Woodpeckers Making Holes in Cedar Siding
Unfortunately, cedar siding seems to get a lot of damage from woodpeckers particularly if the house is adjacent to a wooded area. Large holes like you are describing sound like roosting or nesting holes. These holes are often placed in corners and can go into the insulation. Legally all woodpeckers are protected so can not be legally killed without a federal permit. This means that most control methods are some form of disturbance. Recommendations include:
- Visual deterrents - Hang up items that will blow and swing in the breeze to scare them away. You can try windsocks, mylar/reflective tape, scare eye balloons, plastic windmills etc.
- Netting - Get netting which is used to protect fruit from birds and place over the corners of the house if possible to exclude the birds. The netting can go from the overhanging eve to the siding but needs to be out about 3 inches to keep the bird from pecking through it.
Woodpeckers may also be attracted to insects in the siding. My suggestion would be to use some deterrents to try and repel the woodpeckers and most importantly get the house checked and treated for insects. Cornell also has some excellent information on woodpecker damage and control