We are three biologists. After sixteen days of studying the Costa Rican rainforest with a group of teachers from a WWNFF Institute, the three of us elected to try a natural history observation of the forest using the methods of Grinnell. We picked a site near trail SOR 500 on the northeast corner of La Selva Biological Research Station. Susan Sprenke began her observations on the bridge near SOR 500, David Fletcher stayed near the river, and I chose to sit next to a large kapok or ceiba tree. On the walk to the site we observed several blue tailed lizards, Amieva festiva.

As I sit down with pencil in hand, the howler monkeys are making a big racket overhead. They settle down after a while except for the big male occasionally roaring a warning. The day is warm, about 85 fahrenheit and the sky is slightly overcast. We are in La Selva on the edge of the experimental forest. Experimental manipulation of this part of the primary forest is forbidden.

My seat is the root of Ceiba pentandra a kapok tree. The fluff in its seedpod was once used for padding and life preserver stuffing. This giant has buttress roots that are 10 meters high. The buttress roots extend from my seat to 12 meters toward the Southeast. I have mistaken handwash for mosquito repellant so my first observation is that mosquitos are repelled by tea tree oil or alcohol in the handwash from the rainforest of Belize. They still occasionally bite. Fortunately they seem to have a pecking order and only come for blood one at a time. If they were rude like the mosquitoes in Louisiana they would all rush me at once. Do they have a pecking order like chickens?

It is nearly noon and birds still call. There is a background noise of insects buzzing that never ceases. A spider is on the leaf in front of me. She holds the two front pairs of legs close together and appears to have six legs. Perhaps she is pretending to be an insect. Her abdomen has two fake eyespots to further confuse predators about her direction of escape. A large roach hangs upside down on a leaf nearby. The leaf is a strangler fig. Its host tree is doomed to die in the shade when the leaves of the fig reach the canopy. The tree is a palm, Weltia regia, that produces a long pod with exposed seeds down its side. Butterflies of orange and black pass regularly in front of me. There is a strange odor in the air. We have seen tracks of a collared peccary.

A large bromeliad has fallen from the canopy and lies against a root of the ceiba. Two beautiful scarlet flower clusters jut from its rosette of water trapping lily-like leaves. The howlers are dropping some liquid from above. I hope the plants appreciate the fertilizer. They missed me by one meter. A large rotting log lies to my right.

It is a nurse tree for several shrubs and has provided a natural edge that allows me to see better and allows palms and Dieffenbachia to grow in front of me. White bracket fungus grows on a stump near the base of the fallen giant. The stump is a meter high.

Two blue tailed lizards race across the leaf litter in front of me. Intent on the chase, they ignore me. We returned to the station for lunch and from the suspension bridge, we spot a very active otter swimming below.

At 1:45, I am back in my study area. The temperature is now 88 Fahrenheit and humidity remains about 100%. Since we arrived at La Selva, there have been only two brief showers. This is the rainy season, but Daniel Jansen describes this mini dry season that Costa Ricans expect each year.

Leaf cutter ants are carrying there cut outs of leaves along a root at my feet. Their trail is not well manicured like those of the ants near the station. They are really struggling to get their load of leaf fragment home. When they succeed, the leaves will nourish fungus which is the food of the ants. A broad-billed motmot just flew to a perch in front of me and ate its prey. I couldn’t see what he caught, but the list could include insects, lizards or small vertebrates.

A breeze is just beginning to knock down debris from the canopy. An agouti just spooked and ran into the brush to my right. This is an little rodent that is considered good food by many people. No wonder he is so quick to run away.

From where I sit, I can see about six trees that emerge above the rest of the canopy. There are dozens of other large trees, some with fruit. The rubber tree to the southeast is loaded with ripe and ripening fruit.

The fruit is the size of a tennis ball but flattened toward the stem . The terminal side looks bumpy and the stem side has many flattened sepals. Its flesh is bright orange. I can see with the binoculars that some of the fruit has been eaten. This is the edge of a primary forest. I am less that 200 meters from the river so I can hear some traffic on the road on the other side. People from the research station walk by occasionally but they don’t notice me. A small brown lizard rushed out of the litter in a vain attempt to capture a damselfly with smokey violet wings and a scarlet mark near the wing base. He remained in the same postion for over twenty minutes.

