Biodiversity unparalleled in Costa Rica's Corcovado National Park

Sheltering one of the Americas' most pristine rainforests, this remote strip of Pacific coastline near the Panama border offers world-class opportunities for wildlife viewing and jungle hiking. Since its founding in 1975, Corcovado has been attracting research biologists and nature lovers from around the globe. Thanks to its isolation and vast size (263 square miles), it boasts a level of biodiversity virtually unparalleled elsewhere on earth and provides dependable habitat for dozens of endangered species, including jaguars, ocelots and other large cats.

Tucked into the jungle on the ocean's edge, Estacion Biologica Sirena — Corcovado's administrative and research headquarters — is the logical base for exploring the park. Professional naturalists (and tourists willing to pay the stiff price) can arrive by small plane at Sirena's grassy airstrip, but most visitors choose the more affordable, adventurous and eco-friendly alternative of hiking into the park. Multikilometer trails converge on Sirena from the north, east and south, each bringing you into intimate contact with Corcovado's magnificent wildlife.

The most convenient starting point for hikers wishing to loop through the park is Puerto Jimenez, a rough-and-ready town on the Osa Peninsula's eastern shores. Served by regular hourlong flights from San Jose, as well as by buses rumbling down the Interamericana highway, Jimenez has everything from simple cabinas to cushy beachside resorts. It's also the perfect place to stock up on water, food and other supplies before hitting the trail into the wilds of Corcovado.

From Jimenez, colectivos (shared jeeps) make the twice-daily run over rutted dirt roads to Carate, a small settlement on the Pacific Coast at the park's southern edge. The trail north from Carate to Sirena runs 12 miles along a stunningly wild stretch of coastline. It's a hot, mostly shadeless slog up the beach, but there's plenty to keep you distracted — rusty shipwrecks, coconut-laden palms and constant wildlife viewing opportunities. Alert hikers will almost certainly spot scarlet macaws soaring from the jungle into the wide-open skies above the Pacific. With persistence and luck, you may also sight more elusive animals such as toucans or the endangered Baird's tapir. Note that careful planning is critical here, as sections of the beach are impassable at high tide. If your timing is off, or if you simply want to linger before continuing to Sirena, you can take refuge in the cluster of eco-lodges near Carate.

Sirena, at the very heart of the park, is the ideal place to settle in for a multiday stay. With advance reservations, you can camp or sleep in basic dormitory accommodations and eat simple meals at park headquarters.

Easy trails through the amazingly tall, vine-draped primary rain forest offer a total immersion experience. Brilliant blue morpho butterflies flutter among the trees, spider monkeys rampage through the lower branches and howler monkeys send out their unearthly roars from the canopy, while industrious leaf-cutter ants and shy little agoutis march and scurry about the forest floor. Near the mouth of the Rio Sirena, where sharks and crocodiles play, an elevated viewing platform allows you to melt into the forest as you look and listen for wildlife. Just beware the rustling noises overhead. Mischievous monkeys won't hesitate to send missiles raining down from the trees above.

After several days in the jungle, returning to the outside world is a rude awakening. Thankfully, the trails out of Sirena allow plenty more time to contemplate Corcovado's majesty.

To exit the park without retracing your steps, continue north 15.5 miles along the beach (passable only in the December-April dry season) to San Pedrillo ranger station, near the town of Bahia Drake, where flights depart for San Jose; or cut eastward 11 miles through the heart of the rain forest to Los Patos ranger station, then onward to La Palma, served by regular buses between San Jose and Puerto Jimenez.

By Gregor Clark Lonely Planet