Figure 2.

An example of song imitation in a clutch of five male siblings raised by their parents to the age of 90 days. The song motif of the father and that of its sons was recorded when the latter were 108–110 days old. Relative duration, similarity and hatching date are shown under the song motif of each sibling. The father’s song motif is shown five times, aligned with each son’s song to facilitate comparisons between notes.