Archive for the ‘Stejneger’s Dirt Frog’ Tag

BEETLES: HIDING IN CLEAR VIEW   6 comments


Wildlife, nature, fauna and flora of Costa Rica.

It has been another week of sunny days and rainy nights.  Last month the immediate area experienced almost 28 inches, (706 mm), of rain.  That is approximately 1 inch per day.  However, as to be expected, the pattern of precipitation was not that evenly spread.  There were several nights with really heavy downpours which accounted for a third of the total.  There were more nights when it rained hard but not in a deluge and then there were nights when there was no rain.

Atop Cabo Matapalo, at 500 feet, (150 m), above sea level, there is little chance of flooding, all the water is runoff.  This time of year the ground is saturated so when there is a torrential downpour the water may remain on the surface forming large areas of standing water which quickly drains away.  The creek water level is high and rushes down the channels, falling over rapids, cascades and waterfalls and finally flowing into the sea.  After a night of very heavy rainfall, the creek will have turned murky brown with the volume of sediment it is carrying.  Given a few days of sun the water will have returned to its crystal-clear state, inviting you to plunge into its cooling depths as a relief from the hot and humid atmosphere of the forest.

A Typical Rainy Season Day In The Forest

You wake in the morning, opening your eyes but still not fully conscious.  You had a good night’s sleep, restful and undisturbed, but were brought out of your slumber by a distant roaring sound.  It is still dark outside so what time is it?  Early, pre-dawn, and the roar is heard again, this time joined seconds later by a response, louder roaring but much closer to your cabin.  All of a sudden the roars are echoing around the forest.  To many, the first-time visitors to a Central American rainforest, this could only be large ferocious beasts gathering to collectively do you harm.  To the more savvy, seasoned visitor this is a familiar wake-up alarm call, Howler Monkeys, announcing their location to one another so that different troops can keep their distance during the course of the day.

It did its job as far as you are concerned, you are now fully awake.  The first light of dawn starts to brighten the sky, throwing the form of the trees into dark silhouettes.  Here you are only 8⁰ north of the equator so the dawn twilight does not last for long.  The sun rises rapidly and the grey sky turns blue.  The birds are awake now.  Flying overhead are noisy macaws and parrots heading off from their roosts to the feeding grounds.  Their squawking and screeching is not the most melodious of avian calls.  From within the forest the Chestnut-backed Antbird, Black-hooded Antshrike and the Bright-rumped Atilla are some of the first choristers to greet the new day.   The males are vocally drawing up the bounds of their territories.

It is after breakfast and the sun is now high in the azure sky.  The temperatures have rapidly risen from the cool chill from when you opened your eyes.  The air is still.  You grab your camera and head off into the shade of the forest.  The only sound is that of cicadas, their loud calls increasing in intensity, volume and pitch as the morning progresses.  Here and there from different points in the unseen depths of the forest, obscured from your vision by the trunks of the trees are more birds calling.  The familiar “Who cooks for you” of the Short-billed pigeon, the high-pitched squeaky call of the Black-mandibled Toucan, it sounds more like a rusty pulley that needs oiling than the call of a bird.

You see many things close at hand to photograph, flowers, fruit, a beetle, a praying mantis, small frogs and lizards.  Up above you the Spider Monkeys put on an impressive display of acrobatics as they swing through the tree tops.  You can’t miss Spider Monkeys with their high-pitched chattering and high-energy crashing through the tree tops.  This is in complete contrast to the languid slow moving and deeply voiced Howler Monkeys.  You come across a troop of White-faced Monkeys, more leisurely in their pursuit of a meal.  You see them peeling away bark and turning leaves, always gleaning, looking for the small creatures that make up the bulk of their diet.

It is approaching midday.  The sun is directly overhead.  Despite being beneath the shade of the canopy, the temperatures have risen dramatically.  Combined with the high humidity, conditions have become like those in a well stoked sauna.  If the air was still outside the forest, within its confines there is not a breath of air.  The sweat is rolling down your face and your clothes are now soaked.  Thankfully you brought a lot of water with you and a packed lunch.  Time to take a break for some respite in order to recover you waning energy levels.

As you sit, taking in the sounds around you, a rumbling can be heard off in the distance, thunder.  You finish your sandwiches, take a swig of water, pack everything into your bag and head off down the trail once more.  You stop to photograph a line of Leaf-cutter Ants.  You need to get close to the ground and have some patience to capture the individual caste members.  You are rewarded a little later with a swarm of Army Ants, incessant in their drive forward flushing out non-flying arthropods.  They are accompanied by a mixed flock of ant-birds, woodpeckers, woodcreepers and Grey-headed Tanagers, all in a heightened state of excitement as they feed on the flying insects driven out of hiding by the Army Ant assassins.  Lots of photographic opportunities here.

It is now much later; the almost unbearable temperatures have dropped and the sun is sinking fast towards the western horizon.  Also, that rumbling is getting louder and the sky is rapidly darkening in the east.  You have filled your memory card with images so it may be astute to pick up the pace now and head back to base.  Before too long a breeze picks up and the tree crowns begin to sway.  Loose leaves and small twigs come tumbling down from the canopy.  It is rapidly darkening and the breeze becomes a wind.  The trees are now swaying more violently and you can hear branches being snapped and crashing down.  All of the monkeys start to shriek in objection to their homes being shaken in this manner.  The advancing storm has no ears and cares not for their protestations. Light rain begins to fall.

