The origin of human music? Male palm cockatoos use a stick to beat rhythmically on hollow trees

The palm cockatoo, Probosciger aterrimus, is a gorgeous bird found in New Guinea, the Aru Islands of Indonesia, and northern Australia. They can live for ages; there’s one report that a female gave birth for the first time at age 65, though I’m not sure I believe it since the oldest confirmed age in captivity is 56, and they probably have shorter lives in the wild. (Wikipedia notes “anecdotal evidence indicates a palm cockatoo reaching 80 or 90 years of age in an Australian zoo”.)

Regardless, the birds are long-lived. They are likely Australia’s largest parrot, have the most massive beak of any parrot (part of their diet consists of very hard nuts and seeds, but they also eat grubs and fruit). They are also “basal” cockatoos; that is, molecular evidence show their ancestors to have branched off earlier than any other living cockatoo from the common ancestor of all cockatoos. Here’s a pair:

The species is sexually dimorphic, but apparently only in that females have a slightly smaller upper mandible. They pair up during the breeding season (I’m not sure if they pair for life), and females lay one egg every two years—an incredibly low reproductive rate that makes them vulnerable to extinction, particularly as their habitat disappears.

Here’s a diagram of their features:

And here’s their range in green. The birds studied here, which show an unusual drumming behavior, came only from one area on Cape York, the Australian peninsula shown below. That behavior apparently isn’t seen in New Guinea populations (see the implications of this below).

What makes these birds extra special is that they are apparently the only species in the world besides humans that produces a rhythmical beat using a tool. (Not even primates do this.) They drum on tree trunks with a trimmed stick or seed pod. (Of course other animals, like crickets, produce rhythmical sounds, but do so using their body, not tools.) Why the palm cockatoos do this isn’t yet clear: it could be territory-marking or some kind of sexual display, since apparently only males do it, and do so significantly more often when females are around.

This also may be the only report of tool use in an animal when foraging isn’t involved.

The report of this behavior is the subject of a six month old paper in Science Advances by Robert Heinsohn et al. (reference below, full pdf free here).  The authors analyze the drumming, show that it’s rhythmical and differs in speed among males, and then engage in what I consider unwarranted speculation that this is somehow connected with the origin of human music. The paper itself is quite good, but the speculations about its connection to human music are premature and probably wrong.

Here’s what the birds do.  The males (and perhaps occasionally some females) break off a piece of stick about 2.5 cm (1 inch) wide and 15 cm (6 inches) long, and use either that or a seed pod from Grevillea glauca (“Bushman’s clothes peg”) as a drumstick to beat out a rhythm on a hollow tree trunk or branch. The twig is held in the left foot (why not the right?). The behavior was first described in 1984, but studied intensively only recently, with the results published in this paper. Here’s a G. glauca seed pod:

Below is a video made by the authors summarizing their work and showing the drumming. It also plays up the notion that this study sheds light on human music because, like our music, cockatoo music a). involves tool use, b). is rhythmic, c). has a beat that differs from drummer to drummer, and d). is amplified by beating against a hollow tree. Note that the authors witnessed only one drumming event per 100 hours of observation, and that the study took 7 years of hard work! Kudos to them.

In this video, the only episode of drumming shown, using a seed pod, starts at 2:05:

And two more videos of the drumming behavior. In the one below, drumming is shown at 8:32:

This one shows more instances of drumming, and is shorter:

Next, some details of the work.  The authors looked at 18 wild male cockatoos performing 131 sequences of drumming; apparently they can identify individual males and tell males from females. The males varied in their frequency of drumming: the range of average rates of tapping goes between one tap every 0.09 seconds to one every 2.77 seconds.  The analysis below, which compares the actual rhythm with that expected under a pure Poisson distribution (random beats of a given average frequency). These are six males, with the actual rhythm shown at the top and the Poisson-generated rhythms (using the mean rate) at the bottom of each rectangle. You can see that the real beats are much more regular than a random distribution of beats. This is the evidence for rhythmicity, and it’s strong. It also shows the variation among males:

Now it’s not clear why they do this, but it appears to be some kind of sexual display, since it’s performed significantly more often when a female is present than when she’s not (p < 0.001), though they still drum when the the ladies aren’t around (26% of the time compared to 68% of the time in the presence of females). This may be either a pair-bonding ritual or a form of sexual display: perhaps the male’s rate of tapping or its loudness tells the female something about her putative mate. It may also serve a territorial function, too.

