Search Results for: red throated caracara

Red-throated Caracara research: natural history and classification from 1765 to 1838

This is the illustration of the Petit Aigle d’Amerique from “Planches enluminées d’histoire naturelle” 1765

I mentioned last week in my introduction to the Red-throated Caracara that there is very little known about the species. While details of the life history of these birds are still hazy, the existence of the bird has in fact been known to scientists for quite a long time. To know a species, we must first be able to recognize it as distinct and to give it a name. There is a formal protocol for this, that has been developed and refined through time, and it so happens that the Red-throated Caracara has a long history in zoological classification. I normally find the subject of early nomenclature work to be a bit dry, but I am pleased to report that work with the Red-throated Caracara has been a surprisingly pleasing visual endeavour from the outset.

The first published description that I can find on these caracaras belongs to Buffon, Georges-Louis Leclerc, Comte de Buffon to be exact, one of the pioneering Enlightenment era naturalists. Buffon’s 1765 description consisted of an engraving and a name, “Aigle d’Amerique” in the “Planches enluminées d’histoire naturelle“, a 24 volume set of coloured engravings done mainly by F.N. Martinet, a talented engraver. This work was commissioned by Buffon and supervised by Daubenton, so authorship is a bit muddled, but on the whole, the work is mainly attributed to Buffon. He recognized this species as an eagle, rather than a falcon, as he considered the shape of the bill, down turned at the end, to be more eagle-like.

Drawing inspiration directly from Buffon/Martinet/Daubenton’s work, the first written description seems to be that of an Englishman, one John Latham, who described the bird quite well and called it “the Red-throated Falcon” on page 97 of his 1781 book “A general synopsis of birds“. It is unclear why Latham placed this species with the falcons, although he was quite correct to do so.

Here is Latham’s original description, which gives the name Red-Throated Falcon, and notes the occurrence of the species in Cayenne and other parts of South America

I think it is a moft beautiful fpecies too!

While this is a step along the path, it was not yet the official scientific name of the Red-throated Caracara…Latham’s description may have been useful, but it is not considered the first official species description. That honour goes to Pieter Boddaert, who, in 1783 gave this species its first Latin binomial: Falco americanus in “Table des planches enluminéez d’histoire naturelle de M. D’Aubenton: avec les denominations de M.M. de Buffon, Brisson, Edwards, Linnaeus et Latham, precedé d’une notice des principaux ouvrages zoologiques enluminés“. As the species name “americanus” now has precedence, it has remained attached to the Red-throated Caracara to this day.

In 1786 Gmelin (who was an associate of Carolus Linnaeus) named it Falco aquilinus, but this is considered a junior synonym, as it was published after Boddaert’s F. americanus.

In 1816 L.P. Vieillot moved this species to “Ibycter” in “Analyse d’une nouvelle ornithologie élémentaire“. This was the first written communication that applied the genus name “Ibycter” to the Red-throated Caracara, which has more or less stuck, and also a new common name “Rancanca” which has not. I am very intrigued by the origin of the name Ibycter…I have not found what it refers to, whether to mythology or if it is just an obscure word…Anyone out there have some insight?

The first real natural history information on the Red-throated Caracara comes from 1834, with the publication of “La Galerie des Oiseaux“, also by L.P. Vieillot. Delightfully, “La Galerie” also includes an image of the species!

Lithograph from Galerie des Oiseaux featuring the Red-throated Caracara. This is presumably attributable to Godefroy Engelmann, a lithographer based in Paris.

In addition to the new name, Ibycter Leucogaster, Vieillot contributed some real natural history to the scientific record, noting their loud calls and group living habits. In addition, having read Vieillot for the first time last week, I was shocked to read his statement that these caracaras are “ordinarily accompanied by toucans”. This habit, which apparently earned them the local name “Capitaines des gros-becs (Toucan Captains!), is not just some 19th century BS either, it was also made by Thiollay in his 1991 paper.

Thiollay noted several species that could be described as toucans accompanying the caracaras: The Guiana Toucanet Selenidera culik, Black-necked Araçari Pteroglossus aracari, Green Araçari Pteroglossus viridis, Channel-billed Toucan Ramphastos vitellinus and the Red-billed Toucan. The latter species was the one most commonly found accompanying the Red-throated Caracaras. But we get ahead of ourselves. Let us stay in the first half of the 19th century, shall we?

Red-billed Toucans often do follow Red-throated Caracaras. They also sound like a small dog barking.

