Palm cockatoos (Probosciger aterrimus) are the only non-human animals known to create tools to make sound, shaping sticks and seedpods for drumming. A study of this remarkable behavior shows many similarities to human percussion, suggesting some features of the way we make music may be very old indeed.
Although we talk of birds and whales “singing”, it's generally a capella. Musical instruments are rare in the animal world (with a few notable exceptions) and restricted to objects they find, not make. Palm cockatoos, inhabitants of northern Australia and Papua New Guinea, are the exception. The Australian birds have been observed shortening sticks and reshaping seedpods into drumsticks, and using them to hit hollow tree trunks or limbs repeatedly.
The drumming is incorporated into vocal and visual displays to attract mates, but long drum solos are common as well. As a paper in Science Advances notes: “This behavior is remarkable because tool manufacture among nonhuman species is rare and almost always occurs in the context of solving problems related to foraging, but palm cockatoos use their tools only to make sounds.”
Palm cockatoos live in relatively underpopulated locations, so even though scientists have been aware of the behavior for more than a century, it is relatively understudied. Even footage of it happening was mostly collected for this study.
Lead author Professor Robert Heinsohn of the Australian National University recorded 18 wild male palm cockatoos and analyzed their drumming, focusing on the seven longest sequences recorded, which included between 27 and 92 taps, some drumming twice as fast as others. He showed the taps have non-random timing, representing a genuine rhythm. “Some males were consistently fast, some were slow, while others loved a little flourish at the beginning,” Heinsohn said in a statement. “Such individual styles might allow other birds to recognise who it is drumming from a long way away.”
Heinsohn told IFLScience the behavior appears to be part of a courtship display, usually happening when females are around. Although the cockatoos form long-term partnerships, they do undergo breakups, and the males need to continue to impress partners if they want to keep them, rather than only having to woo once. Moreover, Heinsohn noted that breeding only takes place on average once every two years, and if a male “wants to entice his mate to breed, he needs to turn her on.” It appears some sexy drumming is part of that.
What females look for in drumming is unclear, but the behavior possibly evolved from demonstrating a strong (left) foot to drum with, a nest stable enough to make a good resonant sound, and a powerful beak capable of tearing up sticks and shaping seedpods. Since the cockatoos can live to 100, there is plenty of time to practice.
Drumming is seen in other species, for example chimpanzees, but this is usually done with parts of the body on hollow trees. At most, chimps may use a rock to produce more sound, but even our closest relative is not known to shape the rocks for best effect. Moreover, chimpanzees don't appear to use a beat. The cockatoos, on the other hand, will shape seedpods if they can get them, and rip twigs off branches in the absence of a seedpod, to produce the ideal drumstick.
Heinsohn admitted to IFLScience that describing the research as significant for understanding how human music evolved is “a stretch, but a meaningful stretch.” He added: “There is no other example in the animal world, so the process is remarkably analogous, we couldn't let it go without comparing and contrasting. It's a totally independently evolved trait, which converged from nowhere. It makes a hint at what might have happened for humans.”
Parrots, raptors, and crows are only distantly related, so presumably it is a coincidence that so many signs of extreme avian tool use come from the same part of the world. Yet it is noticeable that the palm cockatoos of Cape York live roughly half way between New Caledonia's famously adept crows and the raptors of the Northern Territory that have reportedly mastered fire.