Of the two MOLTS, the one in spring is most easily discernible because the contrast in color between worn winter pelage and fresh summer pelage is considerably greater than that between worn summer pelage and fresh winter pelage, and because the progress of spring molt is seemingly more regular than that of autumn molt.
"Geographic Variation in the Harvest Mouse, Reithrodontomys megalotis, On the Central Great Plains And in Adjacent Regions"
J. Knox Jones B. Mursaloglu