Wildlife, nature, fauna and flora of Costa Rica.

A Typically Tropical Day

A typically tropical day here at Bosque del Cabo, on the Osa Peninsula in Costa Rica; warm and sunny during the day but later in the afternoon, the clouds started to gather and by the early evening it was grey and overcast.  Every night, almost on schedule, at six o’clock the rain comes down.  This year has been slightly wetter than normal for the wet season.  That makes it a good year for the frogs though.  The main amphibian breeding season is over and the numbers of individuals are starting to decline but there are still more than during the dry season.  It only takes a few rainless days followed by a torrential downpour to have some species rekindle their ardor

.Many of the trees are in fruit at the moment so flocks of tanager species can be seen in and around the grounds accompanied with cotingas, tityras, manikins and euphonias.  Some, like the frogs are resident and commonly seen on a daily basis, others, more elusive, make a rare but welcome sighting.  This week has seen a flock of Turquoise Cotingas, (Cotinga ridgwayi), both male and female feeding in the fig trees.

Capuchin Monkeys Eating Toucans

The ever present Capuchin Monkeys have been entertaining and horrifying everyone at the same time recently.  There have been sizable flocks of Black-mandibled Toucans, (Ramphastos ambiguus), feeding on figs.  Many of the visitors have gone out to get that once in a lifetime close up photo only to be confronted by the bloody spectacle of a pair of monkey paws throttling the life out of the bird then rendering it apart, consuming the flesh and finally dropping the large and distinctive beak to the ground.

Red-eyed Green Tree Frog Feature

Agalychnis callidryas. Hylidae. Phyllomedusinae. Osa Peninsula. Costa Rica.

Male Red-eyed Tree Frog, (Agalychnis callidryas), calling for a mate.

Red-eyed Green Treefrog literally describes the picture poster child of Costa Rica.  Anything that features the name Costa Rica will generally be accompanied by an image of this beautiful frog.  It is fairly widespread throughout the country in areas of wet or rainforest.  It is not easily going to be mistaken for any other frog, despite there being several different species of Red-eyed Green Treefrogs, they are all very distinctive.  The most popular tour by far at Bosque del Cabo is the “Sunset Tour”, which I lead every night at six.  Of course visitors have seen monkeys, sloths, macaws and toucans during the day, but for many the star of the daily nature show does not emerge until the sun has set.  As they breed all year round, more so in the wet season, I can almost guarantee that at least one male of this very popular wildlife sighting will be sitting calling, green bodied, blue and yellow barred sides with those bulging red-eyes simply inviting a photograph.

Red-eyed Green Tree Frogs are widespread throughout the moist forests of Costa Rica.  Here they can be found year-round, the males calling every night, but more particularly in the wet season.  During the day they tuck themselves away under the leaves at the top of the trees to escape the skin-drying effects of the tropical sun’s rays.  At dusk, as darkness descends, they awaken and begin the nighttime activities of feeding and reproducing.

They breed in still water so the pond is the best place to find them.  The males make their way to a perch at a lower level from which they will begin their amorous serenade.  If you stand and listen then you will hear the “Chuck, chuck” sound that many people mistake for a nocturnal bird.  During the dry season the calls will probably be in vain, the females are not interested at that time of year.  However, when the rains begin the situation changes.

The females are much larger than the males, their bodies have to accommodate all of the eggs.  They select a breeding partner for the evening depending on the bass of the male’s call, the lower the better.  She makes her way to the chosen mate who then climbs on her back.  She carries him to the water where she proceeds to absorb water through her skin which in turn fills her bladder.  With the male still holding on tight she then locates a suitable leaf overhanging the pond and will commences to lay her eggs.  As the eggs leave her body the male fertilizes them externally.  The 50 – 100 eggs are contained within a protective, clear gelatinous coating.

The larvae develop for approximately 7 or 8 days and eventually the egg mass liquidizes and the tiny tadpoles drop into the water.  Here they will grow and finally metamorphose into a miniature copies of the adult, leaving the water to face the challenges they have to overcome before reaching breeding status themselves.

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






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