Before revision:  The bare-bones hallmark of this new control is a strongly nonlinear speed-restoring force that ignores small deviations of the individual speed from its natural reference value , while ferociously suppressing larger speed fluctuations. Numerical simulations of self-propelled particles flocks in the same size range as the empirical data fully support our theoretical results .
After revision:  The bare-bones hallmark of this new control is a strongly nonlinear speed-restoring force that ignores small deviations of the individual speed from its natural reference value , while ferociously suppressing larger fluctuations, is the only mechanism reconciling scale-free correlations with biologically acceptable flocks' speed, a result that we confirm through numerical simulations on self-propelled particles flocks in the same size range as the empirical data fully support our theoretical results .