  The existing consensus is that flocks are poised at criticality, entailing
long correlation lengths and a maximal value of Shannon mutual information in
the large-system limit. We show, by contrast, that for finite flocks in the
long observation time limit, mutual information may not only fail to peak at
criticality---as observed for other critical systems---but also diverge as
noise tends to zero. This result carries implications for other finite-size,
out-of-equilibrium systems, where observation times may vary widely compared to
time scales of internal system dynamics; thus it may not be assumed that mutual
information locates the phase transition.
