If you don't already have a pump, you could use an aquarium aerator too, and it wouldn't clog, though you'd have to weather-proof it somehow. I have the GFI in a dry part of the garage and run a long extension to the pump. I've had lots of fun with the kiddie pool. It has a sand bottom, and I blocked off a corner with big rocks and filled the space with small rocks to make a shallow spot. The pump spurts some water up underneath a big rock, and depending on the wind, it either comes down as a sheet or a trickle into the shallow area.
Ripples can escape into the bigger deeper section.
The only bird I ever got to come to my regular birdbath was a crow that liked to soak his takings, turning it into a disgusting mess. Some of the increased traffic is because my shrubs and trees in that corner are finally starting to grow up a bit, but the giant-sized bird bath seems to have made a real difference too.