Tag Archives: corvus

Of Jackdaws

A juvenile western jackdaw (Corvus monedula spermologus) is served water by some nice humans in Supetar, Croatia.

While jackdaws are still listed as in the genus Corvus (with other crows) in most literature, many workers argue that the two species of jackdaw (western, C. monedula, and daurian, C. dauuricus) should be in their own genus Coloeus.  Indeed, they have long been listed in the ‘sub-genus’ Coloeus and a 2007 paper looking at the genetic diversity, using mitochondrial DNA of certain species of corvids, supports the assertion that jackdaws should be in their own genus.  In fact, the International Ornithological Union and Birds of South Asia: The Ripley Guide by Rasmussen and Anderton both list them as genus Coloeus.

Semantics aside, these small corvids have long been recognized as being morphologically distinct from the rest of the genus Corvus.  They are small (the smallest of genus Corvus) and very sociable; as evidenced by this video.  They are a common urban bird and thrive just as well in human dominated landscapes as they do in remote landscapes, like a number of other corvids.  However, jackdaws also differ from other crows in that they nest in crevices/holes, much to the distress of many a chimney-owner.

And while I’m on the topic of crows that are proposed as distinct from the others, another sub-genus, Corvultur, has been previously proposed for the fan-tailed raven (C. rhipidurus), white-necked raven (C. albicollis), and thick-billed raven (C. crassirostris) due to their close geographical relationship and unusually thick bills.  However, this division is not very robust, and a 2012 study placed white-necked and thick-billed ravens as closely related, but fan-taileds sorted out closer to pied crows (C. albus) and then common ravens (C. corax) and brown-necked ravens (C. ruficollis).  However, unlike the Corvultur, both jackdaw species still remained very distinct from the rest of genus Corvus, forming the most basal group.

All of that said…I hope you enjoy this video of a jackdaw getting a nice cool drink of water after coercing some primates into opening a bottle and pouring a cap-full for it.

(Preview image for this post by John Haslam from Dornoch, Scotland.)

Photo copyright Jolyon Troscianko

Regarding Tool Manufacture and New Caledonian Crows

I tend to leave incidental posts, responses to Tumblr posts, and Tumblr replies to the Tumblr incarnation of this blog, trying to keep this official Coyot.es space more for original content and longer posts.  However, this reply was lengthy enough and contained enough original material beyond the initial reply that I thought it would be good to post it here.

This comment is a reply to my correction of the source page for the incorrect NowYouKno “fact” on Tumblr.

I appreciate you pointing out this distinction, though manufacture versus use is sort of a continuum, depending on how we are defining “manufacture”.  It is true that New Caledonian crows are amazing tool makers (something I give lectures about on a nearly annual basis when I talk about animal culture), but more than three species make tools.  Chimpanzees, of course, are tool makers, along with documentation of manufacture in orangutans, mandrills, and Asian elephants.  This is leaving out animals that develop tools or can be taught to develop tools in captivity (ex. bonobos, hyacinth macaws, and a Goffin’s cockatoo, just to name a few).  Also depending on how complex the manufacture, gorillas have been observed breaking off large sticks for stabilization, woodpecker finches have to break off cactus spines to use them (and more recently they are modifying non-native blackberry spines), and bottle-nosed dolphins have to select and break sponges off their substrate to use them.  I still assert that we will probably find a lot more tool use and manufacture in the wild, the more chances we get to observe different species in the wild.  There are certainly many anecdotal and incidental observations of many more species creating and using tools.  However, what you have to keep in mind is that if an animal gets along fine without making and using tools, then there’s not point in them doing so.  Tool manufacture and modification, while really cool to us, isn’t always necessary for other animals.  In chimpanzees and humans, for example, tool use is integral in how we forage and exist in the world, but for other species tool manufacture and use may only be needed on occasion, when a situation calls for it.

In the case of New Caledonian crows, they, like woodpecker finches, live in places that lack woodpeckers.  This is significant because it leaves open the niche that specializes in locating, removing, and eating wood boring insects.  Rather than spending the time to evolve physical adaptations to do this (like woodpeckers have) these two species use tools to the same ends.  Arguably, there is a distinction between woodpecker finches (which are actually most likely in the tanager family, despite the common name) and New Caledonian crows when it comes to the cognitive department.