In 1838, the first popular work to mention this species was published. The Society for the Diffusion of Useful Knowledge published their Penny Cyclopaedia with the express (and proto-socialist) idea to bring scientific knowledge to the working classes. This was kind of like the Wikipedia of 19th Century Britain. Here is their entry (with an illustration!) for the Red-throated Caracara (on the bottom right). This is part of a much larger section of falcons in general, and is quite commendable for its completeness.

This brings us to the middle of the 19th Century. Darwin was just about to arrive back from his voyage on the Beagle, Wallace was yet to set sail for Pará (where he would collect a Red-throated Caracara!), and the world of natural history was yet to be turned on its head by the revelations of Natural Selection as formulated by these two.

I am sure there are many taxonomic references I have left out that I could have usefully employed, but my attention must be elsewhere at the moment. I will return to the early world of ornithological literature, specifically the second half of the 19th Century at a later date. If you are eager to see a list of early synonyms and their references, look no further than page 22 of Strickland’s Ornithological Synonyms below.

This is the short early history of the scientific description for just a single species of bird. Of course, there are many many others who share a more or less parallel track through the literature. What I find fascinating is that I can do a few short hours of study on the internet and bring to you this history without even visiting a library or a museum. Thanks go out to the Internet Archive and the Biodiversity Heritage Library websites, who make trawling through and accessing this literature possible. An thanks to you for reading!

The Red-throated Caracara: introducing my favorite loud bird

Jan30

The Red-throated Caracara, Ibycter americanus, is the subject of my academic research and the namesake of this blog.

This beautiful raptor may look like a strange vulture or a hawk, but it is actually in the falcon family. It is classified in the subfamily Polyborinae. This group includes the caracaras, forest falcons and some others, and is thought to have split from the rest of the falcons some 14 million years ago . The caracaras are oddballs in the falcon world, as they are not swift-flying, long-winged aerial hunters, but for the most part rather slow-flying generalists and scavengers, many of whom spend a lot of time walking on the ground. There are currently five recognized genera of caracara, with 10 species.

This is a Crested Caracara, Caracara cheriway. These birds are more typical of the group, found in open habitats. (photo CC Licenced by Manjith Kainickara)

This Yellow-Headed Caracara, Milvago chimachima is a smaller generalist predator, also found in open habitats. A beautiful photo by Bart vanDorp, taken in Minas Gerais, Brazil.

Caracaras are for the most part birds of open habitats, from windswept Patagonian plains to sunbaked Venezuelan llanos to the open cattle country of Central Florida. Bucking this trend, the Red-throated Caracara is a forest specialist, preferring densely forested habitats from Central America to southern Brazil. And unlike most of its relatives, it is not a generalist predator or a scavenger, but rather a specialist predator of social wasps. This unusual diet is mirrored in the Old World by the Honey Buzzards, of the genus Pernis. It is this unusual dietary choice which led to me taking on my PhD research, the main objective of which was to determine how these caracaras manage to prey on well-defended social wasps without getting injured.

The warning coloration of these Apoica albimacula tell most predators to stay away, and with good reason.

In addition to the diet, the social behavior of Red-throated Caracaras also stands out. Unlike most falcons, this species is rarely seen alone, preferring to travel in groups of up to 15 birds. They are extremely loud birds and are in almost constant vocal communication with each other. If you want to hear what I am talking about, listen to this!

Yeah, we bad… The Red-throated Caracara is one of the most sociable (and loud) raptors you are ever likely to meet.

This species, and most caracaras in fact, have rarely been studied. Prior to my work on these strange birds, only one study has focused on their behavior, showing that they exhibited some degree of cooperative breeding, and that they appeared to be defended against their social wasp prey by “a powerful chemical repellent”.

Because I have become so enamoured of these caracaras, I would like their tale told more widely, and this blog will be one of the vehicles to do so. In some upcoming posts, I will begin to tell the story of my research on these (ridiculously cool) animals. My research has been a fascinating journey, which is not over yet. You are most welcome to tune in to future posts to learn more about the world of the Red-throated Caracara.

References

FUCHS, J., JOHNSON, J. A. & MINDELL, D. P. 2012. Molecular systematics of the caracaras and allies (Falconidae: Polyborinae) inferred from mitochondrial and nuclear sequence data. Ibis 154:520–532. Blackwell Publishing Ltd.

THIOLLAY, J. M. 1991. Foraging , home range use and social behaviour of a group-living rainforest raptor , the Red-throated Caracara Daptrius americanus. Ibis 133:382–393. Wiley Online Library.

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.

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

Jan12

“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!

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.

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.

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.

