Birdbaths found in stores run the gamut from inexpensive resin or plastic models that aren't very attractive all the way up to heavy cement or stone structures that are large, ornate and expensive. Rather than settling for one of the store-bought extremes, create your own birdbath from items you likely already have around the house. The materials needed are quite flexible and can be tailored to your own available supplies -- the important factors are that the birdbath won't easily fall over and that the bowl for the bath is shallow with sloped sides so birds can enter and exit safely.
Stack several vases or plant pots top to top or bottom to bottom, looking for surfaces that line up well enough to be stuck together permanently with adhesive. Alternatively, stack successively smaller flower pots upside down atop one another, such as a 16-inch pot on the bottom, upside down, followed by 14-inch and 12-inch pots, all stacked within one another with the smallest on the top outside the rest. Any of these options will form the base of the birdbath.
Squirt silicone sealant around the top or bottom rims of the areas of stacked vases touching one another to create a permanent bond. Press the objects together for a minute or so, and then set them aside until the sealant cures, as recommended on the package instructions. If using terra cotta pots, apply construction adhesive to the top rims or bottoms touching one another, if the pots are the same size. A stacked series of pots within one another does not require adhesive.
Set the birdbath base on a level location outside in an area safe from predators. Select a a plant pot tray or shallow bowl with a flat bottom that can be adhered to the homemade stand. Apply silicone sealant or construction adhesive to the bottom side of the bowl or tray and press it atop the birdbath base, holding it in place for a minute or so. Allow the sealant or adhesive to dry completely.
Fill the bowl of the birdbath with an inch or so of water using a garden hose or watering can.