Almost every state park, including those in the city (like Robert Moses Park on Long Island) charge an entry fee.the public zoo in NYC is in a small corner of Central Park. Walking through Central Park, and all the green spaces in NYC is free of charge.
Central Park Zoo charges an entry fee...
You are scrambling now. You know that public parks often charge entry fees, many don't but some do.
http://www.centralparkzoo.com/plan-your-trip/hours-and-rates.aspx
	