Thresholds for the detection of gaps in noise, temporal integration, and difference limens for duration were measured in several species of birds using avoidance conditioning and the method of limits procedures previously described for the parakeet. The threshold for the detection of gaps in white noise bursts is about 3–5 msec for the house finch. Temporal integration functions showing absolute threshold as a function of tone duration for field sparrows and parakeets reveal a "time constant" of 200–300 msec. Difference limens for duration obtained at six durations of a 2.86-kHz tone for the parakeet show Weber fractions, D/D, in the range of 0.10–0.20. These data are compared to similar data available for the human and the results of these experiments are discussed in relation to the characteristics of avain vocalizations and the role of hearing in song learning and song production. [Work supported by NSF grant BNS75-19431.]