I tried for several years to make a bucket of mud available to my mason bees and I experienced the same thing.  I finally got the holes in the right place to keep the mud moist for a long time.  But I never, ever saw a bee using it, and no mud was gone.  I am 99% sure they never used it.

I have tried to observe where they are getting mud, and it is always in some kind of hole, either made by me or by a mole, gap under a rock/root/log, etc.  I think the bees are VERY picky when it comes to harvesting mud.  e.g. they will often dig a small "cave" in the side of a larger hole - and they will ALL use this little cave, even when there is a giant hole with tons of exposed mud.

I will often drive a spade blade all the way into the ground then rock the space back and forth to make a 1" gap in the ground, which they use sometimes.  But they greatly prefer a nice big hole with lots of mud/moisture options.  I will sometimes refill these with water (at night) if we get a hot/dry spell.

Here are some videos of my bees gathering mud: https://photos.app.goo.gl/Hu5D.....byj4r8Wpy7

Rooney said
What tools do you use to make those video clips like that?

Haha just my phone.  No editing at all.

Had to go out there and verify where the correct food supply is and so you were right and I stand to be corrected about my false claim of grape pollination. No ants were found on the fruiting buds on the grape. The correct assessment as of this morning is that I have several prunus mahaleb cherry along the same fence that the grape is on. Half of my cherry trees there are aphid infested but not in flower. I never understood it to be possible that ants harvest sweet substances back to the nest, so I think that's why my initial assessment was off. 

Sounds like you know more than the little I know about grapes. Do grapes just pollinate themselves?

I have been growing grapes for quite a few years.  Small scale, just enough for farmers market sales and for my red wine needs. I was fortunate enough to know Lon Rombough before he passed and Bill Schulz from Philomath as well.  Bill had 300+ grape varieties on his place and was nice enough to let me tour his pace in the fall and get cuttings in the late winter.  So most of my varieties came from Bill and Marion.

Good question Chris!  I know Bill Schulz was a member....just one of those things I guess I never got around to with my busy life.  I have never been very computer literate.  Was a member of NAFEX and NNGA but have been inactive for many years.  Just recently I was looking something up and stumbled onto this forum and thought it looked like fun.  And by golly, it is.

I listened to Lon lecture about grapes at Oregon State while I was an Ag major there (or shortly after).  I remember he said he thought a grape grower would make a fortune growing his favorite 'Swenson Red' grape variety.  So I got cuttings from Bill Schulz some time later and planted a row of them.  For years Lon would offer to come prune my Swenson Red if he could get cuttings for his small grape nursery business.

I kept telling Lon after I had experience with 'Swenson Red' that most of the customers actually prefer seedless grapes to which his reply was that folks need to be educated that seeded grapes are worth it when the flavor is as fantastic as the Swenson red.  My answer to that was it's the customers that teach us.... not the other way around!

rabbiteye I sent you a DM, not everybody is interested in wine.  Let me know if it doesn't come through. There have been some technical problems with DMs.