For grass and legume seed producers in the Willamette Valley, Oregon, the gray-tailed vole can cause yield losses of 50% or more. A study was conducted in the spring of 2023 to evaluate the effectiveness of diphacinone and chlorophacinone rodenticide baits applied in tamper-proof bait boxes for controlling voles. Eight treatments (5 rodenticide baits, non-toxic chicken feed, untreated control, and grower standard) were tested in a commercial tall fescue seed production field in a randomized complete block design with four replicates. Motomco Titan bait boxes with IQ trays were used, which allowed activity inside each box to be detected. Boxes were placed in the damaged areas of the field in mid-April. Pre-weighed bait was replaced, and activity data was downloaded weekly for eight weeks. Crop growth was monitored with drone aerial imagery collected before, during and after the bait box treatments. To evaluate the impact of vole damage on yield, seed was harvested from 50 cm sections of a crop row in damaged (n=16) and undamaged (n=16) locations. While signs of vole activity continued throughout the study, there was little to no clipping of reproductive tillers by voles – a major cause of yield loss in vole-infested fields. Bait consumption and activity in boxes was observed in all boxes. No differences between treatments were detected. Aerial imagery data correlated strongly with seed yield and tiller counts from the yield plots. Interestingly, the strongest correlation with yield was found for the flight conducted before the bait box treatments were applied, suggesting that damage caused before the start of the experiment had a lasting effect on crop yield.