A New Year’s Heat Wave   Leave a comment


Felipe del Bosque Blog January 7th 2013

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A New Year

The dry season is upon us now.  We have had very little rain over recent weeks and that we have had has amounted to little more than an occasional short light shower with intermittent heavier showers later in the evening..  The temperatures are rising and the sun is shining all day long from dawn to dusk.  The skies are blue with rarely a cloud to be seen.

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This change in the weather stimulates a change in both plant and animal behavior.  Over the next few weeks it will be possible to see a number of trees starting to flower.  Already the Monkey Comb Tree, (Apeiba tibourbou), has been flowering and the early fruits that have fallen prematurely can be seen lying on the forest floor like small lime green sea urchins.  Later they will fall as larger brown spiny balls.

The Ajo Tree or Garlic Tree, (Caryocar costaricense), is producing its first flush of bright yellow flowers.  They don’t smell as good as they look, unless of course you have a liking for Italian food.  They give off the odor of garlic, albeit not as strong.  There is very little wind present in the forest and so the trees rely on animal agents for pollination and seed dispersal.  Bats are very important pollinators and seed dispersers which is why the plants reliant on these animal agents give off strange musky smells.  That includes the Garlic Tree which uses the scent of garlic to attract in nectar feeding bats which become covered in pollen that they then transport to the flowers of other Ajo trees affecting pollination.

Ajo Flower

Another tree with a showy display of flowers has been in bloom over the past week, the Jacaranda, (Jacaranda mimosifolia).  Its crown has been adorned with a spectacular display of small purple trumpet shaped flowers but the spectacle is short lived and now it has shed most of the flowers which lie covering the ground as a lilac carpet.  Jacaranda is not a native to Costa Rica, it is originally from Argentina.  It is however now found growing all over the world where conditions are suitable because of the colorful soft pastel lilac display set off against the green of the canopy.

Jacaranda

Sounds of the Summer

Now is the time of the mass cicada hatchings.  For 2 years the nymphal cicadas have bided their time burrowing in a mole-like fashion beneath the soil, tapping into the vascular system of plant roots and feeding on the copious sap.  They have grown in size, periodically shedding the exoskeleton before emerging and climbing up the vegetation to start the final few weeks of their lives.  To do this a profound change in the insect has to occur.

The last nymphal stage climbs up the trunk of a tree or a shrub, never very far, at the most about 6 feet or so.  You can quite often see the eerie looking hollow shells, which resemble some imaginary mediaeval beast, suspended in terminal animation, sometimes in collective groups beneath the leaves of plants,.  Down the back you will find a split in the skin where on some previous evening the adult will have swollen in size splitting the exoskeleton and then extricating itself by pulling out backwards only to emerge as a completely different looking creature.

Cicada Exoskeleton

The newly freed adult has wings that need to be pumped with fluid which flows through the veins until the clear cellophane-like material has been expanded and stretched tight.  It is now ready for flight and when ready it takes to the air making its way into the leafy canopy above.  This is the reproductive, dispersal and final stage in the life of the cicada.

Cicada

The males have two sound producing organs on the abdomen each of which is called a tymbal.  They act like the skin of a drum but instead of drumsticks beating on them it is muscular action that vibrates the membranes which results in the production of sound.  The brighter the sun and the hotter the daytime temperatures the more vigorously the cicadas call and with a greater intensity.

As we move into the mid period of the dry season, ever more cicadas emerge.  At the zenith of their activity, the sound becomes intense.  The cacophony rises and falls with each passing cloud, reaching a crescendo under a clear sky.  Later in the day as the light levels falter and dim, the cicadas reciprocate with a drop in noise levels.  Eventually they stop.  This though is only a momentary blessed relief on the ears as once the sun starts to dip below the horizon a new cicada, the Sundown Cicada, starts up to serenade the last flickering rays of sunlight filtering through the forest.  Its calling is no less intense than its daytime cousins.  But once the sun takes a final bow and darkness descends, it is as if someone has hit a switch and they all stop at one and the same instant.  Now out come the crickets and katydids to carry on the insect orchestra nocturne.

The function of the calls is to attract a mate.  When a female arrives and selects her chosen suitor, they pair up, the female subsequently lays her eggs in the bark or leaf tissue where they develop and hatch.  The larvae fall to the ground and begin the life cycle anew by tapping into the tree roots once again.

