Fig. 5

Syllable type usage presented in non-metric multidimensional scaling (nMDS) plots and pie charts. NMDS plots of syllable types emitted during (a) introduction and (b) interaction phase comparing unrelated pairs (blue dots) versus related pairs (red triangles). Letters in black indicate the syllable types; each symbol represents one breeding pair. Distances between the symbols represent similarities of breeding pairs in the syllable type usage. Short distances of symbols to letters indicate syllable types that were most representative for each breeding pair. c Pie charts representing proportions of each syllable type used by unrelated and related pairs during introduction and interaction phase. Both visualizations show similar results of syllable type usage