Archive for the ‘Milky Frog’ Tag

Pluvial Songs   6 comments


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

After four months of continual sun and no rain the weather briefly changed.  Over the course of the last week the clouds had been gathering, a portent of what was about to happen.  There were several nights with a brief light drizzle, not enough to dampen the ground but just enough to wash the layer of dirt covering the plant leaves.  Then one night the sky grew dark and a heavy shower dropped enough water to soften the hard, dry ground.  Finally, one afternoon a really heavy deluge poured out of the heavens, two and a half inches is as many hours.  Immediately the Fitzinger’s Rain Frogs, (Craugastor fitzingeri), started calling.  This was to herald a sudden coming to life of several amphibian species.

Fitzinger's Rain Frog. Felipe del Bosque. Osa Peninsula. Costa Rica.

Fitzinger’s Rain Frog, (Craugastor fitzingeri)

Over the next few hours the calls of the Milky Frog, (Trachycephalus venulosus), began increasing in number and intensity.  The sun was setting, the daily environmental trigger that stimulates the frogs into emerging from their daytime hiding places, but over the dry season only one or two individuals of few species.  Now, however, a greater number of participants was joining the choral gathering.

Milky Frog. Philip Davison.

Milky Frog, (Trachycephalus venulosus)

The Banana Frogs, (Dendropsophus ebreccatus), which for the past four months had been restricted to a solo, forlorn crooner was now accompanied by many more to form a backing group.  The loud nasally calls of the Masked Smiliscas, (Smilisca phaeota), entered to swell the ever-increasing cacophony.  All semblance of rhythm, cadence and orchestration disappeared as more and more frogs entered into what was becoming a free for all, each male trying to drown out his neighbor.  Up in the tree tops the Red-eyed Green Tree Frogs, (Agalychnis callydryas), were chirping from all quarters.  Down on the ground boomed the loud whooping of Savage’s Thin-fingered Frogs, (Leptodactylus savagei).  The sound of a mini jackhammer that is the mating call of the Marine Toad, (Chaunus marinus) along with the chucking calls of the rain frogs completed the din.

As the evening progressed, it was however, the calls of the Milky Frogs that became so intense that they could be heard from some distance away.  The ruckus continued well into the night.  The next morning the surface of the pond was covered in a gelatinous film containing the eggs of the milky frogs.  These are some of the fastest developing amphibian eggs I have ever encountered.  Within 24 hours the tadpoles have hatched and entered the water where they can be observed as wriggling black swarms just beneath the surface.  After several weeks they will be seen everywhere as tiny, newly emerged froglets sitting on the vegetation surrounding the pond.

Sadly for the amphibians, that one wet night was all they got.  The next day it was back to normal dry season conditions.  It won’t be long before the rains truly arrive though.  One other creature to be seen around the pond at night, sleeping on top of the vegetation are the juvenile Green Iguanas,  (Iguana iguana), newly hatched.  Their comatose, lime-green bodies can be found at the ends of the long branches but a lingering flashlight beam will soon stir them into a state of semi-consciousness ready to jump off and run away at the slightest disturbance.  If you are lucky you will also catch sight of the newly emerged Common Basilisks, (Basiliscus basiliscus).  They are harder to see as they sleep vertically and are more muted in coloration.  The hind legs sticking out sideways from the stems where they sleep is quite often a giveaway as to their presence.

Green Iguana. Sauria. Felipe del Bosque.

Green Iguana, (Iguana iguana)

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

Flying in the Face of Mystery   5 comments


Felipe del Bosque Blog April 15th 2013

title copy

Water Music

There has been a little more rain falling over the course of the past week.  More particularly there was one night with more rain than has been experienced recently.  It rained all night at a steady light drizzle and that was enough to dampen the trails and refresh the plants.  It also served to fool the frogs which burst into action thinking the summer had ended.  The night following the rain the Milky Frogs, (Trachycephala venulosa) came out in huge numbers.  The sound of their calls could be heard from some distance which upon approaching the pond became deafening.  The grassy areas away from the pond were the scene of an exodus by Savage’s Thin-fingered Frogs, (Leptodactylus savegei), whose patience had been tried by their noisy cousins and were consequently moving off to quieter and less boisterous locations.

Milky Frog

The males were out in force.  Wherever you looked there were calling frogs.  They were calling from the vegetation above the pond and most numerously in the water.  They were grabbing hold of anything that came near in the hope that it was a female.  Enough of the males must have found a female because the following morning the pond surface was covered with Milky Frog eggs.  These frogs must take advantage of short term breeding pools because the tadpoles develop into the free swimming stage overnight.  In two days the pond was filled with a writhing black mass of tadpoles.

Trachycephala venulosa

The crabs are always stimulated into action during the dry season if there has been even the slightest amount of precipitation.  Having had several nights of light rain the forest floor has been alive with crab activity.  But following two or three days of drying weather they disappear down their burrows once again.

Pigging Out On Cats

There has been one cat spotted on the grounds of the lodge last week.  A female Puma, (Puma concolor), was seen on the driveway by the Titi Trail entrance.  It was mid afternoon and she was just standing at the side of the road oblivious to the presence of humans passing by.

The small herd of White-lipped Peccary, (Tayassu pecari), is still wandering the grounds.  They have been in the same location for five weeks now so it could be that they are going to stay.  They regularly pass by the front of the restaurant on their way to the Pacific Trail where there is a fig tree fruiting.  There is a lot of monkey activity in this particular tree and with monkeys being wasteful feeders they are throwing a shower of half eaten fruits to the ground which is keeping the peccaries well fed.

There has also been another fig tree fruiting in front of the cabins near the restaurant.  This has resulted in daily influxes of different species of monkey, some of which are all in the same tree at the same time, presenting some easily accessible and wonderful photographic opportunities.

