Dooling, R.J., Mulligan, J.A. and Miller, J.D. (1970). Audibility Curve of the Common Canary. J. Acoust. Soc. Am. 47, 67.

The auditory sensitivity of one type of common canary (Belgian Waterschlager) was measured by behavioral audiometry. Four birds were trained by instrumental avoidance conditioning in a double-grill cage and then their thresholds for pure tones (0.25–9.0 kHz) were measured. Auditory sensitivity was maximum from 2.0 to 4.0 kHz and sharply declines for frequencies above or below this region. Indeed, the sensitivity curve appears to be matched to the average spectrum of this bird's songs and calls.