setting was equal parts The Lost World and Jean-Jacques Rousseau. Tropical foliage tinted the air, the purest water swirled around our feet. I scanned the towering red amphitheater and wiped cold spray from my face. Treetop Cessna landings no longer concerned me. If for some reason our exit strategy failed, I'd be content to await rescue right here.
Outfitter: Neblina Forest Birding and Natural History Tours: 866-868-4797; www.neblinaforest.com
Cost: Four- to 15-day trips cost $1,500 to $6,700 and run year-round. (Price varies depending on number of days and group size.)
When to Go: The wet season (December through May) is best for waterfall viewing; the dry season (June through November) is best for bird- and wildlife-watching.