Archives

Symbiosis and inspiration in the jungle

IMG_2932

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.

IMG_0485

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.

IMG_3506

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)!

IMG_8704

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.

caracara

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.

IMG_4962

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

IMG_3611

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.

IMG_1844

IMG_2350

Black Caracara with a morsel

 

 

IMG_2050

When the head was relatively fresh

 

IMG_2370

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.

IMG_2180

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

 

 

We eat fish

IMG_0805On 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.

IMG_0550

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.

 

IMG_0783

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

IMG_0786

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

 

IMG_0388

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.

IMG_1246

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

IMG_1636

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

 

IMG_3940

The adult Rufescent Tiger Heron is a gem.

IMG_5621

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

IMG_5685

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!

IMG_5821

Osprey down here are all migrants from elsewhere.

IMG_2827

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!

 

IMG_1001

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.

IMG_8614

This black piranha will be our evening meal.

IMG_1495

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

 

 

IMG_5556

Peacock bass, grilled.

 

IMG_1840

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

 

IMG_1836

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

 

IMG_1844

With direct flash, the fish looks even more scary!

IMG_1858

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

 

IMG_1813

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

 

IMG_8597

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.

IMG_2074

The tiger catfish are absolutely gorgeous.

 

 

IMG_8951

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

IMG_8969

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

 

IMG_8742

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

IMG_3548

Aimara drying in the sun.

 

 

IMG_3515

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

 

 

 

 

On the river

 

IMG_1482

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.

IMG_0022

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.

 

IMG_0074

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

IMG_0140

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

IMG_0160

Jonathan takes pictures from the plane.

IMG_0144

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

 

 

IMG_0165

Coming in for a landing at the airstrip in Annai.

 

IMG_0169

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

IMG_0173

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

IMG_0182

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

IMG_0192

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.

IMG_0194

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.

IMG_8470

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

IMG_8481

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!

IMG_8622

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.

IMG_0288

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.

 

IMG_0297

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

IMG_0621

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

IMG_0638

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.

IMG_0241

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.

 

 

 

 

A journey to meet the Red-throated Caracara in Guyana

 

IMG_1663

Recently, I made a long journey in South America, up the Rewa River in Guyana, in search of caracaras and other Amazonian fauna.

The story of this trip takes a bit of explaining. Last year, after our abortive research mission to Honduras, Catherine and I were holed up at my mom’s in Victoria writing our respective theses. We had little occasion to go to Vancouver, but in April we both needed to go over to take care of some administrative details at the university. While sitting in the lab after managing our red tape, the phone rang. As usual, no one in the lab jumped up to get the phone, so I picked it up and found that the person on the other line was looking for me, and wondering if I wanted to talk about caracaras.

 

IMG_1803

Jonathan Meiburg, looking at home far up the Rewa, in the heart of the Amazonian forest region.

 

Well, after a good 90 minute conversation about my favourite loud birds and their relatives, I found out that the fellow I was speaking to was Jonathan Meiburg, a professional musician and a student of the biology and biogeography of striated caracaras (the fabled “Johnny Rook” of the Falkland Islands). I found out that Jonathan was a great student of caracara biology, and had written a wonderful thesis on the Johnny Rook (which he should really put online…I am not kidding, it is an absolute pleasure to read!) which also covered the biology and paleontology of the other caracaras.

We continued to keep in touch from that time, until last fall when Jonathan invited me to accompany him on a journey to the Amazonian forest to meet the Red-throated Caracaras, which he and I agree are the oddest of a very odd group of birds. The plan was to go to the Republic of Guyana, where Jonathan had some acquaintances working, and to journey up the Rewa River to the heart of Ibycter territory: the primary rainforests of the Amazonian bioregion.

total journey

In the following posts covering the trip, I will not stick to a travelogue format, but rather will skip around, introducing the characters (human and otherwise) we met along the way. As I write this, Jonathan is still out there in the forests of Guyana, hunting for the elusive heart of Amazonia, no doubt being serenaded by the harsh screams of the Red-throated Caracaras.

river HDR2

 

 

Are ants really the primary predator of wasps in Neotropical forests?

