Viking Orbiter images of the annual south polar cap on Mars show elongated bright features that are associated with craters and resemble wind streaks seen elsewhere on Mars. The seasonal behavior of these albedo features indicates that they are accumulations of CO2 frost. They appear in the fall, shortly after the annual cap has formed, and some survive as outliers for as many as 70 days during the cap's retreat in the spring. The frost streaks indicate a prograde circulation pattern of near-surface winds around the pole with a definite component away from the pole. There is evidence that this prograde pattern persists throughout fall and winter. As the cap is receding in spring, and in the summer when the annual cap is absent, a retrograde circulation pattern around the pole, again with a definite component away from the pole, is indicated by dark crater-associated streaks and other eolian features. The higher albedo of the frost streaks relative to the surrounding annual cap is probably due to a slightly more complete coverage of the ground by frost within the streaks. From their persistence during the spring recession of the main cap we estimate that some frost streaks near 60¿S contain up to 120--130 g/cm2 of CO2 frost, or about 3 times the maximum amount in the surrounding cap at these latitudes. We suggest that the frost streaks represent accumulations in the lees of craters of wind-transported frost, indicating that frost is effectively redistributed by winds within the polar caps. Threshold wind velocities required are estimated to be one half or less of those needed to initiate dust movement at equatorial and temperate latitudes.