Dressed in Black Under a Full Moon   1 comment

Felipe del Bosque Blog Sept 23 2010

Temp High 92°F  Low 72°F          Precipitation 3.24 ins

Last night it rained so hard that this morning most of the grounds were submerged under water and it looked like we were stranded in the middle of a massive lake.  Over three inches of rain had fallen overnight.  As the morning progressed out came the sun and dried up all the rain.  Unfortunately by mid morning, the rain was back and it did not go again.

Today is the autumn equinox, not that we have an autumn in Costa Rica.  Today night equals day, day equals night, twelve hours of dark and twelve hours of light wherever you are around the world.  Well that is the commonly held misconception, it is not exactly true.  For most people it is as close to the truth as to make little difference.  Today the earth has reached that point in its orbit around the sun where the tilt of the earth is neither facing towards or away from out bright burning star, but lies in a plane parallel to it.  As from this day, as the earth continues its journey, the northern hemisphere days will become shorter and the southern hemisphere days will become longer.  Here at Bosque del Cabo at a point 8° North of the Equator, the difference between the longest and shortest day is a staggering 45 minutes.

The nearest full moon to the autumn equinox is known as a harvest moon.  Both of those events coincided today.  Any full moon, including a harvest moon, when rising low in the eastern sky will be seen as pale amber orange in color.  Moonlight is really reflected sunlight, and if the moon rises just after sunset, its low aspect on the horizon means that the reflected light has to pass through more of the earth’s atmosphere, which scatters the short wavelength blue light and allows only the longer wavelength red light to reach your eyes.  As the moon rises, you once again get that silvery light which washes over everything and casts those soft moon shadows beloved of both poets and romantic artists alike.

There was a real dearth of sightings today and because of the heavy cloud cover we did not get to see the moon either.  I had hoped to capture an image of it as it rose over the Golfo Dulce, its light reflecting across the expanse of water.  There will be other opportunities.  You know it is shining bright above the clouds though as you don’t need a flashlight when walking around grounds this the evening.

The newly discovered Olive Treefrogs were calling tonight. It sounded like yet another individual has found its way to the pond, taking up the numbers to three.  There were a lot of Parachuting Red-eyed Green Treefrogs calling tonight too.  It could well be that by tomorrow morning we have an explosive breeding episode.

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

Over the years at Bosque del Cabo, I have recorded the presence of some 350 species of butterfly.  Many of those species I have only ever seen once, I take the photograph, (sometimes), and then I never see them again.  It always makes me wonder just how many species there are on the grounds of Bosque del Cabo given all of those one off chance encounters.

Pyrrhopyge phidia zenodorus

So it was with this Red-headed Firetip, (Pyrrhopyge phidias zenodorus).  This individual was perched low in a bush just behind the Bosque restaurant.  I don’t know how common in numbers of individuals they are but as a species it is well distributed throughout Central and tropical South America.  Red-headed Firetip is literally descriptive.  Look at the bright red head and the fiery red tip to the abdomen.  The wings have a beautiful deep black satin luster with white trimming to the trailing edge.

Theorema eumenia

Another black butterfly that I have only seen once but again had the good fortune to be carrying the camera when I did so was this tiny hairstreak, (Theorema eumenia).  I found it; or rather it found me, in a similar location behind the restaurant.  There are only 9 recorded specimens in Costa Rica, one of them from just along the coast in Corcovado National Park.

Sarota chrysus

Finally one day as I was returning from my butterfly count, as I crossed the suspension bridge I noticed a very small metalmark that I had never seen before, Sarota chrysus.  Every time I had the photograph composed, the butterfly nicely in frame, everything set and ready to press the shutter release, the subject would fly off and I thought I had lost it.  This was causing me a great deal of frustration as I did not at that moment know what I was looking at and didn’t know if I could commit all the potentially diagnostic features to memory.  Eventually it did land, but never in an entirely convenient situation.  So with a great deal of physical contortion and not a little discomfort I finally managed to capture its image.

Text and Photographs are taken from the forthcoming book:

The Natural History of Bosque del Cabo by Philip Davison

Species List for the Day


Spider Monkey


Grey Four-eyed Opossum


Red-lored Amazon

Scarlet Macaw

Grey-necked Wood-rail

Pale-billed Woodpecker

Chestnut-backed Antbirds

Chestnut-mandibled Toucan

Roadside Hawk

Turkey Vulture



Northern Cat-eyed Snake


Marine Toad

Red-eyed Green Treefrog

Parachuting Red-eyed Green Treefrog

Banana Frog

Olive Treefrog

Tink Frog

Fitzinger’s Rainfrog


Anartia fatima


Posted September 24, 2010 by felipedelbosque in Philip's Nature Diary

One response to “Dressed in Black Under a Full Moon

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  1. Love the black butterflies…I don’t know that I’ve seen either of them…Maybe next time..sorry I missed sloshing in the mud…bet Ben would have loved that and I think he has new rain boots!!! Sorry too that you missed the harvest moon. It was bright here…enjoying your blogs! (want to see that new frog too, so hope they multiply!!!)


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