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).

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.

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.

Best two wasp nests I ever spent: the case of the Black-throated Antshrike

Oct29

Female Black-throated Antshrike. Photo by Phil Stouffer. What an impressively fierce-looking bird!

Remember my post last week on the White Woodpecker preying on wasp nests? Well,if you browsed that issue of Revista Brasileira de Ornithologia, you may have noticed that I published an article on a similar topic!

This is another account of a bird preying on wasp nests, one that was completely unexpected. This involved the Black-throated Antshrike, Frederickena viridis. Black-throated Antshrikes are members of the Thamnophilidae, or antbirds, a largely Neotropical family known for being associates of army ants. Basically, these birds “attend” army ant raids and parasitize the ant colony by quickly grabbing the insects, lizards and arachnids that flee the approaching ant swarm.

Eciton burchellii army ants. These impressive swarm raiding ants kick up quite a lot of prey from the leaf litter, which antshrikes are only too happy to steal.

During fieldwork in 2010, we caught a male Black-throated Antshrike is doing its own dirty work, striking wasp nests, causing the wasps to abscond, and feeding on the brood. Here is the video (edited for time, as the whole attack sequence lasted 42 min):

A: Polybia scrobalis B: Polybia bistriata

The two wasp species in question were Polybia scrobalis and Polybia bistriata, which we had placed in a video arena for our experiments documenting Red-throated Caracara feeding behaviour. In some ways, you could say that the antshrike was parasitizing us! This was all recorded as intended by our automated video system, which reacts to motion in the video stream and records the action with a 5-s pre-recording buffer. On that morning, my field assistant Tanya Jones and I were just getting up and having breakfast when this antshrike was attacking. By the time we were done breakfast, the antshrike was too!

A few things to note: Unlike their behaviour with the Red-throated Caracaras, this Polybia scrobalis colony fought back. At 0:30, 1:22 and 1:45 in the video, you can see wasps attacking the antshrike, and in the second two instances, the antshrike plucking off the wasps.

Wasp on antshrike at ~30s

Wasp on antshrike at 1:22

Wasp on antshrike at 1:45

For comparison, here is an attack on the same wasp species by Red-throated Caracaras:

So why do the wasps attack the antshrike and not the caracaras? Can these wasps can evaluate the threat posed to the colony and adjust their defence/retreat appropriately? Maybe the wasps somehow evaluate the odds of successfully driving away a predator and abscond if nest defence is likely to be hopeless. After all, the workers which are killed in nest defence are still a loss. Continued defence piles up the losses, and if defeat is inevitable, it is better to retreat with your worker force intact.

Alternatively, it could be that the colony the caracaras attacked was worse off in some way, and more likely to abscond, but the possibility remains that wasp defensive behaviour against vertebrates is plastic. There is definitely room for some exciting research here.

Considering the White Woodpecker, the Black-throated Antshrike, and the Red-throated Caracara (among others) it seems that more and more vertebrate predators are being found that prey on wasp nests. In these cases, it appears that the birds are minimizing the risk of stinging by inducing the absconding response of their swarm-founding prey before moving in close to feed on the larvae.

While I was a little upset that these nests fell to the antshrike rather than giving me more data on caracara predation, getting a paper out of it and learning something new was well worth it.

Male Black-throated Antshrike. Photo by Phil Stouffer.

It takes a crazy bird to mess with these gals…

Mar25

Social wasps have many dramatic and painful ways of saying” don’t mess with us”, but some animals just don’t take the hint. Red throated Caracaras are one of these foolish/awesome creatures. If you are in Victoria BC this Wednesday, come out to my talk for the Victoria Natural History Society’s Birder’s night to find out more about loud birds messing with painful wasps. 7:30 pm, March 27, Fraser Building room 159.

Untitled-3

Official blurb:

Like the Old World Honey Buzzards, the Red-throated Caracara is a specialist predator of social wasps. Because social wasps are well defended with stings and are avoided by many birds, we were interested in determining how caracaras deal with the defensive wasps. Using video traps to observe caracara predation on social wasps we found that they use several behavioural strategies to avoid wasp defences. Separate work using nest cameras found that up to 7 adult birds were involved in the feeding of a single chick, possibly making the species one of the most social of the Falconidae. Join Sean McCann as he talks about his 5 years of research in the South American rainforest on the unique foraging biology of this species. We meet at 7:30pm in room 159 of the Fraser building. Everyone is welcome. Bring a friend and a coffee mug.

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., 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.

To Houston and back!

