Thank you; that was very helpful.
I know about carpenter bees. We have a few and they generally hover "in your face" but have never shown aggression. They live at the house next door and one protects the front porch, the other protects the eaves/overhang.
This is the first year I have ever had an actual nest of Bumble Bees (that I know of) and it is under my mobile home. I do not walk within 4 feet of the area and am watchful when in their flight path.
There could well be another nest I have not yet discovered.
The only new or unusual thing I had done in the area was to empty 2 bags of potting soil (which had been sitting under a tree for several months) and to haul some finished compost to add to the potting soil. I was guessing there may have been one or more Bumble Bees in either of those two things, the bags of soil or the bin of compost. Either way I have learned to treat Bumble Bees with a bit more respect - kind of the way I treat snakes; nice to have in the garden but I wouldn't want to surprise or upset one.
Thanks again for all the help and advice everyone!
