Fig. 2. (A) Representative sonomicrometry (top) and corresponding EMG (bottom) recordings from a quail during a vertical take-off. The resting length of the muscle (LR) is indicated before the flight. Variability in both recordings towards the end of the flight coincides with the bird flying into the mist net at the top of the flight chamber. (B). Expanded detail of three wing strokes, revealing the temporally asymmetrical strain trajectory (70.3 % of the time spent shortening and 29.7 % of the time spent lengthening for these three strokes). Note that, in this individual, the strain distribution is asymmetrical, with lengthening of +6 % and shortening of –14 % relative to LR. However, for all the birds for which measurements were obtained, the strain was distributed symmetrically relative to LR (lengthening of +11 % and shortening of –12 %, relative to LR; see Table 1).
