Dooling, R.J.  and Saunders, J.C. (1974). Threshold shift produced by continuous noise exposure in the parakeet (Melopsittacus undulatus). J. Acoust. Soc. Am. 55, S77.

Parakeets were trained for behavioral audiometry and then exposed to an 86-dB-SPL -octave band of noise centered at 2.0 kHz for three days. Thresholds were periodically measured during this time and, after 72 hours, the noise was terminated and the decay of threshold shift was followed in a similar manner until recovery was observed. This procedure was then repeated at three additional levels (76, 96, and 106 dB) of the -octave band of noise centered at 2.0 kHz. The threshold shift measured at frequencies exhibiting the greatest loss (2.0 kHz) appears to reach an asymptote (ATS₄) after 9–12 hours of noise exposure. The level of ATS₄ also increased with the level of the -octave band of noise. The decay of TS was related to the level of the noise, and, thus, the amount of ATS4. For exposures of 76 and 86 dB, the decay of TS was complete after 9–12 hours in the quiet. The exposure at 96 dB required three to five days for complete recovery, while that at 106 dB was slower and not complete with an average value of PTS of about 8 dB.