So my family has a pretty large pond on our property. Not only is it great for keeping koi and goldfish, it attracts a ton of wildlife. Deer, frogs, diving beetles, dragon flies, swallows, robins, juncos, ravens. Even a bald eagle stopped by once. Unfortunately, a great blue heron also joined the party. In less than 2 days it has eaten all of our fish. Even with us constantly scaring it away.

From what I can tell by researching, almost every deterrent is an eventual losing battle with these obnoxiously persistent birds. I know that swans can be very territorial, and most species are primarily herbivorous so they wouldn't eat the koi.

Would a swan, or pair of them, be able to protect our pond from a great blue heron? If it's a losing battle, I don't want to put their lives in danger either, since they would become part of our family as well. I was just curious if this would be a viable option.

Thank you.