Within a shorter time than you would have liked, the sky above you has turned black.  The rumbling thunder has become loud and explosive, now accompanied by almost instantaneous flashes of lightning.  The rain comes out of the heavens with an ever-increasing intensity.  The canopy is being lashed.  Leaves and branches are torn from the trees by the sheer weight and force of the water being poured upon them.  Lightning is cracking and fissing around you, the storm is immediately overhead, these are thunderflashes and this is not a safe place to be.  The path at your feet which moments earlier was soft and damp is now a running river albeit only a couple of inches in depth.  The question is should you stop and find shelter or should you persevere on.  You chose the latter option.

Your step quickens, not too fast as you don’t want to slip and fall.  You hear a sharp crack above you, then a loud snap and a huge branch comes tumbling with force through the understory.  It hits the ground so hard that it stands upright as if it had been planted.  The flashes are lighting up the whole sky in a blinding white light.  Each boom of thunder causes you to flinch.  It is raining so heavily that you can barely open your eyes due to the stinging pain it causes you.  But you are almost there, the path out of the forest is up some stairs and around a bend on the trail.  The steps are now a series of cascades but the tumbling water does not hinder your stride.  You will soon be back in the dry comfort of your cabin.

Just as you step out of the forest and into the open garden area, the driving rain suddenly subsides to that of a light summer shower.  The black sky starts to lighten and the deep rumbles roll off into the distance.  Each flicker of lightning is still causing flashes but now over on the horizon.  Thankfully you had the foresight to pack all of your equipment into a waterproof camera bag before the deluge descended and it seems to have served its purpose well.  The rain becomes drizzle and finally peters out then stops.  The sky is now pale grey and the sun sinks to the point where the final rays light up the underside of the clouds in a deep orange.  You have just experienced a typical September day in a Costa Rican rainforest.

Beetles Hiding In Clear View

Beetles, there are thousands of species and yet if you go out with the intention of finding them you may become aware very quickly that they are not as obvious as you have thought.  Turning over rocks or peeling rotten bark from fallen trees may produce one or two species but nothing in profusion.  That is why when I head off into the forest it is never with the purpose of photographing anything specific, not unless I have seen something that I wanted to return to.  Some people go out having birds or mammals as their goal, I am always looking for smaller things, as regular readers of the blog will already know.  The camera will have my favorite 105mm macro lens attached and will be set to take photos of all manner of mini beasts in darker conditions.  The shots will be hand held as I only take the tripod if I have a certain subject in mind.

Last week I found two different species of beetle out in the open aspect of a sunny forest edge.  They were in separate locations but within the same area.  They were both sitting on top of a leaf, in bright sunshine and would not stay still.  I had to keep maneuvering around the subject to try and get a decent image.  Every time I had things set, they would turn their backs to me and wander off along the opposite length of the leaf.  Finally, after much repositioning, I managed to obtain some acceptable photographs.  One of the problems with photographing beetles is the hard, smooth and glossy exoskeleton that many of them have.  It reflects the light from the flash gun.  To obtain the depth of field that I prefer, with a moving subject I have to use very small apertures and by necessity I need to add extra light with flash.

The first beetle is a Pleasing Fungus Beetle, (Cypherotylus asperus), in the family: Erotylidae.  I am not sure why they are pleasing but fungus beetle refers to their main dietary item which may come as no surprise, fungus.  The bright red blotches against a black background is aposematic, or warning coloration.  If molested or attacked, the Pleasing Fungus Beetle emits a foul-smelling odor that would cause most would be predators to back off.

Rainforest animals. Rainforest insects. Rainforest Beetles. Coleoptera. Erotylidae. Cypherotylus asperus.

Pleasing Fungus Beetle, (Cypherotylus asperus)

The second beetle is a Leaf Beetle in the family: Chrysomelidae.  They typically have the domed body, clubbed antennae and are multi-colored.  But as there are almost 50,000 species in this family I have, so far, been stumped as to which species this is.  Should any beetle expert be reading this and would like to provide a name I would be most grateful.  The clue to the diet is once more in the name.  They feed on the leaves of a variety of vegetation.

Rainforest animals. Rainforest Insects. Beetles. Coleoptera. Chrysomelidae.

Leaf Beetle, (Chrysomelidae sp)

The Earth Moved

Walking through the forest you can often have your attention momentarily attracted by some small movement down in the leaf litter.  It may be ants, spiders, lizards, frogs or a myriad of other small creatures that live concealed beneath the carpet of rotting leaves.  It is the tread of your footfall that will disturb them and have them run for cover out of harm’s way.  Depending on the speed of the animal you may lose sight of it very quickly.  Some move from leaf to leaf.  Generally if any of these litter living denizens gets below the leaves it will be gone and unless you are lucky you will just have to imagine what you saw.  Occasionally though one will freeze when exposed to the light.  Last week, my size 13 boot thudding into the ground caused a tiny frog to jump out of the imminent descending disaster.

There are several small frogs that inhabit the dark and damp environment of the forest floor.  The squat body shape of this one revealed its identity almost immediately.  It was one of the rather delightfully named dirt frogs, this one being a Stejneger’s Dirt Frog, (Craugastor stejnegerianus).

Rainforest animals. Rainforest amphibians. Frogs. Anura. Craugastoridae. Craugastor stejnegerianus.

