Fresh water is essential for the health of backyard birds in the winter. In cold weather my usual birdbaths are retired to prevent ice damage. To offer the birds water I spent two dollars at the local dollar store. I use an oil drip pan, on top of a deli tray for stability, and place this set-up on my bird bath fixture. It works great. To keep the water flowing through icy temperatures and snow I pour a pitcher of water on top about three times a day. Even in heavy winds the plastic birdbath holds firm.
Here’s a dove during yesterday’s snowstorm, getting a drink from the makeshift birdbath. I hope you can see through my window screen. No matter how quietly I try to sneak that window and screen up to photograph the birds, they are always wise to me, and quickly fly away.
*Added this tip after posting: My water pan (oil drip pan) is a 5. This plastic is considered safe for food storage. More info can be found here: Which Plastics are Safe for Food?