Hmmmm, I really like it that the birds come as well -
maybe I could put sand in half of the inner saucer and leave a pool in the other half - the bees could still drown, but the smart ones could use the sand and the birds would still be happy -
from a Darwinian point of view, the smarter - wise to the water bees would survive happily sucking sand and the dummies who went for the pure water or who leaned into the water from the brick center would meet their maker.
Of course given that the queen is the only fertile one in the bunch, it wouldn't change evolution, now, would it.
BTW, how does she get water since I understand that she only leaves the hive to swarm?