Is this genetic or learned? We don’t know, for all observations were made on wild species. It may well be a learned cultural phenomenon, as it’s only found on Cape York, but in that case its use as a display trait to attract females becomes less likely, for females would have to learn what the different beats and loudness say about a given male, and sexual selection like this is almost invariably based not on learning but on the coevolution of a male trait and female preferences—both are genetic. Or, the trait and preference could be genetic, but have evolved only in Australia. Hand-rearing birds in the absence of any sound cue would reveal whether the trait is “hard wired”.

What about its bearing on the origin of human music? The authors report that chimps have been seen to drum, but using their hands, not tools, and, with the exception of one captive male, don’t do so rhythmically. Given the absence of the crucial features of “human music” in our closest relatives, but only in distantly related cockatoos, what does this say about the origin of our own music? To me, not much—this may well be a convergent behavior in humans and palm cockatoos. But the paper relentlessly harps on the relevance to human music, and here’s the authors’ spiel:

Our demonstration of a nonhuman species using manufactured tools to produce rhythmic sounds has broad implications for understanding the evolution of music. Palm cockatoo drumming conforms to several musical features that are statistically universal among human societies, including the use of percussion, a regular beat, and repeated components. However, it differs in a key characteristic. Among humans, a regular beat is significantly associated with dance, group-based activity, and percussion. In palm cockatoos, a regular beat is usually the product of a solo activity linked to percussion but not to group-based activity or dance. This difference between humans and palm cockatoos is important because, whereas the present-day tight associations between rhythm, dance, group-based activity, and percussion make the origins of human rhythm difficult to disentangle), palm cockatoos indicate that regular percussive rhythm can evolve as part of a solo performance by males to females.

In conclusion, our analysis demonstrates that the tool-assisted drumming displays of palm cockatoos have key hallmarks of human music as distinct from other forms of communication, most notably language. These include performance in a consistent display context, regular beat production over long sequences, repeated components, and individual signatures or styles. Regular rhythm is widespread among human societies and is strongly linked to dance, group-based activity, and percussion, but the origins of our preference for a regular beat remain obscure. The simple, regular drumming displays of palm cockatoos in just one population in northern Australia may provide a much needed comparative clue to help solve this riddle. Palm cockatoos suggest an evolutionary link between regular rhythm and solo-based percussive performances by males to females. This supports Darwins contention that a regular beat has primeval aesthetic appeal across species, and points to the distinct possibility that the preference for a regular beat in human societies had other origins before being co-opted into group-based music and dance.

If a “regular beat has primeval aesthetic appeal among species”, why doesn’t that appear in any primates, if it has to do with the origin of human music? And, as the authors note, palm cockatoos don’t dance (though the famous cockatoo Snowball does dance to a human-generated musical beat, and I’ve seen him do it). Further, if this has to do with the evolution of music, there has to be a genetic component to the birds’ behavior, and that hasn’t been shown. (Note again that it’s seen in only part of the species’ range, though that doesn’t rule out genetic differentiation among areas.)

The authors are trying to sell their results by saying that it has “broad implications for understanding the evolution of music,” but I don’t see that it does. That’s just sizzle to boost the appeal of an already palatable steak.  The data are interesting enough as they are, and raise other and more answerable questions. Why do the birds do it? Do females prefer a certain rate of drumming? Are the interpopulation differences cultural, genetic, or a mixture of both? So far all we have is a convergent behavior, one that, to me at least, says nothing about the origin of music in Homo sapiens.

h/t: Vidya

________________

Heinsohn, R., C. N. Zdenek, R. B. Cunningham, J. A. Endler, and N. E. Langmore. 2017. Tool-assisted rhythmic drumming in palm cockatoos shares key elements of human instrumental music. Science Advances 3, online.

55 Comments

  1. ThyroidPlanet
    Posted January 9, 2018 at 12:57 pm | Permalink

    Interesting – I agree with PCC(E).