Jan27

It is a wonderful thing to give a talk to an enthusiastic audience, especially when comes with a chance to travel and meet new people. I was very lucky to have had this opportunity last week when I went to Houston Texas to give a talk on Red-throated Caracaras to the Houston Audubon Society.

Mary-Anne Weber, along with Juanita Perkins arranged for me to travel to Houston to give this talk, and were my most gracious hosts during my trip. I did not have to stay in a hotel, but instead stayed with my friend Cullen Geiselman, a bat researcher who I met at the Nouragues Station.

I am very grateful to have had this wonderful opportunity, and I thank all of the people who came out to hear me talk.

The Houston Audubon is located at the Edith L. Moore wildlife sanctuary, and has about 17 acres of woodland protected.

One of the first things I looked for at the Sanctuary was ants, and I was lucky enough to find this Leptogenys elongata colony.

These are members of the subfamily Ponerinae, and are much different in form from the myrmicines and formicines I am used to.

As their name suggests, they are gracile (slender and long limbed) and likely either run fast or climb trees. On this day, they weren’t going anywhere quickly because it was cold and rainy.

On Friday, after my talk, I went out with Mary-Anne Weber and Joe Smith for a birding outing. Here is something we don’t often see in Canada!

This osprey allowed a close approach using the time-tested technique of pretending we didn’t see it!

A couple of local dogs who thought they owned the place!

Several osprey were fishing in the stormwater retention ponds.

A white pelican flies by some construction. This is likely to be another Canadian visitor to Houston.

White pelicans engaged in feeding. They are not spectacular divers like Brown Pelicans, but they sure are majestic. .

This is a juvenile Cooper’s Hawk, which Mary-Anne ID’ed correctly. I was thrown off by the white splotches on the back, which we do not often get on the West Coast.

From the front it looks much like our Cooper’s Hawks.

Everything is bigger in Texas, including the Great Blue Herons! Well, all over the east they are bigger than our West Coast form.

The closest approach of a White Pelican.

Back at the Sanctuary, I found some more ants, this time a very very tiny myrmicine. Any ideas about what this is?

The workers were dimorphic, with this large headed form being present.

I even managed to find a jumping spider, despite the cold wet weather.

And finally, a mystery ground spider, which we will be in a better position to ID after this summer, when Catherine and I will attend a workshop in spider taxonomy in Arizona.

After I left Houston, I took the opportunity to do some aerial photography of the western landscapes we flew over. Here the mountains and deserts look like an alien landscape with the desaturation of distance.

White Woodpecker preying on wasp nests!

Oct21

Melanerpes candidus approaching the nest of social paper wasps. Photo by Miguel Rangel Jr. used under terms of a CC-BY-SA licence.

In the latest issue of Revista Brasileira de Ornithologia, I found a paper on a topic near and dear to my heart: birds preying on wasp nests. In this case, it is an account of the White Woodpecker, Melanerpes candidus preying on the nests of Polybia paulista. In this paper, Ivan Sazima describes the predation tactics used by this woodpecker when attacking a large, well-defended nest. Ivan conducted this research at Parque Ecológico Prof. Hermógenes de Freitas Leitão, in the state of São Paulo, Brazil.

Like the Red-throated Caracaras I studied, the White Woodpecker appears to exploit the absconding response of these swarm-founding wasps in order to secure its meal of wasp brood. Rather than inflicting rapid, catastrophic damage, however, the woodpecker takes its time, approaching the nest gradually and tapping the branch to which the nest is attached. During this approach, some of the wasps come out to sting, and if this gets too fierce, the woodpecker will retreat. Sazima attempted this tactic himself with a similar nest of P. paulista, and got stung severely for his efforts. Sazima suspects that the continuous nature of the woodpecker’s disturbance is what is required to induce the wasps to abandon their nest. Also, the agility of the birds at evading attacking wasps also means they can keep this harassment up longer than an unprotected human.

This paper is a valuable contribution to the study of wasp and bird behaviour, as it highlights that certain anti-predator strategies of social wasps (stinging, alarm recruitment) can be defeated by exploiting the evacuation swarming (absconding) behaviour of these wasps. Bearing this in mind, it is no wonder that so many species of swarm founding wasps have cryptic nests to escape the detection of diurnal vertebrate predators.

I especially love one of the concluding sentences:

The foraging behaviour of the White Woodpecker reported herein results from so-called anecdotic, natural history oriented observations, often disregarded by theory-trained biologists. Nevertheless, this kind of observation draws attention to phenomena that later may prove more widespread or commoner that previously thought.

