The frequency of occurrence of small-scale convective vortices at the Mars Pathfinder lander location exhibits a diurnal variation similar to terrestrial dust devil observations. The 79 vortices detected via their pressure signatures during the 83 sol mission, when combined with an assessment of the incompleteness of data temporal coverage, implies that at least two vortices passed by the lander site each sol. If the vortices are dust laden, as inferred from lander imaging, then the observed vortex frequency is capable of maintaining the observed atmospheric dust load against sedimentation loss. The time-of-sol variation in vortex occurrence provided by Pathfinder, when combined with orbiter imaging of dust devils at a very limited time of sol, offers a potential means of quantifying the effect of these small-scale vortices upon the atmospheric dust cycle.