Fig. 2.
Comparison between the two relevant time scales of active matter, as inferred in 14 natural flocks using our inference method based on exact integration. Histograms of the neighbour exchange time τnetwork versus the local alignment time τrelax = 1/Jnc, show that the relaxation of orientations is much faster than the turnover of neighbours. Note that the experimental sampling time dt = 0.2 s (dashed line) is of the same order as the alignment time, justifying the use of exact integration. Inset: the scatter plot of τrelax versus τnetwork shows no correlation between the two quantities.