Archive for the ‘Black Vulture’ Tag

A New Age Begins   3 comments


Week Ending 11th December 2015

Weekly Weather

Average High Temp 101ºF (38.3ºC)               Average Low Temp 75ºF (24.3ºC)

Average Rainfall 1 ins (25.4mm)                    Total Rainfall 7 ins (177.8mm)

Wet and Dry

The dry season at Bosque del Cabo Rain Forest Lodge always experiences a stuttered beginning.  The lodge is located on the south west tip of the Osa Peninsula, Costa Rica overlooking the Pacific Ocean to the south and the Golfo Dulce to the east.  The region is covered by some of the last remaining tropical forest on the Pacific Coast of Central America.  Due to the pronounced seasonality of the area having a profoundly dry five months followed by a wet seven months the forests here are more correctly classified as tropical seasonal forests as opposed to tropical rain forests which are not subject to the annual dry period.

The heaviest rains of the year fall between September and November.  By December the daily deluge abates and we gradually see more of the sun.  It is easy to be lulled into a false sense of “the summer is here” as commonly a few dry, bright days with blue skies will be followed by another week of torrential downpours.  But eventually the faltering weather passes through the transitional phase and settles into a more predictable pattern.  Given a few weeks of steady, dry heat and the plant life will begin to flower.  The number of butterfly species and individuals that had dropped in the wet season begins to build once more so the days are now filled with beautiful, brightly colored wings adorned in poster reds, yellows and orange dancing around the flower heads.

There is never a shortage of mammal or bird sightings.  Currently there are many migratory warblers and tanagers chattering noisily in mixed flocks as they move from tree to tree in search of insects or fruit to eat depending on their specific diet.  The resident bird populations do not mind those long distance travelers returning to spend the winter in the warmer climes of the tropics and join quite readily with their travelling cousins in large flocks.  Monkeys abound in the trees, constantly on the move looking for food whether it is flowers, young leaves, fruit or insects.  Under the trees the large ground living rodents, Agoutis, feed on the fallen fruit and large heavily coated seeds.  Solitary male White-nosed Coatis are on the lookout for anything they can get their paws on; grubs, crabs, bird’s eggs and chicks as well as fruit or discarded food in the bins of the restaurant.  The gregarious females with young patrol in large foraging packs looking for the same food as the males but not with the same bold abandon.

The peace of the hot still sultry afternoon atmosphere is occasionally permeated by the call of a mammal or bird.  The ever active Spider Monkeys let out a series of high-pitched shrieks which sporadically turn into a hysterical frantic screaming match.  From deep in the forest the doleful Howler Monkeys bark and roar their disapproval of some irritation.  The White-faced monkeys oblivious to the presence of human observers chitter and chatter amongst themselves.  Coming from the surrounding vegetation are the chirps and cheaps of the warblers and tanagers.  But for the most part the soporific pulsating heat and the throbbing silence serve to create a languid attitude for visitors to the tropics.

Feed Me

All of a sudden the siesta is interrupted by a harsh ear-piercing screech.  Several birds of prey inhabit the area and neither the hawks nor the falcons have been blessed with a melodious call.  Commonly seen sitting at the top of the palms or on the ground are the Yellow-headed Caracaras, (Milvago chimachima).  Despite their raptorial appearance these elegant members of the falcon family are generally carrion feeders.  They can also be seen riding the backs of cattle feeding on bovine ticks.  Due to their association with cattle they are commonly seen in open pastureland.  Until 1973 they had not been recorded in Costa Rica but following widespread deforestation their distribution and geographical range spread north from Panama into Costa Rica and they can now be seen in Nicaragua.

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That nasty nasal screech was an adult Yellow-headed Caracara calling from on the ground but there was another call, similar yet more urgent.  Not too far from the adult was a newly fledged youngster that was making its first foray from the nest.  It had not yet mastered the art of flight and was demanding food from the parent bird that was watching warily over its offspring’s pitifully laborious progress hopping and jumping across the ground.  The brown speckled shabby looking youngster bore little resemblance to its sleek yellow-faced dark-browed parent standing guard over its precarious and vulnerable position.

