Herons are the bane of larger ponds in suburban or rural areas.
These long-legged fishers of expensive koi are quite the predator. Not only do they kill fish but their long beaks have been known to puncture liners in their efforts to spear dinner. They are quite patient, standing motionless for long stretches of time until the fish come out of hiding.
How Do You Train Your Fish?
Fish that are trained to come to water disturbances for feeding are particularly prone to be eaten by this bird. They come out expecting to be fed a main course and instead are the main course.
So this all begs the question, “How do you deter or control this major pest?”
Particularly big dogs that don’t like big birds. My Labrador retriever was one such dog. Mind you, she chased just about everything, including the frogs, ducks, and muskrats as well. She wasn’t choosy, just effective. I don’t believe she ever caught any of them except for frogs and I don’t want to know about those.
Those who have ponds claim realistic statues of herons deter these birds because the heron is territorial and when they see one standing beside a pond, the real bird won’t come in.
Mind you, when the bird standing beside the pond hasn’t moved in three years, the real bird kind loses its concern.
I’m told that statues with bobbing heads work well for a time. I know several gardeners who regularly move their statues around the garden making a bit of a game of it.
In short, don’t count on these statues working for very long (if at all).
Transparent nylon fishing line suspended ten feet above the pond in a checkerboard grid (squares three feet wide) will tangle the birds and prevent them from getting a good landing or takeoff.
Birds can’t see the line and hitting it once or twice (use the strongest test line you can buy) will tend to deter them. I do know of a heron that decides to land outside the grid zone and walks over to the pond.
These automated motion-detectors shoot water and/or sonic noises have been effective for some gardeners as well. But again, the birds learn to avoid or lessen their fear over time.
Hide The Fish
Build good fish hiding holes in the middle of the pond so your fish have a refuge from the birds and the hot sun. You’ll find they’ll use them quite regularly. These work.
Mind you, the heron will try to outwait the fish so it is a game of patience and wits. But a fish refuge is still a good idea. Use a large tile such as an eight-inch diameter drain tile and cover it with rocks so it doesn’t move. This is an excellent hiding hole for fish against other predators such as raccoons.
And of course – a combination of the above works as well as anything possibly can. For example, if you install 100-pound fishing line on top of the pond area and a deer fence (plastic and almost invisible in the landscape) you’ll have them controlled top and sides.
If you move the statues around constantly and have a dog, you’ll have them controlled
But it’s going to take vigilance and constant attention once these birds discover you’re serving lunch.