Yes, the heron has returned.
I surprised the heron last night–or it surprised me, or neither surprised either, depending on how one perceives it. But the heron was at the fish pond and the fish went into hiding again.
I’m hoping the problem was that i had moved both scarecrows back a bit further from the pond. last night i moved one of the scarecrows right to the spot I saw the heron flying up from, and it had not returned this morning, although I did see it at the upper gully pond.
I have decided to let the upper gully pond be a fishing ground for the bird as much as possible. The bird will need to have someplace to hunt, and if the pressure is too extreme it may start to directly challenge the scarecrows rather than avoid them. It is unreasonable to expect the heron to leave forever, and guiding it away from a more valuable area to another place is always going to be more effective in the long term than simply trying to deny access altogether.
It is possible to set up complete exclusion zones, but one of the goals should also be to balance energy with payoff.
I know that my goldfish pond is out of balance, and I have been willing to sacrifice some energy through the summer to creating and moving scarecrows around. But I’m not willing to extend that energy to the other ponds, and with luck the heron may decide that looking for catfish is easier than taking a chance looking for goldfish.