Great post! I knew someone here would be more familiar with bee
habits than I am. No rain for a long, long time. Everything is
stressed. Hardly anything green, much less blooming.
I think it's the moisture in the pots. But why those covered with
sand? There are pots with the same potting mix without a layer of
sand and while they get on them, not nearly like they do those with
the sand layer. They do prefer those with the wetter surface, but
sand dries very quickly under my conditions, so they dig into it.
Also there are shallow pans with water - for the dogs and seedling
pots. They go there, but prefer the damp pots. Safety, maybe?
Toads come out in the same kind of weather and hang around those pans.
They are definitely not swarming. I've seen that. The last time I
saw that (some years ago) they had found an entry into the siding on
the house. I stopped that up quickly. Didn't want a wall filled
with honeycombs! Probably the water here at the house is why I'm
seeing huge numbers of them when the weather is warm. There may be
more than one hive. I had more natural pods last year than I've ever
seen. Their activity may be the reason. True bee pods. I have a
very light hand using insecticides, so they should be relatively safe
here. Only when the grasshoppers get really bad and that occurs
after bloom is over. Also, I don't have bloom like that great photo
you posted of Wyoming Cowboys. That was a treat in the drought
plagued winter we're having. I can dream and the bees would love it.