I think they're carpenter bees. I found one hole on the underside of a handrail that I plugged but haven't found any more holes yet.
I did some research on them and found out that the female hangs around the 'nest' and the males are the ones that buzz around people. I also found out that the males have no stinger - - - that they're all 'bark' and no bite. So now I just shoo them away.
I fear that they are nesting in the foundation piers under my deck. It's a place I can't access, ugh . . .
>>>I think they’re carpenter bees.<<<
That is good... They are very good pollinators - Many greenhouses use them to pollinate their indoor crops.
I would suggest giving them an easy alternative to using your house for their holes... I must say though, aside from the aggressive females, they are harmless. Everyone worries about their home being severely damaged by them and plug the holes... Once the damage is done, there is not really any harm in letting them use the hole... the part you plug is just the entry... About an inch into the hole is a 90 degree turn and then the actual egg chamber is sometimes a foot long.
An easy way to control them is to give them an easy home... They reuse the holes year after year. In greenhouses, they build them nests. If you take a 2X6 and a 1X6, lay the one inch board on top of the 2 inch one, and drill a 1/2 inch hole 1 1/4” deep. Stagger the holes, making 4 across the board kind of stair stepped and a foot apart in each line... Then remove the 1” board and you will see the mark on the 2” board use a router and round bit, and make 1’ long channels beginning at each marked drill mark. Then put the two boards back together and fasten (nail, screw, peg or whatever method you choose) Hang the two boards with the holes down, under an eave.
While they do not produce any honey for you, they are very good pollinators - They just look scary... The males are very curious and will try to get a closer look at anything that moves - actually they have no stinger and are just looking for a receptive female. The females are too busy gathering pollen and laying eggs to worry about you unless they catch you messing with their nest... then they do use their stinger to protect their offspring.
Oh, they prefer aged weathered wood if you are building a nest. This could be an easy introduction for your grandson in beekeeping. Remember honey is only half the benefit of bees... Your fruit, vegetable and flowers will all benefit.