But low shrubbery too close to a birdbath can be a perfect ambush spot for a neighborhood cat. In general, the lower the birdbath, the more open space needed around it. Birds prefer baths with textured bottoms that provide firm footing. 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.