Step 1 : Introduction to the question "Which U.S. city has designated the plastic pink flamingo as its official city bird?"
...In 2009, the city of Madison, Wisconsin officially named the plastic pink flamingo its city bird. The quirky honor recognizes the flamingo's long association with Madison culture, dating back to a famous 1979 prank in which thousands of plastic flamingos mysteriously appeared on the lawn of the University of Wisconsin–Madison. Originally created in 1957 by designer Don Featherstone, the plastic flamingo has since become an iconic symbol of Americana. Madison remains one of the few cities in the world whose official bird isn't a real bird at all.