Squirrels are abundant in residential yards and urban parks where they are regularly seen rapidly scurrying about while enthusiastically collecting and stashing nuts. While house mice and norway rats are easily the two most common and economically significant rodent pests of households, squirrels are also known for invading homes where they often inflict costly damage. The frequency of squirrel pest issues in and around homes follows a cyclical pattern, as the rate of both squirrel infestations and squirrel-induced property damage incidents increase as squirrel populations increase. The boom and bust in squirrel populations is well reflected in annual changes in roadkill abundance, as squirrels are struck and killed by moving vehicles more frequently during years when their population numbers peak. For example, during 2018, those who commuted to work on New England highways were astonished at the massive amount of roadkill littering highway margins. Experts claimed that hundreds of dead squirrels could be found along highways for every mile driven. The cyclical boom and bust of squirrel populations is driven by the changing abundance of nuts produced each year by trees.
A variety of tree species in forested, urban and suburban areas produce nuts that squirrels consume, collect and stash in the ground. Acorns, hickory nuts, beechnuts, and walnuts are the most important squirrel food sources because they remain preserved for long periods of time. Every few years, trees produce excessive amounts of flowers and pollen, which in turn, results in an overwhelming abundance of seeds and nuts that squirrels cannot possibly deplete. Naturally, the squirrel population skyrockets during these years, with 2016 and 2017 being the last years in which nuts became widely available to squirrels in the mid-atlantic region. However, the amount of available nuts decreases in the following years, resulting in a food shortage for squirrels. In response to this shortage, squirrels travel far and wide in search of any available food source, including residential properties and even within homes. This is why the rate of residential squirrel disturbances increased dramatically in Pennsylvania during 2018.
Have you ever encountered signs of a squirrel presence within your home?