The Western Red Bats, (Lassiurus blossivillii), are still roosting between the dried leaves of the thatch.  Last week one female was observed with two baby bats suckling.  The Tent-making Bats, (Uroderma bilobatum), have also been seen under several tents that have recently been created near the restaurant area.

Tent-making Bat Roost

Hanging out At The Pond

Roseate Skimmer

With the sun still shining brightly on a daily basis the water from the pond has been progressively evaporating.  With no rain to replenish the volume, the water level has dropped.  The vegetation sitting on the surface of the water and surrounding it at the back provide perfect perches for the dragonflies and there are always several species present in greater or lesser numbers.  There are two large red species, the Roseate Skimmer, (Orthemis ferruginea), and a king skimmer, (Libellula herculea), that take the prime upper landing spots, chasing away anything that dares to try and usurp their positions.  There is a smaller species, blue in color, a tropical dasher, (Micrathyria ocellata), which prefers to establish itself on the lower growing vegetation.  If you sit and watch you will see the dragonflies land, rest and then quickly take to the air, hovering over the water ready to chase off any other individual invading their space or ready to snatch an unsuspecting meal from the air.

Tropical Dasher

Katydids always make fascinating subjects due to their multifarious forms and colors.  They all have the distinctive katydid shape which is not too dissimilar to the grasshoppers and crickets t which they are closely related.  It is the divergence from that general body plan that makes them so compelling.

Katydid         Katydid         Katydid

Many of the katydids are green in color and resemble the vegetation in which they can be found feeding.  Then there is a movement away from simply mimicking the color of the surrounding leaves into more elaborately disguised forms.  The wings start to take on the distinct appearance of the leaves themselves, veins and all.  The leaves mimicked can be broad or narrow and the veins are now accompanied by cross veins and pits.  The leaves then turn brown and the katydid takes on the form of a dead leaf.  Theses leaves start to have patches of mould and fungus as well as holes ripped in them and amazingly evolution has copied these features exactly until it is almost impossible to tell the katydid apart from the long dead and now decaying leaf it so closely resembles.  This particular individual was at a point of looking like a dead leaf but not yet with all the other accoutrements.

One thing to be aware of when looking under leaves for subjects to photograph is the presence of paper wasp nests.  They are very common around the grounds and come in all sizes and shapes.  This was a large tubular shaped nest that was established under a palm frond and is being continually added to thereby extending its length.

Polybia Paper Wasp Nest

The nest is a papery structure constructed from a pulp that wasps produce by chewing up woody material.  Occasionally they remove the very bottom layer and add to the sides so the tube grows to accommodate the ever increasing number of wasps and the new combs.  The covering to the nest identifies these wasps as belonging to the genus Polybia.  The individual wasps might be small in size but they sting and they do pack a punch.  If disturbed during the day they can defend the nest with a great deal of ferocity.

Flowers and Fruit

There are several distinctive fruits that can be seen around the grounds and in the forests of Bosque del Cabo at the moment.  One of them can be found by the pond and there are many people who have obviously never seen a pineapple in the wild who mistake it as such.  This is the fruit of the Screw Pine, (Pandanus sp), which is native to Australia.  They are commonly grown in tropical regions for their spectacular decorative qualities.

Pandanus sp fruit

Just opposite the pond there are several of Costa Rica’s national trees, the Guanacaste, (Enterolobium cyclocarpum).  The fruit is very distinctive and the Latin name of the tree pays double homage to the fruits; Enterolobium refers to the fruits resemblance to a lobe of the intestine, while cyclocarpum describes the seed pods curled circular structure.

Guanacaste fruit

During the months of December and January the Ajo or Garlic Trees, (Caryocar costaricense), were in flower.  Their bright yellow flowers, borne at the tree tops, give off the scent of garlic which attracts in the nectar feeding bats and they subsequently serve to pollinate the tree.  Once the tree has been pollinated the fruits are produced which fall to the ground.  They are green and stalked with a squashed oval shape.  They have a very oily pulp which is rich in fat and is relished by rodents.  For this reason it is as well not to venture too close to the base of the Ajo Trees while they are fruiting as the increased presence of rodents does not go unnoticed by the snakes, particularly the large dangerous pit viper known as the Terciopelo, (Bothrops asper).  They sit motionless amongst the buttress roots of the tree blending in perfectly with the fallen leaves waiting to ambush any small rodent passing by.

Ajo fruit

Flowering nearly all year round in the Bosque gardens is a plant most people would associate with Hawaii, the Frangipani, (Plumeria rubra).  This is in fact a plant of Central America and not native to the Polynesian islands at all despite their use in the manufacture of the leys.  Near the Bosque restaurant are two color forms, the more commonly seen yellow flowers and these ones in vivid deep purple which would appear to be a cultivar.

Plumeria cultivar

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

Mystery Flight

On the Zapatero Trail atop a juvenile palm leaf close to the ground a nest appeared this week.  Every time the nest was approached the bird sitting on it flew off.  The nest is small and made up of very fluffy vegetative material, which without taking a closer look, would appear to be the soft downy filling of the balsa fruits.  The nest was obviously that of a hummingbird, the question being which species.

White-necked Jacobin nest         White-necked Jacobin nest         Florisuga mellivora eggs

As the nest was approached the bird would fly off, slowly and very low to the forest floor.  The tail feathers would be spread wide revealing white edging.  The bird also flew so slow that it appeared to be almost suspended in the air and being pushed forward.  Following several occasions where the bird would leave upon approach I did finally manage to sneak up on it and get to see enough of the diagnostic features that allowed me to identify it as a female White-necked Jacobin, (Florisuga mellivora).  There were two tiny jelly bean-like eggs sitting in the nest so it will be interesting to see if the nest, eggs, chicks and bird survive.

