I use a stock tank heater in my goldfish tank outside (it's a 64 gallon plastic/rubber stock tank that is above ground here till I move east) - the birds line up on the edge to take a drink. The heater was about $35-$40 US at my local feed store. It can be used in plastic or metal stock tanks. Lin in Texas -----Original Message----- I notice other small birds seeking water during these freezes. If you can figure out some way to keep a container of water from freezing, you will be doing thenm a favor. Which they may return next year by eating pests.