My favourite photos from Guyana

Dec1

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Sometimes, a lucky circumstance presents itself, and you are ready to seize the opportunity. I got many wonderful photos on my trip up the Rewa River in Guyana this spring, but ironically enough, my favourite set of shots came within the first hour on the boat!

We spotted this hawk on the left bank of the river, and we quietly motored over to it. This was a Roadside Hawk (Rupornis magnirostris), a small, primarily insectivorous hawk found from Mexico to northern Argentina. It has quite a boring name, but it is actually quite lovely and unusual, with a body form akin to an accipiter rather than its Buteo cousins.

Anyway, these were some of the loveliest bird pics I got on the whole trip, so please enjoy them!

The hawk was very obliging as a model, turning this way and that, and looking at us with curiosity.

This view shows how close in body form they come to an accipiter. Short wings, long tail, fine barring on the breast, broad bars on the tail.

In fact, other birds are convergent in form to accipiters, notably in America the forest falcons.

Such a lovely hawk! For larger versions of these images, click here.

Drifting on the Rewa

Nov28

To get back to my posting on the trip to Guyana I made this spring, I should get some of the most charismatic megafauna out of the way.

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OK! Are you still with me? Let’s talk about drifting on the Rewa! When we reached our highest-upstream camp on the Rewa, Josey, Brian and Rambo took Jonathan and I out “drifting” several times, basically motoring upstream a few kilcks and then drifting and paddling the boat downstream, in the hopes of seeing wildlife that would otherwise be scared by the motor. We did this several times, most often in the evening to get views of all the animals that come to the river to bathe or drink.

Using the drifting technique, we were able to see several family groups a capybaras, a species I had not previously seen in daylight!

The boat was not as quiet as a canoe, but after days of motoring on the river, this was pretty nice!

The capybaras were often accompanied by large horseflies. Surprisingly, none of these flew over to us, even when their hosts slipped into the river.

The capybaras take to the river when disturbed, and can even navigate extremely fast currents. I remember many times at Parare in French Guiana being startled by big capybaras splashing into the fast-flowing Arataye. This stretch of river was much more sedate, so allowed us to see the animals swimming quite well.

As usual, some of teh capybaras has things perched on them. This is a giant cowbird, which feeds on ectoparasites on the large rodent. Even Black Caracaras do this, but we did not see one doing so.

Drifting quietly also allowed us to spy wildlife we might have missed from going to fast: this iguana was well-concealed at most angles.

We also saw a number of tapirs, which often come to water to bathe in the morning an evening. These are the largest of the South American ungulates, and are very impressive see!

The tapir is a very shy creature in the wild, probably because they are hunted by anybody who can kill them! Unlike capybaras, which breed rapidly, tapir are one of the many species that quickly drop in population with even moderate hunting.

Here was a female tapir we saw at noon, not drifting. I did not get a shot of it, but she had big wounds in her flank, likely from a jaguar or puma. Rather than a relaxing bath, this poor tapir was likely hiding from a predator in the water.

This is what a tapir looks like shaking off!

They look much more elegant when their snout isn’t flapping madly!

Gorgeous animals! We felt really lucky to be able to see so many of these shy and magnificent creatures!

Guyana: a myrmicine trapjaw ant

Jun8

Sometimes, I never really know just how special the subjects I photograph really are. During the second night we spent on the Rewa river, I was dealing with blistered, sunburned hands as well as moderate fatigue. After dinner, it was tempting to crawl into my hammock and snooze, but I forced myself to go out, at least for a bit, and try for some nighttime arthropods.

A leafcutter trail briefly caught my attention, but doing any elaborate setup for shooting was beyond me that evening.

Right in our camp, just a few metres from the cooking tarp, I found these amazing ants. At first I thought they were leafcutters, but when I got closer I realized that this was some kind of myrmicine version of a trap-jaw ant! I had never seen these in French Guiana, and in fact did not know of their existence. These were Daceton armigerum, one of only two species in the genus, related to the leafcutters, but tree-dwelling and predaceous. They have evolved these amazing, lightning-fast mandibles, like their ponerine equivalents, which they use for seizing prey. Their extremely crazy-shaped heads contain the heavy musculature needed for this strategy, and a trigger mechanism to release all of the force built up in a single stroke. For a great paper on this, showing the internal morphology, click here.

