Figure 5. Vocal interactions within groups across reproductive stages.

(A) Vocal interaction matrices. Examples of vocal correlation indices (from −1 to 1, see colour scale) resulting from PSTHs for all bird and call-type combinations during different phases of the trials (different days indicated above each box), for trials I, II, and III (n_birds = 6, 8 and 8). All initiating birds (x-axis) and responding birds (y-axis) are represented by capital letters (pink: females, blue: males) and are subdivided into the five call types. Note that grey squares (= zero values) indicate there was no significant interaction in the respective dyad and does not mean there were no vocalisations (see ‘Materials and methods’). Same capital letters indicate members of a pair, and within-pair interactions can be found in the diagonal from top left to bottom right. Note an increase in within-pair interactions and a decrease in overall group interactions with progressing reproductive stages (left to right). Inserts in Figure 5A (lower right corner) explain the different interaction levels in the group (highlighted in pale blue) and the call-type interactions (highlighted in pale yellow). The dark grey diagonal from bottom left to top right represents within-bird interactions which were excluded from the analyses. Same-sex interactions are emphasized by pink (female–female) or blue (male–male) outer lines. In trial I, white squares represent missing values. The dataset is available at http://datadryad.org/review?doi=doi:10.5061/dryad.vt69s. (B) Within-pair vocal interactions at different breeding stages. Summary graph of positive within-pair calling interactions in relation to different call-type combinations, sex and the detailed breeding stages (n_pairs = 10). Initiating birds' call types are plotted on the x-axis and percentages of positive responses (pink: females, blue: males) are plotted on the y-axis, in the corresponding call types. Note that both females and males were initiating and responding birds. Source data are available at http://datadryad.org/review?doi=doi:10.5061/dryad.vt69s.

DOI: http://dx.doi.org/10.7554/eLife.07770.010

Figure 5—figure supplement 1. Increasing specificity of within-pair vocal interactions.

Vocal activity (number of distance, tet, stack, cackle, and whine calls, green points = means, green lines = standard errors) and specificity of vocal interactions within pairs (red bars) and with non-pair members (grey bars) over the breeding stages (UP: Unpaired, NN: No nest, Inspec: Nest inspection, Terr: Nest defence, Build: Nest building, Lay: Egg-laying, Incub: Incubating). Note that the pair specificity of vocal interactions increased across breeding stages, and after birds had paired, they always shared more interactions with their partner than with other group members. Also note that for this graph, only trials II and III (n = 16 birds) were included due to the missing values in trial I (would allow investigation of within-pair interactions but not of vocal interactions from the entire colony). Sample sizes were thus 16, 25, 12, 14, 22, 12, and 10 observations coming from 10, 8, 8, 12, 16, 10, and 6 focal birds. Source data are available at http://datadryad.org/review?doi=doi:10.5061/dryad.vt69s.

DOI: http://dx.doi.org/10.7554/eLife.07770.011