I have a mosquito problem in my backyard. I also have 3 birdbaths. Is there something that can be put into the birdabth water that is safe, but will prohibit mosquitoes from breeding there?

Put a product that is commonly called "Mosquito Dunks" into the bird bath. The product needs to contain Bacillus Thuringiensis Israelenis. It will not harm the birds, etc. I have found this product in a granular form several years ago. The granular is much easier & economical to use in bird baths than the dunks. If all you can find is the dunks, break them up into 1/8 or 1/4 pieces. I also use horticultural cornmeal in my bird baths. It keeps the algae to a minimum. About a 1/4 to 1/2 cup seems to work well. Good Luck!