What happens when nature takes a bird, already a part of a large-brained, cognitively complex genus of birds (Corvus) and puts it on an island that has a goldmine of a niche to fill?  You get the incredible New Caledonian crow (Corvus moneduloides).


(Photo copyright Jolyon Troscianko)

Drs. Russell Gray and Gavin Hunt observed these birds in the wild manufacturing and using tools.  The earliest documented account of tool us in NC crows was by an explorer who reported the use of anvil sites to crack open nuts and snails in 1882.  In 1909 Le Goupils observed NC crows probing a dead log with a stick-tool (reported in 1928) and Orenstein gave a more detailed report on crow tool-use in 1972, but it was Hunt (his first study published in 1996) and Gray who brought attention to these incredible corvids and who still do work on them today.  In 2000, birds were taken from New Caledonia and sent to England to be studied by Alex Kacelnik‘s Behavioral Ecology Research Group (BERG) at the University of Oxford.  Two of these birds were Betty and Abel.  Betty blew the minds of the world when she spontaneously bent a metal wire into a hook to retrieve food after Abel made off with the hooked tool.

Part of the reason the NC crows were brought into captivity by Kacelnik was to see if the tool behaviors were innate or due to complex cognition and problem solving, or even if they were cultural as Gray and Hunt suggested.  The BERG found that young NC crows, with no training or example, had a proclivity for tearing materials and probing holes with other objects.

So if the birds could manufacture and use tools completely on their own, what makes them more noteworthy than woodpecker finches or other animals that innately use tools?  What makes them rival and often exceed chimps in the cognitive department?  Tradition, the understanding of the functional properties of their tools, innovative use of tools, and cumulative tool evolution all combine to make NC crows stars in the world of animal cognition.

Gray and Hunt found that different tool types were being used by NC crows in different regions of New Caledonia.  These tool types were not reproduced by Kacelnik’s captive crows, which lends more support to those tools’ forms being based on a tradition, or culture, rather than just a genetic ability to make them (after all, humans babble as a precursor to language).  NC crows also understand the functional properties of the tools they use and make.  They use a range of materials and techniques for making tools, demonstrating that it’s the crow that decides on the tool, not the material.  Understanding of the functional properties of their tool was also demonstrated by Betty bending the wire, and again in further experiments.  One experiment even showed that the crows could determine the rigidity of tools that would be appropriate for a task.  Finally, NC crows show cumulative tool evolution, something we humans still clung to as unique to us.  Cumulative tool evolution is the ability to take a tool and modify it to a different or better function and build on previous technology.  The tools that were created by precisely snipping and tearing Pandanus spp. tree leaves (the form of which were not replicated by Kacelnik’s captive birds) showed strong evidence of enhancement over time.  Hunt and Gray found and compared tool types and their functions from all over the island, including historical records of negatives left in leaves up to four years old.  Their findings suggest that the Pandanus tools have had significant improvement on their shape and functionIf this doesn’t blow your mind, I don’t know what will!!

Researchers have since found evidence of cumulative tool evolution in chimpanzees as well.  And thus, the battle for most cognitively complex non-human tool user rages on between chimpanzees and NC crows.  In recent years, the ability to use tools to get tools (or meta-tool use) has been a focus of attention, with several studies demonstrating that NC crows can figure out what tool they need for a task, and use other tools to get the appropriate tool (here’s a video).  There have also been studies into the brains of New Caledonian crows, among other cognitive work that shows that these birds are truly complex animals that blur the line between human and non-human intelligence and understanding of the world around them.  Click here for The University of Auckland’s page on NC Crow research still run by Gray and Hunt, and here for a list of their publications which go well beyond what I’ve related to you here.  Both researchers at The University of Auckland and The University of Oxford are continuing work on these birds, so you should keep an eye out for their continued publications and findings.

I’m a huge fan of NC crows, if it wasn’t apparent.  One of my most treasured possessions is a genuine Pandanus tool made by a New Caledonian crow.  I even had one of Hunt and Gray’s papers signed (how big of a nerd can I be?), but that was sadly destroyed in a flood.  It is a life goal to make it to New Caledonia and observe these birds in the wild.  Thank you Pamela Turner for giving me an excuse to blather about NC crows and I hope all of you who read this now appreciate them as much as I do!

Finally! A movie that’s fair to Corvids!

