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Songbirds may need to practise singing every day to maintain the quality of their performance.

Male zebra finches (Taeniopygia guttata) learn a unique song, usually from their father, in the first 90 days of their life. They then sing thousands of variations of that same song daily throughout their lifetime. Here is a typical example.

But here is what it sounds like after two weeks without singing. The song鈥檚 structure is maintained, but the bird sings at a lower pitch and聽for a shorter length of time.

These recordings were taken by at the Korea Brain Research Institute in Daegu, South Korea. The songs are generally used to attract a female partner, but it is unclear why the birds continue to sing when they are isolated from others, he says.

Kojima and his colleagues stopped 16 adult male zebra finches from singing for two weeks. They did this by placing a small weight on their necks that prevented them from getting into a posture that allowed them to sing. The weight didn鈥檛 significantly affect the birds鈥� ability to eat or drink, says Kojima. The researchers removed the weight at night, as the birds don鈥檛 typically sing at this time.

鈥淲e think that if the [singing] muscle gets weaker, the birds cannot make a high-frequency, high-pitch sound,鈥� says Kojima.

After two weeks of being allowed to sing again, the finches regained the ability to do so at a higher pitch and for a longer amount of time.

To find out how exactly the lack of practice affected the birds鈥� singing abilities, the team repeated the experiment with six finches that were made deaf by removing their cochleas, parts of the inner ear that are used for hearing.

Just as with the first experiment, these birds were worse at singing after two weeks of no practice, but their ability recovered after they were able to sing for two more weeks.

This suggests that the decline in performance after being unable to practise is due to a lack of muscle use 鈥� particularly the muscles in their vocal organs, called syringeal muscles 鈥� rather than a lack of auditory feedback, says Kojima.

鈥淚 suspect that other birds which sing will also need to practise daily to maintain their abilities,鈥� he says.

鈥淚n some ways, this seems obvious to me: we all know how 鈥榰se it or lose it鈥� applies to pretty much everything we do,鈥� says at Clemson University in South Carolina. 鈥淚f the birds can鈥檛 use their syringeal muscles for two weeks, the muscles get a bit flabby, but they鈥檒l bounce back and tighten up pretty quickly once activity is restored.鈥