A tiny Stejneger’s Dirt Frog, (Craugastor stejnegerianus)

The dirt frogs are totally terrestrial frogs, they live their whole life on the forest floor and never need to go to water as many amphibians do.  They still have moist skins through which they largely breath and therefore by necessity can’t leave the confines of the damp environment under the trees.   There are several species that live in this area and Stejneger’s Dirt Frog is one of the commonest.

They belong to the family: Craugastoridae or the Fleshbelly Frogs.  Typical of this family is the reproductive habit of direct development which negates the necessity of them having to return to water to reproduce.  The frogs pair up, (I can’t say I have ever heard these frogs calling), and the female lays her eggs amongst the leaf litter on the forest floor.  There are only about 20 – 30 eggs but they are fairly large in comparison to the adults.  The egg is packed with yolk and the tadpole develops within the egg, there is no free-swimming tadpole stage.  After about 8 weeks a tiny copy of the adult emerges.

Rainforest animals. Rainforest amphibians. Rainforest Frogs. Anura. Craugastoridae. Craugastor stejnegerianus. Osa Peninsula. Costa Rica.

Dorsal view of Stejneger’s Dirt Frog, (Craugastor stejnegerianus)

As you are walking through the forest, if you keep your gaze lowered scanning the ground then you will surely see a small piece of the earth move.  Given closer inspection then you will probably find you are looking at a dirt frog.  But take a photograph as they are not always easy to identify.

Fying Dragons.

A few weeks ago I managed to photograph a dragonfly with black bases to the wings, a Black-winged Dragonlet, (Erythrodiplax funerea).  This week I managed to capture another dragonfly but with the inverse situation of having black tips to the wings, the Large Woodskimmer, (Uracis fastigiata).  This one was found in a different area to the previously mentioned species but they had been there for several weeks.  This species was found in secondary forest, in a light gap and always close to the ground.  Once again my attempts to take a picture were always doomed to failure because every time I lifted the camera to my eye, they would fly off.  But as we know with photography patience is a virtue and finally after several weeks I got lucky.  This one stayed still long enough for me to get several pictures.

Rainforest animals. Rainforest Insects. Dragonflies. Odonata. Libellulidae. Uracis fastigiata

Large Woodskimmer, (Uracis fatigiata)

Unlike the dragonflies which can be found in open sunny locations around a body of water that have fast flight and hover, these forest species seem to be more sedentary and perch on low vegetation and only seem to move if disturbed.  Having excellent eyesight adapted to detect movement it does not take much to disturb them.  It could be that they are sit and wait predators just diligently watching for the right sized meal to pass by before taking off to capture it.

Philip Davison Is a Biologist, Writer and Photographer Based in Costa Rica

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Jumping in Dutch Red Dirt   2 comments


Philip Davison Nature Diaries. Bosque del Cabo Rain Forest Lodge.

The days are now consistently sunny, hot and dry.  Changes are happening in the observable flora and fauna.  Butterfly numbers are increasing in terms of both the number of species and the number of individuals.  But the numbers are still very much lower than would be expected for this time of year.  It could well be that the extended and intense rains of November resulted in the death of many larvae and pupae.  It may take time for those numbers to recover, especially considering the continuing decline seen over the recent two decades.

This time of year is usually noteworthy for the trees and other rain forest plants coming into flower.  There is some visual evidence of several trees coming into bloom but once again not in the number or variety associated with the onset of the dry season.

One other creature notable by its absence at the moment are the cicadas.  January is regarded as the start of a three month period when, during the day at least, your eyes are subject to a continual sonic bombardment of an indescribable intensity.  The larval stage of the cicada is spent below the ground where they feed on sap from plant roots.  It is not beyond the bounds of possibility that many of the larvae were drowned thereby reducing the number of emerging adults which are generally to found in millions this time of year.  For many people that aural attack will not be missed but the ramifications on the ecosystem may have long lasting effects.

Red Alert

One feature of the transition from the wet into the dry season that is very evident as you walk through the forest at this time of year is the production of new leaf.  The feature that makes the new leaf so obvious is the color – red.  Cabo Matapalo is on the South West tip of the Osa Peninsula, Costa Rica.  The location is only 8⁰ North of the Equator.  Any sunlight hitting the earth’s surface at this latitude is therefore intense sunlight and significantly high in ultra violet radiation.  Ultra violet radiation damages developing tissue.  The plants produce a red pigment called anthocyanin which is deposited over the developing chloroplasts and protects them from irradiation.

Anthocyanin

Red is the Color of New Leaf in the Rain Forest

As the chloroplasts mature the plant reabsorbs the anthocyanin and now lays it down as a layer on the bottom of the leaf surface.  Light hitting the forest floor is only 1% of that hitting the canopy so light is of a premium.  Light hitting the leaf will pass through and be bounced off the underlying red layer and reflected back up through the leaf surface so that any light required by the plant to carry out photosynthesis it missed on the way down it will pick up on the way back through.

Many of the young leaves hang droopily facing down.  Those that have no anthocyanin and not having developed much chlorophyll, look pale and ghostly in the in the gloom beneath the canopy.  At this point they are flaccid and not until water is absorbed by the cells do they become turgid and assume their horizontal light gathering aspect.

Fatima Fiesta

One of the butterflies that exhibits very profound seasonal fluctuations is the White Banded Fatima, (Anartia fatima).  It is one of the commonest Costa Rica butterflies.  It is hard to miss with the white bands on the wings contrasting starkly with the dark brown ground color as it flies in open sunny areas such as gardens and disturbed ground.  It can be seen visiting a wide variety of nectar plants.

