Someone a few weeks ago posted about using quail feeders to feed the bees, and the bees getting trapped inside the jar. I do the same, and thought I'd share this:
I cut a long, narrow piece of window screen, bent it into a circle and folded the ends together such that it fits snugly around the plastic quail feeder base (where the jar screws in), covering the opening. So far, no bees inside!
I also have a chicken waterer, which is slightly larger. I cut a small pice of screen that would cover the opening and extend to the bottom of the feeder trough, and taped it to the bottom with electrical tape. That seems to work, too, but don't know how long the tape will hold out. The quail feeder trough seemed to narrow to try this.
For what it's worth...
“The keeping of bees is like the direction of sunbeams.” -Henry David Thoreau