Belgian Waterslager canaries have less sensitive hearing at high frequencies and produce songs with more energy at low frequencies than wild-type canaries. A backcross pedigree between Belgian Waterslager canaries and a domestic strain with wild-type song revealed inheritance patterns consistent with a factor of major effect located on the Z sex chromosome affecting both poor high-frequency hearing at 4 kHz and the relative energy in the spectra of the learned songs of males. Hearing thresholds at 4 kHz were significant predictors of the relative amount of song energy at 4 kHz for individual males. One hypothesis for the mechanistic basis of this correlation between hearing and song abnormalities is that a reduction in the ability to hear higher-frequency songs biases males towards learning lower-frequency songs.