Bumble bees are the only bees native to North America that are truly social. They live in colonies, have different divisions of labor or castes, and have overlapping generations, usually with multiple broods throughout the spring, summer, and fall. However, unlike the non-native, European honey bees, the bumble bee colony has an annual life cycle. At the end of the summer the foundress queen, her workers and male offspring will all die; only the newly emerged, fertilized queens (gynes) survive to hibernate through the winter. In the spring, she will found a new nest that eventually may grow, depending on the species and available resources, to 50 – 500 individuals. Bumble bees need a cavity in which to build their nest. The queens are opportunists, looking for any suitably sized cavity. Sometimes this is above ground, such as in hollow trees, abandoned bird nests, rock walls, or under a tussock of grass, but they mostly nest underground. An abandoned rodent hole is a favorite, as this space is warm and already lined with fur. Learn more about bumble bee nesting here.