Bob, I modified my Prarie Blaster and My Jack in the Box to hold a crow.
The steel rod that comes with the PB is too tall to hold a decoy without falling over. I shortened the rod so the crow decow sits about 1 inch above the caller. The rod for the PB is stouter than the one that come with the Jack in the box. You can buy extra rods from Foxpro for 5 bucks each.
I use a GHG decoy. It has a hole in it's belly that that the ground stake goes into that a wine cork fits tight into. I cut a slit in the cork for the rod and shoved it into the stake hole.
The GHG decoy is a little heavy and I am looking for a lighter decoy for both of them.
When I'm not using my owl topper the crow goes on it for extra movement. I have my Jack in box mounted on a pole that I can raise to 14 feet. We have used a flapping crow at the owls feet for years.