Unlike the ponerine trap jaw ants, they are quite fast and active, with seemingly large colonies contained in hollow trees.

Adult-adult trophallaxis is a difficult affair with these massive jaws, and the ants seem to use their maxillae for this.

I can’t get over these amazing heads!

A few of the ants walking towards nest entrances had prey, such as this pretty but unfortunate beetle.

Social life: most ants that passed each other on foraging trails up the tree at least antennated each other. It seems that other than tiny Crematogaster, no other ants are tolerated on this tree.

A few workers were carrying males, but whether these were alive or dead was hard to tell.

The males looked very different from the workers, as with most myrmicines, but really not that different from a lot of other mymicine males.

Nest entrances seemed to be scattered around the trunk, and these workers looking out show that there are definite castes in this species.

Some nest entrances were busier than others! Here are some males poking out along with a range of various-sized workers.

With a bit of waiting, the males came further out.

Daceton armigerum was certainly one of the oddest ants I had ever seen. If I had known how unusual it is to photograph them in situ, I probably would have devoted more time to photographing them.

The lesson is, even if something is big, obvious and odd, if it is from the rainforest, it may not have received much attention!

Gronenberg, Wulfila. “The trap-jaw mechanism in the dacetine ants Daceton armigerum and Strumigenys sp.” The Journal of experimental biology 199.9 (1996): 2021-2033.

Moffett, Mark W., and John E. Tobin. “Physical castes in ant workers: a problem for Daceton armigerum and other ants.” Psyche: A Journal of Entomology 98.4 (1991): 283-292.

Guyana: the other archosaurs

May23

On my trip to Guyana, I was not only on the lookout for birds, but also their relatives, the crocodilians. Guyana is home to 4 species of caiman, including the largest and smallest species in the world.

On the Rupununi and the lower Rewa, I was amazed at how many black caiman there were. Paleosuchus niger is the largest caiman, and in my mind I still thought of them as very rare. Conservation efforts and a reduction of hunting have caused a definite improvement for this beautiful species across their range.

These large caiman can be dangerous, so while in their territory we made sure to bathe in shallow water where we could see them coming. With predators such as this, you are probably safe if you do not enter a good ambush zone, such as a place with a steep dropoff.

Rambo holds a baby black caiman, which we found in an aggregation near our camp one night. In Rambo’s hometown, Yupukari, there is a conservation and research outfit called Caiman House where the locals participate in monitoring and study of black caiman. Rambo has experience capturing, tracking and nest monitoring these impressive animals.

Jonathan posing with a beautiful little caiman. The babies tend to stick to protected “nursery” areas, as they are easy prey for birds and large fish.

If you want a juvenile caiman to open its jaws, a little tickle on both sides of the base of the lower mandible will produce this posture.

Above the major rapids, the Rewa is devoid of black caiman, and instead spectacled caiman and dwarf caiman abound. Here is a Schneider’s dwarf caiman cruising by our camp. I had seen Cuvier’s dwarf caiman in French Guiana (small ones living in small fast creeks), but seeing the adult Schneider’s was a revelation. These guys get fairly large, and inhabit even slow-moving sections of the river.

Brian tossed a piranha piece at this dwarf caiman, and it seemed to know exactly what was going on. It has probably seen several fishing groups upriver and has learned that when a boat pulls in, fish pieces from cleaning are often tossed out. This one had some fishing line attached, so we could try to haul the beast into shallower water. By the time the caiman got it’s feet planted, any further movement of the caiman was impossible!

All of the crocodilians we met were quite shy, and even large black caiman would flee if we caught them in shallow water. This dwarf caiman was willing to come for tossed fish, but not if we were too close to the water’s edge.

Some of the bolder caiman would stay on the bank as our boat passed, but most of them would flee for deep water.

If you go out in the woods in the tropics, be sure to look out for the local crocodilians! They are fascinating and beautiful animals.

Symbiosis and inspiration in the jungle

Apr24

A large nest of Polybia liliacea. This is one you probably do not want to disturb!

Compared to my time in French Guiana, I found that travel by river offers a much greater volume of observations than walking in the forest. When I was in French Guiana travelling trails on foot, I was lucky to encounter one example of a particular habitat in a day, but on the boat I could see the same type of habitat many times over. Needless to say, this was a great natural history lesson in the making.

