Charleen fixed a sugar syrup mixture in that feeder to keep the bees away from her hummingbird feeder. She used lava rocks to keep them from accidently drowning. She was worried that the tornadoes that hit close to her might have damaged the bees nectar sources for a bit. Jan (Mekos) is planning to set up a plain water one this summer.
The rocks can be gravel, pebbles, marbles plain old garden rocks or whatever. The purpose of the rocks is to give the bees a landing surface which will allow them to collect water without drowning from falling in accidently. This would also help butterflies.
