Water is used by wildlife for drinking and bathing. Additionally, species such as amphibians (frogs, salamanders and the like) damselflies and dragonflies need water to reproduce.
Many backyards and neighborhoods have no open water whatsoever. In fact, open water is often not found nearby. This can seriously limit the number and kinds of wildlife that will use a yard.
Believe it or not, you can actually attract for more birds with water than food.
Water can be provided by adding a small pond or bird bath to your yard. If you decide to purchase a bird bath, select one that has a gently sloping basin that is not over more than an inch and a half to two inches deep at its deepest point.