Years ago I noticed this activity near Vancouver, B.C. At times in late winter the bee activity at a feeder was enough to noticably deter smaller bird users of the feeder. The bees were wading into the loose seed and leaving with pellets on their corbiculas. Grain dust I supposed. A remarkable thing was that the bees actually carried millet seeds from the feeder to hives 200 ft away, and stored them in cells. When I inspected the combs, the seeds (maybe a teaspoon in total) would fall out as the combs were rotated. The seeds were discarded out the entrance and later sprouted at the foot of the alighting board. K. Clark