The most effective deterrent of Heron yet! The Scarecrow is alerted to an approaching bird or animal by sensing both heat and movement, it then releases a noisy 3 second bust of oscillating water. This has proved to be a highly effective, yet harmless method of keeping persistent fish eaters away from ponds. Only uses 2 cups of water per cycle. Easy to assemble and install, batteries not included. Sensitivity of sensor can be adjusted for readings up to 35 feet away. Use with or without scarecrow decals.