The scare spider is a visual deterrent against woodpeckers. This battery operated product is noise activated by a woodpecker drumming on the structure. The spider will then react by dropping down about 18 inches on a string and retracting back up again. It is sometimes sensitive to other environmental factors, such as construction or heavy traffic, so it may go off randomly, but has been very successful in helping deter woodpeckers from coming back to an area.