Fig. 3.

Signal plasticity in a male duet. a Chirp duration, duty cycle and time difference between leader and follower chirp onset (Δt) during a 8 min sequence of a 1:1 phase locked duet of two males with similar solo chirp periods (2.2 s). b Chirp duration of both males shown as a function of Δt. Note that chirps of male A and B differed in duration, but both males produced shorter chirps when singing as followers. c Relationship between the time difference of chirp onsets and chirp endings. The dotted red line indicates a situation without any chirp plasticity