Finally!  A film (Maleficent) that portrays a raven accurately and fairly (though the CG flight animation could use some work).  Not to give too much away about the film, but this is the first movie where I’ve seen a raven portrayed as a “good guy”.  In fact, the raven, Diaval (renamed from Diablo in the animated movie), is the most morally consistent character in the film.

I can’t say more without giving away too many spoilers, but if you like corvids, especially the crows, see this movie.  I saw it on a whim and I was pleasantly surprised, not just by Diaval, but by the film as a whole.

This film gets The Corvid Blog’s endorsement!

(GIF from Cinemablend.)

Where’s Jenn?

I apologize for the lack of posts, however it’s not due to a lack of doing corvid-ee things!  Beyond the constant working on my dissertation (about American crows), the past few weeks have been busy with a bit of travel, particularly to natural history museums, and now to the 50th Annual Animal Behavior Society Conference (which starts tomorrow).

I’ve got a lot to talk about when I’m back home, but for now I’m going to leave you with some photos from my visit to the American Museum of Natural History‘s collections.  Natural history museums have wonderful public displays, but the bulk of their materials are in their collections, not on display.  The AMNH has six floors of bird specimens alone, and I was able to examine Corvus species I’ve never seen in life, heck, they had all of them, so I learned a LOT about the fine physical features of birds I’ve only seen in photographs and illustrations.  There is a huge difference between a photograph and a bird in the hand…including me squealing and babbling incoherently in excitement.

Sitting in front of a collections cabinet at the AMNH, looking through skeletals of various Corvus species.  (Shirt is from Raven’s Brew Coffee.)

Perhaps the most exciting specimens for me. These are Grey Crows (Corvus tristis), a species found all over New Guinea. We know very, very little about them, but we do know that their coloration throughout their life history is just, well, bizarre. It was an unbelievable treat to get to see and handle these specimens!

I have joined the Coyot.es Network!

The Corvid Blog and myself have joined the ranks of the Coyot.es network and I’m excited to be here!  For my Tumblr followers, I encourage you to check out this network of interesting biodiversity blogs!  My posts will still show up on Tumblr, but they will be created and primarily managed here.

I feel this image is relevant to this development:

This image was taken by Dave Stiles in Yellowstone National Park, found via his Flickr account. Click the image to visit the original page for this image and let Dave know how awesome this photo is!

Ravens tend to materialize, as if by magic, when it comes to kills by large predators.  Coyotes, while excellent hunters in their own right, also take advantage of mountain lion and wolf kills, so both raven and coyote are common to see around such sites.  Nothing like the two mythological tricksters spending a moment together 😉

Crow Display Question

From combackzinc via Tumblr:

“I have three non-releasable American Crows, and my wild-reared adult ‘male’ displays some interesting calls and behavior. Could I get you opinion on what’s going on here? w w w.youtube.c o m/watch?v=LaGR4WXi4FQ”

The short answer, unfortunately, is that I don’t know (I’m referring to the bird that begins standing on the “stump”).  The long of it is that I’ve seen this kind of call/display (bow followed by a guttural/soft/odd vocalization) before, in many contexts.   I’ve seen it used when two birds greet one another at a communal foraging site or at their home territory.  I’ve seen it used after a territorial issue is resolved between two families.  I’ve seen birds, totally alone (i.e. no one to signal to), just sort of start up these kinds of calls.  I’ve also seen it as a common posture for birds in captivity to mimic certain sounds. It could also be a self-soothing, and sometimes even aberrant, behavior in the context of captivity.

As it stands with American crows, we still have a lot left to uncover about their vocalizations.  Heck, many people don’t even realize crows make a lot more sounds than just the classic “CAW!”.  Their repertoire includes the sounds in the above video, soft cooing (a personal favorite), atonal rattling, musical rattling, and mishmashes of bizarre clicking and gurgling noises, not to mention they can mimic humans.  (Here’s a website that has the atonal rattle call followed by the cooing.  And here’s another site with lots of American crow calls and some other corvids.) …I’m sure you know all this, having raised and kept captive crows, but I thought I’d mention these things for my other readers.

I apologize that I can’t give you much insight in to your bird’s behavior, but I do recommend recording the context in which it occurs and trying to work from there.  I’d love to know what you find, or have found!  I firmly believe crows have far more complex vocal communication than what we are currently aware of, and that it’s highly, highly context dependant, the work just needs to get done 🙂

Also, thank you so much for including the second paragraph disclaimer on your video 🙂