2:50 Brown bird flew up to a vine on the side of the ceiba and stared at me briefly. I can’t be sure of the ID because it is so dark, but it is some type of forage gleaner. A bullet ant is crawling on a Dieffenbachia leaf about 2 m away. It appears to have an egg in its mouth. It moves randomly about on top of the leaf for 2 minutes and disappears beneath the leaf litter.

The ground slopes away from the base of this ceiba tree at a fairly steep angle of 20 degrees. This makes it easy to see the bromeliads in the trees nearby. There is a constant rain of bits from the canopy above, especially when there is a breeze.

3:10 a slight breeze and beginning of a little rain starts the howler monkeys roaring and shouting. My clear plastic poncho allows note writing to continue. The major worry is the digital camera, but it is stored in a plastic bag inside my fanny pack. The binoculars are waterproof. How did Alfred Wallace make his great jungle observations without technology, especially plastic? The sound of rain in the forest is like a small waterfall. Howlers continue.

3:15 My crowd of mosquitoes disappeared when the rain began. They must need shelter from the drops that are bigger than they are. I see bright light to the southeast reflected from a large thunderhead. The rain continues.

Two chestnut mandibled toucans flew into the rubber tree to feed on the fruit. Rain is slacking. Mosquitoes are back.

3:25 The surface of the Dieffenbachia in front of me is only 10% covered with raindrops. Dripping continues from above. I wonder if one can move in the rainforest without killing something. I just noticed a large millipede curled up under the leaf litter. I must have been stepping on him. He doesn’t seem to be mortally wounded. The leaf cutter ants resume their work.

3:39 Big woodpecker is going TAP TAP. He is probably marking his territory. I keep searching for the red head of a lineated woodpecker which I have seen in this area, but all I am finding is the scarlet of bromeliad flowers.

3:45 The woodpecker is now accompanied by the drums of a marching band across the river.

4:02 Drums stopped finally. I can occasionally hear a loud truck on highway 4. I hear undergrowth rustling and twigs snapping but can not see the cause yet.

4:07 A strong breeze knocks down branches. About 7 m away with binoculars I see a damselfly that has the bottom third of its wings scarlet and the rest a smoky violet. The body is black. It sat in the sun for 5 minutes.

4:19 frogs call again. Wind to south brings the sound of trucks on the highway. Palms are common in the understory here.

I see two species from my seat on the root. One is the walking palm, Socratea exorhiza with its aerial prop roots that have spines. It can grow more props to move toward the light of a gap in the forest when it is young. The other is a food producing palm, Welfia regia that has a large set of hanging structures with the palm nuts hanging on the outside. When it is empty and falls on the trail the locals call the structure the octopus.

4:28 The howler sometimes sounds like a big hound dog that has treed something, but he usually makes a raspy croak while inhaling and exhaling.

4:31 the temperature has dropped to about 78 and the breeze finally has reached ground level. Howlers are still intermittent.

Wow! I just about got hit in the face by a speeding hummingbird! He moved by my face so fast I hardly got a look at him.

A Welfia palm in front of me has a strangler fig that reaches about to the beginnings of its fronds. I think it is about 20 m high and the fig reaches about 16 m. The lower leaves are oblate and the middle leaves are arrow head shaped and larger, about a foot long. The upper leaves are oblate again.

4:44 A rubber tree is about 75 m away and the fruit has already attracted toucans. The leaves are alternate and large. The fruit is about 4 cm in diameter and flattened from the terminal end to the stem end. Bark is grey with dark patches.

4:50 Cow or bull lowing in the distance. Bird calls repeatedly. High whistle is followed by two short bell like whistles. 0 = whole note, Q = quarter note then the call is 0 QQ Long bell like call to SE is chiming in, length is three quarter notes.

4:59 Chatter of mealy parrots, little wren feeding under the strangler fig due S of me. sun is nearly gone, but tentative ID is white breasted woodwren.

5:10 The night chorus is beginning, but it doesn’t seem as noisy as one that I heard in the Amazon of Peru over 17 years ago. I still hear trucks on the highway and that damned cow.

Oropendula calling to the west. Leaf cutters working again. They don’t use the trail at my feet very much or the nest is very deficient of workers. Haven’t seen them since about 3 PM. Some rocker with a boom box is driving by on the highway across the river.

5:20 A peccary just walked down the hill to my right about 5 m away. She crossed in front of me, ate a Dieffenbachia leaf and continued down the hill.

5:40 Moved up the hill overlooking the river to find Fletch and head for dinner before all light is gone. Saw lots of peccary and howlers in the tree overlooking the river, 1 adult male, two females a juvenile and a young on the back.

