Archive for the ‘Nature-photography’ Tag

FROGS OF COSTA RICA: LARGEST AND SMALLEST   Leave a comment


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.

Following lunch I went for 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.

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 in the forests of the Osa Peninsula.

Amphibian, Savage's Thin-fingered Frog, Leptodactylus savagei, Costa Rica, Veridion Adventures, Nature Photography, Travel

Savage’s Thin-fingered Frog, (Leptodactylus savagei)

Savage’s Thin-fingered Frog, (Leptodactylus savagei), is a veritable behemoth of a frog, second only in size to the female Marine Toad.  It is 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 a 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 creature predating upon 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.

Amphiibian, Stejneger's Rain Frog, Craugastor stejnegerianus, Veridion Adventures, Nature Photography, Travel

Stejneger’s Rain 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.

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SKIPPERS: BEST SEEN IN CLOSE UP   1 comment


Skippers: Best Seen In Close Up

Rainforest butterflies. Costa Rica. Hesperiidae. Pyrginae. Staphylus mazans. Mazans Scallopwing. Veridion Adventures.

Mazans Scallopwing, (Staphylus mazans)

Tropical Checkered Skipper, Pyrgus oileus, Pyrginae, Costa Rica, Veridion Adventures, Nature Photography, Travel, Adventure

Tropical Checkered Skipper, (Pyrgus oileus).

Skippers, you probably wouldn’t even notice them.  Many of the skippers are small, less than the size of your little fingernail, chocolate brown in color and fly close to the ground.  Even when you do capture one on camera, the diagnostic features required to identify it may not be obvious.  Quite often the female has different coloration and markings to the males.  Literature pertaining to skippers, guides and keys; they are all sadly lacking.  Skipper identification is therefore left to the experts and even then that may take some time.  I too, initially paid small attention to them, at least until I started to photograph them.  For whatever reason they seem to be sensitive to sound, light or the slightest movement, so when it comes to capturing the image you have spent so long composing, as the lens focuses, off they go.  If using flash, you also need to be using a high shutter speed because if you are using anything below 1/250 sec all you will have taken is a photograph of is the leaf where the skipper had been perched.

Purple-washed Skipper Butterfly, Panoquina lucas, Hesperiidae, Hesperiinae, Costa Rica, Veridion Adventures, Nature Photography, Veridion Adventures, Travel,

Purple-washed Skipper, (Panoquina lucas)

Trailside Skipper Butterfly, Anthoptus epictetus, Hesperiindae, Hesperiinae, Costa Rica, Nature Photography, Veridion Adventures, Travel

Trailside Skipper, (Anthoptus epictetus). Flash Jump.

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Eyelash Viper and Tropical Frogs   2 comments


Local weather conditions may differ drastically from year to year and during 2009 the Osa Peninsula experienced a particularly rainless dry season.  Normally, from December through to April, there is at least some rain, not much; it is after all the dry season, but last year, barely a drop.  This was then followed by a very dry wet season.  When the rains should have arrived in May, they did not, and this condition carried on unabated throughout June and July.  For visitors to the Osa Peninsula, the conditions could not have been more perfect, lots of hot, sunny days, perfect vacation weather.  But that interruption in the natural rain cycle was having a profound effect on the fauna and flora of the area.

Rain forest trees are very dependent on their water source and if this becomes limited in supply, they begin to suffer environmental stress.  The first obvious sign is that they will shed leaves.  Should the stress continue, they begin to shed branches.  Finally, if we end up, as we did in 2009, with a drought in a rain forest, the trees divert a lot of energy into reproduction to ensure the passing on of their genetic material lest they themselves die.

That is exactly what we saw in 2009.  Visitors were treated to a canopy high display of flowering, rarely equaled, with a veritable kaleidoscope of color; yellows, reds, purples and pinks painted like a pastel infusion among the normal mix of greens at the treetops.  Some of the trees did not just flower once; they produced blooms two or three times throughout last season.  The exuberant flowering display led in turn to a profusion of fruiting, the trees were quite literally hanging with fruit.

This series of events led in turn to a very good reproductive year for those animals whose diet depends to a greater or lesser extent on nectar or fruit, such as Spider and Howler Monkeys, Toucans, Hummingbirds and Manakins.  This year visitors have been treated to the sight of huge flocks of toucans and a great many of the female Spider and Howler Monkeys carrying young ones.

But what a difference a year makes.  In a complete reversal of last year, 2010, so far, has been a wetter than normal year.  Rather than the tired looking yellows and browns evident in last year’s vegetation, this year has remained luxuriously verdant and that bodes well for another group of animals; the amphibians.  Despite a myriad of problems causing global declines in amphibian populations, here on the Osa Peninsula, the frogs are still holding their own.

Veridion-Adventures Red-eyed-Green-Tree-Frog Agalychnis-callidryas Nature Photography Travel Adventure Holidays

Mating pair of Red-eyed Green Tree Frogs, (Agalychnis callidryas)

There are certain species that one can almost rely upon to be present right throughout the year; Marine Toads and the picture postcard child of Costa Rica, the Red-eyed Green Treefrog.  With the onset of the rains though, all those species that have been noticeable by their absence for the previous five months emerge once again, sometimes in numbers so large that it begs the question, “Where has such a biomass of amphibian life been hiding for almost half the year?”

