There are over twenty species of woodpeckers in the United States. Woodpeckers have chisel-like beaks and long, flexible tongues designed for drilling and probing under tree bark. They are equipped with powerful claws and stiff tails that help prop them up while climbing trees. Most species peck on dead and dying trees to feed on insects that bore into the wood such as carpenter ants, bark beetles, and wire worms. Others may eat plant material such as nuts and seeds. They may store these foods in tree cavities for later consumption. Some may be attracted to suet and sunflower seeds from local bird feeders. Woodpeckers use their beaks to dig out cavities in trees for nesting sites where they lay their eggs in the spring. During the fall they dig cavities for nesting sites. There are nine species known to peck on man made structures. This pecking behavior can be broken down into three categories with separate causes and explanations.
When a woodpecker is hammering at a specific area in the springtime without resulting in a cavity, it is probably a behavior called drumming. Rather than singing to attract mates or announce their territories, woodpeckers drum at sites within their domain to announce their presence. They usually choose something that will produce a loud, resonating sound when they peck at it. They then visit these sites regularly to "drum" out their territory. Drumming is a seasonal behavior occurring only in springtime.
Woodpeckers feed on insects by locating the sounds they make inside wood. If a structure is infested with insects, the woodpecker will drill small holes to extract them. However, woodpeckers cannot distinguish the difference between the noises an insect makes while burrowing through wood and the sound that electricity makes while going through the walls of our houses. Therefore, a woodpecker may drill holes in the siding of our homes in its search for food.
Woodpeckers create their nests by building cavities in trees and on occasion in our homes. Nest holes are round and deep and may occur at loose knots in the siding of houses. Woodpeckers often start a hole and then abandon it to start another in a preferred site. In some cases, they may be confused when the hole penetrates siding and they encounter insulation. Sometime the cavity is completed and nesting will continue in the wall of the building.
Preventing a problem
Tips: Scare tactics like twirled Mylar tape, windsocks, and eye spot balloons may be effective in discouraging all three of these behaviors. These items will flutter in the wind and the movement frightens woodpeckers. In addition to movement, eyespot balloons also frighten by having large predator-like eyes.
Solving a problem
How do I control drumming?
When woodpeckers are drumming, they are usually looking for something to peck on that will make a lot to noise. Therefore, if you muffle the resonating quality of the object they have chosen chances are they will stop using it. To do this, you can cover the object with a blanket or foam rubber padding.
How do I control feeding?
If insect infestation is the cause of this problem you need to remove the insects. You may wish to consult a pest control specialist. If they are attracted to the sound of electricity running through the walls of your house, muffle these noises by hanging foam rubber padding or a blanket over the area.
How do I control cavity building?
This could be the most difficult behavior to try to control but it is also the least common. Be sure to keep in mind that this is another seasonal behavior and it will only be temporary. If the cavity building can be discouraged before the cavity is fully built, the woodpecker may try to relocate and excavate elsewhere. However, they may return the following year and try again. Usually a combination of scare tactics and prompt repair to the excavation areas are somewhat effective in trying to discourage cavity-building activities. You should fill shallow holes with caulk or wood filler as soon as they are created. Larger holes and loose knots can be filled with wooden plugs or window screen and then caulked. You may also try to offer ready-built nesting boxes, which they might choose to use rather than making their own.