Tag Archive | predation

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

FrederickenaViridisF1

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.

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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):

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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.

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Wasp on antshrike at ~30s

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Wasp on antshrike at 1:22

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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.

 

FrederickenaViridis1

Male Black-throated Antshrike. Photo by Phil Stouffer.

White Woodpecker preying on wasp nests!

Melanerpes Miguel Rangel jr

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.

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

 

 

A group of Golden Eagles hunting elk?

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I am always a fan of raptors, and have a special place in my heart for social and predation behaviour. Here is a story that combines all three! In the latest issue of Journal of Raptor Research, a remarkable observation of a large group of Golden Eagles harassing elk on a steep ridge is reported (but paywalled).

Matt O’Connell and Michael Kochert witnessed and filmed the astonishing sight of at least 8 eagles repeatedly stooping at a group of elk, either trying to drive them off a cliff, or perhaps just playing around.

Golden Eagles are known to prey on ungulatessometimes by driving them off cliffs, but the authors are cautious at definitively stating the motivation of these birds. I would suggest that the hypothesis of play and that of predation are not mutually exclusive. I could certainly see a great selective advantage for these carnivorous birds to engage in “play” that sometimes results in the grisly death of a large ungulate.

If you would like to see the video, here it is below. What do you think?

[youtube=http://www.youtube.com/watch?v=anyg6RAxTi8&w=720&h=405]

 

References

Bergo, G. 1987. Eagles as predators on livestock and deer. Fauna Norvegica Series C, Cinclus10:95–102.

Deblinger, R.D. and A.W. Alldredge. 1996. Golden Eagle predation on pronghorns in Wyoming’s Great Divide Basin. Journal of Raptor Research 30:157–159.

Erwins, P.J. 1987. Golden Eagles attacking deer and sheep. Scottish Birds 14:209–210.

Zettergreen, B. 2006. Golden Eagle attacks and kills yearling mountain goat. Wildlife Afield3:27–28.

 

Do Red-throated Caracaras kill and eat people?

A lesson in how not to infer predation…

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Is this bird plotting a murder?

Red-throated Caracaras (Ibycter americanus) are impressive birds that are  brightly coloured, extremely loud, and travel around the forest in gangs.  They seem to act as if they own the forest, and alarm call vigorously whenever they see you or any other potential threat. I have seen them chase away Harpy Eagles (as have others!), as well as Toucans.

Sounds like a badass bird! If you do a Google Scholar search for “Red-throated Caracaras and Predation“, you might find some surprising things. In the primatological literature, they are listed in several papers (1-2) as being predators of Saguinus mystax, the Moustached Tamarin, a small monkey. This is quite odd, as to my knowledge there is only a single account of Ibycter americanus taking vertebrate prey: Anolis and Ameiva lizards found in the stomach of a single bird shot in Mexico (3).

Certainly, other caracara species, such as the similar, but more distantly related Black Caracara (Daptrius ater) do prey on vertebrates. The Black Caracara has been reliably reported preying on fish (4) and juvenile caciques (5).

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Saguinus mystax. From Wikimedia Commons, User:Postdlf

But the Red-throated Caracara is a different species, with different habits, and is not well-known to take vertebrate prey.

So where does this idea come from?

All the references that I could find about predation on tamarins by Red-throated Caracaras come from a thesis (6) by a researcher named Maria Marleni Ramirez entitled “Feeding Ecology and Demography of the MoustachedTamarin Saguinus mystax in Northeastern Peru”, published in 1989 at the City University of New York. The exact passage about this predation incident appears on page 87 (Daptrius americanus is a former name for the Red-throated Caracara that is no longer used):

“Raptors flying overhead invariably elicited strong alarm responses from the tamarins. Moustached tamarins gave several alarm calls per day that were apparently directed towards birds, thus suggesting that they may be important predators of tamarins. The tamarins’ reaction to attacks by raptors was very strong, as indicated by the loudness and duration of the calls. Daptrius americanus was observed to attack and barely miss a juvenile S. mystax. The moustached tamarins reacted by giving very loud screeches at the same time the Daptrius was diving towards the juvenile.”

Now to be fair, I have been attacked by Red-throated Caracaras (see video), but I never have inferred from this that these birds were trying to prey on me (Although one did strike my ear while I was climbing their nest tree). Or perhaps I didn’t take it personally!

The following video was taken by Tanya Jones in 2009, and shows a group of Red-throated Caracaras diving at me as I climbed their nest tree. I am located right behind the bromeliad; part of my foot is visible below.

[wpvideo yVCCO2E6]

And that is the danger of inferring predation by witnessing one antagonistic encounter between two species, with no video records or stomach contents. Because in my book, predation involves killing and eating the prey, and this was not observed here. In fact, my research, as well as one other study, show that the predominant food items consist of wasp larvae and fruits (7,8), with not a single vertebrate among them. I would not say that Dr. Ramirez’ observation constitutes predation.

'cause doesn't this look better than a monkey?

’cause doesn’t this look better than a monkey?

What I interpret this situation to have been is a mobbing attack on monkeys by caracaras defending a nest site, or merely defending their territory from occasional nest predators. I have seen caracaras chasing Toucans in a similar fashion. I have no doubt that the caracaras could kill, and possibly eat a tamarin (They have an average mass of around 500 g, or roughly the size of a small caracara), but surely some stomach contents would have showed up to indicate such an event. Other than the account of lizards in the one shot in Veracruz,  I can find no such records.

Thus I think that it is definitely premature to list the caracara as one of the “known predators of Saguinus mystax”. Instead, I would probably put the two species in a long list of “animals in the jungle that don’t like each other very much” and leave it at that.

There is still much we do not know about this charismatic bird, or indeed about the trophic relations of rainforest animals in general, but hasty generalizations from a single observation are unlikely to improve matters.

References

  1. Heymann, E., and V. Schaik, 1990. Reactions of wild tamarins,Saguinus mystax and Saguinus fuscicollis to avian predators. International Journal of Primatology 11: p.327–337. 
  2. Lledo-Ferrer, Y., A. Hidalgo, E.W. Heymann, and F. Peláez, 2009. Field Observation of Predation of a Slate-Colored Hawk, Leucopternis schistacea, on a Juvenile Saddle-Back Tamarin, Saguinus fuscicollis. Neotropical Primates 16: p.82–84.
  3. Lowery, G.H., and W.W. Dalquest, 1951. Birds from the State of Veracruz, Mexico. In University of Kansas Publications, Museum of Natural History. p. 556, Lawrence, Kansas: University of Kansas Publications.
  4. Olmos, F., and I. Sazima, 2009. Fishing behaviour by Black Caracaras (Daptrius ater) in the Amazon. Biota Neotropica 9: p.2–4.
  5.  Robinson, S.K., 1985. Coloniality in the Yellow-Rumped Cacique as a Defense against Nest Predators. The Auk 102: p.506–519.
  6. Ramirez, M.M., 1989. Feeding ecology and demography of the Moustached Tamarin (Sanguinus mystax) in Northeastern Peru. PhD Thesis. City University of New York. pp. 87-88 (email me for a copy of the relevant pages)
  7. McCann, S., O. Moeri,
    T. Jones, S.O. Donnell, G. Gries, and S. O’Donnell, 2010. Nesting and Nest-Provisioning of the Red-throated Caracara (Ibycter americanus) in Central French Guiana. Journal of Raptor Research 44: p.236–240.
     (email me for a copy!)
  8. 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: p.382–393.