Felipe del Bosque Blog September 9nd 2013
Light and Dark and Wet and Dry
The weather seems to be holding out. As yet the really torrential rain has not arrived. Normally by mid September the rains starts to fall continuously. Up to, and including this week, we have had a continuation of that same pattern of nice bright sunny days and a small amount of rain falling at night. The end of the week was particularly good for visitors with clear blue skies and bright sun which warmed things up and made for good hiking conditions.
Once again the cats have refused to bless us with their presence this week. In fact it appears to have been a relatively quiet week on the Titi Trail, with only the Collared Peccaries, (Tayassu tajacu), and Agoutis, (Dasyprocta punctata), making their daily appearances. The occasional Paca, (Agouti paca), Nine-banded Armadillo, (Dasypus novencinctus), and Common Opossum, (Didelphis marsupialis), wandered by but that was about all.
Snakes and Ladders
Snakes are never the easiest things to find. That may come as good news to many people but there are those who come to the tropics with the sole purpose of seeing snakes. They have read the guide books that are lavishly illustrated with photographs of many exotic serpentine forms. There are stories of huge man-eating constrictors, of deadly venomous snakes, the bite of any one species spelling instant death for the unfortunate victim. They come brandishing grab sticks and snake hooks ready to participate in a luxury of dream fulfillment. Off they go into the forest grinning from ear to ear in eager anticipation of a day crammed with new discovery only to return with the setting sun deflated and disenchanted. Maybe after sunset when the forests are dark the snakes will come out. Hopes renewed, vigor restored off they go again but arrive back some hours later with the same loss of optimism. Truth to tell there are snakes during the day, there are snakes at night, there are snakes in the trees, there are snakes on the ground, in fact there are snakes everywhere all the time, it is finding them that can be such a thankless task.
Two of the commonly encountered snakes around the lodge are the boas, (Boa constrictor), and Cat-eyed Snakes, (Leptodeira septentrionalis). The boas generally are found in very close proximity to the kitchen/restaurant area. Wherever there are people there is food. Wherever there is food there are rodents. Wherever there are rodents there are snakes. Most the boas that turn up in the restaurant area are smallish, about 3 feet or so in length. They sometimes insert themselves in the thatched roofing for a period of several days. Occasionally they can be found in the lawns or the bushes and trees in the garden at the front of the restaurant. That is what happened this week, this particular individual was seen at different locations at different times around the garden. It first turned up in the bar, then it was found at the base of a tree behind the bar. A few nights later it was encountered after dinner crossing the lawn in front of the bar and finally it settled into one of the bushes at the side of a path between the bar and the cabins.
As I have already stated, finding snakes is never an easy task but there are occasionally those who throughout their travels in Costa Rica haven’t come across one but would like to see one. In that case I always suggest going out with me at night because as much of a guarantee as I can offer I do generally find snakes in a certain location once the sun has gone down.
The Bosque pond for many years has been the breeding area for many amphibians. The pond is manmade and was originally put in as a decorative feature. Initially it only had one plant of any size growing behind it but over the years, with the exclusion of the over enthusiastic gardening team, a lot of vegetation has proliferated forming a green wall around the back and to the two sides of the pond. This in turn has resulted in the arrival and building of amphibian populations that require still water to reproduce. In the beginning a few individuals of a few species arrived to take advantage of the newly formed habitat. Progressively this was added to as more and more species arrived and their numbers began to build.
Frogs and frogs eggs in abundance, particularly during the main amphibian breeding season of June, July and August would naturally attract the attention of those creatures that feed on such things. That is exactly what happened. One of the principal predators of frogs and their eggs are Cat-eyed Snakes. During the amphibian breeding season they can sometimes be seen in numbers of up to 50 individuals cruising over the vegetation with their heads underneath the leaves assiduously searching in particular for the eggs of the Red-eyed Green Tree Frog, (Agalychnis callidryas).
Red-eyed Green Tree Frogs lay a gelatinous mass of approximately 50 eggs on the underside of the leaves overhanging the water. The eggs develop until about 7-8 days, the egg mass then liquidizes and the now developed tadpoles wriggle free and drop into the water where they will develop and grow before emerging as tiny froglets some 6 weeks later.
