The theory is the woodpecker will see his own image and think it is another bird's territory. Owl images generally are unsuccessful for frightening woodpeckers. Where woodpeckers are persistent, use two or more of the visual frightening devices simultaneously. Because some birds drum to produce noise to attract mates, deadening the sound-producing area by filling the hollow space behind the wood sometimes works to discourage them. In other cases, woodpeckers are frightened away with persistent loud noises such as banging pots and pans together, firing toy cap guns or yelling.
Woodpeckers occasionally drill on houses to obtain insects in the wood.
Since insects seldom infest well-seasoned wood in Colorado, woodpeckers hammer holes to obtain insects primarily during the first two years after house construction. Insecticides or wood preservatives may deter woodpeckers by killing the insects. All North American woodpeckers are primarily cavity nesters that excavate their own cavities, but some species occasionally use existing cavities or nest boxes. Placing cavity-type nest boxes on buildings in the vicinity of northern flicker damage has shown some success. Nest boxes are worth trying where other methods have failed.