I could not agree more. Please head over to read the paper yourself, as the photos of the behaviour are great, and the text well worth the read.

Update: See another wasp predator in action here.

Photo by Márcio Vinícius Pinheiro, shared under the terms of a CC BY-NC-ND 2.0 licence.

Sean McCann: Research and CV

For a complete list of my publications, awards, and work experience, download my Curriculum Vitae. For a more informal tour of my research, follow along!

Education and Research

For my BSc Honours thesis, I studied overwintering mosquitoes in sheltered habitats around Victoria BC. Using temperature and humidity dataloggers, I investigated what conditions were correlated with mosquito presence.

During my Masters at the University of Florida’s Florida Medical Entomology Laboratory, I worked with Dr. Cynthia Lord to investigate factors predicting fecundity in two species of Culex mosquitoes. For this study, I developed photographic techniques for counting egg rafts that allowed for analysis of fertility. Age, bloodmeal size and body size were all significant predictors of the number of eggs produced by females, and interactions between age and size were evident in Culex quinquefasicatus. You can read the thesis here, or a paper originating from this work here.

For my PhD thesis at Simon Fraser University, I worked with Dr. Gerhard Gries to study the foraging and nesting biology of the Red-throated Caracara. Our first paper on the subject was the first detailed description of the nesting biology of these enigmatic raptors using nest camera recordings. . (Photo by Philippe Gaucher).

Our second published paper on these caracaras is an in-depth investigation of the unique predation behaviour of these birds on social wasps. We investigated the hypothesis that these birds were chemically defended from counterattack by their prey, and used analytical chemistry and video recordings to demonstrate that they are not. I have also published a video teaser for the paper, as well as a blog post describing the research. The full paper can be found online here.

During my research on Red-throated Caracara predation behaviour, I also recorded a Black-throated Antshrike preying on social wasp nests. This has been published as a note in Revista Brasileira de Ornithologia.

We are continuing to publish papers orginating from my thesis research, and manuscripts detailing comparisons of caracara wasp predation rates with army ants as well as an investigation of social and territorial behaviour are coming soon. These studies also relied heavily on videography.

A side project of my PhD research was studying the pheromone-mediated alarm and attack behaviour of Vespula wasps. This is exciting research, and the results will soon be published. I am particularly proud of the innovative bioassay technique I developed using simultaneous two channel recordings and automated counting. This manuscript is currently accepted in Journal of Hymenoptera Research.

In my time at SFU, I have collaborated with several members of our laboratory as well as other researchers. One of my favourite contributions was with Mike Hrabar, investigating the reproductive behaviviour of Xenos peckii, a strepsipteran parasite of Polistes wasps. My role in this study involved using high speed videography to capture the upwind flight and mating of the short-lived male strepsipterans. Our research resulted in what I think is a seminal paper on the subject.

I have also collaborated with Catherine Scott, investigating in both the field and the laboratory the mating behaviour of Latrodectus hesperus, the western black widow spider. My role in these studies involved assistance with fieldwork and design of laboratory bioassays for quantification of male courtship behaviour. Check out the lab study here, and the awesome field study here.

I have also assisted Dr. Ann Ray in investigating pheromonal communication in Elderberry Borers of the genus Desmocerus. My role in this study was in field bioassays of pheromone chemicals. This research has been published in PLOS-ONE.

I have continued my research with Red-throated Caracaras, helping to coauthor the first published record of a nest of these birds for Central America. These are photos I took in January 2014 of Red-throated Caracaras in a pine forest near Gualaco, Honduras. The population of these wonderful birds is perilously low in Central America.

Keeping up with my interests in both mosquitoes and photography, I published a new species record for BC from a photograph I took in 2011.

Another photo of mine led to another collaborative species range expansion paper, this time, Aedes japonicus being detected in BC for the first time!

During the last semester of my PhD, I helped Dr. Rob Higgins with field studies of invasive Myrmica ants in the Lower Mainland of BC. My duties were to conduct fieldwork on natural history, distribution and behaviour of these ants.

Teaching and outreach

During my PhD I taught the laboratory component of Insect Ecology, teaching insect anatomy, physiology and insect identification. I received a Departmental teaching award for this in 2010.

In 2013, I assisted with a project at the Vancouver International airport to investigate the insect fauna at the facility to find out what might be attracting Barn Swallows over the runways. I taught 3 undergraduate students the basics of insect ID and guided them through the data collection project.

I have always tried to incorporate outreach into my schedule, participating in youth science outreach, and giving several public lectures to non-academic audiences.