IMG_1975

 

“Ants, particularly army ants, exert such strong predation pressure that they are considered to be the main driving force in the evolution of Neotropical social wasps, to the point of influencing their nest architecture.” –Corbara et al. 2009

It is not too surprising that many tropical ecologists consider ants to be such superior predators. Come across an army ant swarm, and you are likely to witness many hundreds of acts of predation playing out before your eyes on the jungle floor. An army ant swarm is like a blitzkreig, and it would seem that nothing can stand in its path. Even social wasps, normally so aggressive in nest defence, will abandon their nest immediately rather than risk the entire colony in a vain attempt to repel the tens of thousands of army ant raiders.

But is it really accurate to infer from these types of observations that the risk of predation by ants on nests of social wasps surpasses that of all other predators? This never really sat right with me, particularly considering how an army ant predation event on social wasps is a random, and probably relatively rare event. Army ants cannot see, and they do not target wasp nests in particular. Even those species which prefer preying on social insects are much more likely to be raiding other species of ants rather than wasps.

How would army ants stack up against a true specialist wasp predator, such as the Red-throated Caracara? Luckily, I had some data to work with to answer these questions.  I have written this up in a paper in Insectes Sociaux, which unfortunately is not open access, but you can email me for a copy!

[flickr video=8426256672 secret=d098a314bc w=720 h=481]

A Polybia nest brought via an overhead branch.

From our nest camera study in 2008 and 2009, we had footage which showed adult provisioning of single caracara chicks (McCann et al. 2010).  In order to calculate the number of wasp nests per day consumed by the chicks, we lumped all events of provisioning with nest fragments of the same genus being brought within 30 min of each other.

Each of these events was then termed a “unique nest delivery”. By summing the unique nest deliveries daily for the two sampling periods, we found that a single caracara chick eats between 7.8 and 12.4 nests per day. If we assume that the adults are eating just as many wasp nests, a group of 6 adults would consume 46-74 nests per day (not counting the chick). On a per-hectare basis, caracaras could possibly be consuming 0.117-0.186 nests/ha/day.

IMG_5315

Wasp-eating machine! Is the Red-throated Caracara a major source of colony failure in Neotropical social wasps?

 

To compare this rate of predation with that of army ants, we needed an estimate of army ant density. Unfortunately, only one method for assessing Eciton density has been developed, for Eciton burchellii.

This method was developed by Nigel Franks, and relies on the predictable behaviour of swarms of this species (Franks 1982). These ants raid in a roughly linear column from their bivouac site, extending the raid 7 m per hour. The landscape at any given time is thus like a plane with many lines of ants of similar length scattered about it at random. The probability of encountering a swarm is thus proportional to the density of colonies in the area, and by repeated walks of suitable length, an estimate of the total density can be made. Mathematically-inclined readers may realize this is an extension of the problem of Buffon’s Needle*, and relies on similar calculations Incidentally, Buffon also published the first species description of the Red-throated Caracara. You can read about that here.

Catherine Scott and I went to the Nouragues station in 2012 to perform an estimate of the Eciton burchellii density in order to calculate the potential impact of army ant predation on social wasps.

trails etc

Here are the three trails we surveyed. We walked each trail 5 times, for a total of 72 km. Each encounter with an Eciton swarm is marked with an X. We encountered Eciton burchellii only 5 times, translating to a density of only 0.021 swarms/ha.

Our estimate for Eciton burchellii density was a moderate 0.021 swarms/ha, pretty well comparable to other lowland rainforest sites. But how many wasp nests could each swarm take? Well, there is no easy answer for this, but there was only one study that documented rates of army ant predation on social wasps. Ruth Chadab published an estimate of 1-3 nests per day taken by Eciton hamatum, a related species with a greater predilection for social insect nest plundering (Chadab, 1979). Because we had no estimate for daily wasp nest predation for E. burchellii, we used Ruth Chadab’s estimate of 3 nests per day as a rough approximation. This translates into 0.06 nests/ha/day, or 24 nests per day in a 400 ha caracara territory.