Another flying creature that proved to be something of a mystery was a butterfly that was observed near the entrance of the Zapatero Trail.  It landed facing down on the trunk of a small tree.  I managed to get some good photographs but that did not initially help in its identification.

Over the past thirteen years I have inventoried over 360 species of butterfly on the grounds of Bosque del Cabo.  That has been at ground level, if I had the time and funding to set up canopy traps that number would surely have increased dramatically as many of the butterfly species are only to be found at the tops of the trees.  It stands to reason that on occasion should one find itself at ground level that it would be a no more than a fortuitous chance encounter.  So many of the 360+ species I have recorded are individuals that I see once or twice but never again.

With this individual I was fairly confident I knew what I had at least as family was concerned and it would take just a quick look through my reference library to get the species.  Well looking at plates in one book after another then visiting online reference sites I was somewhat baffled by the fact that I could not find anything remotely resembling the species I had photographed earlier in the day.  As of posting this blog, the search continues.

Mystery Butterfly

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 0.01 ins.  Total Weekly Rainfall 0.08 ins

Average Daily Rainfall 0.3 mm.  Total Weekly Rainfall 2.0 mm

Highest Daily Temp 91°F.  Lowest Daily Temp 77°F.

Highest Daily Temp 32.8°C.  Lowest Daily Temp 22.6°C.

Species List for the Week

Mammals

  • Mantled Howler Monkey
  • Spider Monkey
  • White-faced Capuchin Monkey
  • Common Tent-making Bat
  • Western Red Bat
  • White-nosed Coati
  • Agouti
  • Red-tailed Squirrel
  • White-lipped Peccary

Birds

  • Red-lored Amazon
  • Scarlet Macaw
  • Great Curassow
  • Crested Caracara
  • Mangrove Black Hawk
  • Lineated Woodpecker
  • Wedge-billed Woodcreeper
  • Black-hooded Antshrike
  • Chestnut-backed Antbird
  • Short-billed Pigeon
  • White-tipped Dove
  • Rufus Piha
  • Long-billed Hermit
  • Blue-crowned Motmot
  • Blue-crowned Manakin
  • Red-Capped Manakin
  • Chestnut-mandibled Toucan
  • Bright-rumped Atilla
  • Buff-rumped Warbler
  • Dusky-capped Flycatcher
  • Great Kiskadee
  • Great Tinamou
  • Black-throated Trogon
  • Masked Tityra
  • House Wren
  • Black Vulture
  • Turkey Vulture

Reptiles

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

Amphibians

  • Banana Frog
  • Black and Green Poison Arrow Frog
  • Fitzinger’s Rain Frog
  • Golfo Dulce Poison Arrow Frog
  • Marine Toad
  • Milky Frog
  • Red-eyed Green Tree Frog
  • Savage’s Thin-fingered Frog

Butterflies

  • Antirrhea philoctetes
  • Archaeoprepona demophon
  • Caligo atreus
  • Caligo eurilochus
  • Colobura dirce
  • Dione juno
  • Dryas iulia
  • Heliconius erato
  • Heliconius ismenius
  • Heliconius sapho
  • Hermeuptychia hermes
  • Marpesia furcula
  • Mechanitis polymnia
  • Mesosemia zonalis
  • Morpho helenor
  • Morpho Menelaus
  • Opsiphanes tamarindi
  • Philaethria dido
  • Pierella luna
  • Pyrgus oileus
  • Strymon megarus

Plants

  • Alamandra  cathartica Flowering
  • Alpinia purpurata Flowering
  • Apeiba tibourbou Fruiting
  • Arachis pintoi Flowering
  • Arundina graminifolia Flowering
  • Attalea rostrata Fruiting
  • Bauhinia variegata Flowering
  • Brosimum utile Fruiting
  • Caryocar costaricense Fruiting
  • Cascabella thevetia Flowering and Fruiting
  • Citrus spp  Fruiting
  • Clusia rosea Flowering and Fruiting
  • Clusia vallerii Fruiting
  • Cocos nucifera Flowering and Fruiting
  • Crestentia alata flowering and Fruiting
  • Costus speciosus Flowering
  • Couroupita guianensis Flowering and Fruiting
  • Dypsis lutescens Flowering and Fruiting
  • Etlingera elatior Flowering
  • Ficus citrifolia Fruiting
  • Ficus insipida Fruiting
  • 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
  • Inga spp Fruiting
  • Ixora coccinea Flowering
  • Lantana camara Flowering and Flowering
  • Lagerstroemia speciosa Fruiting
  • Morinda citrifolia Fruiting
  • Musa acuminate Flowering and Fruiting
  • Nephelium lappaceum Fruiting
  • Pachira quinata Flowering
  • Piper auritum Flowering and Fruiting
  • Piper nigrum Fruiting
  • Piper umbellatum Flowering and Fruiting
  • Pleiostachya pruinosa Flowering
  • Plumeria rubra Flowering
  • Psychotria sp Fruiting
  • Stachytarpheta frantzii Flowering
  • Zammia sp Flowering

 

 

It Sounds Like Fishing For Fruit   4 comments


Felipe del Bosque Blog April 23rd  2012

Wet’n Dry

The weather this week has been more or less as the week before.  There has been some rainfall but not a lot and the rain that we have had has been interspersed between days of clear skies and sunny conditions.  In fact the sunny conditions prevailed as the week progressed.

One unusual feature that seems to accompany the start of the rainy season is the water in the creeks, which at this time of year is already at a low level, suddenly drops as the rains begin. This would seem to be counter intuitive; more water falling from the sky you might think would then finds its way into the creeks and consequently the levels rise.  My theory, and I would stand to be corrected on this point by any hydrologist, (I would dearly love to hear from a hydrologist on this point is one is reading), is that the initial rains soak only the top levels of the soil.  If it only rains for a few days followed by dry days then the high temperatures and dry atmosphere might cause increased evaporation at the top soil level resulting in water being drawn up from lower levels by suction and capillary action reducing the amount percolating into the creeks through the springs.  This is just an idea not necessarily a fact, I have to do some more research on this one.  But the fact remains, the rains have started and the creek levels have dropped.