Whtie-banded Fatima. Nymphalidae. Nymphalinae

White-banded Fatima, (Anartia fatima)

White-banded Fatimas can be found throughout the year in greater or lesser numbers.  This week the numbers started to increase very rapidly.  In some locations there were dozens of them, all looking fresh and new.  But once they reach a peak in numbers and the short-lived reproductive frenzy is over then it will not take long for them to start to take on a tattier appearance and finally within a couple of weeks they will have more or less all gone again.  But later in the year the cycle will repeat.

Dirty Frogs

As the dry season progresses then the creatures that live on the forest floor take shelter in the moister damp conditions beneath the leaves that litter the ground during the heat of the day.  As you walk on the trails and your feet disturb those leaves that disturbance will flush the smaller creatures from their hiding places.  You will see displaced skinks, beetles and frogs seeking safe refuge from your footfall and the sunlight.

Rough-skinned Dirt Frog. Anura. Craugastoridae

Rough-skinned Dirt Frog, (Craugastor rugosus)

There are several small frogs that inhabit the forest floor.  These are the rain frogs mostly in the genus: Craugastoridae.  On the forest trails there are two species in particular that you may come across, the Rough-skinned Dirt Frog, (Craugastor rugosus), and Stejneger’s Dirt Frog, (Craugastor stejnegerianus).  The Rough-skinned Dirt Frog, as the name suggests, has a skin covered in many protuberances.  Stejneger’s Dirt Frog on the other hand has a smoother skin and a generally darker area behind the eye.

Stejneger's Dirt Frog. Frogs

Stejneger’s Dirt Frog, (Craugastor stejnegerianus)

Both these species have life histories that have allowed them to decrease their dependency on water and become more terrestrial in habit, certainly in respect to reproduction.  Whereas most amphibians must return to the water to breed, the rain frogs pair up and lay their eggs amongst the leaf litter on the forest floor.  The microclimate beneath the leaves is damper than that above which suits both the frogs and their eggs, it stops them from drying up.  Aquatic egg-laying frogs face the problem of having many predators in the water that will feed on the eggs and the tadpoles.  Rain frogs do not face the same intense predation pressure and can therefore produce fewer but larger eggs.  The larger size of the egg allows full development of the tadpole within a protective gelatinous coating.  A larger amount of yolk is provided which supplies enough sustenance for the frog to complete development and emerge four or five weeks later as a tiny copy of the adult.

Craugastor stejnegerianus. Amphibia.

Stejneger’s Dirt Frog – One too many flashes and It’s Away.

Jumping in Color

Moments after photographing Stejnegers’ Dirt Frog I noticed a tiny black speck of a leaf which moved in a very distinctive and familiar fashion.  The almost indiscernible black dot was a jumping spider.  It had turned to look at me which is how it gave away its presence.  I had to turn the camera lens on it and take same photographs to truly appreciate the amazing little creature I had in front of me.

Jumping spiders belong to the most diverse spider family: Salticidae of which there are more than 5,000 named species around the world.  In Costa Rica there is not a wealth of reference material you can consult in an effort to make an identification.  Sometimes family level is about as far as you can go.

Jumping Spider. Osa Peninsula.

Unidentified Jumping Spider, (Salticidae).

The most distinctive feature of the jumping spiders is the large anterior forward facing eyes.  These give the spider the ability to see things at close range.  They can be seen orientating themselves to watch you.  That is what this one was doing with me.  Unlike their web-building relatives, the jumping spiders hunt their prey down.  Once they identify a potential meal they will pursue it and at the last moment pounce on it, deliver the venomous bite and consume it.

Their visual abilities allow them to use coloration as a cue in mating.  The males may have brightly colored legs and pedipalps to court the females.  This species had bright blue legs and yellow pedipalps.  When a male sees a female he performs a series a ritual dance moves which include lifting his legs in a certain sequence as well as moving in a series of set maneuvers in front of her.  All the while the female is watching, scrutinizing the performance.  One blunder and she will leave having no further interest.  Each species of jumping spider has a very specific dance routine thereby negating the change of courting the wrong type of girl.

Salticidae. Spiders.

Unidentified Jumping Spider. Look at Those Eyes.

Dutch Piper

One of the most distinctive flowers of the forest understory is that of the Aristolochia vines otherwise known as the Dutchman’s Pipe Vine.  As with most flowers the sole purpose is the achieve reproduction through pollination.  Many plants have evolved ingenious means by which to use the flowers as a means to this end.  The Dutchman’s Pipe is one of them.

The flowers are named after their resemble to the carved tobacco smoking pipes used in Holland.  But to a carrion fly they look somewhat different.  Carrion flies are attracted to the fetid odor of rotting flesh.  The flowers of this species of Dutchman’s Pipe, (Aristolochia gaudotii).   give off a scent which mimics the stench of a putrefying body.  The pale yellow base color reticulated with maroon blotches visually emphasize the illusion.

Dutchman's Pipe. Aristolochiaceae.

Dutchman’s Pipe, (Aristolochia gaudotii)

The flies land but find themselves incapable of maintaining a footing on the slippery oily inner surface of the flower and slip down into the interior.  They are unable to make an immediate escape as their exit is blocked by a barrage of downward pointing stiff hairs.  They are trapped.  During the period of vegetative incarceration, the fly struggles violently in order to gain its freedom.  This results in the body becoming covered in pollen.  The following day the stiff hairs wither and the fly finds its exit clear only to fly off and respond to the same trickery.  This time it transfers the pollen thereby pollinating the flower after which it will be released from its temporary floral prison with a fresh coating of pollen.

