A Report by Matt Harris,
a member of the Upstate Herpetological Association


Upstate Herpetological Association member Matt Harris, and former UHA President, Ken Barnett, led a group of 13 UHA members, relatives and NYSDEC biologists on a herping and birding trip to Costa Rica's famed Corcovado National Park. Corcovado is situated on the remote Osa Peninsula in the Southeastern part of the country, only a stone's throw from Panama . In the following article, you will learn about the abundant wildlife found there, which has prompted some to call Corcovado the ‘most biologically intense place on earth'. We encountered many herptiles and other animals on our trip, including poison dart frogs, white-lipped peccaries, Baird's tapirs, American crocodiles, common caimans and deadly fer-de-lances!!

Part I: Arrival; hiking through Corcovado ; snakes and frogs galore!!

After getting a taste of the tropics in 2002, we decided if we really wanted to experience the remote, untouched Costa Rica , we need to do 2 things on the 2003 trip: 1) Go during the rainy season and 2) venture deep into the heart of Corcovado National Park . In 2002, I mentioned to Kenny that I wanted to go to Costa Rica to hunt for bushmasters. Within weeks, Kenny and his wife Gaye, decided they were going as well and we researched several ‘Eco-lodges' and decided on a little known, no-frills lodge situated near Carate on the Pacific coast of the Osa Peninsula. This area, while remote, is still an 11 mile hike from the heart of Corcovado National Park – 11 rough miles along beach, over jagged, exposed rocks, through dense jungle and requires crossing 1 major river teaming with large crocodiles and bull sharks! And that's assuming you've hit the tides just right!! While we saw an abundance of wildlife for only being our first time there (and you really can't complain about trees with a dozen scarlet macaws squawking in it), we simply wanted to see the areas that were completely untouched by human encroachment.

Back in October I mentioned to Kenny, that this year, I was planning on hiking across the Osa Peninsula to get a first hand view of the more remote parts of Corcovado National Park . This particular hike follows a river from the Golfo Dulce on the north side of the Osa Peninsula , up through the lowland tropical wet forest, and finally up into the mountains on the northeastern boundary of the park where it enters at the Los Patos Ranger Station. From Los Patos, it follows a couple of knife-edge ridge tops and drops down onto the Corcovado plain, where it then follows the Rio Sirena and then the Rio Pavo on its way to the Sirena Biological Station and ranger station. The entire distance from the trailhead near La Palma on the North, to Sirena is approximately 17 miles. Logistically, the hike takes about 2 days if you spend a night at Los Patos and take time to explore the surrounding forests for animals, as well as, getting to the trailhead itself! The first 5 miles of the trail to the Los Patos ranger station takes you higher up into the hills and you enter the habitat of the black-headed bushmaster ( Lachesis melanocephala ). Kenny wasn't keen on hiking and wanted to spend more time around the Sirena station, taking day hikes to explore the handful of trails that emanate from there. This was a result of researching journal accounts of the vast amounts of herpetofauna that have been catalogued in the area. In the meantime, we had made contacts with several herp-related researchers in Costa Rica , who further solidified the notion, that SIRENA IS THE PLACE TO GO!!!!!!

Sirena grass airstrip

Sirena grass airstrip

After much discussion (and extreme difficulty contacting the National Park service in Costa Rica to make reservations), Kenny decided to contact a gentleman, Mike Boston, whom we learned of through the lodge owner on last years trip. Mike actually leads treks into Corcovado National Park and is a connoisseur of fine Guaro. After contacting him, we decided to hire him to guide our trip. Rather than have just one plan, we decided to run to options: I would hike across the peninsula, with our guide Mike, while Kenny and Gaye would fly directly to Sirena (there is a small grass airstrip there—more on that later—it deserves a page all its own!!) Suddenly now, over the course of two months, the trip was actually becoming a reality.

In the meantime, through casual conversation, several UHA members expressed an interest in going along as well. Kenny had mentioned it through casual conversation at the DEC, and suddenly several biologists in the Endangered Species Unit were eager to go along as well. What started out as 3 now became 13!!!

On April 22 nd , we departed Newark for San Jose . After arriving around noon , we all piled into a van for the short ride to our hotel. Our luggage had only been thrown on the roof rack and wasn't tide down so Kim Corwin kept a watchful eye out the back in case a piece fell off. After checking in and getting settled, we headed to the nearby bank to exchange money. One dollar equals approximately 350 Colones-the currency of Costa Rica . We leisurely strolled around San Jose and ate dinner at a local restaurant off of the pedestrian mall. The restaurant features wood roasted chicken served with the traditional beans and rice. Most Costa Rican dishes consist of beans, rice and some small portion of meat. It may sometimes contain fried plantains (baking bananas) or wild yams. In comparison to Mexican food, Costa Rican food is not as spicy, almost bland.

The next morning, we woke and ate breakfast. At this point I, Jim Chapman and his daughter Carrie left for our charter flight to the village of Puerto Jimenez , where we were to meet our guide, Mike. The rest of the group was to leave a little later for their direct flight to Sirena. Upon arriving at the airport, Jim, Carrie and I checked in and waited. Only about 20 minutes later, Kenny and the group arrived for their flight. Only then did they realize that their flight would actually occur in two stages—first a flight to Puerto Jimenez, and then a flight from PJ to Sirena. In fact, due to weight concerns, some of their luggage was going on our flight in a twin-prop commuter aircraft rather than their smaller Cessna. We arrived in Puerto Jimenez and met our guide. We then waited for the rest of the group, as Mike had to give Kenny some supplies (such as mosquito netting) to take to Sirena so we didn't have to carry it on the hike.

