Since Insects seldom infest well-seasoned wood in Colorado, woodpeckers hammer holes to obtain Insects primarily during the first two years after house construction. Few chemicals that have objectionable tastes and odors are effective for repelling woodpeckers and none are currently registered for that use. However, some of the sticky bird repellents stain wood in hot weather. 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.
Nesting woodpeckers defend their territories and keep other woodpeckers away. Inside dimensions should be about 6 x 6 inches, and the total height should be 22 to 26 inches. A front-sloping, hinged roof will shed rain and provide easy access. Fill the box with sawdust to entice the bird to remove the sawdust to the desired level. Supposedly by removing the sawdust, the bird is fooled into constructing its own nest.