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From Sublime to Ridiculous

Another bird seen either high or low is the Turkey Vulture, (Cathartes aura).  As you look up into the deep blue tropical sky it is likely that you will see flocks of birds soaring on the thermals.  Silhouetted against the azure background the shapes and shades circling above you will help discern the different species present.  Long thin wings bent back from the center like a Batman motive combined with a forked tail easily characterize the Magnificent Frigatebird.  A huge bird with broad, wide wings fingered at the end and divided into a monochrome white leading edge and black trailing edge leave no mistake that this is a King Vulture.  Similar in shape but uniformly dark except for grey fingered tips is the Black Vulture.  Soaring with them with the same wing form but with longer tail and complete grey trailing edge is the Turkey Vulture.

On the ground there is no mistaking the Turkey Vulture for its head bare of feathers is bright red.  Like the Yellow-headed Caracara the Turkey Vulture feeds on carrion but unlike its falcon cousin which locates food visually, the vulture has a highly developed olfactory sense and can locate the chemical signature of decomposition following the plume of molecules of death to their source hidden beneath the forest canopy.  They can often be seen beneath the palm trees feeding on the fallen palm fruit.

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Vultures are not everyone’s favorite bird but they play a vital ecological role in disposing of rotting carcasses and rubbish that won’t make to a landfill site.

Fruit and Nuts

Sitting beneath the palm trees in the company of vultures one will more often than not see Agoutis, (Dasyprocta punctata).  These large ground living rodents are related to Capybaras, Coypus, Pacas and more familiarly Guinea Pigs.  Along with the vultures they are waiting for the palm nuts to fall.  Agoutis are essentially seed eaters and have the ability to sit back on their haunches while holding the seed in their front paws which they can manipulate and turn allowing them to easily gnaw through very tough seed coats such as nuts.

At the moment there are a lot of fruits on the grapefruit tree which when ripe fall.  Eagerly awaiting this softer option dropping from above there are some Agouti individuals that pick up the sizable citrus prize in their mouths and carry it off to be eagerly consumed.  They do not eat the peel but rather the soft juicy segments inside.

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Whereas during the day vultures and Agoutis can be seen frequenting the palm trees at night it is possible to see another creature that utilizes the palms.  If you look a little more closely at what might seem like old and dropping palm fronds you will see that they will have had another force at work.  Something has nicked through the veins of the frond to be point where it folds over.  Take a look inside and there you will most likely find the culprit responsible for this chiropteran topiary – the Tent-making Bats, (Uroderma bilobatum).

The Tent-making Bats use the tents as either day roosts or night roosts.  If they are using them as a day roost there can be as many as forty bats hanging under the frond.  They regularly change the location of each roost they are using as predators would quickly figure out where to get an easy meal.  One of the commonest predators of the tent making bats are the Squirrel Monkeys.  During the day they identify which roosts are being used by the bats climb to the fronds above and then drop onto the roost.  The startled bats come fluttering from underneath where they are picked off by the monkeys.

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Currently they are being used as night roosts.  Once the sun has set the bats leave the day roosts and fly to the selected night roosts where they wait until it is very dark before they go foraging for food.  The Tent-making Bats are fruit-eating bats and use night roosts which are never more than 80 – 100 meters away from the nearest fruiting trees which in this area are figs.  The carry the figs in their mouths back to the night roosts whereupon landing they then hold the fruit between their wings, peel off the skin with the teeth and eat the pulp.  Just before the sun rises they leave the night roosts and return to the day roosts where they will pass the day sleeping.

Philip Davison is a biologist, writer and photographer based in Costa Rica.

Long Nosed Damsel Smells of Death   2 comments

Felipe del Bosque Blog March 18th 2013

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Open Wide

The weather continues to be hot and dry.  The skies are clear blue during the day and filled with stars at night.  The cracks in the forest floor are widening and deepening.  There is a certain amount of dust in the air being raised from the parched roads.  It is settling on the vegetation giving it that drab and tired look.

The White-lipped Peccaries, (Tayussu pecari), are still making their daily circuits of the grounds around the main lodge area.  They have now been here two weeks and show little sign of leaving.  Their habit of slowly walking around the grounds with little concern regarding the attention of the visitors makes them an easy photographic subject.

The Puma was seen one night by the staff as they left the lodge.  It was crossing the road by the Titi Trail. There is a large Fig Tree, (Ficus citrifolia), fruiting in the gardens in front of the restaurant.  This is attracting the attention of lots of animals particularly monkeys and toucans.