After taking care of the gear and supplies, we departed with Mike into town to grab a bite to eat. It was only around 10:30am . Mike said we wanted to leave for the trailhead, which was about an hours ride, around noon and we should be hiking no later than 1PM in order to make the 3 ½ hr hike to the ranger station before dark. In the jungle, it tends to get dark much earlier. Our ride to the trailhead took about an hour to cover only 15 miles. When we got to La Palma , our driver stopped on a dime to point out the large male green iguana crossing the road. It was a beautifully impressive green iguana - unlike your typical pet-store iguanas! We continued on the dirt road that paralleled the Rio Rincon for about another mile until we could go no further. This was where the ride ended…..and the ADVENTURE BEGAN!

Dendrobates granuliferous

Dendrobates granuliferous

Late April is the end of the dry season in Costa Rica . The Rio Rincon at this time of year was only about knee deep in the rapids and waist deep in the bigger pools - of course, every big pool probably held a resident spectacled caiman ( Caiman crocodilus ). They usually hide in underground burrows under the banks and emerge at night to sit and ambush prey. Our hope was that the wet season would come early this year. As Mike had pointed out, the past years dry seasons had been exceptionally dry as had the previous year's wet-season. We could only hope the rains would come. As we hiked along the river, we could hear the calls of Dendrobates granuliferous, the granular poison-dart frog from the steep, moss-covered slopes along the deeper pools. It wasn't as hot and humid as we'd expected and a few brief afternoon showers cooled us off. It also helped wake up the frogs and bird life in the jungle canopy overhead. Mike kept pointing out the shrill, echoing call of the Chestnut-billed toucans high up the trees.

After an hour and a half of criss-crossing the stream more than a dozen times, the trailed made a hard right turn into a tall grove of heliconias. The trail then ascended a steep mud slope, rising about 400 feet in elevation through a series of switchbacks. Some sections were lined with circular discs cut from felled logs, but were not much help being covered with a slick layer of mud. Most of the Osa has a red-clay substrate. Mike heard the call of the bi-colored ant bird, and told us that when these birds are heard it means that there are usually army ants nearby. These ant birds habitually follow swarming army ants to feed on the arthropods that they flush from the leaf litter. In fact, ants dominate the tropical forests - we had to keep watching our step because the leaf cutter ants usually used the hiking trail like a super-highway and would stream 20 or 30 meters ahead before breaking off into the forest……they are an ABSOLUTELY AMAZING creature to watch! We spotted a small ‘rocket' frog ( Colostethus flotator ), which is closely related to the Poison-dart frogs of the genera Dendrobates and Phyllobates .

Leaf cutter ants

Leaf cutter ants

After another hour or so, the trail started to go down. At one spot, the trail meandered back and forth around some trees and Mike pointed out that a friend of his had seen a bushmaster crossing the trail here several weeks ago—I could only drool! About 15 minutes later, we entered a clearing and off to the left stood the lone wooden, single-story building that is the Los Patos Ranger Station. Mike greeted the rangers warmly and enthusiastically – they were all his good friends, he explained! We dropped our packs and removed our shoes to let our feet breathe. Immediately behind and above us, high up in the canopy, a troop of Howler monkeys was frolicking in the trees. While staring up at the monkeys, a pair of toucans soared overhead into the trees. Mike pointed out some jars on a table that contained snakes preserved in alcohol. In one jar was the faded head of a black-headed bushmaster that the rangers had killed not too long ago – supposedly to protect visitors, but we were the last people who wanted protecting from awesome snake!!! Another jar contained a baby terciopelo but was almost white from the alcohol.

After about an hour of rest, during which we ate trail mix, candy bars, and tins of tuna and mixed vegetables we bought at the Pulperia in Puerto Jimenez, we were eager to begin exploring. Jim had bought plain tuna, and I thought I had gotten the same, but Jim saw my look of dismay when I opened mine up to see a bunch of mixed vegetables! My depression turned to satisfaction after I stirred it up and found some tuna underneath. READ ALL SPANISH LABELS CAREFULLY! It ended up being pretty tasty! We walked across the field, which serves as the pasture for the rangers' packhorse, and headed down a trail. Not five minutes down the trail Mike caught a snake about 28 to 30 inches long. It turned out to be a juvenile tropical bird-snake ( Pseuetes poecilonotus ). It was starting to get dark and the frogs were starting to call so we kept searching. We kept hearing the shrill, high-pitched “TINK” of the ‘tink' frog ( Eleutherodactylus diastema ) and homed in on one sitting on top of a tall fern. Another distinct call caught our ears, and turned out to be that of a glass frog ( Hyalinobatrachium colymbiphyllum ), which nearly drove us nuts! We narrowed the call to be emanating from a heliconia leaf, only to find a silent female sitting there. The call is so shrill, that when made close to the ear it seems to hit a resonance and make your ears ring, like someone struck a triangle right next to your head! We kept searching almost possessed to find the frog making this call, when suddenly a light bulb went on in my head. ‘Wait a second….' I thought. I flipped the heliconia leaf over and sure enough, sitting on the underside of the leaf, clung the tiny little male. These are called glass frogs because their visceral organs can be seen through their transparent abdomens. They are orangish-green in color with small white dots. They are only about a half-inch long.

