The first thing to do is to confirm which bee you have. The two common candidates are bumblebees and another native bee that is easy to confuse with them – carpenter bees.
Carpenter bees (genus Xylocopa) are large bees, but despite their size, they are gentle giants. Carpenter bees, according to Attracting Native Pollinators by the Xerces Society, are not as fuzzy as bumblebees (genus Bombus) but they (and especially their abdomens) are shinier. Carpenter bees are solitary, in contrast to social bumblebees, which live in small colonies (though in much smaller numbers than honeybees).
Despite their name, carpenter bees are not likely making bookshelves or furniture with the wood of your house, and neither are they "eating" it. Like 99% of all bees, they only eat nectar and pollen, and use the wood to make tunnels that act as a "nursery" or nest for their young. They discard some of the wood they tunnel out, and use other small chips to partition their brood cells in the tunnels. They often nest in the structural timber of buildings, though a good coat of paint is usually all it takes to deter them. Unfortunately, that may not be an easy solution for the fascia that lies under your soffits, a common place to find carpenter bees. Carpenter bees don't do much severe damage and only target soft wood. In fact, they may be alerting you to rotting wood that needs attention!
The best gentle action if you seem to be cohabiting with carpenter bees is to watch the area where the nest is, and when the bee leaves the nest, use caulk or wood dowel with carpenter's glue to plug the tunnel. Put up wooden blocks or tree stumps where the bees can nest instead – a bee hotel, so to speak.
On the other hand, if you have a bumblebee nest, it is likely in the ground, abandoned rodent burrows, grassy tussocks, or rock wall jumble, and according to bumblebee expert Sheila Colla, there really is no safe way to move a bumblebee nest without killing them. If you can tolerate its presence, know that these "teddy bears of the bee world" will only sting if they feel threatened, and giving them a wide berth to carry on their business may make everyone feel better. In the fall, the queen is the only member of the colony to overwinter, usually in leaf litter, and you can dig up the abandoned nest at that time. Fear of Stings and Bumblees are Essential are both useful resources for anyone who would like more information.
The following tips from the BeeSpotter website are useful in telling carpenter bees and bumblees apart:
"Carpenter bees are commonly confused with bumble bees. One easy way to tell the difference is to look at the abdomen. If the abdomen is shiny and not hairy, you probably have a carpenter bee. Carpenter bees may also have much larger heads, proportionally. The pictures below compare a carpenter bee (on the left in each picture) to a bumble bee (right)."
For pictures of both bees, visit http://beespotter.mste.illinois.edu/topics/mimics/
For more information:
Buzz About Bees website has solutions that don't involve harsh pesticides or outright killing of carpenter bees at http://www.buzzaboutbees.net/carpenter-bee-control.html and for bumblebee nests at http://www.buzzaboutbees.net/bee-nest-removal-bumblebee.html
Photo: Carpenter bee thorax and wings. Julia Wilkins