Gone Fishing

One night when I had no takers for the night tour, I decided to go to the pond alone and try to photograph some of the amphibians.  While I was looking for some suitably placed subjects, I noticed a single Cat-eyed Snake, (Leptodeira septentrionalis), sitting on the rocky edging to the pond.  I usually try to get pictures of the head and front end of snakes as being rather linear animals is not easy to get them all in the frame unless you are stood some way back.  This individual was in a semi curled position so I thought I could get some close pictures of all the body.

         Cat-eyed Snake         Cat-eyed Snake

As I set up the camera, the snake slipped over the edge, head down with its tongue constantly flicking in and out, searching the surface of the water.  Lying just beneath the surface were hundreds of Milky Frog tadpoles resulting from the adults that had emerged en masse, paired up and spawned on the first evening of rain a week or so earlier.  The eggs had hatched within two days and now, no more than two weeks later, the tadpoles had started to grown legs.

It was the seething mass of tadpoles that was attracting the attention of the snake.  Cat-eyed Snakes can be seen throughout the year in greater or lesser numbers, (greater during the height of the amphibian breeding season, June – August).  They are specialist feeders on frogs and frog eggs, but tadpoles will make an acceptable substitute when the other options are not readily available, such as now at the back end of the dry season.

Cat-eyed Snake         Red-eyed Green Tree Frog Eggs         Cat-eyed Snake

The snake would approach the water, about 6 inches below the pond edge.  The seething and shimmering mass of tadpoles were lying on the tops of water plant leaves directly below the surface.  It was the movement of the plants that was attracting the snake’s attention.  The fishing could not have been simpler.  Open mouthed the snake simply had to strike out a few millimeters in front of it and a snack would be obtained.

Cat-eyed Snake

Following the consumption of each and every tadpole caught, the snake would withdraw on to the flat rock edge and rest for a couple of minutes before eating again.  There weren’t just tadpoles, it was readily devouring the small froglets that had emerged from the water and were sitting on the Water Lettuce above the surface.

Cat-eyed Snakes are nocturnal snakes with large eyes that have vertical pupils that look just like the eyes of a cat which give the snake its name.  During the height of the amphibian breeding season they can be seen in numbers sometimes in the region of 40 or 50 at the back of the pond, moving over the vegetation but with their heads underneath looking for the eggs of the Red-eyed Green Tree Frogs.  Frogs eggs are a perfect protein packed meal which neither fights back nor runs away.

The Cat-eyed Snakes are venomous but they are rear fanged and the venom has the potency to kill little more than a frog.  They are not inclined to bite so pose no danger to visitors to the lodge.  I sat watching and photographing this individual for about 45 minutes and then left to let it continue its amphibian rich banquet.

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

Batman

While out on a tour through the forest, one of the guests with me noticed what she thought might be a bat hanging from a small fallen branch close to the ground.  Closer inspection through my binoculars revealed that she was in fact correct, it was indeed a solitary bat roosting out in the open a couple of inches from the ground.

Short-tailed Fruit Bat

Costa Rica is a very small country, about the size of West Virginia.  On the mainland United States there are 44 species of bat, which without exception are all insectivorous.  Costa Rica has probably 111 species of bat of which 80 species are estimated to live on the Osa Peninsula.  Here we have insectivorous, nectar feeding, fruit eating, carnivorous, fishing and blood feeding bats.

Short-tailed Fruit Bat

Bats are the second most diverse order of mammals after the rodents, but inversely to rodents, there are more species of bats in the tropics and more species of rodents at higher latitudes.  Costa Rica is only 0.03% of the land surface of the earth but contains 12% the total bat diversity of the earth so it is a very special country as far as bats are concerned.

Short-tailed Fruit Bat

The way the bat we were looking at was hanging made it difficult to identify any further than family.  I could see it was one of the Leaf-nosed Bats, family, Phyllostomidae.  We continued walking but I had the intention of returning after the tour with a camera to try and get some closer photographs.

Short-tailed Fruit Bat

When I returned from the tour, I quickly ate lunch and then headed back out with the camera to get the photos of the bat.  It was still in the same position at the same location, suspended from a small dry twig, on top of a live Leaf-cutter Ant nest surrounded by fallen branches.  I could get a picture from some distance, but to try and identify the bat I needed to get close.

I shot a few exposures from about 6 feet away, then progressively made my around 360° trying to obtain images from all angles.  Then I moved in closer, gently removing some of the branches that were in front of the non moving creature obscuring a clear image.  Eventually I had to lie down on the ant nest to get the profile close up of the head.  This final action drew the wrath of the Leaf-cutter soldiers who commenced carving through my flesh and drawing blood.  Needless to say, I took the photos as quickly as I possibly could.

When I returned to my cabin it was time to identify the bat and that is no easy task.  Several distinguishing features allowed me to get to the family.  The most obvious was the distinct nose leaf that I could clearly see in that profile shot that had been so painfully acquired.  This puts the bat in the family Phyllostomatidae which translates more or less literally from the Greek into “leaf opening”.  I could also see the bat had a small, almost indiscernible tail which put it in the family Carollinae – the Short-tailed Fruit Bats.

Now came the hard part, identifying the species.  One of the photographs I had taken of the ventral side, nicely revealed under the chin a central wart with a series of smaller warts lining the underside of the jaw.  So now I knew I had an individual in the genus Carollia  but that is as far as I could get.  To identify the bat to species would require me blowing on the fur to observe the depth of agouti, (the depth of gray layering in the fur) and I would also need to see the dentition.