    I’d add that “Music” is just as nebulous as anything. The crows (corvidae to readers, I guess) in the park are also “musical” by the authors definition – in other words, so what YES I KNOW THIS IS WITH A TOOL but still, “music” is, as I think Pinker has said, a “spandrel”, an impression left upon the observer of meaning oh dear I’m rambling…..

    • ThyroidPlanet
      Posted January 9, 2018 at 12:59 pm | Permalink

      … ok I came down a bit – another comment:

      Heartbeats – breathing – those have rhythmicity, of different variations. I wonder of the connection of the male cockatoo hearts and diaphragms to the operation of their heads with the nut in the beak….

      • ThyroidPlanet
        Posted January 9, 2018 at 12:59 pm | Permalink

        Stick not nut

      • Posted January 9, 2018 at 1:28 pm | Permalink

        The ones I saw in the videos were using their feet.

        • ThyroidPlanet
          Posted January 10, 2018 at 1:06 pm | Permalink

          Touché

          ^^^^joking

  2. DrBrydon
    Posted January 9, 2018 at 1:08 pm | Permalink

    They say the Spring
    Means just one thing
    To little lovebirds;
    We’re not above birds,
    Let’s misbehave

    The song Let’s Misbehave from Cole Porter’s Anything Goes.

  3. Posted January 9, 2018 at 1:11 pm | Permalink

    Why only one foot? I read awhile ago that birds show a preference for footedness* in terms of grasping things. Perhaps this is the reason and they haven’t sampled enough to see any right footed drummers.

    I agree the connection to human music is extremely weak.

    *I think right footedness though, which doesn’t fit the observations. I’ll need to search for the articles.

  4. Posted January 9, 2018 at 1:28 pm | Permalink

    “They are also “basal” cockatoos…” Interesting birds, but I have an ongoing problem with the concept of “basal”. Any fork produces two branches. How is one of the two deemed basal and not the other? It seems to me that basal came into favor when it was finally recognized that “higher” and “lower” were not objective categories. To me, basal still has that problem.

    • Posted January 9, 2018 at 1:29 pm | Permalink

      I believe it’s time. They were the first to branch off. Other groups diverged later.

      • Posted January 9, 2018 at 2:06 pm | Permalink

        No, my point was that a fork produces two branches at exactly the same time. How do you choose which of the two is “basal”? My suspicion is that it involves a subjective judgement of which is the more important branch (not basal), but that gets you back to exactly the problem with “higher” and “lower”.

        • Posted January 9, 2018 at 2:33 pm | Permalink

          I see what you’re saying.

          Here’s how I see it. Say, from phyogenetic analysis, we find that clade “A” (a group of closely related species) appeared 1 million years ago producing the fork you speak of.

          We also find that later clades “B” and “C” (and “D”, etc) appear. Our phylogenetic analysis shows that clades “B” and “C” are more closely related to each other than they are to clade “A”.

          This means clade “A” is basal – or closer to the last common ancestor- than any of the other clades.

          That’s how I understand it. I welcome any corrections.

          • Posted January 9, 2018 at 3:30 pm | Permalink

            Yeah, me too, but cladistics–or systematics in general–it not my area of expertise.

          • Posted January 9, 2018 at 6:37 pm | Permalink

            OK, but suppose clade A also undergoes subsequent branching producing sister clades A1, A2, A3, A4 etc. Now who is basal? I guess I just don’t see it as a very useful concept, adding little to just laying out the phylogeny.

    • Posted January 9, 2018 at 3:55 pm | Permalink

      Species in the basal branch have retained certain primitive traits so it better resembles the common ancestor, while the other branch has species with more derived traits.
      Lemurs represent a basal group of primates, with some claws on their fingers, and a long, wet, dog-like nose.

      • Posted January 9, 2018 at 6:33 pm | Permalink

        That helps, but it still seems to me to involve some subjective judgments in selecting traits to evaluate. Would a highly intelligent marsupial judge eutherians to be basal?

