In Denmark, there is a dozen species of the usually big, strong and furry bumblebees of the genus Bombus. In contrast to honey bees bumble bee colonies only live one season. In the autumn all the workers and the old queen die. There are some young queens who – after having mated – goes into hibernation and thereby saving the family through the cold period. Early the next spring, they come out and find suitable places to establish new colonies.
Most bumble bees construct their nests in the ground, in an abandoned mouse nest or between stones in a stone wall. An empty nesting box for titmice, a cavity wall, a crawl space or an insulation mat in an attic are also good places for a bumblebee nest. The nest is lined with vegetable fibers, moss or hair, and the workers build brownish wax pots used to store eggs and food supplies. The colonies are not very large – and often consist of a maximum of 400-500 members.