Aristolochia gaudotii. Carrion Fly.

Dutchman’s Pipe. Looking Down Through the Prison Bars.

Philip Davison is a Biologist, Writer and Photographer Based in Costa Rica

 

Wildlife Capital of Costa Rica   3 comments


Felipe del Bosque Blog November 25th 2013

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Dry Times

It could well be the the transition is occurring.  This week began with a little rain and eventually that became less and less.  The sun was shining most days and with clear blue skies to make sure the butterflies were active.

This week I have instigated the butterfly and amphibian counts again. The project that I had been collecting data for over many years needs finishing.  Many years ago I started monitoring the dynamics of both butterfly and amphibian populations.  These were being measured against temperature and precipitation figures respectively to try and evaluate as to whether the climate of the area might be changing and if it is what affect that may have on the flora and fauna of a tropical season forest such as exists at Bosque del Cabo.

Three is the Magic Number

There have been several exciting sightings at Bosque del Cabo this week.  While conducting my butterfly counts I found a Baird’s Tapir, (Tapirus bairdii), print in the soft earth near where the trail exits onto the main driveway.  The print was very obvious due to its large size and distinctive three leaf shaped toes.  The tapir is an odd-toed ungulate an order of mammals, (Perissodactyla), that also includes horses and rhinoceroses.  There have been several records of tapirs passing through the bosque property over the years but as to where they came from or where they were going is currently unknown.

If you have been following the blog you will be aware of the fact that some months ago a small herd of White-lipped Peccaries, (Tayassu pecari), appeared in the grounds of Bosque del Cabo.  Every day they would do their rounds passing in front of the restaurant just after lunch before making their way through the mango orchard.  They could also be seen and most smelled out on the trails in close proximity to the lodge.  Progressively though the numbers dwindled.  As with the tapir we are not sure how they made it here but we were certainly glad to see them as they are normally an indicator of more pristine forest conditions.

White-lipped Peccary

Now there are two, a male and a female, who have taking a liking to the garden area in front of the restaurant.  Every day they are seen feasting on the fallen fruits of the palm trees, a variety of species which are producing small red fruits at the moment.  If approached he loudly clacks his teeth, his long shaggy hair stands on end and he runs off grunting in irritated disapproval of being disturbed.  The female is a little more relaxed and tolerates close approaches before trotting off a short way before commencing feeding.  This is one of those enigmatic animals that people hike for days through Corcovado National Park with a vain hope of seeing, along with the tapir.  Here they are in the grounds of Bosque del Cabo Rainforest Lodge for all to see while eating their breakfast.

The reason that Bosque has acquired the reputation as the wildlife capital of Costa Rica is that the 800 acres of grounds has a huge selection of habitats within which reside a phenomenal amount of biodiversity that is not too difficult to experience.  This week a three of our guests, Courtney, Che and Jermaine arrived from Texas and Los Angeles.  The first question they asked was “where can we see a Puma”.  I related a tale of a wildlife photographer who had photographed a Puma on the steps of the cabin in which they were staying.  That particular scenario was unlikely to repeat itself.  But the next day just after breakfast one of the Che was walking across the lawn and came face to face with a beautiful female Puma that was walking between cabins Congo and Mariposa.  He returned to the lodge to inform the other two guys who immediately headed over to the area where the cat had been seen, cameras in hand.  There was the Puma lying in the shade, completely indifferent to the presence of those trying to capture its image.  Many thanks to Courtney Bennett for allowing us to use the photo.

Puma

Changing Scales

There are several species of anolis lizards to be seen around the grounds of Bosque del Cabo.  Some are literally everywhere, in the buildings, in the gardens and in the forest.  The most common is the Golfo Dulce Anolis, (Norops polylepis) which is small but quite often noticed due to the males extending the bright orange flap of skin under the chin which is known as the dewlap.  A slightly smaller anolis is the Common Anolis, (Norops limifrons).  It may be a  delicate looking lizard but nonetheless is very robust in defending its territory.  The males of this species have a small snow white dewlap.  If a rival male enters its territory it will bob its head up and down furiously and then chase the potential invader away.

Norops limifrons

While the forest trails remain damp then some of the amphibian species can be seen during the day.  The Black and Green Poison Arrow Frogs can still be found in numbers on the trails by the restaurant.  On some of the longer forest trails if you watch down by your feet you will see tiny frogs of which there are several species.  These are the dirt frogs.  There are two commonly found species, Stejneger’s Dirt Frog, (Craugastor stejnegerianus) and the Rough-skinned Dirt Frog, (Craugastor rugosus).

Stejneger's Dirt Frog

The dirt frogs and the related rain frogs are totally terrestrial frogs, they don’t return to the water to reproduce.  The male and female pair up, the female lays around 10-30 large yolk-filled eggs which the male fertilizes.  The whole process of development takes place within the egg so there is no free-swimming tadpole stage.  After 7 or 8 weeks a tiny copy of the adult emerges from the egg.

Something Old, Something New

The clouds of Green Urania Moths continue to increase in number on a daily basis.  Wherever you walk numbers beyond counting take to the air.  At eye level the metallic green bars on the velvet black wings glint and shimmer as they fly from shade to sunlight and back again.  Look up above your head into the sky at tree level and you will see endless black silhouettes lazily drifting to and fro.