IMG_5739

We conclude that Red-throated Caracaras, as specialist wasp predators, are comparable to army ants in their predatory impact on social wasps. Taken together with other species, such as monkeys, antshrikes (McCann et al. 2014) and woodpeckers (Sazima 2014), social wasps are at considerable risk from vertebrates.

So what about vertebrate predators and the adaptations of social wasps against them? If we look carefully at social wasp behaviour, it is easy to see how much vertebrate predation has influenced both behaviour and nest architecture. For one, massed stinging attacks are ineffective against ants, and are definitely a feature that protects wasp colonies from vertebrate attack. Audible warnings, such as those produce by Synoeca, would not be effective against ants, nor would visual camouflage (ants hunt by scent, and army ants cannot see anyway).

leipomeles

Visual crypsis of Leipomeles dorsata nest.The envelope of this nest is fitted carefully to the underside of the leaf, and made to resemble it in colour.   Photo by Alex Popovkin, used under a Creative Commons 2.0 licence.

Likewise, armouring of a nest, such as is seen in some Epipona and Chartergus wasps (Richards 1978), would have limited effect on ants, as they can enter and take prey through any opening a wasp can. Analogous armouring consisting of a mud envelope is evident in this Polybia singularis nest. In 5 seasons I worked at the Nouragues camp, this nest never fell prey to the caracaras.  What is  notable about the nests of most wasps with armoured envelopes is that they are often located high up in trees, easily visible on distal branches. The wasps may gain some protection from ants by nesting so high, which they can afford because they are (by virtue of the strength of their nest) already relatively safe from vertebrate attack.

IMG_2842

Nest of Polybia singularis, with an envelope of hardened mud. Such nests can weigh up to 5 kg! This nest was never taken by caracaras in all the years I studied at the Nouragues station.

 

As more and more naturalists describe and publish their observations of Neotropical biology, we are continually discovering new things. I hope that this study, gained in a few short months of research adds to the understanding of the role of vertebrates as predators of social wasps, especially the important role of the Red-throated Caracara. In a future post I will take up the issue of the diversity of wasps taken by caracaras, and what some of the numbers might mean for tropical wasp biologists.

Please do go and read the paper, and if you do not have access to it email me for a copy!

References

CHADAB, R. 1979. Army ant predation on social wasps. PhD Thesis. University of Connecticut, Storrs, CT.

CORBARA, B., CARPENTER, J. M., CÉRÉGHINO, R., LEPONCE, M., GIBERNAU, M., and DEJEAN, A. 2009. Diversity and nest site selection of social wasps along Guianese forest edges: assessing the influence of arboreal ants. C. R. Biol. 332:470–479.

FRANKS, N. R. 1982. A new method for censusing animal populations: The number of Eciton burchelli army ant colonies on Barro Colorado Island, Panama. Oecologia 52:266–268.

MCCANN, S., MOERI, O., JONES, T., and GRIES, G. 2014. Black-throated Antshrike preys on nests of social paper wasps in central French Guiana. Rev. Bras. Ornithol. 22:300–302.

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.

RICHARDS, O. W. 1978. The social wasps of the Americas excluding the Vespinae, p. vii, 580 p., 4 p. of plates : ill. (some col.) ; 2. British Museum (Natural History), London.

SAZIMA, I. 2014. Tap patiently, hit safely: a preying tactic of the White Woodpecker on social wasp nests. Rev. Bras. Ornitol. 22:292–296.

 

 

 

 

Article in the Bulletin of the ESC published!

 

Untitled-1

Wow! Are those rays of glory coming out of my browser window? Yes! Yes they are! It all happened when I loaded up my latest article on Red-throated Caracara biology! It was published in the March edition of the Bulletin of the Entomological Society of Canada, and gives an exciting entomological overview of my research with these loud and amazing birds. So head on over and check it out, and while you are there, check out the rest of the awesome entomological content as well.