Saturday, July 28, 2001

4:15 AM nearly tripped over a turtle on the trail at SOR 300. At SOR 400 made photo of a small armadillo. It got spooked and ran away.

5:02 Light rapidly increasing. I hear a broad-billed motmot close by. Its almost light enough to see what I am writing without a light. I haven’t used the headlamp since sitting on the root of the same ceiba tree that I studied yesterday. Big frogs calling to S and ESE down by the pond. Peepers calling from low shrubs in every direction, hard to tell exactly where they are. Doves coo. Frogs to W chime in now. Fungus here is glowing white with dawn’s first light. Some types locally do phosphorescence that looks like jungle night lights, a faint glow visible after your headlamp has been out for a minute or so. What is the reason for such a large expenditure of energy? Does anyone know?

5:08 Peeps, frogs still calling. Another motmot calls to the N by the river. All the tree trunks are now visible as dark silhouettes.

5:10 Howlers roar to the N by the river. Repeated Whistles of a bird to the N and E. A single long note with an upward inflection at the end. Repeated three times. Water has been dripping from the canopy since I sat down here this morning. There is a fog that partially obscures the distant trees. It is more like a haze.

5:17 Large frogs have ceased their calls. Peepers still chirping. One bird continues his one note call. A TAP TAP announces the presence of a large woodpecker on his signal tree to the S. Just two quick taps are followed by silence. Wait two, fifteen, seventeen seconds, then again. The tapping was recorded until 5:41. The variation between taps was apparently random. Occasional pauses of half a minute but usually only a wait of 5 to ten seconds.

5:30 Susan and Jenelle passed by on the trail. I can hear Jenelle’s boots flopping down the path and caught a glimpse of her to the S on the CCL trail.

5:39 Howlers roaring in unison N by river where Susan has started her observations.

5:47 Morning calls continue; clacks, squeaks, whistles, howls, TAP TAP, cacophony.

Large cicada buzzed my face and lit on the buttress of the ceiba tree to my left about 2.2 m up on the side. Calls are diminishing.

6:18 Variegated squirrel doesn’t seem bothered by my photo attempts. He is back lit so they won’t be good. He is eating Welfia seeds.

6:32 Squeals and screams to the S. Loud rustling in the brush, then silence. The squirrel has stopped feeding and is listening too. He has a charcoal tail, rufous belly and feet, back is a mix of the two.

6:37 Another crash to the S. Again and again. Squirrel disappears. Monkey in tall tree to the S is rushing at the others around him. They rush off to the SE. He stands his ground. A mother with a little one on her back is staying near him. Damn peccaries have moved close to me, within 4 m. At least 4 are here and they stink so bad it is hard to breathe. It’s also hard to watch the movements in the trees with peccaries at your feet. Woodcreeper lands on a vine on the kapok and zooms away after one quick photo.

7:04 Mealy parrots are in the rubber tree to the SE. At least four monkeys are moving toward the tree. They swing with their tail, hands or feet on anything that is handy. They do use the vines to swing across openings.

7:11 Monkeys are directly overhead now. Parrots are fussing.

Several hundred fruit flies are swarming the white fungus now. Monkeys are moving toward the fruit tree on the edge of the clearing by Rafael’s house, a well known location at La Selva. It is abandoned.

7:25 Monkeys are back overhead but several are moving back toward the rubber tree to my SE.

7:57 A laughing call from one monkey makes me realize that they have all been silent since the fight at 6:45.

8:20 I moved to CCL trail to get the light at my back to photograph the monkeys not collecting in the rubber tree from several directions. There were 12 in the tree at one time. Got a photo of the rubber tree fruit.

8:45 All is silent. I can see one monkey from my ceiba tree root. The have eaten lots of fruit and seem to be taking a siesta. I can only see one monkey. He is in a fork apparently asleep. Occasionally he scratches.

8:54 toucans arrived near rubber tree, but seem reluctant to feed so close to the monkey sleeping in the tree.

9:26 Silence. The monkey still sleeps. A breeze is beginning. A few white clouds are forming to the east and SE. Still all blue to the west.

9:30 Two green flies buzz my arms. Are they hungry? I am. It’s time for breakfast.

Study of a Natural Area

La Selva Biological Station

Costa Rica, July 2001

Dave Fletcher's Notes Susan Sprenke's Notes David Lesley's Notes

Saturday, July 28, 2001