Raccoons were a brooding and menacing presence in the town of Pawnee. There is an infestation problem that has been occurring ever since Leslie herself was born as her mother had to go to Eagleton to deliver her at her birth as the Pawnee hospital had been overrun by Raccoons. This means over a period of decades the infestation still remains.
In Christmas Scandal, April menntions that raccoons are supposed to be nocturnal. Ron responds that in Pawnee they are active 24/7. He then mentions that if the raccoons aren't removed from the Christmas village, "they'll hunt the children for sport".