Carol, a pond friend of ours, wrote into us recently and had a great question about heron decoys.
Last fall, a Great Blue Heron came into her fish pond and may have taken out any number of fish. It was hard to tell just how many, but some were likely eaten, and while eventually they did get the bird to move on, she was worried about the return of another one.
It’s a valid concern for fish pond owners, particularly in the spring and fall when herons are migrating around. They’re always on the lookout for an easy and tasty meal, and fish ponds tend to provide that in droves. These easy pickings tend to keep a bird around, and it’s not unheard for them to clean a pond out in a few days of feasting.
But this doesn’t have to happen to you…or Carol.
Now over the years, we’ve tried a lot of things, and I’ve talked with many pond owners who’ve experimented with ways to keep herons in check. Keep in mind that the birds are protected by law so non-lethal means are the only options to pursue.
Specifically Carol asked about heron decoys primarily, so that’s where we’ll start.
I used to suggest these decoys, and even sold them in the past, but I don’t any longer. At times I think they were helpful but often enough, we would get word that in some cases, these things would actually draw live herons into the pond. In some ways this makes sense. Wild birds do key off each other quite often. You can see this around your backyard bird feeder for instance, where one bird shows up, and others quickly follow once they realize the first bird found the pot of gold. Birds of prey will often see one bird rising in a thermal, and others will fly over to it and begin to circle as well. And as for herons, I can certainly imagine that even though they may be solitary in nature, if they see one in a good feeding spot, others will probably check it out more closely.
If decoys actually deterred other birds from wandering in, that would be one thing, and probably good enough to suggest their use, but to attract a live heron is the last thing you want. No flashing “open for business” herons signs for me, thank you very much!
Another popularly promoted tool, or array of tools, includes the motion activated sprayers, noise makers, light flashers, or shiny objects. Like the decoy, I’m not going to tell you that these never work. I think research has proven that on any given day, any of these just might deter a bird from causing problems. But I think it’s also fair to say that none of these are full-proof, and none of them will stop a really hungry heron from coming into your pond.
I’ve talked in the past about being careful in terms of training your fish to find by hand, or to come up to you for food. This type of trained fish, in my mind, is kind of vulnerable to any motion near the surface of the pond. Let’s just say if the activity is coming from a hungry bird and not you, that fish will be in trouble.
Provide some in pond shelters, or “koi covers” is a nice thing to do, and providing very deep water may provide some protection. Anything you can do to make hunting harder for the heron is a useful step to take. But again, none of these things are full proof.
So what does work the best?
Well it’s pretty simple really. The only thing that I suggest for heron deterrence these days is pond netting. If it’s in place and covering the pond well, it’s just something that a heron will not want to put up with for long. If I had a choice, I would use the type of netting or pond shelter that had a framework to support the net. This keeps it well above the water, and the only way a heron is going to get to any fish is to pull out a knife or scissors and cut his way through…thankfully the TSA doesn’t allow herons to use these in flight.
You probably won’t need to leave the netting in place all season long, but during times of migration (mainly spring and fall), you’ll want to be ready and watching. And if you have a bird come in or see one in the area, pop the net up and you and your fish will probably sleep better at night.