Hi Andrea,

Bumblebees use existing cavities for their nests. While bumblebees do sometimes take over bird houses, or bat boxes to use for nest building, it's not as common as their nesting in a hole left by a chipmunk, or other animal. The good news is that Bumblebees do not damage property when they nest. Wasps, and carpenter bees chew wood - bumblebees do not. Bumblebees are also not aggressive unless threatened directly, for example with a hand or other object put directly above them - walking by doesn't count as a threat.

The Xerxes Society, an organization for the protection and preservation of invertebrates, has a lot of information on dealing with nesting bees, their recommendation is similar to other expert advice; best for the bees to allow the nest to empty on it's annual schedule whenever possible. In cases where there is a potential risk to bees or humans there are ways to mitigate the risk with barriers, or by carefully moving the nest. Xerxes has some very good information on bumblebee nesting that includes advice on managing nests in inconvenient places.

The Scotland based Bumblebee Conservation Trust provides some guidance on moving nests, as does the Pollinator Partnership.

This OSU fact sheet provides general information about the behavior of urban bees and wasps should you have questions about nesting behaviors of some of our other pollinators.

Thank you for reaching out to Ask a Master Gardener,