We searched for a little longer and found our second Leptodactylus bolivianus , a Central American leopard frog, which was sitting on a log. It was now pitch black out and we were watching it illuminated with our headlamps. While watching it, Mike noticed movement behind it, and saw the shadowy outline of a spiny rat ( Proechmys semispinosa ) sitting at the entrance of its burrow. This was exciting to me because the spiny rat is the primary food source of the bushmaster and terciopelo (even proven to us two days later)! We were definitely in bushmaster habitat! The jungle was loud with the calls of anurans everywhere around us…the rainy season had begun and we were in luck!! On the way back, something caught my eye the seemed out of place on a branch. I saw sticks coming out of a branch at right angles - that is odd for a tree. I looked closer and focused a little, and realized it was a lizard, a helmeted iguana ( Corytophanes cristatus ) sitting on the branch with its legs sticking out like Mr. Pretzel.

Around 7:45PM we went out for a second hike around the ranger station, this time just wandering around the pasture field. We went down near the rangers' garbage pit and found no less than two dozen marine toads ( Bufo marinus ) stuck in the pit. The pit is about 10 feet square and about 5 feet deep preventing the toads from crawling out, but they all seemed happy. Mike picked up the eye-shine of a large Leptodactylus pentadactylus , the smoky-jungle frog, sitting just off the trail. We found several toads sitting in the pasture field, including Bufo haematiticus . Mike remarked that it was the largest one he had ever seen! This toad has very large parotid glands, but unlike most Bufo toads, has smooth warts giving it an appearance not like your typical ‘warty' toad – hence it's common name, the smooth-skinned toad!

Clelia clelia

Clelia clelia

We sat at a picnic table for about ½ hour just listening to the jungle sounds and wondering if the others arrived at Sirena all right. Jim, Carrie and I headed back to the station to turn. Walking by the steps, I noticed a small snake slithering underneath the porch. “SNAKE”-I had to whisper to Mike so I wouldn't wake the rangers who were already asleep. Mike hurried up and dove after it under the porch. The station itself is raised about 3 feet off the ground and the under-story of the structure is completely exposed. Mike is a true adventurer: He grabs the snake first, identifies later! This little snake was the most brilliant shade of crimson I had ever seen—except for the small yellow ring around its neck. It was a juvenile mussurana ( Clelia clelia ). The mussurana is a notorious predator of the jungle, feeding on other snakes including bushmasters and fer-de-lance. Mike pointed out a peculiar fact about these snakes: they never bite when caught and handled. Perhaps that is fortunate, as the mussurana is a venomous, rear-fanged colubrid!! They are very large, beautiful, gentle snakes that turn a charcoal black after a couple years. In addition they are unique in being both rear-fanged (mildly venomous) as well as constrictors!!!! Carrie gave us her mosquito net to put it in so we could take it to Sirena to show the others. The temperature this evening at Los Patos was 81.1F at 4:30PM and dropped to 78.6F at 7:45PM .

The next morning we awoke around 6AM and hoped to depart by 7AM . After a couple cups of coffee and a pack of blueberry pop tarts, we started out around 6:40AM , a little ahead of schedule. About a half mile down the trail, Mike bolted ahead and grabbed a small, brightly colored snake. At first it appeared to be a coral snake, but I figured he must know what it is or he wouldn't have grabbed it that quickly. On closer inspection it turned out to be a “false-coral snake” ( Erythrolamprus mimus or bizona ). The snake was absolutely gorgeous and was the closest mimic to coral snake I have ever seen, even more so than any of the tri-colored milkshakes of the genus Lampropeltis . Mike tucked the snake into a sock so it could make the journey to Sirena as well. We continued on for another 11 miles and around 3:30PM , we entered a clearing---SIRENA at last!!! Along the way, we crossed the Rio Sirena and Rio Pavo, both mere creeks this time of year, and descended from the highlands down onto the Corcovado plain passing an area where the jungle actually becomes more of a dry forest in sandy soil before again entering tropical lowland moist forest. We saw many leaf-litter frogs including Rana warszewitschii and Eleutherodactylus fitzingeri , which Mike pointed out, was quite common.

We relaxed on the veranda for about an hour after dropping our packs in the last remaining bunkhouse. Kenny immediately began rattling off all the various species they had seen. Al, Dave and Mike were recovering after losing a soccer game to “Team Holland”. Soccer? In 80-degree heat and 90% humidity? What were they thinking? Just before dinner we took the two snakes down the trail a short distance to show everyone. We found a sunny spot that would be good for photographs and opened up the booty. After a 10-minute photo-session, we released both snakes and went back for dinner.

After dinner, Mike led a hike down along the beach. Jim, Carrie and I decided to sit it out and relax on the porch of the Sirena Biological Station. I heard many stories of Jim's insatiable appetite!


Baird's Tapir

Baird's Tapir

After a few hours the group returned. They found a cat-eyed snake ( Leptodeira septentrionalis ) but while walking along the beach, encountered a pair of eyes glowing at them from the woods. They stood perfectly still not knowing what it could be, and after a few minutes a large mammal strolled out: a Baird's Tapir ! It paused only inches from Al's hand and he could feel its breath as it sniffed his hand. Absolutely amazing!!!

