I'm new to this forum and to pond management but I couldn't help but reply to this one since I have many blue herons in my area and have for the past 3 years been able to almost completely keep them off my pond. I don't know what is doing it other than every time I see one I fire a load of shotgun pellets over their heads. It seems that all it takes is once or twice and they never come back. Mind you that they are still around, I see them flying over several times a day but they never land in my pond. I keep careful watch every morning before work and every night so that I can chase them away if needed. I suppose it also could be the aerators that scare them off but I only run them for 4 hours in the afternoon. I generally have one or two begin visiting my pond in the spring when they are moving north then after a few blasts they never come back until next year. I've never seen a bluegill damaged by a heron but I have a problem with the white parasites they bring into the pond.

Gotta get back to fishin!