This is Bird Note.

Songbirds delight us with their music, but at times they might sound repetitive.

If you've ever heard a student rehearsing the same bit of music over and over again, you know the feeling. That similarity isn't a coincidence.

Scientists showed that even songbirds have to practice their singing to keep performing at their

best. Researchers studied birds called zebra finches. They kept several male

finches in the dark for a week to discourage them from singing. Without the cue of bright light,

the birds stayed quiet and their vocal muscles weakened. Then the lights came back on and the finches could sing again.

The researchers recorded the finches singing after their break from practicing and compared those songs to ones recorded before the experiment.

They found that female zebra finches preferred recordings of songs from before the males took a hiatus from practicing.

Even after a few days off, females could tell the difference.

So it seems one reason that birds repeat their songs is to keep their vocal muscles in shape.

And, of course, to make sure everyone hears them loud and clear.

For Bird Note, I'm Michael Stein.