This concluded the end of day 3, and we still had 3 days to go!


Part II: Baby crocodiles; feisty peccaries; poison-dart frogs!!

The next morning, we woke and ate breakfast, which was usually served at 6:30AM . Oddly enough, while sleeping in the tropics, the sounds of the jungle tend to wake you early in the morning (invariably it was the resident troops of howler monkeys near Sirena, who begin their howling at around 4:30AM !). On most days, though I would wake up between 5 and 5:30AM , there were usually at least one or two people who had risen earlier and gone out for an early morning hike. We ate breakfast and afterwards, assembled on the porch of the Sirena station to go for a hike down to the beach. Mike suggested we take a stroll along the Guanacaste Trail, which eventually leads down to the beach near where the Rio Sirena empties into the Pacific Ocean .

Now, this is important! Along the one side of the Sirena station, between the kitchen and bunk area, there is step where you go out to the clothesline and spigot to get drinking water. Each day, we'd stroll out there several times to fill our water bottles. This morning, while heading out there, Carrie Chapman looked down and noticed a very large spiny rat ( Proechymys semispinosa ) lying dead next to the step….EEEwwww! Kenny and I looked at it and prodded it a few times to see how stiff it was….not very. We showed it to Al Hicks, because he is a mammal specialist. We roughed up the fur a little to see the coarse guard hairs (spines) which give it its name, but also noticed two areas where the fur was kind of moist like it was slobbered on. Kenny said “I bet this was killed by a snake of some kind”. I agreed, it looked very much the perfect size of that a large snake, such as a Terciopelo ( B. asper ) would eat and the distance between the puncture marks coincided as well. We found it odd that the animal was about 20 yards from the woods, though it was possible the snake (if that's what it was) killed it and never trailed it.

As we approached the end of the Guanacaste trail, Mike motioned for us to stop. In the forest about 20 yds away stood a herd of white-lipped peccaries. We sat motionless watching them root up the dirt on the forest floor when all of a sudden they caught wind of us. “ CLACK-CLACK----CLACK—CLACK—CLACK-----CLACK”- the silence erupted like someone had lit a string of cherry bombs! When startled, peccaries crack their teeth together and the sound of their molars slamming together makes a popping sound like exploding firecrackers. Mike whispered to us that white-lipped peccaries have the reputation of being the dangerous mammal in the Neotropics, and will not hesitate to attack if threatened!! So we quietly stood our ground, looking as unmenacingly as we could make ourselves, and let the herd speed off.

We walked a little further, and no one could avoid the putrid smell of dead fish. Mike explained that after particularly dry dry-seasons (which the area had just experienced), the first heavy rains flush the Rio Sirena with nutrients, accumulated over the dry months on the forest floor and dried up creeks, which deoxygenates the water, and that this kills the fish. Thousands of dead fish of all sizes floated down stream and littered the river banks. The black vultures were happy! And so was a bloated crocodile we encountered at the mouth of the river. This animal appeared to be a large male, approximately 8 feet in length. As we approached closer, the beast inflated its lungs with air exposing its back in a display to let us know he wasn't happy we were around.

As we entered the beach area, Kenny approached a large impressive spiny-tailed iguana ( Ctenosaur similis ), which was basking on a log, to get some close-up video footage. After getting within about 6 feet of it, the lizard shot like a rocket toward the woods and into a hole. These lizards live in burrows right on the forest edge where it meets the beach. Down the beach about 15 yards, we found 3 other female ctenosaurs basking on the sand. These animals, though, were not as nervous and we approached them within about 5 yards while they grazed on various plant leaves along the bank.

After Lunch, our plan was for me to take about half of the group back up the trail to the Rio Pavo (about 3miles) and hike down the Rio Pavo—supposedly a few hundred yards—to where it empties into the Rio Sirena. Mike would take the other half of the group, and they would canoe up the Rio Sirena looking for crocodiles and meet us at the Rio Pavo. Then the two groups would switch and reverse the routes meeting back at Sirena around dinner time.

Our group included me, Kenny, Gaye, Jim, Carrie, Katie and Dave Edwards and we headed up the trail towards the Rio Pavo. About ½ hr into the walk, the skies clouded over and it started to rain. It hadn't rained at Sirena since we had gotten there, and I hadn't seen rain since day 1 on the Rio Rincon. The shower didn't last long, maybe 20 minutes or so, and we didn't get wet as most of the canopy protected us. We approached a small stream with just a trickle in it when I looked down and something hopping along caught me eye. “AURATUS” I shouted. A gorgeous, brightly colored adult Black and Green Poison Frog ( Dendrobates auratus ) was awakened by the morning showers. It was nice find, and apparently a rare one for the area - Mike later told us that in seven years of hiking the trails around Sirena he had never come across any. Without thinking, we caught it and held it to take pictures, but then made sure we thoroughly washed our hands off.



