Water for birds
Birds need water to drink, especially after a meal of dry seeds, and water for bathing to keep those feathers in good flying condition. We sometimes offer birdbaths, but they most enjoy our ponds and stream.
Until we built our pond, I maintained a traditional birdbath as well as a large clay flowerpot saucer that I put on the ground. Different species of birds seemed to prefer one or the other; both were used.
Dripping water attracts birds. I tried both commercial and homemade systems before we had a pond and stream. The homemade one was simply a milk jug with a very tiny hole in the bottom suspended over the birdbath. The commercial one required that the hose always be on and connected. Neither was very satisfactory for us, so we're glad we now have the ponds and stream.
We also provide water in winter.
Keeping birdbaths clean
One reason I like having our ponds is that birdbaths need to be kept clean. When I do luse them (usually just in the winter), I scrub them with an old vegetable brush every three days or so, depending on how much they had been used. This is important for the birds' health, but also (in the summer) to prevent mosquitoes.
For me, it was easier and faster to fill a few gallon milk jugs in the kitchen than to drag out the hose. Depending on where the hose is in relation to the birdbath, this may or may not be easier for other people, but the important thing for me was to develop a system so it was as easy as possible to keep the birdbaths clean.
Placing the birdbaths
I try to locate our birdbaths where birds will feel comfortable and be safe using them. They may feel safer when they're farther from trees or bushes since the bushes may harbor predators; being farther gives them a chance to get away. Generally, 10 to 12 feet from cover is the recommended distance. We also don't place them in the midst of lots of other plants since predators such as cats could hide in the vegetation. Birds don't easily come "up to speed" when their feathers are wet!