All of the bats in the Americas are of the suborder Microchiroptera which literally means “Small Hand Wing”.  The hand of the bat is highly modified with the digits creating a specialized frame supporting an elastic membrane which forms a wing thereby transforming the bat into the only mammal which can truly fly.

As opposed to common folklore which has bats as blind, they are not, they have very good eyesight especially in low light conditions.  As well as having very good eyesight, all of the Microchiroptera use echolocation or SONAR to find their way around at night.  Some bats emit the pulse of sound through the mouth but the Phyllostomatidae emit the sound through the nose.  The specially modified flap of skin that forms the nose leaf is thought to direct the sound.

If the nose of the bat is a highly modified transmitter of sound, the ears are equally highly modified receivers of the reflected sound.  Due to the fact that air does not transmit sound very well the energy that the bat has to put into each pulse of sound to make it effective is the equivalent for the bat of listening to a jet engine, it would deafen itself.  The structure of the ear is such that whenever a pulse is emitted, the muscles in the ear close it for a microsecond and open again to receive the echo.

As may be expected, the Short-tailed Fruit Bats are fruit eaters.  They consume a variety of fruit, the structure of which can be distinguished by echo location.  There are a variety of fruit eating bats in Costa Rica and each species tends to favor a certain type of fruit.  It has been shown the preferred fruit of the Short-tailed Fruit Bats are the low growing Pipers, (related to peppers), many species of which are commonly found throughout the Neotropical forests.

One feature revealed in the photographs that is not commonly considered with the bats is a modification in the placement of the legs which allows them to hand upside down; the legs are back to front. The knees and feet face backwards to that the toes can hook of a twig or projection.  The weight of the body pulls down on a tendon which locks the toes into position so that the bat does not have to expend any muscular energy into holding on, it is gravity that does all the work.  When the bat wants to fly, is simply lets go with its toes, opens its wings and it departs into the night.

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 0.04 ins.  Total Weekly Rainfall 0.27 ins

Average Daily Rainfall 1.00 mm.  Total Weekly Rainfall 6.90 mm

Species List for the Week

Mammals

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

 

Birds

 

  • Red-lored Amazons
  • Scarlet Macaws
  • Great Currasow
  • Crested Caracara
  • Lineated Woodpecker
  • Chestnut-backed Antbird
  • Common Paureque
  • Short-billed Pigeon
  • White-tipped Dove
  • Rufus Piha
  • Blue-crowned Manakin
  • Red-capped Manakin
  • Fiery-billed Aracari
  • Chestnut-mandibled Toucan
  • Cherrie’s Tanager
  • Bright-rumped Atilla
  • Golden-crowned Spadebill
  • Buff-rumped Warbler
  • Great Tinamou
  • Riverside Wren
  • Black-throated Trogon
  • Black Vulture
  • Turkey Vulture

 

Reptiles

 

  • Barred Ameiva
  • Barred Forest Racer
  • Central American Whiptail
  • Common Basilisk
  • Five-lined Ameiva
  • Clawless Gecko
  • Golfo Dulce Anolis
  • Green Iguana
  • Northern Cat-eyed Snake
  • Salmon-bellied Racer
  • Terciopelo

 

Amphibians

 

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

 

Butterflies

 

  • Arawacus lincoides
  • Archaeoprepona demophon
  • Caligo atreus
  • Calycopis isobeon
  • Dryas iulia
  • Eurema daira
  • Eueides lybia
  • Glutophrissa Drusilla
  • Heliconius cydno
  • Heliconius erato
  • Heliconius ismenius
  • Heliconius sapho
  • Heraclides cresphontes
  • Mechanitis polymnia
  • Metacharis victrix
  • Morpho helenor
  • Morpho Menelaus
  • Philaetria dido

 

Plants

 

  • Bamboo Orchid Flowering
  • Black Alligator Tree Flowering and Fruiting
  • Calabash flowering and fruiting
  • Cannonball Tree Flowering and Fruiting
  • Cashew Flowering and Fruiting
  • Clusia rosea Flowering and Fruiting
  • Hog Plum Flowering
  • May Tree Flowering
  • Monkey Comb Tree Flowering and Fruiting
  • Mountain Rose Flowering
  • Passion Vine Flowering and Fruiting
  • Stinky Toe Fruiting

 

Bosque del Cabo April 2011 Nature Review   1 comment


Felipe del Bosque Blog April 2011 Review

The high temperatures experienced in February and March continued into April.  This year the rains came a little earlier than would normally be expected. On one or two occasions we had torrential thunderstorms occurring overnight this month.  The heavy rain caused some very large trees to fall.  One large Monkey Comb tree fell not too far from the suspension bridge.  Even though the rain was lashing down so heavily it was hard to hear anything outside your immediate vicinity, everyone standing in the bar heard that particular crash.

In response to the first rains for 4 months, the amphibians were stimulated into action.  Huge breeding aggregations of Milky Frogs, (Trachycephalus venulosus),  filled the ponds with a choral cacophony of amorous males, each calling for a mate with such voluminous gusto, that their collective sound could quite easily be heard by guests taking their evening meal in the lodge restaurant.

Trachycephalus venulosus

Trachycephalus venulosus

Although the Milky Frogs were the most numerous and vociferous of the pond inhabitants, there were other frogs too vying with them for some breeding space.  We had our first sightings for the impending wet season of the Banana Frogs, (Dendropsophus ebreccatus) and the Masked Smilisca, (Smilisca phaeota).

Dendropsophus ebraccatus

Smilisca phaeota

There are many orchids around the grounds of Bosque, unfortunately most of them growing up at canopy level, but there is one species which grows closer to the ground.  Lady of the Night, (Brassavola nodosa), can be found growing in clumps on several trees close to the restaurant.  Once or twice a year it produces long white trumpet shaped flowers that give off a sweet perfume once the sun has set.  The scent attracts in night flying hawk moths with long proboscises that can be inserted into the deep into the flower searching for the sugary nectar.

