Fig. 5. Mean acceleration-compensated differential pressures for inner and outer tail positions, and distal and proximal wing positions. Also included are acceleration signals for inner and outer tail positions (second pair of traces) and the proximal wing position - the synchronising accelerometer. Tracings of the pigeon through the wing stroke cycle match the timing of the graph. Values are mean ±1 S.D. (shown in black; N=3 pigeons). The vertical red broken lines show the relationship between a peak in both inner and outer tail pressure signal, an upwards acceleration of the wings towards the end of downstroke, and a concurrent downwards acceleration of the tail.