Many people are surprised to find birds causing problems on buildings in urban areas, but birds are actually very common in cities and many species may potentially create problems on buildings. Fortunately, by understanding the birds that most often cause problems, as well as the architectural features that attract them to buildings, nuisance bird problems can usually be addressed by making the building less attractive to the birds.
While any bird can potentially cause a problem on buildings, most problems in American cities are caused by three bird species introduced from Europe—pigeons, starlings, and house sparrows. These birds adapted to living in European settlements and cities for thousands of years, and found an easy life living in and around our buildings when first brought to America in past centuries. Early colonists first brought pigeons to America as a food source, while 19th Century enthusiasts brought over starlings and house sparrows in a misguided effort to control caterpillars (house sparrows) or introduce to America all the birds mentioned in the works of Shakespeare (starlings). All three of these species readily eat discarded human food and nest on buildings—making them the perfect urban invaders. In addition to these non-native birds, a few native birds may cause problems, especially when large numbers congregate on rooftops (crows, gulls, and occasionally vultures) or nest on exterior walls (swallows). In fact, birds that are urban invaders do so well that there are usually more individual birds per square mile in cities than in the countryside!