The hotel's "activities coordinator" wanted us to leave for Corcovado, the Osa Peninsula's featured forest, at 6:30 a.m. so that we could be the first group in. We loaded into the boat with our new guide, Carlos (different from the driver) and headed out along the coastline to Corcovado, which was to the south of our lodge. Along the way, we stopped at a small island/rock, and Carlos pointed out some frigate birds and a brown booby.

We made another wet landing at the Corcovado Ranger Station, and set our stuff down under the tin roof of a public picnic area.

The beach was at a river mouth, and the river ran inland for 20 meters and then curved around into a small lagoon before narrowing again and disappearing into the forest. Carlos pointed out three baby crocodiles hanging out in the lagoon, each of them maybe a foot long. He also showed us two enormous red-throated tiger herons in a tree over the river.

We crossed the river and changed into hiking shoes on the riverbank, then entered the rain forest.

The trails were standard width, and the dirt paths were dark brown and damp. The forest was amazingly green - eventually every direction, including straight up, would end in something green - but not all that dense, and the visibility into the trees was probably 20 or 30 feet. The trees tended to grow tall and not have much low brush, and there was very little ground cover. Epiphytes, plants growing on trees, filled in between the canopy and the floor. There were scattered ferns and elephant ear plants on the floor.

Insects in the jungle drowned out most other noise, and would get louder and quieter, almost like turning a faucet on and off. When the singing died down, the forest would get very quiet, and then the buzzing and the chirping would pick back up again.

Almost immediately, Carlos said he smelled howler monkeys. Part of finding things in the forest was using four senses - sight for finding obvious animals, sound for locating birds, smell for onkeys and touch for finding insects who had already found us. After walking down the path for a few more minutes, we came across a large troupe of spider monkeys playing in the trees.

As we watched the spiders monkeys, Carlos departed and soon came back to report having found the howler monkeys. We watched both for a long time. The spider monkeys were more active, moving around upside down and using their tails a lot. The howler monkeys seemed to move less, and when they did they walked right side up on the trees and didn't use their tails as often.

The spider monkeys were spread out, so we continually came across them as we hiked further into the forest. They were eating figs from the tall, white-barked diamond-leaved fig trees, and some may have thrown remains at us.

After leaving the monkeys, Carlos pointed out different kinds of flora, particularly strangler figs and epiphytes. We also found an agoudi, a small marmot-like creature with an enormous butt, hanging out near a creek mouth, and lots of basilisk lizards running across the creeks as we crossed them.

Eventually, the trail opened out onto the beach. The sun came out and warmed everything up quite a bit. The beach was sharply sloped and had tons of crushed shells.

Carlos was looking for scarlet macaws, which he said preferred a certain type of tree found along the ocean. The foliage was impassably thick right up to the sand except where the trail was cut out.

We couldn't find any macaws, and after a while stopped to rest on some rocks, where we watched silhouetted frigate birds flying in the distance. Soon after turning back, we ran across some howler monkeys. Carlos grunted at them, and they grunted back.

As we walked back along the beach, a coati ran out of the jungle and across the beach on its way to catch hermit crabs in the tide pools. Carlos followed the coati down to the lava rock pools, and directed it back onto the beach, where it unhurriedly strolled past us, paying almost no attention to all the people taking pictures. Although Carlos had been yelling at it and chasing it, the animal never ran, just changed direction like it had been its idea all along to go back to the beach.

We walked all the way back to the ranger station on the beach, cutting through the jungle only briefly to return to the river mouth crossing. After we put our sandals on and crossed the river, Carlos pointed out the mother crocodile floating in the river lagoon. We could see just the eyes and snout sticking out of the water like a stick, until it suddenly disappeared underwater. It never returned.

We moved in to start lunch under the covered roof of the ranger station picnic area, when it started pouring. The rain drummed on the metal roof and gushed off the sides of the station. From time to time, more hikers would straggle in, soaking wet, until there was a crowd under the roof.

When the rain let up a little we prepared to hike up to a waterfall, where we would swim. We walked up along the side of the river, the damp trail rising and falling with the river contours and the trees dripping constantly, like rain even though the actual rain had stopped. The chopped-up river had turned the brown color of coffee with cream.

After 10 minutes or so, we reached a part of the trail where we were supposed to cross the river. The rain, however, had pushed the water level too high, and Carlos didn't want to risk crossing the 30-foot wide river, which he said was three times its usual width. Streaks of white in the brown water showed how quickly the river was flowing.

Carlos said there might be another way to get to the waterfall, which would involve another hour of hiking, so we walked back toward the ranger station a little then took off on anothe trail that headed up into the forest, away from the river. We climbed a long series of steps cut into the dirt path and covered with tree segments, until we reached an observation platform looking out over the ocean and jungle. It was quite a view, down the beach where we had hiked earlier, out over the green jungle and the storm-whipped gray ocean, and up above us into the rainforest. The dark clouds had moved out and still hung threateningly over the water.

We left the lookout and hiked inland, through medium density forest. The visibility into the trees was about 15 feet, until tree trunks got in the way. Although most of the trunks were narrow, we passed some larger trees, including a few that were several hundred years old. One was completely hollow inside, all the way to the top, and we walked in and looked straight up to see the sky, a little point of gray light, hundreds of feet above us. Carlos said there were bats, but we couldn't see any.

At one point, the path opened a little and Carlos spotted two scarlet macaws in a tall, leafless tree. After seeing the macaws, we turned again, this time back toward the river. The forest floor was covered in huge leaves, which were mostly coffee-brown. We found a walking palm, which had grown to 50-60 feet, and a smaller tree in its shadow that Carlos said was probably located where the tall tree had started.

Soon, we could hear the river flowing again, and then we could hear the rushing waterfall. The trail led us down toward the water, but we were still unable to cross, because even at the top of the waterfall the river had swollen to several times its usual width.

Carlos seemed to feel bad about not getting to the waterfall, so he offered to take us to his favorite swimming beach, San Josecito, on the boat ride back.

At the ranger station, we picked up two other hikers from La Paloma, who had been off on their own and seen a boa constrictor, and got back in the boat. We drove up the coast a bit until we got to the swimming beach, a natural harbor protected by a long lava rock breakwater. The jungle was cleared for a house just up from the beach, which Carlos said was for sale for $1 million. No one wanted to go swimming, so we didn't even land.

Also on the way back, a pod of dolphins came over to play in our wake. Some jumped clear out of the water 10 feet from the boat. The dolphins were smaller and browner than California dolphins, and they appeared to have spots. Three or four of them leaped and played around the boat for 15 minutes before we drove on back to the lodge.

As we walked up the hill from the dock to the lodge, a pair of white-faced monkeys appeared on the path in front of us. We got closer and found monkeys infesting the trees, eating, playing and seeming generally unconcerned about the people.