Cicadas belong to the insect Order Hemiptera, Suborder Homoptera Family Cicadidae.  In the adult stage they feed on plant sap as do the nymphs.  When walking through the forest, apart from the sound, you may well find yourself being hit by one of these insect missiles as the cicadas gyroscope doesn’t seem to function too well.  One other phenomenon witnessed by people this time of the year is what seems like a constant shower of rain despite cloudless skies.  When the cicada taps into the vascular system of the plant to feed on the sap which is under high pressure, the liquid is forced through the cicada’s alimentary canal and ejected from the rear end.  The insect will have extracted the proteinaceous element of the sap and eliminates the sugary fluid which the origin of the “rain”.

Sun Worshipers

I like this time of year when we experience the transition from wet to dry as it brings out more butterflies.  With every passing day, so long as the sun continues to shine, the butterflies increase in numbers of both individuals and species.  Many of them are freshly occluded and so their colors are vivid and intense.  There is a patch of Lantana camara not far from the restaurant which is more often than not covered in briefly alighting butterflies of many shapes and color, all taking a quick sip of nectar before moving off to the next bloom.  The yellow and orange blooms must be continually producing nectar as the butterflies flit around, one after the other visiting the same flower head.

Chlosyne theona

Fruit Salad

As the trees come into fruit it increases the incidence of monkey sightings around the producing trees.  Near the entrance to the Bosque restaurant some of the Royal Palms, (Attalea rostrata), are heavy with palm nuts.  Currently on a daily basis the White-faced Capuchin Monkeys, (Cebus capucinus), take time to visit and feed.  They will also feed on coconuts, (Cocos nucifera), many palms of which can be found fruiting year round near the Royal Palms.

It is not only the monkeys but the Red-tailed Squirrels, (Sciurus granatensis), too that enjoy both the coconuts and palm nuts.  They tend to keep a low profile when the monkeys are around but it is not too hard to find them if you look.

The bird life is as rich and varied as ever.  Reptile sightings are good but as might be expected the amphibian numbers are low.  The Black and Green Poison Dart Frogs, (Dendrobates auratus), can still be seen on the forest trails but no longer in profusion as when it was wetter.  Some of the larger frogs such as Savage’s Thin-fingered Frog, (Leptodactylus savegei), and the Marine Toad, (Rhinella marina), have started to congregate around the pond as the forest dries up.

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

Smelling You Out

Over the last week many visitors who have walked the Titi Trail have come across herds of Collared Peccary, (Tayassu tajacu).  There are many stories concerning the ferocity of these distant relatives of the pigs but they are completely without foundation, at least at Bosque.  They don’t have very efficient eyes or ears but they do have an excellent sense of smell.  Although they may have some difficulty seeing or hearing you they will have no problem determining that you are there if you are stood upwind of them.  If you are downwind they will largely be oblivious to your presence.

Collared Peccary

As it happened, one day I was out on the Titi Trail on my own looking to take photographs of whatever may present itself and relying on serendipity to provide the subject material over the course of the morning.  I am always looking for small things, most of my work is macro photography and you will rarely see photographs of mammals and birds illustrating my text.  I could hear ahead of me the sound of grunting and snuffling and it wasn’t too long before a sizeable herd of Collared Peccaries came towards me through the forest.  I stood where I was on the path and readied the camera on the tripod.  I did not move but waited until one or two of the peccaries crossed the path in front of me wholly oblivious to my presence.  I pressed the shutter, off went the flash and the startled animals leapt into the brush at the side of the path.  They weren’t quite sure as to what had happened and as curiosity got the better of them they tentatively returned, looking towards what had moments ago surprised them.  I still wasn’t moving.  Their noses lifted in the air to catch my scent but I was downwind.  Off went the flashes again which this time was too much so they scampered back the direction from which they had initially came to rejoin the rest of the herd.

Tayassu tayacu

Collared Peccaries can be found from the Southern United States down through Central American and throughout tropical South America.  They feed largely on fallen fruits and seeds as well as low growing plants.  They will also eat a small amount of animal life such as grubs, lizards and snakes.  They are usually found in herds and at Bosque have been seen in the vicinity of the Titi Trail numbering more than 20 in a group.

One the back down the road on the approach to the restaurant sitting under a palm feeding on the fallen palm nuts was an Agouti, (Dasyprocta punctata).  Agoutis are not an uncommon sight around the restaurant area on the lawns in front of the cabins.  They are caviomorph rodents related to capybaras, coypus and cavies or Guinea Pigs.  Agoutis are commonly seen around the grounds in the open areas feeding on large fallen fruits.  They are present in the forest too but not as obvious as they skulk around in the undergrowth.

Agouti

There has been a single bat roosting in the thatch of the Bosque restaurant for the past few weeks.  As the sun sets it can be seen cleaning itself and stretching its wings in preparation for its venture into the night air.  At same time as the guests to the hotel are dining in the evening the bat heads off in search of a meal too.

