Caracara interlude #2: scavenger hunt!

May25

On our 12th day on the Rewa River, I had to part ways with Jonathan, Rambo, Josey and Brian. We headed downriver to where I could meet up with a group of Americans (up to study the Arapaima) who would take me back to Rewa Village. When we met up, we found them sitting at the riverside, having just finished a lunch of piranha. We arranged to meet the next day below the falls, and then bid adieu and went to set up camp. Because there was a pile of fish guts going begging, I placed the pile where a nearby Black Caracara could find it.

The caracara came in quickly, but just as quickly a much larger Black Vulture came in to drive the little caracara away.

The caracara, after watching the vulture devour the guts, grabs a stray morsel the vulture has left.

Here the caracara is considering trying for another.

Uh oh! The vulture takes exception to this!

Look at the sand fly as the caracara flees with its modest prize!

Speed and agility win the day.

The caracara strikes again during a momentary lapse in the vulture’s attention.

Again, the caracara flees on foot.

This time the vulture is not as aggressive in chasing down the quicker caracara

To reward the plucky bird, I chase the vulture off.

Black Caracara in moment of glory!

Yum! Sandy fish guts!

Oh no! The vulture returns.

The caracara concedes the fish guts.

Then looks to me to see if I will intervene again.

Because help doesn’t seem to be coming, the caracara proceeds to take a few sand baths.

First the bird scratches the sand…

And then a nice lie-down.

Watching this caracara in action was truly entertaining, and a highlight of the trip for me. These birds seem very intelligent, associating humans with food, and being attentive to opportunity. It baffles me that no one has made a concerted study of their biology and behaviour yet. I can’t wait to get back to visit them again sometime!

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.

A couple of Okanagan snakes

May22

While Catherine and I were exploring the area around Vaseux Lake, We managed to see a couple of snakes I had not yet encountered in BC.

The first species was the yellow-bellied racer (Coluber constrictor mormon), a subspecies of the common racer. Like other racers I have seen, these were super fast snakes!

This was as good as I could manage for an environmental portrait, as the snake could not be convinced to pose.

Large eyes, fast snake!

Like many other Okanagan fauna, the racer is considered vulnerable in BC. Because of rampant development in this area of BC, the status of these beautiful snakes is uncertain.

The second species we found was a beautiful (and BIG) bullsnake (Pituophis catenifer). This awesome constrictor was (long ago) considered a subspecies of the pine snake, and is a species I have always wanted to encounter. We had seen one dead on the road before, so seeing this amazing snake alive was certainly a highlight.

When I pointed out the snake to this guy, he dived right in to catch the snake. I wish I had caught his name, but he was a real Okanagan outdoor lover who had a great fondness for the local herpetofaina. He was also immune to poison ivy, which is why he was able to navigate the ivy filled swamp to fetch the snake.

I managed to get this picture of the snake on a branch, but not much else. This was by far the largest snake of any kind I had ever encountered in Canada. Handling it was not intimidating, although it did musk us a bit. Interestingly, the musk of this snake was not super-offensive like that of a garter snake.

After we let it go, the snake had the last laugh…While the fellow who caught him was immune to poison ivy, I certainly was not, and got a bad case from having handled the ivy oil-laden serpent!

Guyana Riverside Birds

May17

A juvenile Great Black Hawk, Buteogallus urubutinga. These large buteos are probably the most visible raptor along the rivers, although they are often quiet. In French Guiana, they are called “Buse Urubu”, or “vulture hawk”.

Travelling by boat offers many advantages over walking, not only in saved energy and efficiency, but also in that approaching wildlife is often much easier. I have covered many of the fish-eaters we saw along the riverside before, but here are some other species that we saw quite often along the Rewa.

Here the Great Black Hawk appears in adult garb. The long bare legs are well-suited to their habit of foarging on the muddy shoreline. They prey on frogs, lizards and snakes, as well as fish occasionally. I actually did a camera trap study a few years back at a great Black Hawk nest, but the data are pretty sparse due to death of the nestling after a few days.

Another Great Black Hawk juvenile looks ready for action, but probably isn’t. Mostly they sit and call for food from their parents!

A Muscovy Duck in flight. These treehole-nesting ducks are the progenitors of the domestic strain, and are large and impressive birds. They seemed to travel long distances along the river, and spend the night on quiet ponds and branches of the river. None allowed close approach.

