Eating Thin Wet Snails

Felipe del Bosque Blog May 21^st  2012

Inevitable Change

The wet season is truly upon us..  We are now seeing the normal pattern of rainfall, which at this time of year can be erratic; sunny for several hours followed by heavy rainfall and then more sun.  Bosque has once again turned green.

Along with all the new fresh growth goes the old growth.  Some of the larger trees that have stood in place for decades and have aged, feel the burden of weight imposed after heavy rainfall and down they go.  It is not a slow process, there will be a crack, snap and bang down goes the tree in a matter of seconds, the critical point having been reached and exceeded.  It doesn’t have to be the whole tree, more often than not it will be a large branch that breaks and falls.

The falling trees and branches at first may seem destructive.  Falling trees knock over other trees which in turn knock down more trees as they fall.  As branches tumble from the canopy they snag and tear down vines which are entwined throughout the vegetation so dislodging yet more of the plant life.  But this is all part of the succession of regeneration that has occurred on an annual basis over millennia.

The falling trees and branches open up gaps in the canopy and spaces on the ground thereby presenting an ideal opportunity for re-growth.  Those pioneering species whose seeds lie dormant within the soil are stimulated by the now increased temperature and light levels afforded by the gaping hole in the forest canopy, they germinate and rapidly grow to fill the light gap.  All of those shade tolerant saplings that grew to a certain size, stopped and then progressed to storing a lot of energy in their roots are now liberated from the confines of darkness.  They had waited in a state of suspended animation for this situation to arise and when it does up they go fuelled by the potential energy saved for this moment.

The fast growing pioneer species will have flowered and fruited several times before the shade tolerant species overshadow them.  It will then be their turn to produce flowers in the canopy, have them pollinated and then produce a wealth of fruit over many years.  But eventually the ultimate fate of death, for whatever reason, will befall them, over they will go and the cycle will be complete.

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.

www.bosquedelcabo.com

Photo Feature

Slim Shady

This week was a good snake week.  The Tropical Bird-eating Snakes, (Pseustes poecilonotus), were out in force.  There were several individuals of varying size around the bar area.  Due to the excited behavior of one particular female Cherrie’s Tanager, (Ramphocelus costaricensis), I am pretty sure she had a nest in the area.  True to their name, the bird-eating snakes show up as if by magic when there is an occupied nest with potential food in the form of eggs or chicks.

One lunch time a young couple who were staying at the lodge found a snake in the same vicinity that the bird-eaters had been skulking, so when I was informed there was a snake close by, that is what I imagined I was going to find.  When I got to the low lying bush in which the snake had been seen to enter, I was pleasantly surprised to find the long, slender, cordlike body of a Brown Vine Snake, (Oxybelis aeneus).

                 

As the name suggests, the vine snakes closely resemble the vegetation in which they can be found winding their way through.  For that reason, despite the fact that they are reasonably common, they are not that easy to find.

The slender body shape and brown coloration allows them to make their way stealthily towards their preferred prey, the various species of anolis lizards.  An unwary lizard will be unaware of the approaching danger until the snake strikes but by that time it is too late.

The body shape and color as serve to disguise the snake from its predators.  If something does get too close, the Brown Vine Snake opens its mouth wide, exposing a very dark interior and then strikes out repeatedly at its aggressor.  It is however non poisonous and poses little threat to humans.

Towards the end of the week, the new manager of Bosque, Andreas, brought in a snake that he thought might be one of the cat-eyed snake species.  When I had a look, I could see the very blunt nose of a snaileater but I didn’t immediately know which species.  The grey ground color of the body was ringed with bands of black edged in orange.  There was the clue, the diagnostic feature which allowed the snake to be literally identified as an Orange-banded Snail-eater, (Sibon dimidiatus).

                 

This was the first snail-eater I had seen in 12 years at the lodge.  One of the reasons that they may not be encountered too often is the fact that they are nocturnal and arboreal, so unless you are in the tree tops at night, the chances of seeing one are slim.  True to their name, the main item on the diet of these snakes is gastropod mollusks.

In so many years at Bosque I am still thrilled when a new animal or plant turns up.  Many of the butterflies and snakes I have inventoried at Bosque I have only ever seen once.  I would suggest that there is probably a more thriving population than just one, although it could be with the butterflies they were just passing through, but I doubt it.  Still, the incredible diversity of these forests is brought to bear from this once in a lifetime encounters.

Text and Photographs are taken from the forthcoming book:

The Natural History of Bosque del Cabo by Philip Davison

Temperature and Rainfall

Average Daily Rainfall 0.56 ins.  Total Weekly Rainfall 3.93 ins

Average Daily Rainfall 14.3 mm.  Total Weekly Rainfall 99.8 mm

Species List for the Week

Mammals

• Howler Monkey
• Spider Monkey
• Capuchin Monkey
• Agouti
• Alfaro’s Pygmy Squirrel
• Red-tailed Squirrel
• White-nosed Coati

 

Birds

 

• Mealy Amazon
• Orange-chinned Parakeets
• Red-lored Amazons
• Scarlet Macaws
• Crested Caracara
• Great Black Hawk
• Roadside Hawk
• Chestnut-backed Antbird
• Black-hooded Antshrike
• Common Paureque
• Short-billed Pigeon
• White-tipped Dove
• Blue-crowned Motmot
• Long-billed Hummingbird
• Rufus-tailed Hummingbird
• Blue-crowned Manakin
• Red-capped Manakin
• Fiery-billed Aracari
• Chestnut-mandibled Toucan
• Cherrie’s Tanager
• Grey-headed Tanager
• Rufus Piha
• Buff-rumped Warbler
• Dusky-capped Flycatcher
• Golden-crowned Spadebill
• Great Kiskadee
• Great Tinamou
• House Wren
• Black-throated Trogon
• Black Vulture
• Turkey Vulture

 

Reptiles

 

• Barred Ameiva
• Boa Constrictor
• Brown Vine Snake
• Central American Whiptail
• Common Basilisk
• Five-lined Ameiva
• Golfo Dulce Anolis
• Northern Cat-eyed Snake
• Pug-nosed Anole
• Terciopelo
• Tropical Bird-eating Snake

 

Amphibians

 

• Banana Frog
• Black and Green Poison Arrow Frog
• Fitzinger’s Rain Frog
• Golfo Dulce Poison Arrow Frog
• Marine Toad
• Masked Smilisca
• Milky Frog
• Red-eyed Green Tree Frog
• Smokey Jungle Frog

 

Butterflies

 

• Calycopis isobeon
• Dryas iulia
• Eueides lybia
• Glutophrissa drusilla
• Heliconius erato
• Heliconius ismenius
• Heliconius sapho
• Heraclides cresphontes
• Marpesia furcula
• Morpho Menelaus
• Opsiphanes tamarindi
• Parides erithalion
• Philaetria dido
• Pyrgus oileus
• Pyrisitia nise
• Urbanus simplicius
• Urbanus tanna

 

Plants

 

• Bamboo Orchid Flowering
• Lacmellea panamensis Flowering and Fruiting
• Crestentia alata flowering and fruiting
• Cannonball Tree Flowering and Fruiting
• Cashew Flowering and Fruiting
• Clusia valerii Fruiting
• Gustavia brachycarpa Flowering
• Apeiba toubouru Flowering and Fruiting