  5. Steve Pollard
    Posted January 9, 2018 at 1:31 pm | Permalink

    An interesting piece, and many thanks for pulling it all together. I don’t for a minute buy the “origins of music” assertion. The core of the article is interesting enough in itself: in my view the authors detract from it by making this unwarranted connection.

  6. Jenny Haniver
    Posted January 9, 2018 at 1:38 pm | Permalink

    The cockatoos are very cool, but I, too, think it’s a far stretch to try to locate the origins of human drumming in these cockatoos.

    I do, however, think there’s a case to be made in looking to primates for the origin of spectator sports, as evidenced in this video of long-tailed macaques watching a cat fight https://www.youtube.com/watch?v=Rqq2rqQA3FQ, which I may have referenced in the past, but it seems apropos to bring it up here re putative origins of human behaviors. All those monkeys need are some nachos and beer. Then I find this abstract of a study https://www.sciencedaily.com/releases/2017/12/171219110032.htm which asserts that even primates and infants want to punish antisocial behavior. In the video, once the cats are actually fighting, one of them jumps up, plays referee, breaks up the cat fight, and then several of the macaques chase the black

    • Jenny Haniver
      Posted January 9, 2018 at 1:39 pm | Permalink

      “one of ‘them’…” meaning one of the macaques.

  7. Posted January 9, 2018 at 1:41 pm | Permalink

    “…says little about the origin of music in Homo sapiens”
    I agree, it seems a little late after the migration out of Africa. The aborigine (Australia) use a hard wood to get a high pitch rhythmic clicking sound (clapsticks) which is basically 2 sticks and when coupled with a didgeridoo, adds to an amazing haunting sound.
    Didgeridoo use dates back 40,000 years.
    The Pacific Islanders who use heavy and light wood drumsticks on hollow fashioned logs get get really hot rhythms going. There is usually more than one log drum and all different sizes for pitch and different timings.
    And it can be loud.

    • infiniteimprobabilit
      Posted January 10, 2018 at 12:10 am | Permalink

      In Rarotonga the drums (hollowed logs) are typically called ‘pate’ (though there are doubtless other names).

      Northern Group (of the Cook Islands) often use cabin bread tins (solidly made tin cans maybe a foot high by nine inches square) as well / instead.

      It is, of course, always associated with traditional dancing.

      And yes, it can be very loud.

      Plenty of tracks on Youtube, by the way.

      cr

  8. Posted January 9, 2018 at 2:02 pm | Permalink

    So you guys are debating whether this is music? Have you listened to the radio lately? These birds are producing better music than a hell of a lot of “artists”

  9. grasshopper
    Posted January 9, 2018 at 2:06 pm | Permalink

    I have kept birds of one sort or another for most of my life. I have never seen one give birth. Palm cockatoos must be unique.

    Cockatoos in general can be long-lived. The Queen of England used to send a telegram of congratulations to her subjects if the reached the age of 100. Showing that she has a sense of humour, she once sent a telegram to a sulphur-crested cockatoo who had turned 100.
    http://www.abc.net.au/news/2014-11-02/wildlife-park-throws-a-100th-birthday-party-for-an-old-cockatoo/5860770

  10. Posted January 9, 2018 at 2:16 pm | Permalink

    Very interesting. And what wild-looking birds!

    I agree it says little (nothing?) about human music.

  11. Posted January 9, 2018 at 3:08 pm | Permalink

    The unique characteristic about human ‘drumming’ is the consistent frequency of the sounds produced. These marvellous birds are regularly hitting wood to produce sound but it is not rhythmically consistent, as in music (listen to the recordings – could you dance to it?)

    As a musician of 50+ years I’d go crazy trying to ‘groove’ along with a Palm Cockatoo, bless their crazy beaks.

    rz

    • Gregory Kusnick
      Posted January 9, 2018 at 3:39 pm | Permalink

      The rhythmicity claim bothers me a bit too. The basic biophysics of swinging a stick guarantees a greater degree of rhythmicity than a pure Poisson distribution, so that by itself can’t be taken as evidence of human-like musicality.

      • Posted January 9, 2018 at 3:57 pm | Permalink

        The rhythmicity claim isn’t predicated on it being music; that what the authors claim it is. It is rhythmic because it doesn’t follow the pattern one would expect to find in an arhythmic beat. That what those graphs show.

