We can't all be Maria Callas or Freddie Mercury. The ability to sing is a gift, not bestowed on everyone. But singers maintain that it's also about hard work. And now they've been proved right.

In a December 12 article in the journal Nature Communications, a team of Danish, Swedish, Dutch and American researchers provide proof that, for the mandarin diamond at least – also known as the zebra finch – singing well requires daily exercise.

Why mandarin diamonds? "Firstly, because no [human] singer will let you take tissue samples from their larynx," explained Iris Adam, a senior lecturer in biology at the University of Southern Denmark, and one of the researchers. To be completely transparent, the 79 male birds studied at the university didn't give their consent either. But let's just say that their participation was in the name of science.

The male zebra finch also emits a particularly modulated song, which has made it a model animal in the field. And these birds never stop singing – to impress their future partners, to defend their territory, to maintain social ties... Or for no reason at all, at least seemingly. Even when they are alone, they don't just breathe and squawk, they sing.

To investigate the role of training, the scientists took advantage of the fact that birds have two parallel neuromuscular circuits, one per brain hemisphere. By cutting off one of the two circuits, they found that the vocal muscles lost 50% of their volume and tone within two days. But what happened if they were deprived only of the ability to sing? All you have to do is keep them in the dark. The birds called out, but no longer sang. Here again, the scientists noted a loss of half their muscular efficiency: still 50%, but this time within seven days. It was a rapid decline that astonished the research team.

It remained to be seen whether this drop in performance would have any consequences. The researchers therefore arranged for 13 female birds to "choose" between two playback songs. On one side was the male bird before its week in the dark. On the other was the same bird, but afterward. In 75% of cases, the females opted for the former. "It's a fascinating result obtained after particularly rigorous experiments," said Nicolas Mathevon, professor of Bioacoustics at the University of Saint-Etienne.

This led to a number of conclusions. Firstly, males need to train to sing well, and if they don't, they'll suffer the consequences. Secondly, if females choose good singers, it's not necessarily because they are music lovers, but perhaps more out of an interest in fitness. "We think that only the fittest males have time to invest in singing rather than other behaviors, such as the constant search for food," explained Adam. This means they're doubtless also fit to produce good offspring, take care of them and defend the nest.

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