One of the particular habitats we saw a lot of was the meanders of the river, where the river loops and bends around long curves. These bends form spontaneously via the action of vortices along curves in the river, and on the inside of each curve there is high deposition of silt (on the outside is a high level of erosion). This is the process by which oxbow lakes are formed. The result is that the inside curve is an area that was formerly river-scoured, but now has abundant new soil. Within these areas are a sparser forest, dominated by a few fast-growing tree species such as Cecropia and Triplaris (called “Long John” in Guiana). These are habitats that harbor a beautiful example of tropical symbiosis.

Yellow-rumped Caciques (Cacicus cela) bathing together in the early evening. These are highly social birds with colonial nesting.

One of the first things that I noticed about these meander forests is that they more often than not contained a large colony of nesting Icterid birds, either Green Oropendolas, or Red-rumped or Yellow-rumped Caciques, with the latter being the most common. All of these birds are known to preferentially nest in association with large, aggressive wasp species, such as Polybia rejecta and Polybia liliacea. This is thought to benefit the birds in two ways. Number one is that the wasps can help dissuade nest predators, such as monkeys. Number two is that populations of predaceous wasps may reduce the parasite burden (particularly parasitic Philornis flies) that the nestlings endure.

A colony of Cacicus cela nesting in association with Polybia liliacea. We also saw them with Polybia rejecta and Epipona spp. wasps.

In turn, the wasps nest in these particular trees for a reason. They nest in trees that are occupied by Azteca ants, a type of dolichoderine ant that basically owns the tree, with large carton nests containing perhaps millions of moderately small workers and hundreds of queens. The wasps nest here because the Azteca repel one of the wasps’ worst enemies: army ants. Although army ants (Eciton burchellii and Eciton hamatum) vastly outweigh the Azteca individually, the Azteca, by virtue of their overwhelming numbers, can keep army ant columns from advancing quickly up the tree (Servigne 2003). As army ants are all about blitzkrieg, and quickly stripping an area of profitable prey (Kaspari et al. 2011), they have learned to avoid the Azteca trees, which would take a protracted guerilla campaign to overcome. It has been recently shown that the wasps in turn benefit the ants, helping to repel some of their predators, such as woodpeckers (Le Guen et al. 2015)!

Nesting association between Azteca (left), Polybia (centre) and Cacicus (upper right).

In examining again and again the morphology and placement of the nests in these associations, I was struck by a thought: perhaps the birds are also a net benefit to the wasps and the ants as well! I know from my research how formidable Red-throated Caracaras are in destroying wasp nests….What if these large numbers of nesting caciques help protect the wasps from the caracaras? It is not so outlandish a hypothesis, as the large nesting aggregations of caciques have been shown to mob bird nest predators such as monkeys and Black Caracaras and drive them away (Robinson 1985). Perhaps the Red-throated Caracaras may be driven away as well by large numbers of defensive caciques.

Could wasps derive protection from Red-throated Caracaras from cacique or oropendola colonies?

I was amazed by the numbers of large wasp nests we encountered at these sites, in stark contrast to the relatively low numbers I encounter in normal forests. It is not just the presence of ants which is keeping these nests safe, as Azteca occur in large numbers all over the forests. I think something else is going on here to help protect these wasp nests, and I bet it is the birds. Anyway, I would love to go and study this sometime, but this story just reinforces to me the inspiration that I only get by going to the field.

The Black Caracara, a known predator of cacique nests, is sometimes mobbed and driven away by Yellow-rumped Caciques.

References

KASPARI, M., POWELL, S., LATTKE, J., and O’DONNELL, S. 2011. Predation and patchiness in the tropical litter: do swarm-raiding army ants skim the cream or drain the bottle? J. Anim. Ecol. 80:818–23

LE GUEN, R., CORBARA, B., ROSSI, V., AZÉMAR, F., and DEJEAN, A. 2015. Reciprocal protection from natural enemies in an ant-wasp association. C. R. Biol.

MCCANN, S., MOERI, O., JONES, T., O’DONNELL, S., and GRIES, G. 2010. Nesting and Nest-Provisioning of the Red-throated Caracara (Ibycter americanus) in Central French Guiana. J. Raptor Res. 44:236–240.

