Figure 1

Calling activity of zebra finch pairs. (a) Example of a succession of calling interactions between a female (upper panel) and a male (lower panel) zebra finch. Vertical black lines corresponding to calling events are plotted as a function of time (in seconds). (b) Quantitative measurements of calling activity of one zebra finch pair (male in blue, female in red). (b [i.]) Calling events were accumulated in a linear relationship over time; (b [ii.]) the call rates (γ) corresponds to the number of calls (ΔN) in a unit of time (Δt = 30 s); (b [iii.]) The changes of call rates (Δγ) were plotted as the function of time; (b [iv.]) The power spectra (S) and the frequency (f) of Δγ were positively correlated. (c) Statistical summary of all 22 tested zebra finch pairs including 119 days of calling activity. (c [i.]) The density counts of the coefficient of determination (R²) of cumulative calls (bin: 0.1). The values of R² are in range from 0 to 1. With increasing linearity of the data, R² approaches 1. (c [ii.]) The density counts of the R² of call rates (bin: 0.04). With decreasing linearity of the data, R² approaches 0. (c [iii.]) The density counts of the changes of call rates (Δγ) (bin: 0.35). (c [iv.]) The density counts of the slopes for the power spectrum of Δγ (bin: 0.14).