This summer I have had a Red-tailed Bumble-bee nest in a blue tit nest box and watched the workers on sunny days gathering around the entrance hole and fanning their wings to circulate the air around the nest. Can someone pleas tell me if I want to encourage them to nest again next year whether I should clean out the old nest or leave it as it is in case the queen uses it to overwinter in. This year I have planted a lot more herbs and nectar giving plant in the garden to encourage insects and would love to have the bees nesting again next year.