We came to the Rio Pavo and started heading down river…..around one bend and then the next. We walked several hundred yards, thinking that the Rio Sirena has to be around the next bend. We kept slogging through the river because the banks were high and steep in most places and covered in vegetation everywhere else. It seemed like forever and we stopped several times to rest and for Jim to catch up. His shoes were not holding up very well and it was slowing him down. Finally after at least an hour, we heard voices, and then thrashing through tall grass, Mike appeared on the bank. “Mike, it's somewhat further than a couple hundred yards, more like a mile or so”, but we didn't want to tell the others that. We were really glad we would be riding in the canoes on the way back. We asked Mike what they had seen, and he remarked that only a single caiman was spotted, no crocodiles. He had hoped to see some along some sandy areas where they nest as this was hatching season in Costa Rica .

After a half-hour rest, we loaded up the canoes: Kenny, Gaye, Katie and Dave in one and Jim, Carrie and I in the other. Not 50 yards down the trail, I spotted the ventral scales of a snake on a branch overhanging the river, about 20 feet up. ‘WHOA, there's a snake up there' I said. It took several minutes to point it out to Jim and Carrie as the pure white ventrals were tough to see and the snake was a blue color. We managed to get Kenny to turn his canoe around and we paddled over to where the tree trunk and exposed roots clung to the side of the muddy bank. The roots made somewhat of a natural ladder and I climbed out of the canoe while Jim and Carrie steadied the vessel. As I tried to climb up the tree, I realized, a trail of army ants was streaming down the trunk, and they began to bite me on the arms. As I re-thought my strategy, Kenny and the others kept an eye on the serpent trying to force it back in toward me. I finally just bore the brunt of the ants and was able to go maybe 8 feet up into the tree. Kenny grabbed one of the over hanging branches and shook it trying to deter the snake, but as he did, 3 bats flew out of the foliage and zoomed right across the water landing on the tree trunk mere inches from Carries head. They clung there for a few seconds. The snake, meanwhile crawled back toward me, and I got a somewhat decent look at its blue body noting it was around 5 feet long….have to ID that one later.

Baby crocs

Baby crocs

I descended out of the tree and back into the boat. Already we weren't 5 minutes into the paddle and we found a snake….and a tough one to spot at that. Too cool! We proceeded down river, Kenny and Co. moving faster than our boat. We lost sight of them and we're just going at our own relaxing pace, taking advantage of the silence, when I noticed a juvenile basilisk ( Basiliscus basiliscus ) right along the bank on a branch. On the water surface I saw two little bumps moving toward the lizard and tried to convince myself that there were moving and I wasn't seeing an illusion. All of a sudden the bumps started rising out of the water…..then a couple tiny teeth…..then a snout…..HOLY SHNYKIES .A HATCHLING CROCODILE!!! “Oh My gosh….Jim stop…..A BABY CROCODILE!!!! LOOK!!!”…..we stopped the canoe but we drifted too close and the basilisk jumped into a bush. NUTS! We chased away the crocodiles meal…it would've been neat to see the croc grab the lizard. I scanned the shore to the left and Jim pointed out another one basking on a log to the left….a cute little foot-long baby sprawled on a log. HOW DID THE OTHER GROUP MISS THEM??? You gotta go slow and scan everything! I scanned to the right and suddenly could make out the pattern of little scales against a muddy bank…”Hey there's anther one….an another…..and another……HOLY CROW….THERE ARE DOZENS OF THEM!!!”…They were everywhere! We started counting: Two, Four, Six,….Eight…..Too many to count and they were piled on top of one another.

“We gotta go get the others and show them!” …..so we tried to back the canoe out, but we were stuck. We tried not to splash, and almost started the babies but suddenly the canoe got loose as the babies appeared to be making a dash into the river. Don't wanna spook them because we don't know where Mama is!

We headed down stream at a fast clip…..hoping to find the others. They were about 200 yards ahead and we tried yelling to them about 100 yards away…..of course, they couldn't hear us. Finally we caught up and told them we gotta go back, we found a gaggle of crocodiles (not the right term, but—hey, they're close to birds!). We turned around and headed back upstream. We paddeled upstream, above the nest, and floated back down into place, allowing Kenny's canoe to get closer for pictures. Gaye counted the babies and came up with 28 in number. There were probably more! I scanned the bank for signs of Mama, but found none. I spotted some turned up sand behind the tall saw grass on the bank and the sand was littered with broken egg-shells!!! THESE CROCS WERE MERELY A FEW DAYS OLD!!! WHOA!!!!!!!!!

Phyllobates vittatus

Phyllobates vittatus

We spent about 15 minutes watching the crocs and headed back down stream. We made it to the river mouth (where the big adult crocs live) around 4PM and tied up the canoes. The other group was running longer, and it wasn't much before dinner when they arrived. Mike was exhilarated to hear of our discovery of a croc nest since they hadn't seen them on the way up the river. He did bring back a neat find though, a Golfo Dulce Poison frog ( Phyllobates vittatus ). We had now seen all 3 species of poison dart frog endemic to the Osa Peninsula !

Part III: Large fer-de-lances; radio tracking tapirs; and the night- hike out!


After dinner, we decided to lounge around and take it easy. We had been hiking hard for the past 3 days and we all figured a relaxing evening would be nice to “recharge our batteries”. Talking to the two girls at Sirena, who do research on Central American spider monkeys, revealed that behind their cabin there was a water well around which was home to several Red-Eyed Tree Frogs ( Agalychnis callidryas ). This was only 50-75 yards from the lodge, so we figured that would be an easy hike to do tonight, and wouldn't be too physically demanding. Around dusk (a little after 7 PM ) a group assembled and was starting to head back toward the well. We stopped along the forest and tried to home in on the call of a male red-eye tree frog which we heard calling from about 6-7 feet off the ground. Mike Adams found it right away, and it was a really neat site (being the first one I actually saw). It was much neater seeing a bright green frog perched on a leaf, with those huge red-eyes glowing back at you, rather than the dozens of emaciated frogs cooped up in screen cages at local herp shows.

