Find the main drip line nearest your birdbath. Measure the amount of fine tubing you need extending it to the birdbath. Measure along the ground and then the vertical length, so that you can bury the tubing. Add 4 inches for the clip and allowing it to reach into the basin.
Use a drip-system hole punch where you want to attach the tubing. Push a connector into the hole and then attach the tubing.
Dig a shallow 2-inch trench running the tubing over to the birdbath’s base. Hold the tubing down with soil staples and then cover the tubing with soil. At the birdbath’s base, run the remaining tubing up to the basin.
Use a clip or clothespin to hold the tubing on the edge of the birdbath and extending out into the basil. The constriction from the clothespin may cause a constricted flow. Otherwise, push an emitter into the end of the tubing.
Add a fountain or spray attachment instead of a drip emitter if you wish to have a more dramatic water display. The birds will still be attracted and enjoy the water.