A strategic withdrawal from the field

IMG_4011

The last fieldtrip north of Gualaco to map out caracara habitats had a couple of interesting effects on our planning. The first was that Catherine injured her knee from all the walking over rough terrain, and found that last weekend she could barely walk around the apartment. This is not an ideal condition for fieldwork, and will require at least several weeks to heal.

The second thing we realized is just how difficult the terrain will be for doing VHF tracking of caracaras for home range estimation. From our interviews with the local people, it would seem that the caracaras’ range is upward of 6 square kilometres at minimum, and hence our daily tracking success will depend heavily on luck rather than getting good early bearings on our tagged birds. In addition, the initial capture is expected to be much more difficult, because of how long we will need to wait at a capture site before having any hope of seeing caracaras nearby.

All of these factors have led us to re-plan the fieldwork, such that we will return to Canada for several weeks, and return in mid-to late March for the onset of the breeding season. This will also allow us to finish writing tasks that we have had much difficulty with here (there is no power for computing out where we work). In our absence, Isidro Zuniga will continue a biweekly field program of searching out other caracara groups, and marking their locations for later attention.

The caracaras here in Honduras are at severely reduced levels. Whereas once they were very common, they are now so scarce that most people have not ever seen one. By way of example, last week we walked 54 kilometres, this week 56 km, and encountered caracaras but once. Over a similar distance in French Guiana, I would have expected to encounter caracaras 15-20 times. The birds here seem to have much much greater home range sizes than those in French Guiana, perhaps because they are unconstrained by the territoriality of neighbouring groups, or maybe because the density of food (social wasps) is much lower here. Either way, it makes for some difficult realities for fieldwork. Getting sufficient sample size for home range estimation using VHF radio tracking will be extremely difficult, if not impossible. It will certainly not take place over the optimistic schedule I had budgeted for this work.

So when we return, we would like to have in place some further funding to secure an alternative tracking technology, such as GPS or satellite tags; with these at least we could be reasonably sure to get some usable data. We will also focus on the nest monitoring phase of the study, assuming we can find some active nests. This is also expected to be physically demanding work, but at least with nest cameras other fieldwork can be pursued simultaneously.

I will write another post about what we did see on the second field trip, but for now we must concentrate on getting ready to go. Don’t worry, this is not the end, it is only the beginning.

IMG_4877

Getting started!

IMG_5294-2

So after getting settled in Gualaco and taking care of some red tape, Catherine and I, along with Isidro Zuniga will be headed out to the field tomorrow. We expect to be doing a bit of mapping, and getting familiar with the territory, after which we will attempt to do a call-playback survey for caracaras.

I managed to score some sweet GIS layers from the ICF guys in Tegucigalpa, and from what I am seeing, the caracaras being followed last year are in a belt of forest with very limited human habitation. Apparently they are seen occasionally all around, even as far as just east of Gualaco, but their stronghold seems to be where the people are not. Of course, we have no data of our own yet, but soon we shall see!

I am hoping the terrain will be workable, the caracaras amenable and the weather enjoyable! Wish us luck!

In Gualaco!

IMG_3297

Morning in Gualaco, looking southwest. Those are the cloud forests of the Sierra de Agalta National Park in the background.

We have arrived (finally) in Gualaco, after a crazy few days passing from Vancouver to San Pedro Sula to Tegucigalpa. 

It has been quite hectic getting settled, and I am having difficulty re-adjusting to Spanish. We have an apartment now, and so are feeling a bit less nomadic than when staying at the hotel. 

We went out and saw the areas we will be working in yesterday, and they are in really really rugged terrain! The forests are mostly pine (Pinus oocarpa), and the terrain is mountainous and steep in many paces. Much of the region is second growth, and is used for ranching. The forest is rather open, due to periodic burning and grazing, but getting around is still rather difficult due to the topography. We tried some caracara call playback, but had nothing responding whatsoever. This is very different from the situation in Amazonia.

IMG_3288

The rolling pine forests northwest of Gualaco. This is right near the are where caracaras nested last year.

We are planning on staying put for the next few days, but will head out to Tegucigalpa next week for permit applications, and then will do a scouting mission starting on the 20th. With terrain like this, we will most definitely be getting our exercise!