same set-up (more or less) here, and same experience -- they *prefer* to drink out of any puddle they can find, but unquestionably they very quickly learn to drink from the nipple thingys, if there are no other more desirable sources available. i have a few bricks underneath each of mine, to make sure younger birds can reach, and so that any spills/dribbles don't make things too damp. WAY easier to keep clean, and don't have to keep changing the water every day! (my buckets are black, to minimize any algae growth inside, and i always add ACV.)
