For my Aussie friends, who don't have much experience with squirrels, a history of squirrels in Washington, DC from the Washington Post.
An excerpt:
"A little more than a century ago, the District's downtown parks and green spaces didn't have a squirrel population to speak of. Eastern gray squirrels are native to this area, but they had been largely wiped out in the most urban parts of town by the late 19th century because of hunting, which wasn't outlawed in much of the city until 1906.
Looking to fill the squirrel vacuum, nature lovers, government officials and other civic-minded residents in the early 1900s pushed to have areas including Lafayette Square, the U.S. Capitol grounds and the Mall stocked with squirrels. "Several Pairs of Interesting Little Animals to Be Set Free Among the Trees" read a 1901 headline in The Washington Post, announcing plans by the Architect of the Capitol to introduce squirrels to the grounds."