Brassovola nodosa

In comparison, one of the trees on which we find the orchid growing is the Calabash Tree, (Cresentia alata), which flowers and fruits all year round.  Also in contrast to the orchid, the Calabash is a bat pollinated tree and consequently has large pale colored, night flowering blossoms that emits the bat attracting scent of sweaty cheese.

Cresentia alata

Paper Wasps can be identified to species level by the form the wasp’s nest takes.  In general wasps in the genus Polistes have open nests while those in the genus Polybia have enclosed nests.  This nest I found under a leaf with only one female in attendance, probably the dominant reproductive female whose close relatives and nest mates may have been away foraging for food.  You can see eggs and larvae in the open cells while one closed cell contains a pupa.

Paper Wasp

Over the course of the year the numbers of butterflies fluctuates greatly.  Some butterfly species you expect to see almost every day of the butterfly season but others you only see once or twice.  It may well be that they exist in small numbers or they may be secretive or they may inhabit areas such as the canopy where it is difficult to record them without resorting to bait trapping.   Even that may not work as not all butterflies are attracted to the bait.  This particular species, (Callicore lyca), of the Biblidinae subfamily I see only on one or two occasions a year.  This individual was on the Titi Trail and I could never get close to it, the image being captured from some distance using a 100mm macro lens.

Callicore lyra

That same lens was used to capture this White Hawk, (Leucopternis albicollis), which landed above my head in one the open garden areas.  White Hawks can generally be found in the company of moving troops of monkeys.  They have no interest in the monkeys themselves, it is the insect life that the monkeys scatter as they move through the vegetation that make an easily picked off meal for this beautiful raptor.

Leucopternis albicollis

Text and Photographs are taken from the forthcoming books:

The Natural History of Bosque del Cabo by Philip Davison

The Small World of Bosque del Cabo

The Colors of Bosque del Cabo

A Children’s Guide to Bosque del Cabo Rainforest Lodge

Temperature and Rainfall

Average M Temp High 94°F.  Average Daily Temp Low 74°F.

Average Daily Rainfall 0.04 ins.  Total Monthly Rainfall 1.28 ins

Average Daily Temp High 34.3°C.  Average Daily Temp Low 23.0°C.

Average Daily Rainfall 1.0 mm.  Total Monthly Rainfall 32.5 mm

 

Milk Is Not the Solution   4 comments


Felipe del Bosque Blog April 24th 2011

The last few weeks have been so busy that it has been almost impossible for me to sit down and write up my daily nature diaries in the form of a blog.  Now, with spring break and Easter over, I should be able to get back to normal.  This blog is the summary of all that has happened in the natural world forming my immediate surroundings over the last three weeks and so the species lists and total rainfall figures may seem somewhat inflated compared with my recent weekly summaries.

Curious Cats and Kinkajous

Over the past three weeks, there have been several Puma, (Puma concolor), sightings at various locations around the grounds.  Leaving the hotel one night after work, the restaurant employees saw a young male Puma on the main driveway by Casa Miramar.  He stood in the middle of the road and then headed into the undergrowth and watched the departing staff from the safety of the dense low growing vegetation.  Some visitors saw a Puma on the Titi Trail and yet another one, or perhaps the same individual, was spotted in the Citrus Garden behind the restaurant.

Kinkajou, (Potos flavus), activity has started to increase; their noisy whistles and honks adding to the nightly rustlings in the trees above your head.  After dinner, if you hear the sound of something moving in the vegetation above you, and you then direct the beam of your flashlight upwards, invariably a curious Kinkajou will run down the branch to take a look before disappearing quickly into the tree tops again.

Several mammals tend to be seen following the sunset rather than during the day.  The commonest of these are the Nine-banded Armadillo, (Dasypus novemcinctus), and the Virginia Opossum, (Didelphis virginiana), both of which I regularly observe on nightly outings with people on the Sunset Tour or when undertaking my nocturnal amphibian counts.

One morning, a noise which I had heard on many previous instances, was coming from outside my cabin, an arrhythmic thump, thump thump.  I went outside to find the cause of the sound which I knew, in fact, would be a large caviomorph rodent, the Agouti, (Dasyprocta punctata).  When danger threatens, in the same fashion as frightened rabbits, the Agouti thumps its foot against the ground.  On most other occasions this has revealed, upon closer scrutiny of the area around the disturbed rodent, a snake, generally a Boa of greater or smaller dimensions.  This time I could not find the subject of the Agoutis consternation but I am sure it was going to be around somewhere.

After The Deluge

The past three weeks has experienced some of the first heavy downpours of the impending rainy season.  There were several nights when we were subjected to some early evening deluges.

Milky Frog

The resulting reaction to this saturating stimulus is an explosion in amphibian numbers, both in respect to individuals and species.  We had two particularly intense drenchings separated by a week or so.  Both occasions drew the same response, a huge number of Milky Frogs, (Trachycephala venulosus), which seemingly arrive from nowhere, their numbers been very limited on normal count nights.  Following the heavy rain, they appear in dozens, the surface of the pond hosting a dreadful cacophony of calling males whose sole intention is to quickly find a single available female with whom to mate.  Many of them obviously succeed because the following morning the pond and floating aquatic vegetation is covered with their small black eggs.

Most frog eggs in the tropics hatch after a period of about a week, but not so the Milky Frog.  Their eggs are remarkable in as much as they hatch within 24 hours, after which the pond will be filled with small black tadpoles.  Following a further 6 – 8 weeks, the newly metamorphosed golden green colored froglets emerge from the pond.

Last year we had the first time appearance of Olive Tree Frogs, (Scinax elaeochroa), at the pond.  Their presence was of brief duration, but enough to fox me for several nights with the new calls I could not recognize until seeing one out in the open calling with gusto.  Their temporary occupation of the pond must have been successful as I have just seen a juvenile in amongst all the other pond regulars.

