Figure 1.

Experimental design and song behaviour. (a) CP for tutor song memorization in the Tutored and Isolate condition, and the conditions used to close and extend the CP, superimposed on a developmental timeline. Red dashed line indicates Isolates have CP for tutor song memorization beyond P65. (b) Graph of song similarity scores showing higher levels of tutor song similarity in Tutored birds compared to Isolate birds. Isolate bird songs were compared to all adult tutors; the highest similarity score is plotted. Symbols reflect which tutor adult was the comparator, numbers next to Isolate data points indicate the difference in song copying scores between that bird and the Tutored bird who lived with the relevant tutor. Asterisk indicates p < 0.05. (Online version in colour.)