The pond is still full of Savage’s Thin-fingered Frog, (Leptodactylus savagei), and Marine Toads, (Chaunus marinus).  It is one of the few remaining damp areas around which they can congregate.  One pair of Savage’s Thin-fingered Frogs paired up and spawned this week producing the characteristic foam nest that looks like a patch of whipped cream that has been deposited on the water surface.  The Marine Toad males have been calling as has a lone male Banana Frog, (Dendropsophus ebreccatus).

Early one evening the Halloween Crabs, (Gecarcinus quadratus), were out in force even before the sun had set.  It has been very dry and those weather conditions normally keep the crabs confined to their burrows where the air has slightly higher moisture content.  Several weeks ago when the crabs became active it heralded the onset of rain.  This occasion was no different as a few hours later the heavens opened and down came .09 inches of rain.  That might not be much but it was enough to dampen the ground for a couple of days and bring the crabs out en masse the following morning.

Trooping of the Monkeys

If fortune favors you then it is not too hard to find all four species of monkey that inhabit Costa Rica on the grounds of Bosque del Cabo within little more than a few hours.  Where there is an abundant supply of food from the fruiting trees it may be possible to predict the time of their daily visits.  Over the last week one group of White-faced Capuchin Monkeys, (Cebus capucinus), has been passing through the grounds every afternoon on their way to a Guaba tree that has a copious supply of bean pods.

White-faced Monkey         Cebus capucinus         Capuchin Monkey

The Capuchin Monkeys usually travel as a mixed sex and mixed age troop in anything up to 30 in number.  They prefer the mid levels of the forest but can be found in the canopy and on the ground.  They have a varied diet consisting of flowers, fruit and young leaves but 65% of the diet is insects, frogs and lizards which they obtain by gleaning the leaves as the move through the forest.  But the Capuchins will also take bigger prey.  At Bosque they are frequently seen catching and eating the Chestnut-mandibled Toucans, (Ramphastos swainsonii), if front of the restaurant.

Cebus capucinus

This particular troop has several females carrying young of differing ages.  The female is sexually mature at about 4 years and will have one or rarely two young every 2 years.  The grey-furred babies are born in the trees and from that moment have to hang on tight as the mother jumps from tree to tree.  By 6 months old the offspring will be moving around independently.  The male mature at 8 years and head to join a new troop, in the other 3 species of monkey it is the females that leave the troop to find a new one into which they will be accepted.

In this troop one of the young males was taking a definite interest in the very new looking baby.  It could well be that he was the females last youngster and has lost out as her attention is devoted to the new arrival.

Unexpected Opportunities

Sometimes an animal appears at an opportune moment to photograph.  It could well be that you are out searching for a specific subject or perhaps just set off on a trail with nothing in particular in mind hoping to capture whatever comes your way.  I generally have a mix of those two situations going on.  I will head off to photograph something that I may have seen earlier or I need an image to complement a piece I may have been writing.  I am always aware that I may happen across sometime else on my journey so usually carry several lenses.  As most of my work is macro photography then it will invariably be several macro lenses.

Last week when I was out I saw a pretty little damsel fly which kept flying off but returning to settle in the same place.  I thought I could get quite close to it and if I did disturb it I was reasonably sure it would come back.  That is what happened.  When I got the pictures back I went through my reference material to identify what species I had.

Agria sp

Damselflies and dragonflies belong to the order Odonata.  Dragonflies tend to be larger, have joined eyes and hold their wings out to the sides.  Damselflies tend to be smaller, have distinctly separate eyes and hold their wings above them when at rest.  Both are aerial predators and feed on a variety of arthropods many of which are caught with lightning quick speed on the wing.  This one had beautiful powder blue stripes.  Wing veination is important in identifying these creatures and I am pretty sure this one is of the Family: Coenagrionidae, (Pond Damsels).  It was by the pond where I found it so the description is accurate.  Beyond that identification becomes more difficult and so I would say it is of the genus Agria but I am not sure what species as they are all so similar.  It is a fairly common genus of damselfly but like so many other forms of life here in Costa Rica their natural history has not been adequately studied.

One day on the underside of a heliconia leaf on the path to the Bosque restaurant I noticed a strange cluster of minute globules each one suspended on a microfilament stalk.  I had seen them before and knew what they were but had never taken a picture.  It was the eggs of an Ant Lion.  The eggs are suspended on the thin threads as opposed to directly on the leaf surface to stop foraging ants from finding them.