MCCANN, S., MOERI, O., JONES, T., SCOTT, C., KHASKIN, G., GRIES, R., O’DONNELL, S., and GRIES, G. 2013. Strike fast, strike hard: the Red-throated Caracara exploits absconding behavior of social wasps during nest predation. PLOS One 8:e84114.

ROBINSON, S. S. K. 1985. Coloniality in the Yellow-rumped Cacique as a defense against nest predators. Auk 102:506–519.

SERVIGNE, P. 2003. L’association entre la fourmi Azteca chartifex Forel (Formicidae, Dolichoderinae) et la guepe Polybia rejecta (Fab.) (Vespidae, Polistinae) en Guyane Française. Universite Paris-Nord.

Caracara interlude #1: Camp scavenger

Apr22

A Black Caracara juvenile watches the camp from the safety of the trees. The juveniles can be recognized by lighter facial skin and black spotting on the undertail coverts.

Remember that Payara head we had left over from our meal? Well, we found a use for it!

We left it out for the Black Caracara (Daptrius ater) a small riverine caracara that often scavenges at human settlements and temporary camps. This behaviour seems pretty ingrained, and most times when we stopped along the river the caracaras would drop by in order to check whether we were cleaning fish or discarding waste.

Black Caracara with a morsel

When the head was relatively fresh

And after some significant feeding! This head is now looking pretty grotesque.

Black Caracaras are small raptors with light wing loading and graceful flight. They are both generalist predators and scavengers (and have been reported to fish!), and were once considered closely related to Ibycter americanus (Red-throated Caracaras). The Black Caracara is also associated with tapirs and capybaras, picking ectoparasites off of their skin. These seem to be the only animals that tolerate these birds, as most others chase them away (they are significant nest predators of other birds, such as oropendolas and caciques).

Nesting behaviour is virtually unknown in this species, with only a single reported nest being observed. I quizzed the locals I met on this trip and met very few who claimed to have seen a nest.

Watching these observant and seemingly intelligent birds is a true joy, and was very inspiring. The relative lack of study of these birds leads me to contemplate studying them in the future. The rivers of this region would be a great base of operations for comparative study of four species of caracara.

These caracaras seem to have a small crest that they erect at certain times.

We eat fish

Apr21

On an Amazonian river, the birds and mammals are impressive, but there is also a huge amount of nutrient cycling in the water. These rivers cover vast areas of forest where huge amounts of protein become available during the wet season. Because of this, the predatory animals along the river are very often piscivorous, feeding on fishes occasionally or exclusively. This post is a brief photo introduction to a few of the fish-eating animals commonly seen along these rivers.

Fishing spiders (Pisauridae) were best photographed at night, as during the day they are extremely skittish and quick to hide. We did not see any giant examples, as I had in French Guiana, but I did not make a concerted search either.

The Green Kingfisher (Chloroceryle americana) is an impressive kingfisher species also found in the Southern USA

The related Amazon Kingfisher (Chloroceryle amazona), by contrast is even more robust and has a much larger bill.

The White-necked Heron, Ardea cocoi, is the Amazonian equivalent to the Great Blue Heron. We saw a great many of these. They would often fly in front of the boat for may hundreds of metres.

The Sunbittern (Eurypyga helias), despite its name, is not a bittern at all, but rather related to the gallinules.

Here is a juvenile Rufescent Tiger Heron (Tigrisoma lineatum), one of the more magnificent of the Tiger Herons.

The adult Rufescent Tiger Heron is a gem.

Something familiar…Sort of. This is a Neotropical Cormorant (Phalacrocorax brasilianus).

This one I remember from Florida. The Anhinga (Anhinga anhinga), or snakebird is like a cormorant which swims with its body submerged. Interestingly enough they also soar on thermals!

Osprey down here are all migrants from elsewhere.

Giant River Otters (Pteronura brasiliensis) were abundant along the Rewa, always travelling in groups. They cooperatively hunt for large fish and caiman, and have some real mustelid attitude!

Giant otter snacking on a fish.

