Bird fountains resemble bird baths, but use a constant stream of running water that is filtered and recycled. This keeps the water clean and reduces the potential for diseases and infections that are found in standing-water bird baths. You can find a bird fountain at any birding supply store or through an online merchant.
Wild bird water coolers are designed to hang from a tree or building, and allow multiple birds to drink without interfering with each other. A central water bottle sits in the middle of multiple trays, reducing the need to refill the trays as in a traditional bird bath. You can find a wild bird water cooler at any birding store or garden supply store.
A hanging-water trough resembles a hanging bird bath but is much smaller. This reduces the chances that the water will become stagnant and diseased. A hanging-water trough is easy to refill and can hang easily from any tree branch or balcony. You can find a hanging water trough at any birding supply store.