Summer damage occurs because leaf cutter bees have paralyzed spiders, stuffed them into the core gaps, laid their eggs on the spiders, and sealed the gaps with leaf fragments. Fall and spring damage occurs because many kinds of insects go into voids and openings to hibernate for the winter, but move around when warm days are preceded by cold nights. Woodpeckers apparently detect this insect movement and peck through the siding to get to them. The only effective damage control technique is to spray an appropriate insecticide into the voids or openings and into the holes made by the woodpeckers. Subsequently, the openings and voids should be sealed with wood filler, or caulking, etc. to prevent re-infestation.
Woodpeckers pecking to drum or to make cavities - Woodpeckers also peck on house siding to drum.
Drumming in the spring is the woodpeckers way of announcing its territory. Drumming usually does not penetrate completely through the wood and usually resembles an up-side down rain drop in shape. Woodpeckers also peck to create fall roost and spring nest cavities, thus penetrating wood, insulation, etc. The resulting hole is round and about the same size as the woodpecker that made it. Woodpeckers can be repelled from drumming and cavity sites with frightening devices that include aluminum foil strips, small aluminum foil pie pans on strings, and balloons on strings that are fastened to the siding and allowed to dangle over the damaged site.