Heidi Hoelting, a musician, listens carefully to the songs of birds. In her piano studio at her home in the woods, she wrote down several variations of the different sounds a Song Sparrow makes. In this BirdNote, Nancy Rumbel plays some of those variations on a bamboo whistle. Listen to all thirteen variations, as played by Nancy.More info and transcript at BirdNote.org. Want more BirdNote? Subscribe to our weekly newsletter. Sign up for BirdNote+ to get ad-free listening and other perks. BirdNote is a nonprofit. Your tax-deductible gift makes these shows possible.