Agricultural seed left in harvested fields is an important source of energy for migrating and wintering waterfowl. However, rates of seed loss from germination, decomposition or depredation have not been quantified for corn, soybean, or grain sorghum. Because seed loss rates directly influence habitat quality and management recommendations for waterfowl and other wildlife, we estimated rates of germination, decomposition, and depredation for scattered seed and aggregate seed heads in 98 harvested corn, soybean and grain sorghum study plots across Tennessee from September - January 2006-07 and 2007-08. Total seed loss in plots between harvest and January was more than 80%. Scattered corn seed was lost primarily (37%-68%) to depredation, whereas soybean and grain sorghum seed were lost mostly (≥35%) to decomposition. Rates of germination generally decreased and decomposition rates increased from October through January for scattered corn and grain sorghum. Rates of loss were related to ambient temperature, relative humidity, and time since harvest. Seed aggregated on seed heads (e.g., corn cobs) was lost more slowly than scattered seed. Where crops are planted for wildlife, harvest should be delayed if possible to reduce seed loss and land managers should consider planting corn instead of grain sorghum and soybean because seed of the latter species decompose rapidly.