Ant Lion Eggs

When the eggs hatch and the larvae emerge they fall to the ground where they burrow in and set about constructing a crater of death.  The crater has steep sides and has been excavated in a substrate composed of loose grains such as sand or soil.  The sides then become very friable and any hapless creature stumbling into this depression in its efforts to escape will find itself dislodging grains and slipping further down the slope.  There awaits the ravenous assassin, the Ant Lion larva.  It has fearsome mandibles that are set open like a man trap.  With its front legs it flicks more sand grains at the struggling victim.  It slides further and further down the slope until finally it hits the bottom and the trap springs shut around it.  The Ant Lion larva sucks out its preys internal juices and discards the freshly drained cadaver.

Ant Lion Trap

Ant Lions belong to the Family: Myrmeleontidae of the insect Order: Neuroptera.  The adult Ant Lions have long thin abdomens but characteristically of this order the wings which are only half the length of the body feature a complex network of fine veins.

Beetles are the most numerous named group of animals on the planet.  The Order:  Coleoptera contains approximately 320 000 named species.  Costa Rica has 47 000 named species of beetle.  Within the Coleoptera the Weevils Family: Curculionidae is the most numerous named family of either plant or animal boasting more than 50 000 species worldwide with 7 500 species found in Costa Rica.  As with most beetles I can quite often identify them to Family level but beyond that takes more of a dedicated coleopterists skills.

Tropical Weevil         Curculionidae sp         Tropical Beetle

The most distinctive feature of the weevils is the long slender snout which is an elongation of the head.  The antennae are borne on the snout where they are supported on the sides but then angle forwards at 90°.  The end of the snout is tipped by the strong mandibles which allow the weevil to eat their way into the seeds and nuts which make up the staple of their diet.  Many weevils feed on plant material as well as fungi.  The larvae of some beetles can become pests burrowing throughout and feeding on living plant tissue.


One day last week when I was walking the Zapatero Trail, the man responsible for trail maintenance approached me and asked if I had seen the Black-throated Trogon, (Trogon rufus), sitting on the nest.  I had walked past without noticing until he showed me a broken off rotten tree about 5 feet high with a hole in it.  I could clearly see the male trogon sitting on the nest so headed back for my camera and returned to take the pictures hopefully without disturbing the bird.  The images weren’t great but I wasn’t prepared to stress the animal in pursuit of a photograph.

Black-throated Trogon

More Flowers and Fruit

The grounds of Bosque are still producing many flowers and fruit to captivate the interest of most casual visitors.  At entrance of the Zapatero Trail the fruits of the Guacimo, (Guazuma ulmifolia), Family: Sterculiaceae, can be found on the ground.  This is one of the fruits that the peccaries seek out when other food becomes scarce.  When crushed the fruits give off a sweet aroma.  Guacimo belongs in the same family as Cacoa, (Theobroma cacao).


In front of the restaurant is a small tree with distinct red flowers that resemble brushes used for cleaning bottles.  For this reason it has been named the Weeping Bottlebrush, (Callistemon vitiminalis).  It is a native of Australia and belongs in the same Family as the Eucalyptus, Mytaceae.  It is widely planted throughout Costa Rica as a decorative ornamental as well as an attraction for hummingbirds many species of which will visit the flowers which are in bloom most of the year.

Weeping Bottlebrush

One of the plants growing around the restaurant gardens produces flowers that are used most nights to decorate the tables.  Not only are they attractive to look at but they also emit a pleasantly scented perfume.  Frangipani, (Plumeria rubra), Family: Apocyanaceae, is a plant recognized by anyone who has visited Hawaii as one of the main components of the leis.  It is in fact a native of Central America not to Hawaii where it is grown as a decorative ornamental.  The plant is used medicinally as a cure for a number of internal and external conditions.  The sweet scent is an attractant for Hawk Moth pollinators that are fooled into visiting the plant with the promise of nectar.  As they move from flower to flower they transfer the pollen but the plant doesn’t live up to expectations as it does not expend energy producing a feed for the moth.


Along with the fruiting fig there is another tree near to the restaurant that has been the location of a daily visit by the White-faced Capuchin Monkeys Guaba, (Inga thybaudiana).  This is one of the Family: Fabaceae – Mimosoideae which when fruiting produce long bean-filled pods.  There are many species of Inga and these ones seem to be liked by the monkeys which use their sharp teeth and strong jaws to tear off the shell and get to the beans inside.