Not long after the vocal manifestation of the Rain Frogs heralded the approaching rainy season, the first actual rains encouraged out of hiding for the first time in five months the nightly sound of little ringing metal bells, that particular sound created by the Tink Frog.  Noticeable by their absence during the dry period, we will now have seven months of dusk till dawn chiming, their calls infinitely preferable to the dreadful din of the Milky Frogs, which thankfully only occurs once or twice at the onset of the rains.  In Spanish the Tink Frog is known as the Martallito, the little metal hammer, because its call closely resembles the tinny ring of a small hammer hitting an anvil.

One other frog to emerge in rain induced numbers are the Banana Frogs which will now be present in greater or smaller numbers at least until December.

Mating Banana Frogs

Fading Beauty

The butterfly season is on the downturn now.  Most numbers of individuals and species occur throughout February and March.  The start of the rains can severely deplete numbers seen but extended periods of sun between the showers will see the numbers rise once again but not to the peaks of the dry season.

One thing that I will notice though is the frequency at which I will encounter a few species of butterfly that I will only see maybe once or twice during the course of the year.  It is always nice to renew this re-acquaintance as well as recording species that I have previously not monitored on the grounds of Bosque del Cabo.

The swirling and frenzied clouds of Green Urania Moths are now diminishing in numbers too.  They will have mated, laid eggs, the adults are dying and the resulting new offspring upon emergence will fly off is search  of new Omphalia vine hence continuing that verdant migration back and forward throughout Central America.

One particular moth has been capturing the attention of some of the visitors walking the trails if only for its initial shock value, the Bird Wing Moth, (Thysania agrippina).  When disturbed it vacates its perch on the side of a tree trunk, taking to flight some enormous floppy bat flying away from you down the forest path only to suddenly disappear from in front of your eyes as quickly as it appeared.  If you approach slowly, you will see the moth has alighted on the trunk of the tree, its wings aligned up to down, its body horizontal.  The wings are patterned with a series of wavy lines that look to all intents and purposes like the bark of the tree.  Only the visually acute will spot them in this position.

Broken Blossoms

There is a constantly changing flux of plants flowering and fruiting.  The recent blooms of Lady of the Night Orchid have momentarily faded.  Walking through the forest you will happen upon many fallen blooms and fruits from vines, trees and their associated epiphytes.

Minute white flowers of the Hobo or Hog Plum, (Spondias mombin), carpet the forest floor like confetti from a secretive woodland wedding ceremony.  The Legato Negro is also in flower, its blooms appear to a rich prize for the Leaf-cutter Ants which harvest them from the tops of the tree crown, descend and carry them over large distances, finally returning to the nest where they will be processed into compost along with any other plant material that enters the subterranean Attine domain.

In recent weeks I have seen the bases of Ajo trees, (Caryocar costaricense), littered with their fallen green fruits.  The fruits have an oily nutritious pulp that the rodents enjoy eating.  The presence of high rodent numbers can attract in another, less welcome by some, visitor to the base of the trees, snakes, in particular, the Terciopelo, (Bothrops asper).  These large pit vipers are ambush predators that sit and wait, sometimes for days on end, for a meal in the form of a small furry creature to pass by.  It is one reason why you should check the base of trees before complacently stepping in to have your photograph taken against some of the giant buttresses.

Two species of Nutmeg Trees have recently been producing the “Golden Fruits” that give the trees their name, Fruta Dorada.  The golden fruits are the hard shelled nuts that upon ripening and splitting reveal the seed that is the nutmeg and the bright red membranous aril that surrounds it.

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

The shorted and stuttered rain induced breeding frenzy of the Milky Frogs was witnessed by many of the visitors to Bosque, some of whom could not contain their curiosity and simply had to go and investigate what was causing the unfaltering ruckus they were hearing over the course of their dinner.  For one young boy the effect was overwhelming, reducing him to tears, seriously disturbed by a sight he, (as far as he is concerned), hopefully will never witness again.

Milky Frog

It is almost impossible for me to give the spoken part of the Sunset Tour over the top of such a din, and I often have to retire to the quieter confines of the garage across the road before I can make myself heard.

Milky Frogs are the largest of the Costa Rican Tree Frogs.  They are sometimes referred to as Marbled Tree Frogs because of the handsome mottled browns and beige of the body color.  As documented above it is an explosive breeder.  I only count it in small numbers, if at all around the pond, but they are obviously there because as I have mentioned, with the first torrential rain, they come out in force, up to 50 or 60 individuals.  It is another frog that has the ability to glide from the tree tops to ground level using widely spread and heavily webbed fingers and toes.  This allows the frog to take advantage of perfect breeding conditions very rapidly.  Significantly other frogs such as the Smoky Jungle Frog were present in much smaller numbers than normal while the one off Milky Frog invasion occurred.  The males grab anything that moves and I think that overzealous behavior may have kept other amphibians at bay.

Milky Frog

When disturbed, the Milky Frog gives off from glands in its skin, a thick white secretion that can prove to be highly irritating especially if making contact with mucus membranes such as mouth, nose and eyes.  In fact it can cause temporary blindness.

It occurred to me that I should go along after dinner and photograph the event.  So after I finished up in the office, I returned to the pond at 11:00 pm.  Just as I arrived, an incredible thing happened, as one all of the frogs stopped calling.  It was so simultaneous that it seemed like an off switch had been hit.  Not only that, but as I tried to compose some exposures, the frogs made a mass exit from the water and ran up the side of the trees like small mice on amphetamine sulphate.  Within a matter of minutes the pond have had been vacated with the same alarming rapidity with which it was occupied only a few hours earlier.