We were all transfixed by the frog when suddenly we heard Carrie yell “SNAAAKKKKEEE….Get Matt there's a snake under the porch”. Carrie had walked out to fill her water bottle and when she was coming back to the steps she saw the body of a very large snake crawling right next to the steps!! She immediately called Jim over and told him there's a snake under the steps. Jim walked over, thinking it's probably some tropical rat snake and at first glance, he couldn't really tell with the poor lighting. He bent down to get a better look and upon seeing the large triangular spear-shaped head with black eye-stripe, knew right away….”Holy Cow, It's a fer-de-lance!” Amazingly, this snake had followed the scent trail of the spiny rat that was laying there earlier in the day. We were right! It was a snake that had killed the rat and some 12-18 hours later, was able to follow the scent trail looking for the rat. It followed it at least 20 yards-the approximate distance from the forest edge to the steps!

Well, now everyone was running over to the station! Several of us asked where it was and I grabbed my hook, a small 24” cage hook-the only one I took on the trip. At this point, it was chaos. I jumped over the railing into the courtyard area and lay on my stomach to get a better view under the bunks. All we could hear were people yelling “It's over here!”, “It's going that way”, “and Everyone stay back!”…..you would have expected to see this snake flying around at Mach 2 with the way everyone was shouting, but when I finally saw the snake, it was very calmly coiling up next to a concrete support pedestal under the station floor. Someone asked “Are you gonna catch it?” to which I replied ‘Well, not with this hook!”. Mike and I deliberated what to do. We had no hooks (or catch bags for that matter) and at first I said “it's probably best to just leave it there” as it was so far under the bunk area, no one could safely get it out. Mike said if we do that, the rangers will most certainly kill it for reasons of safety.

By now, a large crowd had gathered, including the monkey researchers, Jen and Sabrina, and Charlie Foerster, who studies the Baird's Tapir ( Tapirus bairdii ) in Corcovado . Charlie said he had a butterfly net and a large pole we could use if we really wanted to capture the snake, but he too though we were nuts—this coming from a fellow who has survived a puma attack in 1996 while tracking tapirs! Mike went to ask the head ranger for permission to capture and relocate the snake, as even though, they are considered a nuisance, as with all Costa Rican wildlife within the park, it is illegal to capture it.

Martin, the ranger, and Mike returned. Mike showed him the snake and explained what we planned to do. Martin gave us permission, but requested we take the snake about 1 ½ km away on the other side of the Rio Sirena away from any hiking trails to release it. Charlie returned with a butterfly net and a coconut picker—a 7' pole with 2 metal prongs on the end. Right away I figured it'd be difficult getting the snake out because the pole was so long, that as soon as I touched the snake, it would move like quicksilver and I would have no leverage lying on my stomach. It was exactly what happened. As soon as I touched the snake it shot down to the other end of the bunk house. I couldn't drag it out because of all of the concrete supports pedestals supporting the station. We ran down to other end and found where the snake coiled. Fortunately with all the headlamps focused under the bunkhouse, the snake stayed there. By now the ladies who cook meals at Sirena, had gathered in the foray as well. They kept yelling “MUCHO LOCO, MUCHO LOCO!”---yeah we were nuts, but this is what we paid for!

A big terciopelo

A big terciopelo

We chased the snake back and forth a few times, and finally, the snake had enough, it decided to come out from under the building and (apparently) try to make a dash for the woods. Kenny was yelling “everyone get back and let it come out!” This way once it came out, I could deal with it in open ground. I ran around the corner of the building and saw the snakes head emerge….man this snake was gorgeous! And big, longer than either of my captive females, but not nearly as heavy—but still very healthy! I stood back until the snake completely emerged, but didn't approach too close so I didn't spook her (how exactly do you spook a 6' terciopelo?). I snuck up from behind her and positioned the net in front of her head about 12 inches. When I had it in place, I gently tapped her tail, which usually is enough to make them explode like a coil spring! As soon as I tapped her, she lunged like a rocket straight forward into the net and as soon as I saw her tail disappear, I started twisting the net. I fully expected her head to come shooting back out of the bag and then I'd have to pin her with the pole and bag her by hand, but fortunately I got the net off the ground removing any leverage she had and got it twisted several times so she couldn't come out. I laid the net on the ground and put my foot on the twisted section, and asked Mike to go get my laundry bag. We would slide that over it the net and “Double-bag” her. I asked Jim for a piece of parachute cord and first tied the net off, then Mike and I slid the laundry bag carefully over the net. Using another piece of para-cord, we tied off the laundry bag. My first Wild-caught Terciopelo! AWESOME! My heart was pounding, and the adrenalin was racing through my veins! Why watch Animal Planet, when you can do it yourself??? Mike was grinning from ear-to-ear! “Man, I love this!” he said in his Irish accent! “You guys are like a dream group for me!” So much for hunting red-eyed tree frogs!

