Once some birds notice your bird bath or water bowl, they'll spread the word very quickly and other birds will also try it out.
There are a few things you must do to keep them coming:
1. Clean the bird bath and refresh the water daily: if you can, if not, then every second day. A bristle brush is ideal to scrub the sides, followed by a rinse with fresh water. This is a necessary step, or else water will get stagnant, even mouldy, certainly filthy and eventually become a source of disease.
if you have placed a big stone or rock in the middle of the bowl to stop it from tipping over, you may find that this will get mouldy over time. When that happens its best to have a couple of stones, and use them alternately, that gives each one the chance to dry out before being used again.
If the bird bath is not cleaned and refreshed regularly, the birds will stop coming as this will no longer be a viable drinking spot for them.
2. Observe Your Visitors: Make a note of which birds have started to visit your place. Are they able to drink comfortably?