Water for Birds - It's Vital
Whether they are feeder visitors or not, birds need water.
Offering a dependable source of water is probably the simplest and most important step you can take to greatly increase the variety of birds in your yard. It can also significantly increase your enjoyment of your birds by allowing you to watch their often comical antics as they drink, bathe and preen.
We do not recommend putting anything in your bird bath to keep it clean. Every other day you should empty the bath, scrub it with a brush and rinse it well. Refill with fresh water. If the algae builds up quickly, you can use ten parts water to one part bleach solution to clean the bird bath. Be sure to rinse well and place fresh water in the bath.
During freezing weather, use a bird bath heater to ensure that birds have a reliable, open source of water.
How to Attract Birds with Water