Records of the temporal pattern and nature of nectar-collecting visits to individual flowers by bees (including bumble bees Bombus spp. and the honeybee Apis mellifera) showed that bees can avoid revisiting, landing on, or probing, recently-probed flowers. An individual bumble bee, monopolizing a patch of borage flowers, circuited on a regular route so frequently that individual flowers received visits at a modal interval of 3'25 min. Other bees may have been excluded by exploitation competition. Bees were more likely to depart without landing, or to land without probing, when approaching a flower probed within the last minute or two than when approaching a flower probed longer ago. We review possible modes of flower selection by bees, and conclude that bees can, and sometimes do, visit nectar-rich flowers preferentially, sometimes recognizing these in ways not commonly taken into account in studies of foraging strategies.