The continuous sunshine is bringing more and more butterflies out.  The brightly colored Heliconiids or longwing butterflies gaudily dressed in contrasting primary colors of red, orange and yellow can be seen rapidly fluttering from flower to flower.  The shocking electric blue of the Morphos easily catches the eye as they drift down forest rides and stream beds.  In the adult stage the morphos feeding on fallen and fermenting fruit.  If you should find, for example, a lot of figs that have dropped from the tree tops and are covering the ground, you will invariably find several individuals of Morpho menelaus and Morpho helenor imbibing the liquid fruit cocktail.  If they scatter upon your approach they will merely circle and alight again in the same position.

Morpho_helenor_FDB0003 copy

The morphos aren’t the only butterfly to indulge in this sylvian liquor.  Some of the satyrs will join them.  The satyrs are normally brown butterflies with wing patterns that create the illusion of dead leaves.  To this effect they fly close to the forest floor which means when they land their image is absorbed into the background and they essentially disappear from in front of the eye.  Two species seen seasonally throughout the year are Pierella luna and Pierella helvina.

Pierella luna

Metamophosis

This year I have decided to take up the data collection again regarding the project I had started some years ago.  For many years I had been monitoring butterfly and amphibian populations and trying to correlate dynamic changes in their abundance against the prevailing weather conditions in an attempt to evaluate if there is a recordable change in the climate how is it affecting the flora and fauna of a tropical lowland seasonal forest.  I started up the counts again last week.  The butterfly count takes place every Wednesday along the course of a 5 kilometer transect which is divided up into 15 habitat sub zones and is conducted once in the morning and again in the afternoon.

After observing and identifying butterflies for so long I know when I am seeing a species I have not previously recorded.  So it was last week.  A small brown object flitted from up in front of me and landed on the underside of a leaf of a low growing plant.  It would, of course, be in the muddiest part of the trail.  I sank to my knees in a in puddle of brown gooey mud and tried to lower the camera to a point where I could see the specimen which fortunately was sitting still.  I took a shot to get the all important image then slowly eased the tripod forward, shuffling along on my knees.  I progressively managed to get closer and closer each time clicking the shutter.  Due to the low aspect, dark conditions and shooting up into the light the best of the images wasn’t that brilliant but at least it gave me something to work with.

Nascus paulliniae

The butterfly could be recognized as a skipper which in themselves can be notoriously difficult to identify.  The Family is Hesperidae and this was a spreadwing skipper of the Subfamily: Pyrginae.  Now comes the difficult part, genus and species.  Not having the butterfly in my hand I have to rely on photographic comparisons in reference books.  There are lots of skippers and so many of them look the same with only minute differences in coloration or markings.  Eventually I settled on the identity of  this one being the Least Scarlet-eye, (Nascus paulliniae).  That is another new record for the lodge.

Another skipper that turned up amongst the more brightly colored butterflies at the Lantana was a Perching Saliana, (Saliana esperi).  These are small delicate looking butterflies with handsome two-tone wings.  The leading front half of the underside of the hindwing has a rich cream color with a diffuse curved border blending into the soft warm brown of the trailing half.

Saliana esperi

Trampled Underfoot

Every day I while walking around the trials or the gardens I make notes of everything I see and hear which leads to the production of the species lists below.  These are all casual observations, there is no scientific methodology as there is with the above project.  You tend to encounter the larger, louder, brighter and more obvious species more than those that don’t advertise themselves as readily.  To that end I went out to photograph some of the plants that we have around the grounds that most people would walk by and not even notice.

When it is fruiting the Monkey-comb Tree, (Apeiba tibourbou) produces the very distinctive spiny globular fruits that many people make comment upon when they find them on the forest floor.  This time of year all you will find are the old spineless shells.  But you know the new fruits will soon be appearing as the trees are bearing flowers.  The petals are a bright yellow with very hairy sepals.

Apeiba tibourbou         Crotalaria retusa         Gallinita

Another yellow flower is that borne by the Gallinita, (Crotalaria retusa). It is very reminiscent of the Lupins found in English country gardens and in fact belongs to the same family: Fabaceae.  This is normally a plant you would find in open sunny situations.  The pods look like small fat peapods.

There are several purple flowered plants in bloom around the grounds at the minute.  Brunfelsia grandiflora is a small shrubby bush native to South America that is planted in gardens throughout Costa Rica.  When they open the flowers are at first purple but these then fade and eventually end up as white.  It flowers all year long which is why it is a garden favorite.

Finally there are the sedges and grasses which are very difficult to identify to species level unless you can find a good key.  The only one that I photographed that was easy happened to be a sedge with distinct white bases to the bracts which give it the name Little Star, (Rhynchospora nervosa).

Unidentified Sedge         Rhynchospora nervosa         Unidentified Sedge

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

www.bosquedelcabo.com

 

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 0.48 ins.  Total Weekly Rainfall 3.38 ins

Average Daily Rainfall 12.3 mm.  Total Weekly Rainfall 85.9 mm

Highest Daily Temp 92°F.  Lowest Daily Temp 74°F.

Highest Daily Temp 33.3°C.  Lowest Daily Temp 23.1°C.

