This field is now alfalfa - no TRBL in field. Saw group of mostly male TRBL (100) fly away from area when first arrived, came either from the dairy or grain field on the south side of the road. Flew NE and lost them in the distance; never returned. Also saw about 500-600 female TRBL swarming over/in the grain field next to dairy, possibly foraging. No signs of nesting.