A Permanent Pond Scarecrow Installation

A Permanent Scarecrow Installation

The “Scarecrow” is a battery operated motion sensing sprinkler head. Its purpose is to safely and humanely scare away backyard intruders - like plant-eating deer, garden-digging dogs, raccoons, you name it. It is commonly used to protect Koi ponds from the dreaded Great Blue Heron.

The motion sensing part works just like a motion sensor on a outside light fixture. When something moves within its field of view, day or night, water is sprayed at the intruder for a few seconds. It uses only 2 to 3 cups of water per activation and is capable of spraying water about 35-feet.

I bought my Scarecrow after a Heron attacked the fish in my Koi pond. It ate one and wounded another. I haven’t lost a fish since I installed the Scarecrow in March 2003.

My Scarecrow is hard-plumbed to an underground water line I had the good fortune of discovering nearby in my lawn. It is mounted with an accessory bracket (which most dealers don't carry.) I found the stake supplied with the Scarecrow inadequate for holding the unit during the high water pressure blast it produces. I mounted the sprinkler head on a bent pipe nipple to get it aimed better.

The Scarecrow is actually intended to be connected to a garden hose. I feel a little uneasy about leaving a garden hose pressurized 24/7/365. I don’t think they were intended for that kind of continuous pressurization, plus, I don’t want to be tripping over it all year. That’s why I plumbed mine permanently. If one wants to go the garden hose route I would recommend buying the best heavy-duty hose that one can find. If you need just a very short hose to reach your water source then consider a braid-reinforced washing machine hose. A garden hose hookup does give the advantage of being able to move the Scarecrow around until you find the best location for it.

The manufacturer recommends that the water flow be throttled back so that in case the Scarecrow sticks ‘on’ you don't have the full flow and pressure of the line dumping water into your back yard while you're away at work! This can be accomplished by installing a valve and closing it as far as possible so the Scarecrow has just a little more water flow available than it needs to work. Mine has never stuck on.

I made a Lexan disk that presses on the Scarecrow control knob so I can see if the unit is turned on before I walk in front of it. (It hasn't worked every time!) Hey - finally a good use for those AOL CDs! The control knob turns the Scarecrow on and off, and adjusts its sensitivity.

What I see when I head across the patio toward the pond. The fluorescent orange patch on the new Scarecrow dial tells me it's activated.

Scarecrow's off. Safe to proceed.

Later a pressure regulator was added when the city line pressure increased to 150 psi. High pressure can damage the Scarecrow or keep its valve from opening. It needs 30 to 80 psi (pounds per square inch) water pressure. I highly recommend purchasing a pressure gauge. Models are available that screw onto a garden hose faucet. Get one that goes over 100 psi. There is no way to know what your water pressure is without one of these. You should be able to find one at your local hardware store. Rain Bird models P2 and P-2A are examples for under $10. Unfortunately, a good pressure regulator will cost considerably more.

There are other ways to protect a pond from Heron attack. There are Heron decoys, but don’t count on them working. These birds are not that stupid and a decoy may actually attact Herons during nesting season. Some cover their ponds with netting or string fishline back and forth across the pond. Aaack! If I had to do that I wouldn’t have a pond. I have heard that electric pet fences can be effective.

(C) Steve J. Noll