Species List for the Week

Mammals

  • Central American Squirrel Monkey
  • Mantled Howler Monkey
  • Spider Monkey
  • White-faced Capuchin Monkeys
  • Common Tent- making Bat
  • Common Opossum
  • Nine-banded Armadillo
  • Agouti
  • Alfaro’s Pygmy Squirrel
  • Northern Raccoon
  • White-nosed Coati
  • Collared Peccary
  • White-lipped Peccary
  • Baird’s Tapir
  • Puma

 

Birds

 

  • Mealy Amazon
  • Red-lored Amazon
  • Scarlet Macaw
  • Great Curassow
  • Roadside Hawk
  • Yellow-headed Caracara
  • Golden-naped Woodpecker
  • Lineated Woodpecker
  • Pale-billed Woodpecker
  • Black-hooded Antshrike
  • Chestnut-backed Antbird
  • Short-billed Pigeon
  • Long-billed Hermit
  • Stripe-throated Hermit
  • Blue-crowned Manakin
  • Red-capped Manakin
  • Fiery-billed Aracari
  • Chestnut-mandibled Toucan
  • Green Honeycreeper
  • Summer Tanager
  • Bright-rumped Atilla
  • Dusky-capped Flycatcher
  • Golden-crowned Spadebill
  • Great Kiskadee
  • Black-throated Trogon
  • Great Tinamou
  • Black Vulture
  • Turkey Vulture

 

Reptiles

 

  • Basilisk
  • Barred Ameiva
  • Boa Constrictor
  • Cat-eyed Snake
  • Central American Smooth Gecko
  • Clawless Gecko
  • Common Anolis
  • Four-lined Ameiva
  • Golfo Dulce Anolis
  • Litter Skink
  • Mediterranean House Gecko

 

Amphibians

 

  • Banana Frog
  • Black and Green Poison Arrow Frog
  • Fitzinger’s Rain Frog
  • Golfo Dulce Poison Arrow Frog
  • Masked Smilisca
  • Marine Toad
  • Milky Frog
  • Red-eyed Green Tree Frog
  • Rough-skinned Dirt Frog
  • Savage’s Thin-fingered Frog
  • Stejneger’s Dirt Frog
  • Tink Frog

 

Butterflies

 

 

  • Adelpha cytherea
  • Anartia fatima
  • Anartia jatrophae
  • Antirrhea philoctetes
  • Archaeoprepona demophon
  • Astraptes fulgerator
  • Chloreuptychia arnaca
  • Cithaeria pireta
  • Dryas iulia
  • Eueides aliphera
  • Eueides lybia
  • Glutophrissa drusilla
  • Heliconius erato
  • Heliconius hecale
  • Heliconius ismenius
  • Heliconius sapo
  • Heraclides cresphontes
  • Hermeuptychia hermes
  • Hypna clytemnestra
  • Junonia evarete
  • Laparus doris
  • Morpho helenor
  • Morpho menelaus
  • Nascus paullinieae
  • Opsiphanes tamarindi
  • Parides erithalion
  • Philaethria dido
  • Phoebis argante
  • Phoebis sennae
  • Pierella helvina
  • Pierella luna
  • Pyrgus oileus
  • Pyrisitia nise
  • Pyrrhogyra crameri
  • Siproeta stelenes
  • Taygetis andromeda

 

Plants

 

  • Anthurium salvinii Flowering and Fruiting
  • Alpinia purpurata Flowering
  • Allamandra cathartica Flowering
  • Apeiba tibourbou Flowering
  • Arachis pintoi Flowering
  • Arundina graminifolia Flowering
  • Attalea rostrata Fruiting
  • Bauhinia variegata Flowering
  • Brassovola nodosa Flowering
  • Brownea macrophylla Flowering
  • Brunfelsia grandiflora Flowering
  • Cascabella thevetia Flowering and Fruiting
  • Citrus spp Fruiting
  • Clusia rosea Flowering and Fruiting
  • Cocos nucifera Flowering and Fruiting
  • Costus osae Flowering
  • Costus speciosus Flowering
  • Couroupita guianensis Fruiting
  • Cresentia alata Flowering and Fruiting
  • Etlingera elatior Flowering
  • Ficus citrifolia Fruiting
  • Ficus insipida Fruiting
  • Hedychium coronarium Flowering
  • Heliconia chartacea Flowering
  • Heliconius clinophylla Flowering and Fruiting
  • Heliconia latispatha Flowering
  • Heliconia longiflora Flowering
  • Heliconia pogonantha Flowering
  • Heliconia psittacorum Flowering
  • Heliconia rostrata Flowering
  • Hibiscus rosa-sinensis Flowering
  • Hymenaea coubaril Fruiting
  • Ixora coccinea Flowering
  • Lantana camara Flowering and Flowering
  • Morinda citrifolia Flowering and Fruiting
  • Musa acuminata Flowering and Fruiting
  • Pandanus sp Fruiting
  • Pleiostachya pruinosa Flowering
  • Plumeria rubra Flowering
  • Rhynchospora nervosa Flowering
  • Spondias mombin Flowering
  • Stachytarpheta sp Flowering
  • Thunbergia erecta Flowering
  • Thunbergia fragrans Flowering
  • Tocoyena pittieri Fruiting
  • Zingiber spectabile Flowering

 

 

FROGS OF COSTA RICA: LARGEST AND SMALLEST   Leave a comment


 

Wildlife, nature, fauna and flora of Costa Rica.

