I just read the locked thread and at the risk of being called dumber than usual, might i suggest to the pond owner the use of dogs . If the majority of losses occur in the shallow water at the pond edges a well trained dog or two could help immensely. My lazy untrained mutts run herons and ducks off regularly. Who knows how well they'd work if trained. Making the pond edges too deep for the long legged birds to stand in works also. Just my .02 Rich
"Growin up leads to growin old and then to dyin. Dyin to me don't sound like all that much fun." J Mellencamp