Red and Green Macaws (Ara chloroptera) nuzzling on a tree. These macaws, along with two other species, were loud and obvious along the river. They also travel large distances, and sometimes engage in playful mock combat on high branches.

The Blue and Yellow Macaw (Ara ararauna) was also quite abundant. They are a bit larger and deeper-voiced, but sometimes seem social with the other species.

The Swallow-tailed Kite is an amazingly beautiful raptor, which also occurs in Florida. Guyana has both migrants and resident birds.

Black Skimmers, also quite cosmopolitan, breed along the river. We often saw them in company with Large-billed Terns.

The Large-billed Tern (Phaetusa simplex) could be found nesting on sandbars. Sometimes they would dive-bomb our boat.

Three species of swallow were super abundant. We saw White-winged Swallows and White-banded Swallows most commonly, but also Barn Swallows high up on the Rewa.

Dead wood in the river was the favorite perch of most of the swallows. In the evenings, swallows would be replaced by bats and swifts, and sometimes all three taxa would fly together. .

We also saw a lot of nightjars perched on the river, in their usual cryptic fashion.

Here is a Blackish Nightjar, recently disturbed from her nest.

And here is her offspring! Can you see it?

A closer view.

A Green Ibis. These ibises were always a bit disturbed at our approach, and would scramble noisily into the forest.

Rambo checks out some tanagers high in a tree. We didn’t often see smaller species along the river, and in fact I found sedentary camp life in French Guiana was better for seeing these types of birds. What an awesome job it must be to guide people upriver in such an awesome place. If I had the means to do so, I think this is something I might like to do one day.

Some late spring shots in Victoria

May15

In Victoria last weekend, we were not only attending the Ride for Lyme kickoff, we also spent a lot of time outdoors looking for interesting animals. This is the time of year when the camas is in bloom, the snakeflies are out, and all kinds of marvelous creatures abound.

In Beacon Hill Park, dance flies (Empididae) abounded, some of them mating. Here a female snacks on a nuptial gift of a crane fly while the male copulates.

A penultimate Tibellus oblongus waits on the grasses for prey.

A gorgeous carabid of the genus Scaphinotus on a log at Island View Beach.

Not much was sleeping on the dead vegetation, but I did find a number of these bee flies (Conophorus spp.)

At first, I thought this small butterfly was just a pierid, but on closer inspection it turned out to be a Nymphalid. Erik Runquist on Twitter IDed it as Coenonympha california insulana, our version of the Common Ringlet. EDIT: it turns out this is not so common as the name would suggest. This species is endangered in BC, and is considered Red-listed in the province.

A worker of Formica obscuripes succumbs to a crab spider

Some of the black widows had modest egg sacs on the go.

At Ogden Point, a male house sparrow tries to distract me from something.

Fledglings! Pretty cute little buggers.

The camas was in bloom, although we were probably a couple weeks late for the full glory.

We made a special trip up to Mt. Tolmie to find some of the snakeflies, but managed just to find this gorgeous female.

Camas in the evening shadow is quite spectacular.

A gorgeous syrphid (Eristalis flavipes) is quite a convincing bumblebee mimic until it lands.

Quite a dark garter snake…

At Cattle Point, an eagle looks out for an easy meal.

And an otter has found one, in the form of some salmon discards from a fishing boat.

Wine takes fertilizer

May14

The Okanagan is famous for its wine, and vineyards are raking it in and popping up like mushrooms on the floors of the valleys (this is actually one of the major development pressures threatening the scarce habitats). We found an unusual nitrogen subsidy taking place when we ended up on Road 22 outside Osoyoos. I will let the pictures do the talking.

Here he is, an osprey in a vineyard…

Hmmm. Maybe I shouldn’t have had that carp yesterday…

Hmmm. Something is about to happen…

Yep! There it is!

What? What you lookin’ at?

Weirdo.

Heck with this, I’m going fishing.

Ain’t I majestic?

On a mission….yeah…

There were three osprey nests in very close proximity.

This one was closest to the road and was just being started.

In the nearby Osoyoos Oxbows, the osprey found abundant fish.

This area is an osprey-watcher’s dream.

I worry a bit though that not all of the power lines are fitted with shock-proofing insulators.

