That's great to hear John! I'm glad they reacted quick enough to escape the heron in the first place. Will their newfound fear of shadows moving over the pond make it challenging to remove them for the winter? Or do you use some sort of traps in the water? I can't imagine they'll sit still for repeated cast net attempts.
I've tried traps of several kinds, catch lots of the fry that way but never an adult. The same intelligence that I commented on earlier makes them too wary for traps. Even an umbrella net doesn't work very well, and my pond is way too small for a cast net. Some midnight dipnetting will be done likely with limited success, but sadly there will be a wet, miserable, likely cold and altogether unpleasant day coming soon when I will be forced to go into the pond after them. It's not my favourite part of goldfish keeping.