subject: Great Blue Heron and Koi [print this page] Great Blue Heron and Koi Great Blue Heron and Koi
I can tell that spring is here when I saw my first Great Blue Heron out by my lower pond this morning. Actually my dog was the first to notice this 4 foot tall bird stalking the koi from the edge of my pond. My pond is about 25 by 35 feet and the deepest part is 4 feet. I have a stream that leads into the pond creating and easy entry point for herons to wade into. But I do have a few obstacles to make this entry a little more difficult for the heron. First there is a bridge with rails at this point. Just down from the bridge on one side is a waterfall with flagstone 6 inches above the water line. This is not an ideal entry point for the heron, as it is not sure about the water depth near the waterfall and stepping off of a ledge is not inviting either. On the other side the water is more calm and the bird can see that the water is shallow enough to wade in. The only problem is there is a lawn chair in the way and the other side is also lined with flagstone. The heron is still unsure about stepping off of a ledge into the water. By this time my dog is having a fit, wanting to chase the invader from what he thinks is his territory. I finally open the door and my dog bolted out after the heron. He actually made it to the bridge before the bird took off in flight.
Anyone that has a koi pond for more than three years has lost fish to some kind of predator. Having created a beautiful watergarden that looks natural and has crystal clear water becomes an invitation to many predators. The worst by far is the blue heron that can spot the colorful fish in a pond a 100 feet in the air as they fly over head. The population of blue herons has increased dramatically since they have become a protected species. As more people have gotten into the hobby of koi ponds and watergardens they have learned more and more that invading your back yard pond is easy picking. They are also quite smart at learning when to invade without getting caught in the action. Blue herons will make three passes over a site before landing, making sure the coast is clear. They will often land on a roof of a house or a neighbor's house to further make sure the coast is clear. This is why decoys no longer work. If the decoy does not move after a few minutes, they know that it is not real. Herons also have a 330 degree field of vision to alert them of any movement. There is no single method that is fool proof to deter these predators, but there are several ways to give your koi a fighting chance.
The first thing to deter all predators is making the pond deep enough where the koi can get away from predators. This should be at least three feet or more. Having water lilies give them protection over head and koi tunnels will also provide refuse. Don't create an easy entry point. Lining the sides with flagstone at least six inches above the water line helps create a natural barrier. A bridge across the stream just before it gets deep creates a barrier. Instead of having a shallow shelf, consider an island or floating island for shallow water plants. Other ideas for shallow water plants include floating plant baskets that can be tethered or anchored in place. Any heron that steps on a floating plant basket will create a disturbance in the water, sending the fish to shelter. One item that has been proven effective against predators including the blue heron is the Scarecrow by Contech. The Scarecrow is a motion activated sprinkler that uses a combination of sudden noise, unexpected movement, and a startling blast of water to create a memorable and unpleasant experience for the trespasser. A 9 volt battery keeps the unit working for up to six months and is made to attach to a garden hose for 24/7 protection. For more information visit KoiPondFever.com
