Solar on demand water features can be a solar bird bath or any solar fountain that has the added capability of operating not only in direct sunlight, but also on cloudy days or even at night. This is made possible by the inclusion of a rechargeable battery that is charged by the solar panel that comes with your solar powered bird bath. The solar panel comes with an on/off switch that gives you the option of operating your fountain when you desire. Initially the built-in battery does require a couple of days of full sun to fully charge and will normally give you roughly 6 hours of night operation. Battery power is normally used on cloudy days or when you want your fountain in operation at night. During full sun, your fountain is totally powered by the solar panel.
One of the major benefits of having a solar birdbath is that there's no need to have an electrical outlet to plug your fountain into. This definitely gives you more flexibility in the placement of your solar fountain. Take a look at a solar on demand water fountain for your home.