In addition to these avian, arachnid and mustelid predators, we also had to be predators in order to eat during the trip. I dislike catching fish for sport, but when it became clear that there was no other protein along for the ride, we turned to fish with gusto. The fish along the Rewa are diverse and abundant, and can be reliably caught with simple equipment. Under sustained commercial fishing, the larger fish would likely be wiped out completely, but since the Rewa has so few visitors, there are large stocks of big fish available. Catching fish in the dry season is especially easy, as all the fish which ordinarily would be foraging in vast areas of flooded forest are concentrated in the river.

This black piranha will be our evening meal.

Catch of the day: some peacock bass and something we will use as bait tomorrow.

Peacock bass, grilled.

Josy with the “vampire fish” or Payara, Hydrolycus scomberoides

The long fangs of these fish are quite impressive, fitting into slots in the upper jaw.

With direct flash, the fish looks even more scary!

Nonetheless, the payara is good eating. We also used the head for a special project! Stay tuned for the next post!

We did all our fishing with handlines, baited usually with pieces of small piranha. Here Brian and Rambo fish for tiger catfish

Here I am with a tiger catfish, genus Pseudoplatystoma. This is a great fish for eating, and two of these fed us for 3.5 days. Photo by Jonathan Meiburg.

The tiger catfish are absolutely gorgeous.

Further upriver, we caught some aimara (Hoplias aimara), which I was familiar with from working in French Guiana.

Brian and Jonathan with a big aimara. Jonathan is wearing Catherine’s home-made tubular headwear as protection from the sun, and maybe so this fish’s relatives don’t recognize him. All aimara claims for damages should be made to Jonathan’s record label, Sub Pop Records.

The day’s catch, with some to be dried to take home to Yupukari.

Aimara drying in the sun.

Stingless bees taking some of the aimara. Unlike other bees, meliponines feed scavenged meat to their larvae. Bees eat fish too!

On the river

Apr20

For the journey up the Rewa river, we were to travel into the forest by boat. From Georgetown, that involved a flight to the interior of the country. These flights leave from Ogle, a smaller airport on the outskirts of Georgetown. Our destination was Annai, a large Macushi village on the edge of the Rupununi Savanna, and close to our river journey start on the Rupununi river.

At Ogle is where we saw our first caracara! In the distance along the runway, a Yellow-headed Caracara (Milvago chimachima) forages in the grass.

Boarding our flight to Annai on a Cessna 208 Grand Caravan operated by Trans Guyana Airways.

A high view of the dry season rainforests along the Essequibo river.

Jonathan takes pictures from the plane.

The village of Annai, on the edge of the Rupununi Savannah.

Coming in for a landing at the airstrip in Annai.

Leaving our plane behind, with the Rupununi Savannah stretching off in the distance.

The official greeting mantis in Annai. In the hinterlands, greeting mantises are often late-instar nymphs.

Domesticated Muscovy Ducks. The wild ones may be found just down on the river.

The dry season savannah is quite parched-looking, but in the wet season much of the area around Annai is actually swampy and criscrossed by streams.

Here we meet with the owner of the boats we will be travelling in, Ashley Holland, owner of the Rupununi River Drifters ecotourism company based in Yupukari.

Our travelling companions and guides. 1: Rambo, a somewhat quiet guy who has an excellent knowledge of the local bird fauna.

2: Josy, employed nominally as the cook, also extremely savvy in the forest creatures, particularly the black caiman. Affectionately known as the “YGP”or “young grandpa” as he has just become a grandfather!

3: Brian, the senior boatman, a military veteran with amazing mental maps of the rivers at all levels. This is the guy you want navigating shallow twisting channels in the middle of the night based on dimly-seen landmarks.

We launched onto the river without much fanfare, heading downstream to the mouth of the Rewa river. For some idea of how the river looks in teh dry season, consider this picture of a Jabiru stork.

That high bank in the background would be completely inundated in the wet season. That is a difference of about 20 feet, and the river can rise that much in about a week.

Now consider this other photo of the stork. Because it is cool.

We were still in the savannah region, so we did see quite a few Yellow-headed Caracaras.

In addition, Northern Crested Caracaras were also present. In one day, we had managed to see 1/2 of the caracara fauna of Guyana! This one is being mobbed by Southern Lapwings.

Both the Yellow-headed and Crested Caracaras are much more typical caracaras than Ibycter. They are scavengers and generalist predators, filling an almost equivalent niche that larger corvids do in other parts of the world.