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 Powerful Smell of Death

Two very common birds seen at Bosque del Cabo, either on the ground or in the air are the Turkey Vulture, (Cathartes aura), and the Black Vulture, (Coragyps atratus).  On the ground they are easily distinguished by the color of the head which in the Turkey Vulture is bright red while in the Black Vulture is black.  While soaring on the thermals above the lodge the outstretched wings of the Turkey Vulture are overall grey with a black leading edge while those of the Black Vulture are overall black with a pale patch towards the tip of each wing.

Turkey Vulture

Old World vultures have acute vision and can spot a dead animal on open grassland from some distance and from some height.  New World vultures have sometime of a problem; trees.  It is impossible to view a dead animal lying on the ground underneath the canopy.

Black Vulture

When an animal dies the subsequent decomposition of its tissues release certain chemicals that are associated with the scent of death.  As this scent plume rises it is dispersed by wind currents forming a scent gradient over a given distance.  The olfactory lobe of the brain in the Turkey Vulture has been shown to be much larger than other birds and the birds have been demonstrated as being able to follow this scent plume to its source.  The Black Vulture and the occasionally seen massive King Vulture, (Sarcoramphus papa), do not possess this ability but rely on the Turkey Vulture to locate the carrion.  They follow the Turkey Vultures to the forest floor where being more dominant, Black Vultures, or much larger, King Vultures, force the Turkey Vultures off the meal.  Although they are equipped with a keen sense of smell the Turkey Vultures have a weak bill that cannot tear through hide especially the way the king Vulture can.  So despite the fact that they defer to the other vultures, the carrion is rendered into a form that the scavenging Turkey Vultures can later manage.

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 0.00 ins.  Total Weekly Rainfall 0.00 ins

Average Daily Rainfall 0.0 mm.  Total Weekly Rainfall 0.0 mm

Highest Daily Temp 92°F.  Lowest Daily Temp 74°F.

Highest Daily Temp 33.3°C.  Lowest Daily Temp 23.7°C.

Species List for the Week


  • Mantled Howler Monkey
  • Spider Monkey
  • White-faced Capuchin Monkey
  • Nine-banded Armadillo
  • Common Tent-making Bat
  • Western Red Bat
  • Agouti
  • Alfaro’s Pygmy Squirrel
  • Kinkajou
  • White-lipped Peccary


  • Mealy Amazon
  • Red-lored Amazon
  • Scarlet Macaw
  • Great Curassow
  • Crested Caracara
  • Mangrove Black Hawk
  • Roadside Hawk
  • White Hawk
  • Yellow-headed Caracara
  • Black-hooded Antshrike
  • Chestnut-backed Antbird
  • Common Paureque
  • Short-billed Pigeon
  • White-tipped Dove
  • Rufus Piha
  • Blue-crowned Manakin
  • Red-Capped Manakin
  • Spectacled Owl
  • Chestnut-mandibled Toucan
  • Bright-rumped Atilla
  • Great Tinamou
  • Black-throated Trogon
  • House Wren
  • Riverside Wren
  • Black Vulture
  • Turkey Vulture


  • Barred Ameiva
  • Boa Constrictor
  • Central American Smooth Gecko
  • Central American Whiptail
  • Common Basilisk
  • Clawless Gecko
  • Four-lined Ameiva
  • Golfo Dulce Anolis
  • Litter Skink
  • Mediterranean House Gecko
  • Pug-nosed Anole


  • Banana Frog
  • Black and Green Poison Arrow Frog
  • Golfo Dulce Poison Arrow Frog
  • Masked Smilisca
  • Marine Toad
  • Milky Frog
  • Red-eyed Green Tree Frog
  • Savage’s Thin-fingered Frog


  • Agraulis vanillae
  • Anartia Fatima
  • Anartia jatrophae
  • Caligo eurilochus
  • Chlosyne theona
  • Dione juno
  • Dryas iulia
  • Eueides aliphera
  • Eueides lybia
  • Heliconius erato
  • Heliconius hecale
  • Heliconius ismenius
  • Heliconius sapho
  • Heraclides cresphontes
  • Hermeuptychia hermes
  • Marpesia berania
  • Mesosemia zonalis
  • Morpho helenor
  • Philaethria dido
  • Phoebis sennae
  • Pierella helvina
  • Pyrgus oileus
  • Urbanus simplicius


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