Parting of the Red Ways   1 comment

Felipe del Bosque Blog May 8th 2011

I Have Said It Before and I’ll Say It Again

I have stated many times in the past on this blog just how amazing this place is in terms of biodiversity.  That statement applies not only to Costa Rica, a very small country amounting to little more than .03% of this planets total land surface but containing an estimated 5% of the planets total biodiversity, but also to the Osa Peninsula which provides home to much of that flora and fauna and in particular to Bosque del Cabo, which on a daily basis produces unending access to such a wealth of variety of life.

Even though I have been based here on the 650 acres of ground that comprise the area of the lodge for 11 years, I still experience the excitement of seeing new things, almost every time I venture out onto the trails.  It might seem that after such a period of time, complacency might set in and to a certain extend that could be argued as true when it comes to seeing monkeys, coatis, agoutis, toucans and macaws, the creatures that people dream of hoping to catch a glimpse of when visiting.  For a lot of our visitors, those dreams come true, quite often within hours of having arrived, those animals occur in boundless numbers at any location on the property.  For the lucky few, we have been blessed with the good fortune of many cat sightings, some at close quarters and increasingly so, over the past year.

So it was that when I went out on my butterfly count this week I came across two birds on the Titi Trail that I knew I had never seen before.  Thankfully they did not move, but sat on a branch at eye level, no more than 3 feet away from me so that I could get a good look at them.  What I was seeing were a pair of Black-cheeked Ant-Tanagers.  This is one of the endemic species to the Osa Peninsula, you won’t see these anywhere else in the world.  Birders come and visit Corcovado National Park in anticipation of seeing one of these rarely recorded birds and here were two right in front of me.  Despite having the camera with me, conditions were not conducive to obtaining a photograph, but after 11 years of not having seen them, I was happy with yet more special memory.

What Could be so Soft and Fluffy?

Over recent weeks there has been a lot of fluffy cream colored cottony material floating around the grounds.  At first sight it would appear that a child’s soft toy has split apart, spilling its downy contents to be carried, drifting with the zephyrs that gently waft through the grounds of Bosque.  The contents of a soft toy would not be too far removed as an analogy, as that material is of the same origin.

Depending upon its source and location around the grounds the material will belong to one of three species of tree; Balsa, (Ochroma pyramidale), Barrigón, (Pseudobombax septenatum), or Pochote, (Bombacopsis quinata).

The material itself is a loose mesh composed of light fibrous strands that contain the seeds of the tree.  In all three instances they are housed initially in pods, which when ripe and burst explosively releasing the fuzz into the air.  Strong winds are rarely experienced at Bosque, so most plant seeds are dispersed by animals.  At the end of the dry season, these three trees are fruiting and all of them produce a similar but slightly different fluff, all however contain the small dark seeds which are then transported away from the parent plant and dispersed by the light winds.


When the climate changes from wet to dry or from dry to wet, it stimulates a response from amongst the plants and animals here.  The severity or the abruptness of the change can influence patterns of behavior.

Coming as we are to the end of the dry season, a lot of the trees are fruiting.  Noticeably this year, the Mango Trees are producing a bumper harvest which is attracting the attention of the Capuchin and Spider Monkeys.

Several weeks ago we had some torrential downpours which brought out huge numbers of amphibians.  As it the ground dried up again so did the amphibian numbers, at least until last night when another downpour, only of brief duration, encouraged another bout of sexual breeding frenzy in the Milky Frogs.

At the moment the Cannonball Tree has burst into bloom, the Fruta Dorada Trees are producing their golden fruits, containing the nutmeg seed.  The Santa Maria Trees are flowering, their bright yellow spikes proving to be highly attractive to one particular Heliconiid Butterfly, Laparus doris.

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

Ten-legged Marathon-There and Back Again

The day time temperatures started to cool, the rain started to fall, the ground was moist and the air was humid, so one day last week out they came, not just one at a time, but all together.  There weren’t just a few, there were hundreds, nay, rather thousands, hundreds of thousands, Halloween Land Crabs, (Gecarcinus quadratus).  It is this time of year, the onset of the rains that motivates these terrestrial crustaceans to take that annual pilgrimage out of the forest, down the slopes and cliffs, back to the edge of the ocean to reproduce.

The sight to start with is spectacular, the ground awash with crabs, their bright flame orange legs contrasting with the deep purple carapace, gives the appearance of a small scale parting of the Red Sea as you approach, countless numbers of crabs running to either side of you.

The prevailing weather conditions coupled to the phase of the moon prompt the migration; the females must be ready to lay their eggs on the next neap tide during the last quarter of a waning moon.

