In areas where winter temperatures freeze natural water sources, your birdbath is often the only source of water for birds. Any moisture they get from eating snow or ice places so much stress on their metabolisms that the result is essentially negative. There are several ways to prevent available water outdoors from freezing.

Keep waterfalls and fountains running in water gardens and ponds during freezing weather.

Locate birdbaths in the sun so that the water melts for at least part of the day.

Add boiling water to the birdbath at some routine time each day so the birds learn to come when the water is not frozen. Note: some birdbaths may crack from the temperature contrast.

Set out a plastic pan of hot water every morning or late afternoon about the same time and place every day on a regular basis when the temperature is below freezing. Very soon the birds will discover the pan of water and enjoy a drink. In extreme cold, cover the pan with wire mesh so that the birds do not bathe or wet their feet and risk freezing to a perch shortly afterward.

Install a heater in the birdbath. Install a low voltage birdbath heater on your existing birdbath. It automatically turns on when the water temperature approaches freezing. Some birdbath models are already wired with heaters.

Float ping pong balls in the water in ponds and birdbaths. Their gentle movement on breezy days will retard the freezing of the water.