Away from bushes: To protect bird visitors from their primary predator, cats, eliminate places where they can lurk undetected near water sources in the yard. When their feathers are wet from bathing, birds have more difficulty flying. Remove bushes or low-growing plants within two feet of any ground-level bath.
Under a large tree: Placing a birdbath under spreading tree branches screens the birds from attacks by their other predators, hawks. They are less able to spot the birds and cannot attack properly because of the branches.
Up off the ground: Elevate at least one birdbath. Birdbaths on pedestals, stumps, or hanging from branches are safer for birds and easier to clean.
In the shade: In the summer a partially shady spot is best for your birdbath. It discourages algae which fouls the water, requiring more frequent cleaning. However, in the winter put the birdbath in the sun so it can thaw the water daily.
Away from bird feeders: Seeds and hulls falling into the birdbath foul the water.