We were out visiting one of our ponds today and when we got there, there were 50-100 bees all over the pond. I watched several up close and it appeared that they were all getting drinks of water. They'd land on a rock and walk down to water level and stick the tip of their head in for 20-30 seconds, then fly away. They were pretty evenly spread over the whole pond, and I didn't see a nest anywhere. Is this a common phenomenon?