Pond Boss Forums POND CONSTRUCTION Creating habitat Potential idea

Okay I've read on here several people suggesting half tires filled with gravel for potential spawning beds, with a mix of larger and smaller gravel, the larger gravel being there to keep from being swept out when the fish fan away the silt with their tails.
My question is this: I've got the top (basin) portion of a birdbath that has a crack in it which renders it unusable. Would that by itself suffice for a bed? My thinking is the fish could fan the silt off easily enough, I'm just wondering if they'd bed on such a smooth surface. Any thoughts?

It may work. Set it somewhere so you can see if it is being used. Nest spawners sometimes will clean out depressions down to the hard pan or firm bottom and lay eggs there. I've never seen any studies of the egg hatching success on hard pan vs a rubble/stoney surface. Often the interstitial areas among the stones provide protection for the eggs/fry.