An attraction to certain plant species by Bombus terricola, B. bimaculatus, B. perplexus, and B. ternarius was observed. The gathering of pollen was observed as a behavioural act distinct from nectar gathering. Pollen analyses indicated that pollen collectors restricted their activities to a small number of plant species. These bees’ life histories and flower preferences made them potentially effective pollinators of early-flowering economic crops, Ribes spp., and Pyrus Malus in particular, and of common weeds such as Solanum Dulcamara and Hypericum perforatum. The same reasons prevented them from being important in the pollination of Trifolium pratense and Medicago sativa.