Cover smooth surfaces with pebbles or sand. The size of a birdbath is not critical, but those less than a foot in diameter probably will be used just for drinking. Commercial birdbaths are available in materials ranging from concrete, to terra-cotta to plastic. Concrete models are expensive and heavy to handle, but they provide excellent footing and will not budge in severe weather. A plastic birdbath may need its footing altered and its placement secured against strong winds.
Imagination is the key when it comes to homemade birdbaths.
A garbage can lid, ceramic saucer or disposable pie plate will suffice. These need pebbles or sand added to create a gentle incline and provide traction. The sound of moving water is a special attraction for birds. Many stores and catalogs offer complete kits for birdbath fountains. Cover the bucket to keep out debris and prevent evaporation.