The males start first, the larger ones arriving before the smaller ones.  The females are close behind and will arrive several days later.  Rapidly the numbers of crabs grow and soon there are many more females than males.  The males are intent on making burrows to entice the females to mate, each male taking an occasional break from the melee of fighting rivals for space by taking a moisture restoring dip in the waves.  When mating is over, the males, their part in the proceedings now over, make their way up the steep slopes and return to the forest for another year.

The females remain in the burrows excavated into the lower cliff face for about 3 days, after which they start to produce eggs.  The females remain here for about 2 weeks while the approx 100,000 eggs develop in a brood pouch on the underside of her body.

The weather, time and tide have to be right, but if conditions are favorable, at the last quarter of the lunar cycle, the females make their way from the burrows down to the shore.  A neap tide, (the lowest high tide and the highest low tide), ensures the smallest tidal interchange.  The females, now heavy with fully developed eggs, gather over night, then just before dawn, with a turn in the high tide they enter the surf and millions upon millions of eggs are released into the sea.  This may occur on a nightly basis over the course of a week.

The eggs hatch and the now free swimming larvae spend a month in the ocean, progressing through a number of larval stages before emerging as small crabs.  There is a high rate of predation in the sea so only a very small percentage of those that entered will re-emerge.  These now face the arduous journey up the cliff faces and into the forests.  Here they will spend the first 3 years of their lives until having reached a certain size and sexual maturity before returning to the place of their birth.

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 88°F.  Average Daily Temp Low 76°F.

Average Daily Rainfall 0.05ins.  Total Weekly Rainfall 0.36ins

Average Daily Temp High 31.4 °C.  Average Daily Temp Low 24.7 °C.

Average Daily Rainfall 1.3 mm.  Total Weekly Rainfall 9.1 mm

Species List for the Week


  • Howler Monkey
  • Spider Monkey
  • Alfaro’s Pygmy Squirrel
  • Red-tailed Squirrel
  • Agouti
  • Collared Peccaries


  • Orange-chinned Parakeets
  • Red-lored Amazon
  • Scarlet Macaw
  • Great Currasow
  • Grey-necked Woodrail
  • Crested Caracara
  • Roadside Hawk
  • Lineated Woodpecker
  • Pale-billed Woodpecker
  • Black-hooded Antshrike
  • Chestnut-backed Antbird
  • Short-billed Pigeon
  • White-tipped Dove
  • Blue-crowned Manakin
  • Red-capped Manakin
  • Chestnut-mandibled Toucan
  • Black-cheeked Ant-Tanager
  • Cherrie’s Tanager
  • Bright-rumped Atilla
  • Great Kiskadee
  • Great Tinamou
  • Masked Tityra
  • Black-throated Trogon
  • Tennessee Warbler
  • House Wren
  • Black Vulture
  • Turkey Vulture


  • Barred Ameiva
  • Four-lined Ameiva
  • Central American Whiptail
  • Green Iguana
  • Golfo Dulce Anolis
  • Central American Smooth Gecko
  • 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
  • Smokey Jungle Frog
  • Black and Green Poison Arrow Frog
  • Fitzinger’s Rain Frog
  • Tink Frog


  • Anartia fatima
  • Battus polydamus
  • Caligo eurilochus
  • Callicore lyra
  • Calycopis isobeon
  • Cobalopsis miaba
  • Cobares portrillo
  • Cupido comyntas
  • Detritivora gynaea
  • Dryas iulia
  • Eueides lybia
  • Euptychia westwoodi
  • Glutophrissa Drusilla
  • Heliconius cydno
  • Heliconius erato
  • Heliconius hecale
  • Heliconius ismenius
  • Heliconius sapho
  • Heraclides cresphontes
  • Hermeuptychia hermes
  • Hyalyris excels
  • Laparus doris
  • Magneuptychia libye
  • Mechanitis lysimnia
  • Mechanitis polymnia
  • Mechanitis scylax
  • Morpho helenor
  • Morpho Menelaus
  • Panthiades bitias
  • Pareuptychia ocirrhoe
  • Parides erithalion
  • Philaethria dido
  • Phoebis agarithe
  • Phoebis argante
  • Phoebis sennae
  • Pierella luna
  • Pyrgus oileus
  • Pyrisitia nise
  • Quadrus cerialis
  • Staphylus mazans
  • Urbanus proteus
  • Urbanus simplicius
  • Urbanus tanna



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

One response to “Parting of the Red Ways

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  1. Another great one Philip!


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