Jai - I use plant saucers. I used to haul the big cement birdbath bowl up from the lower garden to set on the patio with an immersion heater. This year I bought the biggest plastic pot saucer I could find and am using that instead. It's a couple of inches deep and I can still use my birdbath heater in it over winter. I've also set a couple of broken bricks in it for the birds to perch on to drink. I get various finches and an occasional cardinal drinking out of it.