        • Gregory Kusnick
          Posted January 9, 2018 at 4:33 pm | Permalink

          I understood that. My point is that a dripping water faucet or a flag flapping in the wind would also display the same sort of approximate rhythmicity (i.e. non-conformity to Poisson distribution) simply due to the physical constraints of dripping and flapping.

          • Posted January 9, 2018 at 5:02 pm | Permalink

            Got it. You’re right of course, but these are birds not dripping faucets. So far as we know, no other animal besides us does it in this way – using a tool to generate a rhythm, even if it isn’t “music”. That makes it more than a dripping faucet phenomenon…to me.

            • Gregory Kusnick
              Posted January 9, 2018 at 6:35 pm | Permalink

              There may indeed be more here than dripping faucets, but what’s conspicuously absent from the paper is any attempt to quantitatively compare palm cockatoo rhythmicity with human rhythmicity.

              If we imagine a spectrum with a metronome at one end and a Geiger counter at the other, where do these birds fall on that scale? Where do humans fall? These are questions the authors apparently haven’t bothered to ask, despite their claims about the relevance of this work to human musicality.

            • Charles Minus
              Posted January 9, 2018 at 8:03 pm | Permalink

              Sorry, but I agree with izzzy, these birds are not producing a rhythm. They are making series of irregularly spaced sounds with no underlying pulse.

  12. Paul S
    Posted January 9, 2018 at 3:13 pm | Permalink

    Cool, but I think their conclusions are a bit of a stretch. The samples were too short for me to tell if it was rhythmic.
    It does lend credence to the theory drummers get the chicks.

  13. Posted January 9, 2018 at 3:51 pm | Permalink

    Very interesting! It reminds me of a recent episode of Nova about the intelligence of birds, focusing especially on parrots and their relatives, and Corvids. It was amazing.

  14. bbenzon
    Posted January 9, 2018 at 4:13 pm | Permalink

    The question of whether or not this is music or related to human music is, at best, secondary. What’s important is the rhythmicity. The sounds may not be random, but I agree with rzzzy (#11), there’s no consistent groove here.

    Back when I published my book on music (Beethoven’s Anvil: Music in Mind and Culture, Basic Books 2001) humans were the only creature capable of synchronizing with one another. That, to me, is the key. There is now an extensive body of research about the capacity of humans to synchronize with one another at a resolution of 10s of milliseconds. This appears to be with us from birth. Speech seems to depend on it, with speaker and listener tightly synchronized with one another.

    With the advent of YouTube videos, however, it was discovered that parrots and cockatoos can synchronize with music being played in their presence. Aniruddh Patel (now at Tufts) has investigated this.

    The behavior reported above seems in that general ballpark. The question becomes: can the palm cockatoo synchronize with an external beat, such as provided by human music? That’s an experiment well worth doing/attempting.

    • Posted January 9, 2018 at 5:03 pm | Permalink

      Yes. I took the videos for the studies lead by Dr Ani Patel. Snowball is our sulphur crested cockatoo and continues to have a blast dancing.

  15. Mark R.
    Posted January 9, 2018 at 4:20 pm | Permalink

    I’ve never heard of this amazing bird; thanks for the introduction.

    I suspect you could do an experiment and introduce some male palm cockatoos from New Guinea and see if they pick up the drumming. You could also see if the new non-drumming males were successful finding a mate. Perhaps these birds are difficult to track and observe.

    I hope the work continues on these birds. Maybe linking this to the origins of human music was a way to get more funding.

  16. Posted January 9, 2018 at 4:54 pm | Permalink

    The first time we noticed Snowball “drumming” was when a neuroscientist from San Diego came to observe his dancing abilities. The neuroscientist also happened to be a drummer and began tapping on Snowball’s cage. Snowball picked up a toy laying at the bottom of his cage and began tapping back in rhythm. I guess he didn’t want to be outdone. 🙂

  17. Posted January 9, 2018 at 5:25 pm | Permalink

    Then, there is dancing (and singing).

