I started out posting this as a gag, but the scientist in me found it fascinating for real:
http://jah.oxfordjournals.org/content/100/3/691.fullJournal of American History (2013) 100 (3): 691-710.
doi: 10.1093/jahist/jat353
The Urbanization of the Eastern Gray Squirrel in the United States
Notable quotes:
In The Winning of the West Theodore Roosevelt wrote of the eighteenth-century American backwoodsman's fight against “black and gray squirrels [that] swarmed, devastating the cornfields, and at times gathering in immense companies and migrating across mountain and river.
In contrast, Seton, Vernon Bailey, William T. Hornaday, and other urban-squirrel advocates saw squirrels as opportunities for boys to establish trusting, sympathetic, and paternalistic relationships with animal others.34
Boys who failed to learn the lesson of charity offered by urban squirrels were seen as having fallen outside the bounds of civilized community and as manifesting harmful tendencies that might eventually lead to even more serious consequences.
A few months later a guard in Bronx Park was struck on the head with a shotgun and beaten senseless by the confederate of a squirrel poacher he had attempted to arrest.