Unidentified Bat

It is very hard to identify bats.  First there are a lot of them, approximately 80 species on the Osa Peninsula. Without having them in hand it is difficult to scrutinize those diagnostic features vital to species identification.  Finally they tend to roost in inaccessible places so the best you are likely to see of bats is there silhouettes in flight against a darkening sky.  This one although tucked up in the thatch and therefore difficult to photograph was at least at a level where I could get a picture of some of the face.  That narrows down some of the options.  So we can see it doesn’t have a leaf nose, the ears are smaller and rounded and the fur is orangey brown.   That eliminates it from several families but I still wouldn’t like to say for sure exactly what it is.

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 0.09 ins.  Total Weekly Rainfall 0.56 ins

Average Daily Rainfall 2.40 mm.  Total Weekly Rainfall 14.20 mm

Highest Daily Temp 89°F.  Lowest Daily Temp 73°F.

Highest Daily Temp 31.8°C.  Lowest Daily Temp 23.5°C.

Species List for the Week

Mammals

  • Howler Monkey
  • Spider Monkey
  • Squirrel Monkey
  • White-faced Monkey
  • White-nosed Coati
  • Alfaro’s Pygmy Squirrel

Birds

  • Mealy Amazon
  • Orange-chinned Parakeets
  • Red-lored Amazon
  • Scarlet Macaw
  • Broad-winged Hawk
  • Crested Caracara
  • Mangrove Black Hawk
  • Roadside Hawk
  • Golden-naped Woodpecker
  • Lineated Woodpecker
  • Pale-billed Woodpecker
  • Red-crowned Woodpecker
  • Long-tailed Woodcreeper
  • Tawny-winged Woodcreeper
  • Chestnut-backed Antbird
  • Short-billed Pigeon
  • White-tipped Dove
  • Rufus Piha
  • Long-billed Hermit
  • Rufus-tailed Hummingbird
  • Red-capped Manakin
  • Chestnut-mandibled Toucan
  • Bright-rumped Atilla
  • Dusky-capped Flycatcher
  • Great Kiskadee
  • Golden-crowned Spadebill
  • Riverside Wren
  • Tennessee Warbler
  • Great Tinamou
  • Black-throated Trogon
  • Masked Tityra
  • Black Vulture
  • Turkey Vulture

Reptiles

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

Amphibians

  • Banana Frog
  • Fitzinger’s Rain Frog
  • Marine Toad
  • Masked Smilisca
  • Red-eyed Green Tree Frog
  • Rough-skinned Dirt Frog
  • Savage’s Thin-fingered Frog
  • Stejneger’s Dirt Frog

Butterflies

  • Adelpha cytherea
  • Adelpha heraclera
  • Anartia Fatima
  • Anartia jatrophae
  • Chlosyne theona
  • Dryas iulia
  • Eueides aliphera
  • Eueides lybia
  • Heliconius cydno
  • Heliconius erato
  • Heliconius hecale
  • Heliconius ismenius
  • Heliconius sapho
  • Heraclides cresphontes
  • Hermeuptychia hermes
  • Mesosemia zonalis
  • Morpho helenor
  • Morpho Menelaus
  • Pareuptychia ocirrhoe
  • Parides erithalion
  • Pierella helvina
  • Phoebis sennae
  • Pompeius pompeius
  • Pyrgus oileus
  • Pyrrhogyra crameri
  • Urbanus simplicius

Plants

  • Alamandra  cathartica Flowering
  • Alpinia purpurata Flowering
  • Apeiba tibourbou Flowering
  • Arachis pintoi Flowering
  • Arundina graminifolia Flowering
  • Attalea rostrata Fruiting
  • Bauhinia variegata Flowering
  • Cascabella thevetia Flowering and Fruiting
  • Citrus spp  Fruiting
  • Clusia rosea Flowering and Fruiting
  • Clusia vallerii Flowering and 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
  • Jacaranda mimosifolia Flowering
  • Heliconia chartacea Flowering
  • Heliconia latispatha Flowering
  • Heliconia pogonantha Flowering
  • Heliconia psittacorum Flowering
  • Heliconia rostrata Flowering
  • Hibiscus rosa-sinensis Flowering
  • Hymenaea coubaril Fruiting
  • Hymenocallis littoralis Flowering
  • Ixora coccinea Flowering
  • Lantana camara Flowering and Flowering
  • Lagerstroemia speciosa Fruiting
  • Morinda citrifolia Fruiting
  • Musa acuminate Flowering and Fruiting
  • Nephelium lappaceum Fruiting
  • 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
  • Virola guatemalena Fruiting
  • Zammia sp Flowering

 

 

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