I studied seed-size selection among Mourning Doves (Zenaida macroura) and Eurasian Collared-Doves (Streptopelia decaocto), two newly sympatric species for which mechanisms of seed selection are not well understood. I measured and compared mean length, breadth, and thickness of seeds available to, and consumed by, these species in feeding trials of penned birds. Both species selected corn (Zea mays) seeds that were shorter and narrower than average, but Eurasian Collared-Doves selected corn that was thicker than average and sunflower (Helianthus annuus) seeds that were broader and thicker than average. Mourning Doves consumed corn of average thickness, and wheat (Triticum aestivum) and sunflower seeds of average size with respect to all dimensions. Corn consumption by both species seems limited by seed length and breadth, but Mourning Dove consumption of smaller seed types (wheat and milo [Sorghum vulgare]) appears largely unaffected by seed size. Among larger seed types (corn and sunflower), Eurasian Collared-Doves may select thicker- and/or broader-than-average seeds to maximize foraging efficiency. Sunflower and corn seeds consumed did not vary between species with respect to any dimension, but Eurasian Collared-Doves seemed willing to select, and able to eat, broader and thicker seeds than Mourning Doves, which may limit foraging competition between these species.