  We investigate the emergence of self-organised trails between two specific
target areas in collective motion of social organisms by means of an
agent-based model. We present numerical evidences that an increase in the
efficiency of navigation in dependence of the colony size, exists. Moreover,
the shift, from the diffusive to the directed motion can be quantitatively
characterised, identifying and measuring a well defined crossover point. This
point corresponds to the minimal number of individuals necessary for the onset
of collective cooperation. Finally, by means of a finite-size scaling analysis,
we describe its scaling behavior as a function of the environment size. This
last result can be of particular interest for interpreting empirical
observations or for the design of artificial swarms.