Red-eyed Green Tree Frog Spawning     Red-eyed Green Tree Frog Spawn     Red-eyed Green Tree Frog Spawn

It was while I stood marveling at the truly amazing scene unfolding in front of my eyes that I noticed a pair of amplected Red-eyed Green Tree Frogs that had made their way, despite their boisterous co-inhabitants, under a low lying leaf and they were beginning to lay eggs.  I couldn’t quite get in at a good angle to record the event but managed to get at least several shots.

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 86°F.  Average Daily Temp Low 74°F.

Average Daily Rainfall 0.32 ins.  Total Weekly Rainfall 6.73 ins

Average Daily Temp High 31.2 °C.  Average Daily Temp Low 23.0 °C.

Average Daily Rainfall 7.9 mm.  Total Weekly Rainfall 166.4 mm

Species List for the Week

Mammals

  • Howler Monkey
  • Spider Monkey
  • White-faced Monkey
  • Central American Squirrel Monkey
  • Alfaro’s Pygmy Squirrel
  • Red-tailed Squirrel
  • Agouti
  • Nine-banded Armadillo
  • Kinkajou
  • Tayra
  • Puma
  • Collared Peccaries

Birds

  • Orange-chinned Parakeet
  • Red-lored Amazon
  • Scarlet Macaws
  • Grey-necked Woodrail
  • Great Currasow
  • Pale-billed Woodpecker
  • Crested Caracara
  • Laughing Falcon
  • Mangrove Black Hawk
  • Roadside Hawk
  • White Hawk
  • Magnificent Frigatebird
  • Stripe-throated Hummingbird
  • Wedge-billed Woodcreeper
  • Chestnut-backed Antbirds
  • Black-hooded Antshrike
  • Common Paureque
  • Spectacled Owls
  • Rufus Piha
  • Short-billed Pigeon
  • White-tipped Dove
  • Blue-crowned Manakin
  • Red-capped Manakin
  • Chestnut-mandibled Toucan
  • Fiery-billed Aracari
  • Cherrie’s Tanager
  • Grey-headed Tanager
  • Bright-rumped Atilla
  • Great Kiskadee
  • Masked Tityra
  • Great Tinamou
  • Black-throated Trogon
  • Slaty-tailed Trogon
  • Black Vulture
  • King Vulture
  • Turkey Vulture

Reptiles

  • Barred Ameiva
  • Four-lined Ameiva
  • Central American Whiptail
  • Green Iguana
  • Golfo Dulce Anolis
  • Central American Smooth Gecko
  • Clawless Gecko
  • Mediterranean House Gecko
  • Boa constrictor
  • Cat-eyed Snake
  • Litter Snake
  • Salmon-bellied Racer
  • Terciopelo
  • Tropical Bird-eating Snake

Amphibians

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

Butterflies

  • Adelpha cytherea
  • Adelpha heraclera
  • Adelpha serpa
  • Aeria euromedia
  • Anartia Fatima
  • Anartia jatrophae
  • Anastrus naearis
  • Anatrytone potosiensis
  • Anthoptus Epictetus
  • Antirrhea philoctetes
  • Arawacus lincoides
  • Archaeoprepona demophon
  • Astraptes egregious
  • Astraptes fulgerator
  • Battus polydamus
  • Caligo eurilochus
  • Callicore lyca
  • Callimormus radiola
  • Calycopis isobeon
  • Catonephele numilia
  • Cissia confusa
  • Colobura dirce
  • Copaeodes minima
  • Dione juno
  • Dryas iulia
  • Eueides aliphera
  • Eueides lybia
  • Euphyes vestris
  • Eurema albula
  • Eurema daira
  • Glutophrissa Drusilla
  • Heliconius cydno
  • Heliconius erato
  • Heliconius hecale
  • Heliconius ismenius
  • Heliconius sapho
  • Heraclides cresphontes
  • Hermeuptychia hermes
  • Hyalyris excelsa
  • Junonia everete
  • Laparus doris
  • Magneuptychia libye
  • Marpesia berania
  • Mechanitis lysimnia
  • Mechanitis polymnia
  • Melinaea scylax
  • Mesosemia zonalis
  • Metacharis victrix
  • Morpho helenor
  • Morpho Menelaus
  • Morys valerius
  • Nastra Julia
  • Panoquina evansi
  • Pareuptychia ocirrhoe
  • Parides erithalion
  • Philaethria dido
  • Phoebis agarithe
  • Phoebis argante
  • Phoebis sennae
  • Pierella luna
  • Polites vibex
  • Pompeius pompeius
  • Pseudolycaena damo
  • Pyrgus oileus
  • Pyrrhogyra crameri
  • Quasimellena balsa
  • Rhetus arcius
  • Saliana fusta
  • Siproeta stelenes
  • Temenis laothoe
  • Tigridia acesta
  • Urbanus proteus
  • Urbanus simplicius
  • Urbanus tanna

 Plants

  • Almendra Fruiting
  • Balsa Fruiting
  • Barrigón Fruiting
  • Black Alligator Tree Flowering and Fruiting
  • Cashew Flowering and Fruiting
  • Calabash flowering and fruiting
  • Clusia Vine Fruiting
  • Monkey Comb Tree Flowering and Fruiting
  • Garlic Tree Fruiting
  • Candlestick Plant Flowering.
  • Cannonball Tree Fruiting
  • Figs Fruiting
  • Guanacaste Tree Fruiting
  • Gustavia Flowering
  • Hog Plum Flowering
  • Inga Fruiting
  • Lady of the Night Orchid Flowering
  • May Tree Flowering
  • Manglillo Fruiting
  • Nutmeg Fruiting
  • Passion Vine Flowering
  • Pochote Tree Flowering
  • Psychotria Fruiting
  • Rubber Tree Flowering and Fruiting
  • Santa Maria Flowering
  • Sombrerito Fruiting
  • Stinky Toe Fruiting
  • Ylang ylang Flowering