For a snake feeding on frogs eggs this represents the perfect food package, a high protein diet that neither fights back nor runs away. At the height of the amphibian breeding season the vegetation around the pond can sometimes seem to be a living sea of snakes. Even during the dry season when the amphibian numbers have reduced to only 1 or 2 a night, the snakes can still be found searching for a meal. At that time of year they are normally found around the pond edge waiting patiently for the froglets to emerge or even with their heads beneath the surface of the water fishing for the tadpoles.
The Cat-eyed Snakes are venomous but rear fanged which means they have to hold and chew the venom into the prey. The venom is about as toxic as required to subdue a frog. Also they are not inclined to bite so they pose no danger to anyone getting close to take a photo.
Occasionally one of the less frequently seen snakes will turn up. This week I had a Barred Forest Racer, (Dendrophidion percarinatum), cross my path. These are active non-venomous diurnal hunters and as the common name suggests they move very quickly. They have large eyes and hunt with the head held high above the ground. Any lizard or frog that makes a movement close to them has usually guaranteed its own demise. In a flash the snake will have caught and constricted its prey. With the frogs, they quite often consume the unfortunate individual alive.
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.
Little and Large
The grounds of Bosque del Cabo are not only filled with exotic tropical trees and palms but they also contain a rich variety of shrubby plants too. Many of them are grown for their decorative foliage rather than their showy blooms. A lot of the plants will be familiar to our guests as they are also commonly kept indoors as house plants at higher latitudes.
One plant that can be seen growing in forms both native and exotic is the Dumb Cane, (Dieffenbachia spp). The plant with the uniform green leaves seen growing in the forest is Dieffenbachia oerstedii. It can be found the tropical forests of Central and South America. The variegated leaf variety seen in the grounds is a cultivated form. The plant is deadly poisonous. The leaves contain crystals of calcium oxalate which certainly don’t do your kidneys any good. It is called Dumb Cane because if ingested any part of the plant will cause the tongue and mucous membranes to swell stopping you from talking, (hence Dumb Cane), and sometimes choking and killing the unfortunate consumer. It is therefore not the best plant to have in your house if you have pets or young children that like to chew on leaves. But you can walk into most of your high street plant stores and then out through the check-out with something in your hands that won’t do you a great deal of good.
There are very few animals that will eat Dumb Cane. There is one though that does relish its fleshy leaves and stalks, the peccaries. Somehow the peccaries have evolved a metabolism that detoxifies the plant. In the forests of Bosque you will quite often see the leaves shredded and torn, the ground around the plants well churned up by peccary activity. As the plant can regenerate and grow from stem cuttings, this activity propagates yet more Dumb Cane growth.
The plant is which the Boa constrictor took refuge was another that is not so hard to identify. The leaves are long, thin and pointed like a stiletto. The plant has an overall warm tinge to it as each of the leaves are edged in red. These are the Dracaena plants.
One of the plants found lining the paths at the lodge as well as forming hedges and also easy to distinguish due to the various colors and spotty patterns to the leaves are the Crotons (Codiaeum variegatum). They are not native to Costa Rica, their origins being in South East Asia. Again they are a commonly available house plant. They should not be confused with a whole collection of plants of the genus Croton which are native to Central America but bear little resemblance to the Codiaeum despite the fact that both genera belong in the same family: Euphorbiaceae.
One of the reasons that the Crotons are so popular is the huge variety of colors and patterns produced by the decorative leaves. There are over 100 different recognized cultivars. Reds, yellows and greens in patches, splotches or spots create colorful hedges. One of the commoner plant diseases is chlorosis whereby the leaves loose the chlorophyll and end up with lots of yellow spots. It is thought that the Crotons mimic this with their coloration thereby looking diseased and consequently less appetizing to a herbivore. If the mimicking of plant disease does not put off an animal from eating the plant then it has a backup plan, it contains a toxic sap which is poisonous if ingested and can also cause eczema if it comes in contact with the skin.
Not far from the Bosque restaurant, on the main driveway, is a huge vine climbing a beautiful big Guapinol Tree. The vines leaves are enormous in size and a deep glossy green in color. But the most distinguishing feature of these leaves are the characteristic perforations.
The vine is another commonly grown houseplant. Most people would be familiar with it under a variety of names; Split-leaf Philodendron, Swiss Cheese Plant and Monstera. This is Monstera deliciosa, Family: Araceae, the same family as the philodendrons. The beautiful big split leaves are a typical feature of many an office environment. It is a plant native to Costa Rica, growing as an epiphyte on the trunks of rainforest trees. The leaves start off in low light conditions at the base of the trees as small overlapping shingles. As the plant winds its way up into the canopy where the light levels increase the leaves take on the long stalked, broad form.