I placed the snake and bag next to my bunk and checked it several times before I went to bed to make sure the knots were secure. I think I woke twice in the night too, just to make sure she was still in the bag. The next morning after breakfast, Martin accompanied a group of us along the beach and across the Rio Sirena to release the snake. Even though it's a terciopelo, he wanted to be sure that the snake was released (and we weren't gonna try to take it home with us) and that it was released far enough away from Sirena. The hike along the beach took about 2 hours to go release and get back to the Rio Sirena. The snake was very relaxed when it crawled out of the bag, not stressed at all and not aggressive like the stereotypical stories you hear about fer-de-lance (though, there are other times where they deserve this reputation, but most often they are quite placid animals). On the way back we stopped at a lagoon that was formed by what was once the course of the Rio Sirena. The river is constantly changing course, and this lagoon had a couple small crocodiles in it.

Mike planned to take the canoes back up the Rio Sirena to give the others who didn't see the baby crocodiles a chance to see them and get some close-up pictures. The rest of us took a hike along the Espavales trail, a short trail, that we thought would be easy, to go see an enormous Ficus tree. This hike turned out to be one of the best of the trip. Hiking up the trail, Laura and I were in the back. Shortly up the trail, the others stopped. Now what? Gaye turned around and whispered “Peccaries”. Moving parallel to the trail came a wagon-train of white-lipped peccaries. Oh Boy! Now what are we gonna do? I immediately started looking for a tree to climb in, because these “pigs” were only about 10 yards away. I could hear Jim talking pretty loud and I thought…”what's he doing? If we startle them, they may charge us!” On the other hand, Jim was thinking “If they know we're here, we won't surprise them, and they'll turn around and run the other way”---which eventually worked. In the meantime though, Gaye was obviously concerned, because she would ask Jim what he thought, then turn around and in a whisper ask me what I thought, and be the messenger between two people who really had no idea what was gonna happen, but yet were trying to make the best out of a delicate situation. Fortunately, the pigs moved on, and we continued along the trail.

We came upon huge swarm of army ants spread out across the trail, so I stopped to observe them making little ant-bridges so the other ants had a short-cut over small ditches, saving valuable ant-time. As I stared down at two trails, I noticed how they oddly separated like a divided highway…that was odd. As I looked closer, coiled in this tiny island within a sea of ants, lay a baby female Terciopelo! Wow, and really cute too. I couldn't leave it there or the army ants may attack and kill it. I found small stick, and used it to gently pin the snakes head to the ground so I could get a grip behind the mandibles. Using the 3-finger approach, I pinned the snakes head, grasping it with my index finger between the supraocular scales and my thumb and middle-finger behind the mandibles. I picked it up to show everyone then carried it up the trail about 100yds and release it. Boy, what a cute little snake.

We stumbled upon a troop of squirrel monkeys making all kinds of racket in the canopy. We soon realized why: Two white hawks were perched above the troop and watching the monkeys feeding. All of a sudden with a flash of white, the canopy erupted with monkey-chatter and limbs shaking and one of the hawks dropped down and grabbed a baby squirrel monkey! Monkeys were screaming, limbs were shaking and the whole forest was alive!!! And as quickly as it came alive, it was quiet again, almost as if the monkeys accept that they'll lose a baby every now and then to the winged predators. Such is the equilibrium of life that still exists in ecosystems that are undisturbed by people.

After Lunch, we took a hike up the Rio Claro to search for dart frogs. After the long hike and canoe trip the previous day and the excitement of the night before, Mike suggested an easy hike up the river and the chance to take a swim to cool off. Up this river, Mike has found Dendrobates granuliferous , the granular poison frog, high up in some stream beds that empty into the Rio Claro . We figured it would be a nice hike since we could take a dip in the river on the way back. After slogging through the river upstream for about a mile, we came to a tiny stream cascading down a moss covered ravine. Mike located a tiny ‘ granuliferous' calling from a moss covered cliff. The hike up this little ravine was very slippery and it was tricky climbing up without slipping on the wet rocks. After taking pictures and fruitfully scouring the leaf litter for what we thought was another granuliferous (it turned out to be a leaf-litter frog…possibly Rana warszewitschii ) we head back to the Rio Claro . We found a nice long pool for a swim with a rock ledge on the far bank that made a nice under-water bench. We swam for a half-hour and headed back to the lodge. We arrived in time to change into dry clothes and shower before dinner.

After dinner, we took a short hike along the stream next to the ranger station to look for spectacled caiman ( Caiman crocodylus ). The streams are low still, and generally only the larger pools hold deep water. Each deep pool is home to a resident large caiman, anywhere from 4 to 6 feet in length.

Next morning (it was now Sunday, the 27 th ), we took a leisurely hike to the beach to go swimming. In the afternoon, Mike decided to take a hike higher up into the hills behind Sirena. Since it had some steep climbs and we were pretty tired from the past week, several of us decided to skip this hike. Jim, Carrie and I declined because we knew we'd need our energy for the 11-mile hike to Carate that night. Mike asked Charlie if he would take those of us, who hadn't seen a tapir, out to try to find a tapir. Charlie agreed and said we could find one only a short distance away, and it would be an easy walk. We went up the Los Patos trail only a couple hundred yards and turned onto a ‘research trail' marked only with plastic ribbons. In the middle of a of some vines between two small streams we found “Big Mama”, a 600lb tapir with her 6-month old baby, “Nepal”. They allowed us to watch them for several minutes and then waded into a stream before disappearing into the jungle. What a sight! How many people ever get the chance to observe a wild-tapir from merely 30 feet away? (For more info on the Baird's Tapir, see the link at the end of the article).

