Herons are beautiful, majestic birds that have one major flaw. Herons love to feast on Koi, and where better then to find Koi then an unattended Koi pond or garden?
When you first notice a Heron in your garden, you may not even think of these birds as a danger. Herons are 2 or 3 feet tall, with an extremely large wingspan. They appear to be extremely graceful until you realize that the beautiful sight you were just looking at could have potentially been a thief caught in the act.
If you noticed that your fish are missing in action, chances are a Heron is to blame. You may even notice large gapping holes in the sides of your Koi. This happens when a Heron attempts to catch one of your Koi, but does not get a good grip on it. Others will notice their Koi laying on the lawn several feet away from the pond, which is the result of a Heron dropping the Koi after removing it from the pond. While nothing can completely stop this from happening, you can do a few things to detour Herons from eating your pride stock of Koi.
While there are many types of technical equipment available to attempt to detour Herons, you will quickly find that these types of detours will only work for a small amount of time.
Some pond owners place a fake plastic Heron into their garden. This is suppose to detour another Heron from landing there. This works for parts of the season, until mating season comes. Herons will be more likely to land near your plastic Heron when they are looking for a mate.
Various other types of equipment attempt to detour Herons by causing them discomfort. This only works until the Heron gets use to it, or just finds a way around it.
The only way to protect your Koi is by watching out for them. A few simple things will not prevent Heron from visiting your pond, but it will greatly reduce the presence of them.
1) Constantly change your routine. Herons are smart and know when you will typically be present. Visiting your pond frequently at various times during the day will greatly increase the chance that you will catch the Heron in action. If you are unable to vary your routine, you may consider enlisting others to visit your pond as well. Older, trustworthy children in the neighborhood may delight in visiting your pond at various times of the day. Giving them permission to visit whenever they want will allow others to visit when you are unable to.
2) If you catch a Heron in the act, make as much noise and frighten the Heron as much as you physically can. Shout, yell, throw things, or whatever you feel will scare the Heron. The more frightened the Heron is, the less chance he is to return anytime soon.
3) Create a hiding place in your pond for your Koi. More natural Koi pond owners have noticed that after a Heron attacks a pond, it may seem that the Heron has got all the fish, only to notice that the Koi start appearing from strange hiding places once the scare is over. If you purposely provide a place for your Koi to hide in the event of an attack, you greatly reduce the amount of fish that a Heron will leave with. Do not worry about your Koi hiding from you, as they should know and trust that you will not hurt (or eat) them.
4) Do not restock your pond right away in the event of a Heron attack. Waiting to restock may send the Heron searching for new feeding grounds.