Thirsty bees
keeping a bird bath or even just putting a saucer of fresh water out for them. You can do this even if you don’t have a yard–try keeping a saucer of water on, say, a balcony railing or in a window box. If you keep it full, and in the same location, word will spread and the bees will come and belly up. It may take a couple of weeks for a worker to discover the water source, but once she does, she will take that information back to her...