Spawning new species   2 comments

Felipe del Bosque Blog Sept 17 2010

Temp High 83°F  Low 71°F          Precipitation 1.0 ins

Today provided no surprises, from sunrise to sunset just grey and overcast.  Last night, the clouds had cleared momentarily for a brief view of the stars.  The summer constellations are beginning to leave us now.  Scorpius, the scorpion, that obvious curved body with its bright red star Antares, has crawled its way across the heavens and disappears below the western horizon.  Hercules, Pegasus, Andromeda and Cassiopeia still straddle the northern skies.  Those two celestial birds, Aquila, the eagle, and Cygnus, the swan, are frozen in flight with their wings stretching out across the glittering backdrop of the Milky Way.  It is unfortunate that the cloud cover this time of year obscures such heavenly delights from our eyes, the occasional break giving us but a fleeting glimpse of the glorious spectacle above.

I do have a nice 4 inch computerized telescope, with a CCD so that I can do astrophotography.  But the skies here do not afford many opportunities for long term viewing and photography.   Even if the sky is clear, by the time you get the equipment set up, you can more or less guarantee a bank of cloud will have moved its way across the sky and the moment will be gone.  It is also problematical keeping condensation off the front lens after any longer than an hour.  But I think next year I may give it another try.

The birds and butterflies were much the same again today.  I did manage to get some nice photographs of a strange little Leafhopper I had never seen before.

The main highlight of the day though came from down by the pond.  I went to see what was around and there sitting at the poolside was a young Basilisk.  A larger individual, a male with a magnificently crested head and a showy fin running the length of his body, usually sits at the back of the pond but disappears very quickly if anyone gets too close.  The usual dragonflies were in residence, Micrathyria occellata and Orthemis ferruginea.  But last night’s heavy rains had brought the frogs out.

Some of the lawns around the pond area last night had become saturated and small temporary pools had formed.  Male Masked Treefrogs, Smilisca phaeota were out in profusion, their choral congregations filling the air with a repeated, “Mwyaaaa, Mwyaaaa”, each male trying to outperform the others in the hope of attracting a mate.  Red-eyed Green Treefrogs, Banana Frogs, Smoky-Jungle Frogs, Tink Frogs and Fitzinger’s Rainfrogs, all of them calling but being drowned out by the sound of the rain thundering down.  This morning though it was obvious that the rain had not dampened their ardor as there were multiple clumps of egg masses that had been deposited on the vegetation around the pond.  Those Masked Smiliscas that had opted for the more permanent situation afforded by the pond rather than the temporary rain filled pockets in the lawn, had been successful too, layers of their eggs were floating on the water’s surface.

Well what a night that was.  Over the past few weeks there have been two frogs of the same species calling that I just did not recognize.  I have lived here ten years and I know the mating calls of all the different species of amphibian that regularly inhabit the pond.  Some are there every single night of the year, some sporadically and others announce their presence over a period of one or two nights once a year.  These two individuals were taunting me.  One would call from one side of the pond, the other from a point diametrically in the opposite direction.  Several nights ago I had one calling from right in front of my face, but he must been so well hidden that, try as I might, I could not locate the source of the sound.  I couldn’t sleep at night, in my own mind, my professional integrity in tatters.  The frogs were making a mockery of everything I am.  Until tonight that is.

As I was carrying out my nightly frog count, my flashlight briefly caught in its glare what I initially recorded as a female Banana Frog.  As I continued my count, there was that haunting call again, the phantom frog from hell had come to pervade my mind and give me more restless sleep.  It was there in front of me.  My flashlight once again lit up the female Banana Frog, but in reality there was something wrong with this female.  She was not the right color of yellow, more or a jaundiced, sickly yellow and with stripes, was she ill?  The calling, of course had stopped.  What is that?  It is not a Banana Frog at all.  I leaned closer, nearly falling into the pond as I did so, to get a better look.  Yes, I have got you.

I backed off so as not to frighten the new inhabitant off, finished my count and then ran back to my cabin for the camera.  I returned within minutes, it had not moved from under the Water Hyacinth leaf where I had left it and there was the cheeky little devil calling with gusto, ‘ree, ree, ree, ree”.  I got the photos and here they are.  You are seeing it just hours after I did.

I will sleep well tonight.

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.

Photo Feature

The frog that I found tonight calling head down under a Water Hyacinth leaf at the Bosque pond, is actually a very common treefrog throughout Costa Rica.  Despite the fact that it is well represented in other parts of the country, I have never recorded it here, even after ten years of almost nightly frog counts.  The individual in question, the one that had been causing me so much mental anguish was an Olive Treefrog, (Scinax elaeochroa).  Just as the Parachuting Red-eyed Green Treefrog, the Olive Treefrog is an explosive breeder.  After a period of heavy rain, the likes of which we have been experiencing over the past few days, out they come.  At first they arrive in hundreds, then thousands, the noise of such huge numbers of calling males would drive a person to distraction.  Thankfully we have only had the two individuals calling so far.  How I look forward to countless thousands arriving!  When the males do arrive they change color from the darker olive green to a brighter orange.  The vocal sac becomes a very bright yellowy orange.

The Olive Treefrog breeds in temporary pools and we had many of those last night.  They were very temporary as by this morning they had all but dried up.  The two that have been plaguing me with their furtive behavior over the past couple of weeks have always been calling within the vicinity of the pond.  I don’t know why a frog commonly found elsewhere should not have been recorded here in the past.  I do not know why all of a sudden these two individuals turned up.  It will be interesting to monitor if more start to find their way to the breeding pond and if they can compete for space and resources in what is already a very diverse little area.

Anyway it is always satisfying to solve a mystery, especially one that concerns a large part of your life, and that for me, is all aspects of natural history.  So a good night.

Text and Photographs are taken from the forthcoming book:

The Natural History of Bosque del Cabo by Philip Davison

Species List for the Day


Howler Monkey


White-nosed Coati


Red-lored Amazon

Scarlet Macaw

Bright-rumped Atilla

Southern Beardless Tyrannulet

Grey-necked Wood-Rail

Short-billed Pigeon

White-tipped Dove

Common Paureque

Chestnut-backed Antbirds

Black-hooded Antshrike

Chestnut-mandibled Toucan


Green Honeycreeper

Cherrie’s Tanager

Golden-hooded Tanager

Palm Tanager

Tennesse Warbler

Roadside Hawk

Great Tinamou

Black Vulture



Four-lined Ameiva

Northern Cat-eyed Snake


Marine Toad

Red-eyed Green Treefrog

Banana Frog

Olive Treefrog

Gladiator Frog

Smokey Jungle Frog

Masked Smilisca

Tink Frog


Anartia fatima

Glutophrissa drusilla

Heliconius erato

Heliconius hecale

Heliconius ismenius

Heliconius sapho

Heraclides cresphontes

Hermeuptychia hermes

Junonia everete

Morpho menelaus

Phoebis sennae

Pierella helvina

Pierella luna

Pyrgus oileus


Posted September 18, 2010 by felipedelbosque in Philip's Nature Diary

2 responses to “Spawning new species

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  1. Cheers for mystery solved. Great photos.


  2. Glad you solved the mystery Phillip, you had me going for sure. I really cannot wait to get down in late Nov and look for all of these new creatures that you are pointing out in this great new blog. Keep up the good work. Arralee


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