I've heard that placing an alligator decoy in a pond will deter herons from visiting stopping by to eat all the expensive koi that live in it.
This made me curious, because I live in a northern state where alligators don't exist, would a decoy still be effective in deterring herons? Presumably herons migrate south during the winter, and should be aware of the threat that alligators pose, but would they recognize that alligators don't live this far north and ignore the decoy?