    Snowball the dancing cockatoo: “Snowball (TM) is a Medium Sulphur Crested Eleanora Cockatoo that dances to the Back Street Boys and other songs that he rates as having a “very good beat.” He came to Bird Lovers Only Rescue Service, Inc. (a 501c3 not for profit bird rescue and sanctuary) in August 2007 and continues to make us laugh with his fancy footwork. We are currently raising funds to build a bird habitat for Snowball and other birds like him.”

  18. Greg Geisler
    Posted January 9, 2018 at 6:51 pm | Permalink

    Which explains the metal band Hate Beak:
    https://en.wikipedia.org/wiki/Hatebeak
    ;^)

  19. Posted January 9, 2018 at 7:26 pm | Permalink

    I really enjoyed this article. A fascinating read but the idea that this is part of musical evolution, not really buying that.

  20. Posted January 9, 2018 at 9:38 pm | Permalink

    Well, in any case, Jerry should be happy to see a science post generate so much chatter.

  21. Brian salkas
    Posted January 9, 2018 at 10:42 pm | Permalink

    I would be skeptical about the birds interpreting this (the tapping) as music. It would seem strange that a bird would have a concept of rhythm but not dogs or monkeys.

  22. Posted January 9, 2018 at 11:00 pm | Permalink

    I don’t know much about either music or birds but thanks for the science!

  23. Wayne Y Hoskisson
    Posted January 9, 2018 at 11:07 pm | Permalink

    Why would the “drumming” of this one bird be the origin of human music rather than the songs of birds found around the globe? I would vote for the song of the canyon wren but it is found only in the western U.S. and Mexico and no where near the origin of humans.

  24. Dale Franzwa
    Posted January 9, 2018 at 11:47 pm | Permalink

    Yeah, but can these birds drum up a good opera?

  25. infiniteimprobabilit
    Posted January 10, 2018 at 12:27 am | Permalink

    I think the title is a bit of a “come-on”.

    I don’t think the origins of human music need any other-animal inspiration. There are natural rhythms – dripping water being the most obvious – that might suggest a typically repeated sound to a proto-human. And even ones own heartbeat (which can be heard in very quiet surroundings). And animals running. And banging-on-things rhythmically is quite addictive.

    And – we have vocal cords capable of producing a range of notes. This is probably inherent in the design of vocal cords. And there are natural sounds around us of varying pitches – the wind in the trees, the sound a hollow log makes when you hit it – that could easily inspire a proto-human to try to imitate it.

    We use varying pitch when we talk. It seems like a natural thing to try out various pitches just for fun – and you’re singing.

    So my theory – which is mine* – is that music probably arose naturally in humans. No external instruction required.

    cr
    * Doubtless a theory expounded by thousands of others, in reality.

  26. Posted January 10, 2018 at 10:15 am | Permalink

    In the last video, the cockatoo seems to be splintering the wood as it drums, and peels off the splinters of bark and deposits them in the hollow of the tree, thereby building a nest. In this particular scenario, nest building seems to be the purpose of the drumming behaviour.

  27. Posted January 10, 2018 at 12:03 pm | Permalink

    Distantly related: I read a book claiming that baroque and (western) classical music are perceived (partially) not by the regular auditory systems, but by the “remains” of the lateral line. Any thoughts on that?

    • ThyroidPlanet
      Posted January 10, 2018 at 1:06 pm | Permalink

      Book title please

      • Posted January 12, 2018 at 11:51 am | Permalink

        _The Musical Representation: Meaning, Ontology, and Emotion_. (C. Nussbaum, MIT Press.)

        • ThyroidPlanet
          Posted January 12, 2018 at 6:31 pm | Permalink

          Thank you!

          Gonna be a while to get for me though…

  28. nicky
    Posted January 10, 2018 at 1:46 pm | Permalink

    You see, this is why I rarely comment on science posts: one needs some spare time to peruse it, and by the time I am able to do that (yes I still do) we are often days further and commenting is ‘dead’.

    • ThyroidPlanet
      Posted January 11, 2018 at 9:16 am | Permalink

      And your contribution to this scientific discussion is …

  29. Leigh Jackson
    Posted January 11, 2018 at 8:48 am | Permalink

    Fascinating and entertaining. As for the origin of music I think that’s entirely another mystery.


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