Duration discrimination in Northern bobwhite quail

We examined the ability of northern bobwhite quail Colinus virginianus to discriminate along the duration dimension because of its suspected importance in their ability to identify individual covey members. If quail are using variability along this dimension to identify individuals we would expect their auditory resolving powers to be sufficiently refined in that dimension to make appropriate discriminations. Three 2-year old male bobwhite quail were trained using a positive reinforcement technique to discriminate between a 1000 Hz standard (correct) tone 600 ms in duration (100 ms rise/fall time) and a 1000 Hz comparison tone 300 ms in duration (also 10 ms rise/fall time). Quail were then required to discriminate between pairs of tones in which the duration of the comparison tone was progressively increased from 400 ms to 590 ms. Because of the categorical nature of the analysis we concluded that the two tones must differ in duration by 20 ms or more if they are to be discriminated correctly. Our study has shown that bobwhites are able to detect a 3% difference in duration around a standard tone 600 ms in duration, which compares favourably with results obtained from earlier studies with parakeets Melopsittacus undulatus and pigeons Columbia livia. Such a finely tuned duration discrimination ability also suggests that it is possible bobwhites may be using individual variability along the duration dimension of the separation call to identify individual covey members.