Which bird species best imitates R2D2? “Part of sexual selection”
Anyone who has seen the Star Wars films can probably easily recall the characteristic R2D2 sounds. But imitating the white and blue robot? That’s a different story. Henkjan Honing, professor of music cognition at the UvA, investigated how well starlings and nine different species of parrots are able to imitate R2D2.
To begin with the striking, and for the layman somewhat unexpected, result of the study: not one of the various species of parrots – which are often associated with mimicking sounds – but the starling turns out to be the most successful R2D2 imitator.
“In hindsight, however, we could have seen this result coming,” says Honing about the study. “The sounds made by R2D2 were composed in the 1970s by Ben Burtt using a specific type of synthesizer. That device had the ability to produce tones that included both an upward inflection and a mirrored downward inflection. To imitate that precisely, you have to mimic two tones at the same time. We see that parrots – just as we would have to do because we only have one pair of vocal cords – choose one of those two tones. But starlings can copy those sounds exactly because they have two sound sources that they can control independently of each other.”
Bird Singalong Project
The sounds made by the Star Wars character are difficult to transcribe phonetically, but for those unfamiliar with the films: think of old-fashioned, electronic-sounding robot sounds in the realm of “beep-boop.” Add to that the cheerful singing birds and the highly intriguing picture is complete. However, according to Honing, this is more than just a light-hearted study. The study is part of the overarching Bird Singalong Project, which investigates the evolutionary history of music and musicality. ’
“The ambition is to find out what musical characteristics we share with birds, but also with other animals,” explains Honing. “For example, we are also investigating whether parrots and starlings have relative hearing, among other things. In short: what are the building blocks of musicality? Humans mainly listen to melody and rhythm, but what do birds listen to? By finding out which building blocks of musicality we share with completely different animal species, we can say something about the evolutionary, biological history of music. For example, why we need music at all, in addition to language.”
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There are many theories about the origins of music, says Honing. Some musicologists believe that music was invented by humans as a mechanism to keep large groups together. In any case, it seems clear that it is in our genes: “Young babies, for example, already have a sense of rhythm and move to music,” explains Honing, “but there are also known examples of animals that can do this. Take Snowball, the cockatoo whose videos went viral because he dances to the Backstreet Boys. Recognising regularity in music is therefore not a uniquely human trait, as was previously thought.”
By zooming in on the musical characteristics of other animals – including species with which we do not share a direct ancestor – musicologists can say something about the evolutionary added value of music. Honing: “If we share a sense of rhythm or relative pitch with a bird, then that means it was invented twice independently in evolution. Apparently, having a sense of rhythm was a good solution to a particular problem, not only for us, but also for that bird. In this way, we can learn something about the origins of music in the here and now.”
The R2D2 study was conducted using citizen science. This means that the data was not collected in a laboratory, but instead by people at home. The researchers collected more than a hundred videos online in which different bird species imitate the characteristic sounds of the Star Wars robot. Citizen science is used in some fields to complement standard laboratory research.
Sexual selection
The only question that remains is: what problem does a starling solve by being good at imitating R2D2? “Yes, that’s the question, because it’s quite a hassle for that starling, of course,” laughs Honing. “Biologists explain that this has to do with sexual selection. Starlings find new sounds very interesting. They collect these sounds and build up a whole repertoire for themselves. This makes them more attractive to mates. The more unusual, complex sounds they can master, the better.”
In fact, it has long been thought that music originated as part of sexual selection in humans as well, adds Honing. “Showing who you are by demonstrating how well you can dance or how cool you can play the guitar, for example. But there doesn’t seem to be much evidence to support that theory.”