Why are they full of splits and holes? The theory is that the plant is mimicking plant damage. Any herbivore would not select to feed on a leaf that is smashed, bashed and has all the appearance of having already been eaten when there is so much young fresh leaf available in the near vicinity. If that doesn’t work, like so many plants in the same family the leaves contain more of those toxic crystals of Calcium Oxalate.
The name deliciosa derives from the fact that the fruit of the plant, which takes up to a year to ripen is just that, having the delicious flavor of mixed banana and pineapple. But beware, the unripe fruits are as toxic as the leaves and even the ripe fruit can cause a reaction in certain people.
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 0.40 ins. Total Weekly Rainfall 2.82 ins
Average Daily Rainfall 10.2 mm. Total Weekly Rainfall 71.6 mm
Highest Daily Temp 89°F. Lowest Daily Temp 73°F.
Highest Daily Temp 31.7°C. Lowest Daily Temp 22.8°C.
Species List for the Week
- Central American Squirrel Monkey
- Mantled Howler Monkey
- Spider Monkey
- White-faced Capuchin Monkey
- Common Tent-making Bat
- Western Red Bat
- Northern Raccoon
- White-nosed Coati
- Vesper Rat
- Nine-banded Armadillo
- Common Opossum
- Collared Peccary
- Mealy Amazon
- Orange-chinned Parakeets
- Red-lored Amazon
- Scarlet Macaw
- Grey-necked WoodRail
- Great Curassow
- Pale-billed Woodpecker
- Black-hooded Antshrike
- Chestnut-backed Antbird
- Short-billed Pigeon
- White-tipped Dove
- Long-billed Hermit
- Crested Owl
- Red-capped Manakin
- Chestnut-mandibled Toucan
- Bright-rumped Atilla
- Great Kiskadee
- Great Tinamou
- Black-throated Trogon
- Black Vulture
- Turkey Vulture
- Barred Forest Racer
- Boa Constrictor
- Cat-eyed Snake
- Central America Smooth Gecko
- Clawless Gecko
- Golfo Dulce Anolis
- Litter Skink
- Mediterranean House Gecko
- Pug-nosed Anole
- Tropical Bird-eating Snake
- Banana Frog
- Black and Green Poison Arrow Frog
- Fitzinger’s Rain Frog
- Gladiator Frog
- Marine Toad
- Red-eyed Green Tree Frog
- Savage’s Thin-fingered Frog
- Small-headed Frog
- Tink Frog
- Anartia fatima
- Dione juno
- Eueides lybia
- Glutophrissa drusilla
- Heliconius erato
- Heliconius hecale
- Heliconius ismenius
- Heliconius sapo
- Hermeuptychia hermes
- Mechanitis polymnia
- Morpho helenor
- Morpho menelaus
- Phoebis sennae
- Pierella helvina
- Pierella luna
- Polites vibex
- Pyrgus oileus
- Urbanus simplicius
- Alamandra cathartica Flowering
- Alpinia purpurata Flowering
- Apeiba tibourbou Flowering
- Arachis pintoi Flowering
- Cascabella thevetia Flowering and Fruiting
- Citrus spp Fruiting
- Clusia rosea Flowering
- Cocos nucifera Flowering and Fruiting
- Costus speciosus Flowering
- Cresentia alata Flowering and Fruitin
- Dypsis lutescens Flowering and Fruiting
- Fius citrifolia Fruiting
- Ficus insipida Fruiting
- Guaterria amplifolia Flowering
- Heliconia chartacea Flowering
- Heliconia latispatha Flowering
- Heliconia pogonantha Flowering
- Heliconia psittacorum Flowering
- Heliconia rostrata Flowering
- Hibiscus rosa-sinensis Flowering
- Hymenaea coubaril Fruiting
- Hymenocallis littoralis Flowering
- Heisteria acuminata Flowering
- Ixora coccinea Flowering
- Lantana camara Flowering and Flowering
- Musa acuminata Flowering and Fruiting
- Plumeria rubra Flowering
- Psychotria sp Fruiting
- Spondias mombin Fruiting
- Symphonia globulifera Fruiting
- Zammia sp Flowering