The others returned from their hike around 5 o'clock , and exclaimed that they found a large female terciopelo even bigger than the one we released! This one was coiled in the forest with a litter of newborn babies! They had only found her because they went off trail following what sounded like screams of a monkey in distress: That usually means a jaguar nearby!!

That evening, we lounged around the lodge and prepared our gear for the next day's departure. The four of us hiking out, prepared our day packs, as Mike suggested we send our gear on the planes, to save weight for the hike. We took only enough snacks and water plus our headlamps and first-aid kit with us on the hike. This would allow us to cover the 11 miles quicker and we could leave later getting an extra hour of sleep.


We woke around midnight . It didn't take long to pack up and be ready to go. I drank lots of water the evening before, so I was well hydrated. I checked the battery in my headlamp and had a spare…Let's go!

We waited for Mike Adams, as he decided he wanted to hike out for the adventure, rather than fly out. We started down the airstrip around 1 AM and turned into the forest where the trail to Carate begins. This trail must be followed at the right time of day, or A) you will become overcome with heat stress while hiking along the beach or B) You'll be stuck waiting at certain points where you cross rocky promontories which can only be crossed at low-tide. In either case, day or night, you have to wade through two rivers (the Rio Claro and Rio Madrigal), and the first one is inhabited by large crocodiles, and on occasions bull sharks! The bull shark is the only requiem shark which can tolerate both salt and fresh water, and frequents rivers and estuaries. It is also the shark responsible for the most attacks on people! So understandably, we waded across the Rio Claro with some trepidation! With the red glow of a few crocodile eyes to remind us of their presence, and ensure an ample infusion of adrenalin in our veins, we crossed without incident. We lost no hikers, but we lost the trail on the other side! Recent storms had knocked down trees and the trail, at 1 in the morning, was impossible to find. Mike started to slash a trail through the jungle using his machete. Fortunately, the trail follows the beach most of the way, so as long as we heard waves crashing, we wouldn't get lost. The problem was, it was going to take us 6-7 hrs to get to Carate with no delays, and if we had to bushwhack that could easily double the time!! Mike hacked his way out to the beach and we walked the beach a ways until we found the trail again. We stopped at a point where the beach entered a grove of coconut palms when Jim noticed he lost his glasses. He was having trouble with an eye infection, and stepped on a coconut, nearly twisting his ankle. He knew right away where he lost his spectacles, so he and Carrie backtracked and after about 20 minutes, returned, having found the glasses. We now had to navigate a promontory, called Salsipuedes, which means “pass if you can”. It is a barrier at high tide, and its black volcanic rocks are sharp and slippery at low tide!

We navigated it with few difficulties and made our way along the beach, sometimes, going inland. We stayed close to the surf. We were lucky that the tide was ebbing as the wet sand near the is harder and easier to walk on compared to the dry soft sand further up the beach. At the halfway point we had another rocky promontory to cross, called La Chancha. This too presented us with a formidable barrier of sharp rocks, and also poses a problem at high tide. We were thankfully that Mike had hiked this trail many times and knew the ropes!

Normally, if you hiked this trail, you'd be asking for trouble to do it in the daytime because of the exposure to the sun. At night, though, it's cool and we took full advantage of the ebbing tide to make good time. The sunrise was truly spectacular. Mike pointed out a sea-turtle floating out in the surf. We passed the hull of an old shipwreck shortly before approaching the Rio Madrigal. We had one more area of wet rocks to cross and after getting over them, we stopped at a stream that was spring fed, in case we need to refill our water bottles. Jim wasn't doing well. For the past several hours, he was running a fever and had vision problems with his eye-infection. We decided at this point, that we would all make it to the Rio Madrigal together (merely another 1km), and then Mike and I would go ahead to the Pulperia (store) in Carate to wait for the taxi. If Jim, Carrie and Mike A. didn't make in time, we'd have the taxi wait for them. It was now 6AM .

Just an hour later, Mike and I arrived at the Pulperia, covering the last three and a half miles at a brisk pace – the prospect of a cold beer hastened this pace towards the end!! Amazingly, the others were only a half-hour behind us, arriving at 7:30AM . Jim was feeling better by then, being able to move at his own pace, rather than the grueling sprint we were setting. In the meantime, we relaxed, slaking our thirsts with a few more beers and sodas, compared notes on our many aches and pains, and waited for the colectivo taxi to arrive.

During the last six days, we had hiked over 35 miles through steamy jungle, waded across croc and shark infested rivers, and along deserted beaches. We had bagged a 6' Fer-de-lance, canoed with crocodiles, and confronted white-lipped peccaries, and survived un-scathed! It was time for a rest. We all slept on the near 2-hr collectivo ride around the peninsula back to Puerto Jimenez. We weren't there long when Kenny and Dave Adams strolled into Carolina 's Restaurant in Puerto Jimenez. We were starved and chowed down on burgers and Coca-colas, which we were craving!

For more info on the Bairds Tapir Project, Proyecto Danta , or to adopt a Tapir, such as ‘Big Mama', you check out Charlie's website at: http://members.aol.com/crfoerster/index.html