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.
Once established, nesting woodpeckers defend their territories and keep other woodpeckers away. Inside dimensions should be about 6x6, and the total height should be 22 to 26 inches. Pack the box with sawdust. Supposedly, by removing the sawdust, the bird is fooled into constructing its own nest. Woodpeckers are classified as migratory, nongame birds and are protected by the Federal Migratory Bird Treaty Act.