Quantitative Tools for Examining the Vocalizations of Juvenile Songbirds

Figure 6

Measuring progress in song development. Each colour represents a different bird. For each bird, an early model and late model were built of the first and last 100 samples available; all other samples were compared against both models and their difference calculated, so that negative scores suggest a sample was more typical of the early model, and positive scores suggest a sample was more typical of the late model. Each point is the mean of all samples for that day, and error bars indicate standard error. All birds progress from being essentially early-like to being late-like, but unevenly and at different rates.