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It don’t mean a thing if it ain’t got that swing, goes the Duke Ellington song. By that logic, some bird songs really do mean something: at least a few bird species can swing in the same way that human musicians do, �鶹��ý can reveal.

This claim has been made based on a mathematical analysis of the songs of one species, the thrush nightingale. Not all of the musicians �鶹��ý spoke to agree that what the thrush nightingale is doing can be called swing – but several said they have heard other species of birds singing that definitely do swing.

The most swinging birdsong of all is that of the veery thrush of North America, says of the New Jersey Institute of Technology. This is hard to hear at normal speed, but when the veery’s song is slowed down you can spot how it sings a long note followed by a short one, and then repeats this pattern.

Here’s the veery at normal speed:

And slowed down:

“It’s like a Miles Davis trumpet solo,” says Rothenberg.

Off the beat

In the narrowest sense, swing means delaying the off-beat, says . This means pairs of notes are played long-short instead of being of equal duration. Dum dum dum dum becomes dum-da, dum-da.

This kind of swing is typical of jazz and related styles of music developed in the early 20th century, but it was also used by some 17th-century musicians (“notes inégales”).

Swing is also used in a much broader sense to describe music that has a swinging feel, which it can have even if the off-beat is not delayed. “It’s this quality of unevenness that is so hard to quantify,” says Rothenberg. “You have to feel it.”

Or as jazz pianist Fats Waller is said to have put it: “If you gotta ask, you’ll never know.”

To find out whether other birdsong can possess this quality, Tina Roeske of the Max Planck Institute for Empirical Aesthetics in Germany and colleagues have used a mathematical technique called multifractal analysis to study the rhythms of the thrush nightingale (Luscinia luscinia). The nightingale’s song has subtle deviations in note timing that make it more “expressive”, the team concludes. That is, it swings in the broader sense of the term.

The team has tried to quantity the unquantifiable, says Rothenberg, who likes to play . These birds do swing in the wider sense, he says, using very sophisticated rhythms that we can learn from.

Not all agree. of Macquarie University in Australia is not entirely convinced thrush nightingales can be said to swing. “It’s a terrific study and a fascinating one, but not particularly helped by ‘swing’ being employed in the title,” she says.

However, Taylor, who studies and , says they sometimes do swing. “Some birds sing phrases that seem to momentarily swing,” she says. “If I had a jazz band, I’d let them sit in.”

And Brown too says he has heard other species of birds swinging. One birdsong he heard while hiking in New Hampshire inspired a riff in one of his compositions. “It had an actual swung off-beat rhythm,” says Brown, although he never saw the bird or identified the species. He has also heard hints of swing in the calls of lapwings and corn crakes.

So it seems there are at least a handful of birds that can swing apart from the thrush nightingale.

Why swing it

Whatever you call it, there’s still the question of why some birds vary rhythms in this way.

“They could be introducing subtle variations in an effort to attract the interest of the song recipient, but it could also be that as they get excited they lose strict rhythmic control, or that they become less regular as their muscles fatigue,” says , whose work with scientists showed that at least one bird, the hermit thrush, uses some of the same fundamental musical intervals found in much of human music.

One of the points of swing in human music is to make listeners dance. This is not thought to be the case with birds, but Rothenberg thinks this area needs more study. Even if females don’t dance in response to males’ songs, the males do move.

Some dance while singing as part of the mating display, but even those that appear almost motionless while singing have to move in a certain way to make the sounds, he says. “This is a real growth area in the study of birdsong.”

What everyone agrees on is that we’ve barely begun to scratch the surface when it comes to studying animal music.

“Whether or not we consider some animal songs to be ‘music’, I think it’s beyond a doubt that some have enough in common with human music that we can understand them better by combining musical and scientific methods of analysis,” says Doolittle.

Read more: Music special: Are animals naturally musical?; Tap-dancing songbirds drum with their feet to attract mates