How The Mighty Have Fallen   3 comments

Felipe del Bosque Blog June 5th 2011


Right on Time

You could hear it coming, like a distant train rapidly advancing, the sound got louder and louder.  The Howler Monkeys became perturbed and started to loudly voice their disapproval.  And then it hit, a wall of water, thrashing the vegetation as it fell with great force from the sky.  All sounds of nature were now obliterated by the torrential downpour.  Only this downpour lasted most of the day.  Eventually having delivered 3 inches of rain from the time when it started in mid afternoon, to when it let up late into the evening.

This is the kind of precipitation we can expect for the next few months.  Thankfully it normally occurs in the evening when everyone has sat down to eat in the restaurant.  But it does mean that the paths are now going to become sticky.  This was the first occasion of 2011 when I have had to don the rubber boots.

Over the following nights, the intensity of rain never lessened.  One night, overnight, there was just over 6 inches of rain adding to a 24 hour total of 10 inches.  The ground, already being saturated, could not hold any more water and so the run off was flowing like a shallow river over the lawns.  By morning the rain had stopped and the sun was shining once again.

Fading Out The Sound

The butterfly numbers continue to decrease as we advance further into the wet season.  The amphibian numbers remain high.  Tink Frogs and Banana Frogs are out in force every evening, their distinctive calls audible only until the rain comes down, when they tend to get drowned out.

One of the events triggered by the increasing precipitation is the nuptial flights of the ants and termites.  The reproductive termites leave the nest at dusk and their nuptial swarms will congregate anywhere where there is a light source.

The Leaf-cutter Ant reproductives tend to leave the nest early in the morning following a night of torrential rain.  At the beginning of the wet season, the established queen in the nest lays eggs which will be taken away by the queen’s attendants to brood chambers where the prevailing environmental conditions result in genetic masking of certain genes thereby causing the development of the new queens.  The new queens are huge, bearing little resemblance to the other ants in the nest.  They also have wings, which the other ants do not.

At the same time as the new queens are being raised, the resident queen also starts laying unfertilized eggs which will become the males, they too are winged.  Coming as they do from unfertilized eggs, the males only have one set of chromosomes, the new queens have two.

When conditions are right, the new queens and the males leave the nest together and the air is filled with huge flying ants.

May in June

The eye-catching bright yellow blooms of the Mayo Trees that decorated the forest canopy for the past few months have faded and died.  Their work has been done though, attracting insect pollinators, as those same trees are now starting to produce fruit.

There are still many fruits to be found on the forest floor.  The bright red aril surrounding the nutmeg of the Fruta Dorada instantly stands out.  The yellow pyramidal blooms of the Santa Maria continue to blossom in the lower levels and forest edges.

Philip is a biologist, writer and photographer as well as the onsite naturalist guide at Bosque del Cabo Rainforest lodge on the Osa Peninsula, Costa Rica.

 Photo Feature

Recent heavy rains have caused a lot of tree fall.  Many of the trees that become unstable during the dry season still have the benefit of being “cemented” into the ground by the hard soils.  Once the rains do arrive they soften up the ground.  Trees that were precariously balanced now have the rains adding a burden of weight to the crown that often results in the tipping of that balance and down the tree goes, all of a sudden and without warning.  This is what happened last week when a huge Milky Tree, (Brosimum utile), fell across the path to the Tropical Garden.  The falling botanical behemoth knocked down four other trees as it crashed to the forest floor.

Giant Milky Tree Falls

The trail maintenance team was quick off the mark.  Armed with chainsaws and long levers, they cut a section through the tree which they rolled to one side, once again opening up the path even before lunch was over.

Quick Path Clearance

Milky Trees are named from the copious sap they exude when the bark is damaged.  It is bright white in color and has the runny consistency of cream rather than milk.  It is used by native peoples who tap the tree, collect the sap, which upon hardening is used like chewing gum, one of the original sources of chicle.  The bark is also taken off in large sections, steeped in the water for several days until it is leached.  The bark is then dried and beaten with sticks until it becomes soft and pliable with a nap not too dissimilar to towling, at which point it can be used as blankets or in the making of ceremonial clothing.  One recent discovery of interest is that the sap from the root bark has yielded a cytotoxic isoflavone, which has subsequently been found to be an effective treatment for breast cancer, prostate cancer and colon cancer.