The sun sets rapidly in the tropics; there is no real twilight or dusk to speak of.  Last night as the sun dipped below the horizon, the sky darkened and stars started to appear for the first time in weeks.  At this time, sitting low in the west but just above the level of the trees we are treated to the sight of Venus which is by far the brightest light in the currently moonless sky.  Venus is closely accompanied by Mars which is a little lower and has all but disappeared from view by the time it is dark.  As the evening progresses and Venus slips from view, another bright light will have risen in the east, Jupiter, which will make its way across the heavens to set before sunrise.  If the clouds permit, then the Milky Way is a phenomenal sight this time of year, arching like a translucent creamy smudge across the sky from north to south.

Today started as last night ended, not a cloud in the sky, and apart from a few scattered showers throughout the morning, that is how things stayed.  This time of year we have the daily dawn chorus of Chestnut-backed Antbirds, Black-hooded Antshrikes, Bright-rumped Atillas and the raucous din of the Scarlett Macaws.  All of this has, of course, been preceded by the early morning wakeup call provided by the Howler Monkeys.  The ruckus is normally complemented and completed by the arrival of large numbers of Red-lored Amazons, whose higher pitched squawking simply adds to the cacophony.

Walking through a rainforest after a shower certainly gives the overall impression of dampness.  It has been raining since April and so the creeks and rivulets in the forest have a constant supply of running water.  The ground is both soft and sticky under foot.  With the addition of a shower, the vegetation already dripping with moisture, now most certainly completes the visitors’ expectations of how a tropical rainforest should look.

After returning from the four hour “Primary Forest Tour” I went off to the staff canteen to get some lunch.  That was followed by a leisurely stroll around the grounds to see if any new birds and butterflies had turned up.  One did, a butterfly I had not seen before, and guess what; once again I was not carrying my camera.  Here in front of me on vegetation close to the ground was a very conspicuously patterned Metalmark.  These are small and generally insignificant butterflies, but here was one with a dark background with a concentric series of white dashes and a bright red border to the hind wing, a White-stitched Metalmark, (Napaea eucharila).  I ran over to my cabin to get the camera but when I returned, it was gone.  So, I have found two new species in one week and no images to prove it.  At least I have the images in my head and the records in my diary.

As I write, the sun is sinking one more time.  It is amazing how time flies when you are enjoying yourself.  It is a brilliant sunset, a blaze of bright red which is bathing the forest in a deep luminescent orange glow.  It is now time to head out and see what the evening brings.

Costa Rican Frogs: The Largest and the Smallest

Here we are looking at two extremes; one of the largest and one of the smallest frogs on the grounds of Bosque.

Rainforest amphibians. Frogs. Leptodactylidae. Leptodactylus savagei. Savage's Thin-fingered Frog. Felipe del Bosque. Veridion Avdentures.

Male Savage’t Thin-fingered Frog

Savage’s Thin-fingered Frog, (Leptodactylus savagei), is a veritable behemoth of a frog, second only in size to the female Marine Toad.  They are the only amphibian we know of that eats scorpions, but they are opportunistic feeders and will eat smaller frogs, snakes, really anything smaller than themselves.  Like the Marine Toad, it is very poisonous, having skin secretion called Leptodactylin.  If you handle the frog it is very uncomfortable, but if you then rub your eyes, nose or mouth, in fact any mucus membrane it can be become a very distressing situation.  They do have predators though, more or less the same predators as Marine Toads, i.e. Opossums and snakes.  To that effect they have a secondary defense.  When you catch one it will scream like a baby.  The screaming may shock the predator into letting it go or the commotion could attract the attention of any other predator in the area which subsequently may attack whatever is trying to eat the frog, but most importantly, the screams very closely resemble the alarm calls of young caiman.  If there any adult caiman in the area, they will charge in and attack the frog’s predator which will hopefully, as far as the frog is concerned, allow it to make its escape.

Savage’s Thin-fingered Frog is a foam nester.  The male comes to the water first.  He has massive front legs and gives emits a “Whoop, whoop” call.  The female joins him later, he grabs on to her with his massive front legs, he has two sharp spines on his chest which also help secure her until she is ready to lay eggs.  Once the female has spawned, the male fertilizes the egg mass and then using his hind legs he whips the eggs up with water from the pond and mucus from his body to produce froth.  The eggs develop in the froth until about 8 days at which point the froth dissipates and the tadpoles as they now are have to complete the normal tadpole stage in the water.

Rainforest amphibians. Frogs. Craugastoridae. Stejnegers Rain Frog. Craugastor stejnegerianus. Costa Rica. Philip Davison. Veridion Adventures.

Stejnegers Dirt Frog, (Craugastor stejnegerianus)

Closely related to the huge Savage’s Thin-fingered Frog is probably one of the smallest frogs in Costa Rica, the tiny Stejneger’s Dirt Frog, (Craugastor stejnegerianus).  These are tiny frogs that live terrestrially on the forest floor.  If you ever spot a slight movement down by your feet as you on the forest trails, close examination will quite often reveal a frog no bigger than your fingernail.

Stejneger’s Dirt Frog is one of the rainfrogs.  They do not need to come back to the water to breed.  They pair up and lay only 10 – 30 yolk filled eggs, fairly large in comparison to the frog, in the leaf litter on the forest floor.  The whole process of development takes place within the egg so there is no free swimming tadpole stage.  After about 8 weeks, you will find emerging from the egg a tiny copy of the adult.

So there you have it, the little and large of the amphibian world.

Philip Davison Is a Biologist, Writer and Photographer Based in Costa Rica

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