Where to Use Small gardens, balconies, domestic roofs. How it Works The Peregrine Falcon provides a threat to pest birds, as one of their predators. How to Install The Peregine Falcon can be filled with sand, water or cement. The Peregrine Falcon Decoy stands at 41cm High. Mount the Peregrine Falcon up as high as possible, getting the threat above the pest birds if possible. Move the Peregrine Falcon on a regular basis so the pest birds do not become comfortable with it in the same position. Leaving the Peregrine Falcon in the same position for a prolonged period of time can result in the pest birds sitting next to or on top of the decoy!