This is why it is called a Milky Tree

Anyway, I took the opportunity to photograph the now fallen giant.  As the wood has no great value outside of very light construction and laminates, the Bosque construction team had no interest in the tree other than clearing the section from the path. The rate of decay here is very rapid.  High temperatures and humidity provide an excellent incubator for bacteria and fungi which launch a nonstop attack on the fallen wood.  Then you add to the mix the beetle larvae and termites which will help reduce a solid tree to mush in matter of two years or so.

I will try to photographically record the progressive rotting of the tree by taking a picture at the start of every month.  It will be interesting to see just how quickly the recycling takes place.

Text and Photographs are taken from the forthcoming book:

The Natural History of Bosque del Cabo by Philip Davison

Temperature and Rainfall

Average Daily Temp High 83°F.  Average Daily Temp Low 73°F.

Average Daily Rainfall 2.33 ins.  Total Weekly Rainfall 16.32 ins

Average Daily Temp High 27.8°C.  Average Daily Temp Low 22.3°C.

Average Daily Rainfall 59.2 mm.  Total Weekly Rainfall 414.1 mm

Species List for the Week


  • Howler Monkey
  • Spider Monkey
  • Capuchin Monkey
  • Red-tailed Squirrel
  • Agouti


  • Red-lored Amazon
  • Scarlet Macaw
  • Great Currasow
  • Roadside Hawk
  • Lineated Woodpecker
  • Black-hooded Antshrike
  • Chestnut-backed Antbird
  • Short-billed Pigeon
  • Red-capped Manakin
  • Chestnut-mandibled Toucan
  • Great Tinamou
  • House Wren
  • Black Vulture
  • Turkey Vulture


  • Barred Ameiva
  • Four-lined Ameiva
  • Green Iguana
  • Golfo Dulce Anolis
  • Clawless Gecko
  • Mediterranean House Gecko
  • Cat-eyed Snake
  • Terciopelo
  • Tropical Bird-eating Snake


  • Marine Toad
  • Red-eyed Green Tree Frog
  • Banana Frog
  • Masked Smilisca
  • Milky Frog
  • Small-headed Frog
  • Smokey Jungle Frog
  • Stejneger’s Dirt Frog
  • Black and Green Poison Arrow Frog
  • Fitzinger’s Rain Frog
  • Tink Frog


  • Anartia fatima
  • Cupido comyntas
  • Detritivora gynaea
  • Dryas iulia
  • Eueides lybia
  • Heliconius cydno
  • Heliconius erato
  • Heliconius hecale
  • Heliconius ismenius
  • Heliconius sapho
  • Heraclides cresphontes
  • Hermeuptychia hermes
  • Hyalyris excels
  • Laparus doris
  • Magneuptychia libye
  • Mechanitis polymnia
  • Morpho helenor
  • Morpho Menelaus
  • Pareuptychia ocirrhoe
  • Parides erithalion
  • Philaethria dido
  • Phoebis sennae
  • Pierella luna
  • Pyrgus oileus
  • Urbanus simplicius
  • Urbanus tanna



  • Astrocaryum Palm Fruiting
  • Black Alligator Tree Fruiting
  • Calabash flowering and fruiting
  • Clusia Vine Fruiting
  • Monkey Comb Tree Flowering and Fruiting
  • Candlestick Plant Flowering.
  • Cannonball Tree Flowering
  • Figs Fruiting
  • Inga Fruiting
  • May Tree Flowering
  • Manglillo Fruiting
  • Nutmeg Fruiting
  • Psychotria Fruiting
  • Rosa del Monte Flowers
  • Rubber Tree Fruiting
  • Santa Maria Flowering
  • Stinky Toe Fruiting
  • Ylang ylang Flowering

3 responses to “How The Mighty Have Fallen

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  1. Really like the idea of photographing the tree once a month, will be interesting to see it change over time. Great photos as always. Sounds like I will definitely be bringing my rain jacket!


  2. Love the frog pic :)…….and the info on the tree was most interesting, I too will look forward to watching its decay processs.


  3. Howdy,

    Is it possible to use the picture of the fallen “crying” tree in a report about the Amazon and climate? Who took it? I’ll appreciate if you grant permission for use. Thanks


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