On a misty, 1440m ridge in the Monteverde Cloud Forest in Costa Rica, Central America, I strain my eyes for the 20 kinds of hummingbirds or the 3000 species of other things that our guide Alex declares live in, under and over the jungle canopy.
He seems to spy them effortlessly: "See, over there, a black-faced solitaire thrush." And then: "Look, an aguti - it's a kind of guinea pig."
I'll swear the only way he can perceive the imperceptible is by sneaking in here at dawn to superglue in place stuffed versions of these creatures.
Nevertheless, I do spot a fabled quetzal, the endangered superstar of Central America's aviary.
The regal turquoise creature sits high in the canopy with its 60cm tail feathers trailing below like the train of a monarch's gown.
Monteverde is in the middle of the country - I can see the Pacific Ocean to the west, while the Caribbean sits further east, unseen. My journey started in the nation's unlovely capital, San Jose, the only major "missable" part of this otherwise superb country. The shabby downtown is all burger joints and razor wire yet populated - at least by day - by the most courteous people.
Next morning I'm on a bus heading east out of the urban jungle and into the real thing, the Braulio Carrillo National Park where much of the movie Jurassic Park was shot.
"Enjoy your Costa Rican massage," calls guide Sebastian as we vibrate along the corrugated rural roads. Soon we transfer to a longboat and are gliding through iridescent jungle rivers walled by vertical greenery. The three-hour journey is hypnotic. Almost too soon we arrive at the little Caribbean town of Tortuguero.
"Tortuguero is the maximum expression of life on planet Earth," Sebastian says, with more than a touch of Tico (Costa Rican) hyperbole. Tortuguero National Park is a Central American Amazon, with 21,000ha of dense rainforest (and rain), a sea turtle hatchery and endless kilometres of canals. Each day we prowl these backwaters looking for three-toed sloth and caiman crocodiles.
Our local guide Marlon spots a Jesus Christ lizard. "Where," is of course my first response. It sits motionless, looking nothing like a lizard and virtually indistinguishable from the leaves around it. The green basilisk lizard - its proper name - has a party trick that warrants the "JC" nickname: moving so fast and lightly that it can miraculously "walk" on water without sinking.
I head back west again, climbing Costa Rica's central cordillera spine with its 200 volcanic vertebrae, 11 of the peaks still active. At 1633m, Mt Arenal is the most photographed one, thanks to its symmetrical, Fuji-like cone and eructations. Its namesake town is a Latino version of Queenstown. Like the New Zealand town, backpackers flock to adrenal Arenal for ziplining, rafting, trail riding, mountain biking, bungee-jumping and canyoning thrills.
Costa Rica, with a population of about 3.8 million, is a bridge between two twitchy, post-banana republics, Nicaragua and Panama. It wrestled independence from Spain in 1821 and since then, unlike its neighbours, has largely enjoyed stable government.
With nearly a quarter of its national territory being reserves, national parks or wildlife refuges, Costa Rica has niftily positioned itself in the age of ecotourism as a kind of Jurassic redemption park.
Nowhere is this eco-Eden status more evident than in the town of Santa Elena and its celebrated 5000ha Monteverde Cloud Forest Reserve. Its founders, pacifist American Quakers who moved here in the early 1950s, succeeded in gaining legislated protection for this forest domain that remains home to quetzals, bellbirds and thousands of other species.
Monteverde Cloud Forest is the Garden of Eden with a gift shop. We pay $17 to hike its trails with the eagle-eyed Alex pointing out the "now-you-see-them-now-you-don't" critters that slither and scamper within the jungle's primal topiary.
Some creatures are so rare, so elusive - or simply so intelligent - that they steer well clear of us. These include, I'm told, jaguar, ocelot, tapir and the wattled bellbird. Fair enough but I am satisfied to have seen the prized quetzal and then, at the end of the walk, to come to a hummingbird sanctuary and its feeding station. Here, tiny, brilliant, hyperactive violet sabre wings hover like frenetic helicopters, their wings blurring at 60 to 80 beats per second.
A zipline is what Australians also call a "flying fox". In a 100ha private reserve near Santa Elena, a cable car hauls us up the mountain to a high platform boasting a perfect view of the distant Arenal volcano.
But we're not here for the view. A young Tico guide gives me a safety harness that hooks on to a shackle that's attached to a metal cable stretching over the jungle.
And we're off! Gravity does the rest as we soar 130m across a sea of treetops until we reach a landing platform. We cross to another platform and do it again, rocketing out of the canopy to swoop across a second valley. It's like being Batman for an hour, with a quetzal's-eye view of the forest below. In nine single and tandem "flights" I zigzag down 1320m of zipline until landing, buzzing, back at the cable car station.
While Costa Rica is a favoured holiday and retirement destination for Americans, its Pacific and Caribbean coasts are still largely free of the metastasising resort sprawls that consume tropical shores elsewhere. Little tourist towns dot its coasts, often with a specialty pursuit such as scuba diving, surfing or game fishing, or doing nothing. The best known is the central Pacific coast town of Quepos and its Manuel Antonio Beach. I spend an afternoon here, bodysurfing, reading and snoozing on its volcanic sands before heading towards the adjacent national park.
It's simian city beneath the canopy. Howler monkeys swing unseen but never unheard with their booming bark that rattles the jungle like Tarzan's holler. Equally difficult to spot are the long-limbed spider monkeys but white-faced capuchins are everywhere, including one that's devouring an unfortunate frog.
"I always thought they were vegetarian," says a surprised local man. High in the trees I spot a three-toed sloth moving at glacial speed while lower down, tiny squirrel monkeys flit like quicksilver.
With 850 species of birds, 600 of butterflies, 1200 of orchids and 237 of mammals, Costa Rica could rename itself Noah's Park or Jurassic Ark.
• Fly from Sydney to San Jose via Dallas-Fort Worth on Qantas and American Airlines. flightcentre.com.au and 1300 939 414
• World Expeditions' eight-day Best of Costa Rica tour departs daily, year round and costs $1390. worldexpeditions.com.au and 1300 720 000
• Costa Rica is a year-round destination. The rainy season is from May to November while the dry season is December to April.
John Borthwick was a guest of World Expeditions.