Fig. 3. Comparisons of beak and dance movements for two father/son pairs. Each panel shows the songs of the father at the top and the son at the bottom. Boxes within the sonogram denote song elements present in the song of only one of the pair; these portions of the songs were omitted when matching frames from a father’s song to frames in the son’s song (the matching process was performed using the sonograms, without reference to data on movements). For this figure, the syllable designations in different songs within the same panel correspond to matching syllables (e.g., the syllables within W31’s song were considered to correspond to the syllables with the same letter designations within Bk58’s song). Syllables that had no match in the father’s or son’s song were designated with the letters Q, X, Y or Z. Syllables I, J and K in Pk61’s song were difficult to match unambiguously to corresponding syllables in his son’s song, and the correspondence involving the fewest rearrangements was chosen. The beak movement trajectories for the matching portions of the father/son song pairs are shown immediately beneath and in register with the father’s song. Filled circles connected by a solid line show the beak movements of the father, and open circles connected by a dashed line show the corresponding changes for the son (all lines are cubic splines fitted to the net beak movement, as in Fig. 2). The dance movements were registered and summarized in a similar fashion. Although the fits for the father’s and son’s beak movements and dance were not perfect, the major peaks correspond (see text for statistical analyses). The greatest divergences from a common pattern appear to fall in the segment of the Pk61/DP46 song that was difficult to match unambiguously (syllables I, J and K).
