We feed birds too, and in the winter time, we have a heated bird bath. Very little open water during this time of year, and the poor things end up drinking from contaminated gutters, etc. I can't help them all, but the ones I can, I do. I love those doves in the warmer months. I did not know that about cleaning the hummingbird feeders. Our climate is very dry, mold doesn't seem to a problem on anything, but I won't chance it. Our most common feed is "Black Oil" sunflower seeds, what do you use there Pastor?