Other suggestions. Apparently you’re not the first person to have this problem :)
It really looks like a net is the most reliable way to save the frops. And keep it up, since it looks like herons remember where they had good eatin’ before and will keep coming back to check.
Or, our very own krazykrok can, for a small fee, send you a real live one!
The problem is that crocs don’t differentiate between herons and sweet nieces.
BD beat me to it. Airsoft gun, BB gun or pellet gun. Doesn’t kill 'em, but really hurts like heck.
If you’re sure that the animal protection regs are loose enough in your state may I recommend the Israeli Military Industries “Negev” 5.56mm belt-fed portable machine gun.
Here’s a auto-aiming Paintball Gun. This thing is wicked