Figure 4.

(a) Bootstrapped (n = 1000) dendrogram of average-linkage clustering of median song strings recorded at different locations and years, based on LSI analysis. (b) Bootstrapped (n = 1000) dendrogram of average-linkage clustering of theme presence and sharing among different locations and years, based on DSI. Red dots indicate AU values greater than 95% where divisions were stable and likely to occur. Red boxes indicate the resulting clusters. The labels are structured as follows: Location_Year_Sub-Location_SongIdentifier. Sub-locations are included for New Zealand 2016: STB = South Taranaki Bight; CS = Cook Strait. Two song types (A and B) were present in New Caledonia in 2015.