When they do emerge, it is with only one thing in mind; reproduction.  Around the breeding pools, the cacophony of the calling males renders it all but impossible to make yourself audible.  The initial heavy rains of the season immediately encourage a response from Costa Rica’s largest treefrog, the Milky Frog.  Within hours on the evening of the first downpour a full breeding choral congregation of males, in numbers upwards of fifty will have accumulated in the pond.  The deafening din of their ardor can be heard from great distances.  After several nights of this repeat performance, they once again decline in numbers until it is only a very occasional chance sighting that you will experience during the remaining rainy months.

Now is the time of the frog though and during the next seven months we are treated to a nightly chorus of serenading males of different species, some of them more melodious than others; the jackhammer mating call of the Marine Toad, the chuck of the Red-eyed Green Treefrogs, the sound of little metal bells tinkling from the Tink Frogs, clipped chirps of Banana Frogs and what you would swear sounded like two blocks of wood being knocked together that announce a Gladiator Frog male is looking for a mate.

Veridion-Adventures Banana-Frog Dendropsophus-ebreccatus Nature Photography Travel Adventures Holidays

Banana Frog, (Dendropsophus ebreccatus)

Yet there is one more amphibian phenomenon that only a lucky few experience; the explosive breeding display of Parachuting Red-eyed Green Tree frogs.  This is the second species of Red-eyed Green Tree frog to be found on the Osa Peninsula.  They are rarely, if ever seen, living as they do at the tops of the trees, but several times during the rainy season following several days of concerted torrential rain out they come, and they come in their hundreds.  They receive the parachuting part of their name from having large hands and feet that are extensively webbed.

Veridion-Adventures Parachuting-Red-eyed-Green-Tree-Frog Agalychnis-spurelli Nature Photography Travel Adventure Holidays

Parachuting Red-eyed Green Tree Frogs, (Agalychnis spurelli). Mating pair

Taking the monsoon-like conditions as their cue, they launch themselves from above, opening the hands and feet, spreading the webbed fingers and toes, allowing them to effectively ‘glide’ to the lower levels.  The males and females pair up and then not long before dawn they start to lay eggs, everywhere, covering the surfaces of the leaves overhanging the ponds.  The eggs develop for seven to ten days, liquidize, slip off the leaves and plop into the water which is where the normal tadpole stage will then take place.  The explosive breeding frenzy has to end before sunrise; the frogs need to take shelter from the drying effect of the sun’s harmful rays on their delicate skin.

If you are out early enough you will be awestruck by the sight of hundreds of pale green frogs trying to climb up into shadowy parts on the underside of leaves.  Sometimes the weight of such huge numbers will snap the vegetation in which they are attempting to seek refuge.  It really does have to be seen to be believed.

Eyelash Viper Feature

Veridion-Adventures Eyelash-Viper Bothriechis-schlegelii Nature Photography Travel Adventure Holidays

Eyelash Viper, (Bothriechis schlegelii). Gold phase – Oropel

In all my years living on the Osa Peninsula I have seen the elusive Eyelash Viper, (Bothriechis schlegelii), on only four occasions.  It is not necessarily because they are rare but more to do with the fact they are very cryptically colored, the point of which being, to avoid being seen by both predator and prey.  Although they come in several color forms, the ones I have seen at Cabo Matapalo have all been the green mottled morph. The camouflage coloration blends the contours of the body perfectly against the moss covered branches of the plants where they sit as ambush predators awaiting the approach of a small lizard, frog, bird or rodent on which they feed.

The most distinguishing feature of this small pit viper are the two spine-like scales protruding over the eye giving it the name Eyelash Viper.  There is no definitive answer as to why it has these scales, possibly to push vegetation out of the way which may scratch the snake’s unlidded eyes.  One other eponymous feature  to the pit vipers is the small hole on the front of the face between the nostril and the eye.  These house acute sensory apparatus that detect very small changes in background infrared radiation allowing the snake to detect the presence and location of it prey.

Veridion-Adventures Eyelash-Viper Bothriechis schlegelii Nature Photography Travel Adventure Holidays

Eyelash Viper, (Bothriechis schlegelii). Motteld phase- Bocaraca

The Eyelash Viper is a small snake, especially given the size some other vipers can grow to.  It is a nocturnal predator and will take a variety of prey ranging from frogs, lizards, birds and mammals. Unlike terrestrial vipers which envenomate their prey, release it, then seek it out after it has died, the arboreal vipers have a strongly prehensile tail and tend to hold on to their prey after biting.

Eyelash Vipers are distributed from Mexico down through Central America into Venezuela.  They prefer shrubby vegetation found in secondary growth.  In Costa Rica the yellow morph is know as the oropel, (golden skin), while the mottled morph is known as the bocaraca.

Due to its size, cryptic coloration and preference for resting during the day in the lower areas of vegetation it is responsible for biting those people who work in those areas.  Although deaths from the bite of an Eyelash Viper are rarely fatal, there can be some long term issues with impairment of movement particularly if bitten on the hands.  Viper venom varies between species and can be quite complex in chemical make-up.  Generally they contain a cocktail of fast acting proteolytic enzymes that cause a multitude of effects including tissue necrosis and death.

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