Ride for Lyme!

May13

These aren’t the ticks you’re looking for…These are Dermacentor andersoni, the Rocky Mountain wood tick. They do not transmit Borellia, but nonetheless are a spectacularly ornamented hard tick. Male is in the centre, flanked by two females.

This weekend, Catherine and I went out to Victoria to spend Mothers Day with my mom, who years ago suffered a debilitating illness caused by a spirochaete, Borrelia burgdoferi. This spirochaete, as far as we know, is transmitted in an enzootic cycle between ticks and various small mammals, reptiles and birds. When it spills over into the human population, it can cause symptoms ranging from mild rash and arthritis to fatal swelling of the brain and other organs, with just about everything in between represented. It is the most common arthropod-borne illness in North America, with hundreds of thousands of infections annually.

Primarily this disease is transmitted by black-legged ticks (Ixodes ricinus), but Ixodes pacificus, the Pacific black-legged tick is also a competent vector. While the main hotspots for Lyme transmission in Canada is southern Ontario and Quebec, there is growing evidence that locally acquired infections in BC may be becoming more common.

Nonetheless, the disease is often misdiagnosed, unrecognized, or otherwise not regarded as serious by a large proportion of the medical establishment, who are convinced that a quick round of antibiotics will kill the parasite. This is often true, but it seems that it is not always the case. Some of the most severe manifestations of Lyme disease go on to be persistent, leading to progressive debilitating symptoms. This chronic form of Lyme is the most controversial, as the leading treatment orthodoxy does not recognize the existence of long-term infection.

The existing diagnostic criteria are often insufficient, for while they pick up the so-called classic Lyme symptoms very well, an unknown percentage of sufferers never experience the characteristic bulleseye rash (erethema migrans) or early arthritic symptoms. Molecular techniques used for diagnosis are designed only for those sufferers presenting with classic Lyme symptoms, and even at this they have very poor performance. So the situation in Canada is there is transmission of a debilitating parasite, which can be difficult to diagnose and treat, and medical and disease-control officials are unwilling to acknowlege the extent and nature of the problem.

Anyway, something is being done to address this illness, both from a public information perspective as well as from a fundraising one.

Two young fellows from St. Catharines, Ontario are undertaking a cross-Canada bicycle ride to raise money for and awareness of the disease. Daniel Corso and Tanner Cookson have a friend named Adelaine who was recently affected by Lyme disease, and realized what a tough and enduring problem the disease would be in her life. Discovering that the treatment options and diagnostic situation in Canada need to be updated, the two decided that their love of athletics may offer some kind of solution in the form of an endurance fundraiser. If nothing else, their ride might help raise Adelaine’s spirits.

On Sunday, they began their effort with a rally at Victoria’s Centennial Square, where they announced the ride and introduced their support team (their dads!). Since it was Mothers Day, they also made a special effort to acknowledge the mothers affected by the disease (like mine).

For more information on Lyme borelliosis in Canada, visit the CanLyme website, and to follow along with Tanner and Daniel’s ride, check out rideforlyme.ca.

This is a really important health issue in Canada, and this is a great way to raise awareness and funds for research. If you happen to be on their route, be sure to go and cheer them on!

Below are some pictures from the Victoria events.

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Back from vacation!

May8

We have been back nearly a week now, and the time in the Okanagan was absolutely amazing! I have not had time to work up many posts, but I hope to do so very soon. In the meantime, here are some landscapes to give an idea of the environments we were in.

Going on Vacation!!!!

Apr24

So Catherine and I have a week off this coming week, so we are planning to go for a bit of a vacation in the Okanagan. We will be mostly in the boonies, camping and searching for critters, so will be out of contact for a bit. It also means I will have to interrupt my series on the Guyana trip. When I come back it will be all Guyana, all Okanagan, all the time!

Our transport will be a venerable old Honda Civic that Catherine picked up for 500 bucks! It has new brakes and everything so should be a safe and reliable steed to carry us eastwards.

We are going to look for a long list of interesting animals, from scorpions and rattlesnakes to a few special spiders (Argiope, Antrodiaetus, Latrodectus [of course!)). Catherine and I will be trying to get some shots of rubber boas as well. Who knows what we will see! This will be a time for us to get out and get busy searching for whatever we can find. I think it will be awesome.

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.