Soilman....some folks burn yellowjackets nest out with gas and a match, some use chems. I'm a organic gardener and prefer not to posion the land. What i do is suit up, turn on the water hose, stick it down the entrance (almost always in the ground) and drown what down there.
I usaully wait until almost dark, when there all in the nest. Some folks don't like this method because it may take two days or so to wipe them out. They don't like to let there water pump run that long...
Cyndi....thats so cool with the bumbles in your birdhouses, what size is the entrance hole to those birdhouse that the bumbles moved into...?