Bees/bumblebees or ?

Behind our house is an old 2 story house that is used for storage. Probably built around 1900. Well last night hubby was n the back porch of it moving something and the wall by along the porch started humming. Yikes. Haven't noticed anything flying around in yard or in garden or flowers. I mow by it every week. Guessing it may be bees. But haven't noticed any. Leaving it alone until it gets cold or we have a problem. Any ideas besides bees. The wall is hollow. Just wood siding on outside and wood on inside.

Either bees or hornets is my guess.....they both sometimes like to build in walls

Whatever they are they are there until cold weather unless they cause a problem.

Maybe carpenter beatles they look just like a bumble bee but they eat a perfect round whole in wood and build a home inside. We had them once at home hard to get rid of.

Not bumblebees, they are ground dwellers.

Mowed around there this morning and didn't see anything flying around.

Observe the wall from a distance to determine what species are involved. If it "looks" like Honeybees ... call a local bee keeper for positive identification & possible removal. They may even pay you for the colony removal. If they're ID'd as "Africanized" Honey Bees ... they may remove them or eradicate them.

If they are not Honeybees ... an exterminator may have to be called in.

Call a local bee-keeper. There are specialists that will come and relocate honey bee colonies, which is what they are most likely if you can hear the buzzing from outside. Honey Bee colonies have become a valuable resource since the recent Colony Collapse Disorder (CCD) has started.

Didn't see anything today..

Curiosity would get the best of me till I gave that wall a good poke and ran just to see what came out.

Hogsters phone

Make sure someone is recording that! The hole world would like to see that...:Rofl

Could very well be honey bees. Could possibly be yellow jackets, or a few "solitary" boring bees (Mason/Carpenter).
Usually yellow jacket colonies aren't large at this time of year, and the solitary bees are very loud individually (sound like little helicopters) but they are few in number and aren't easily confused this the strong low Hummm that is associated with a honey bee colony.

I'm a beekeeper and used to do removals like this for a living. The best course is to pick a mostly sunny day, and between 9am and 6pm, stand back from the house about 20' or so, on the side that you think you heard them, and survey the entire wall and roofline in that area, looking for foragers coming and going. A healthy colony is about 50k bees, and on a sunny day a peak forage hours, you'll see about an average of 1 bee every couple of seconds. 30 bees or so per minute. Focus on gaps in siding, and especially behind gutter fascia, around window frames, flashing around chimneys or exhaust vents, etc.

As far as removal, I would recommend finding a beekeeper with CUTOUT/REMOVAL experience, not just a beekeeper. These jobs are one part beekeeping, and one part construction/remodeling, and there is liability involved.

Regarding the comment above re: Africanized bees... we don't have those at ALL in MO. Their northernmost summertime range is AR/TN, and they die back southward during the winter (due to differences in their gathering/storage behavior vs standard European honey bees).

The outside of building was covered in tin when no one lived in it any longer. It is a wall that is on the porch. I'm not poking it. Lol. The house we live in was built later. 1950. The farm has been in the family for 150 years and I am guessing that this old house was the original. It has a rock foundation. I haven't been seeing any bees in the garden. I would think with that many I would be seeing them on my flowers and in the garden. The building is in the yard.