Whoever willfully and knowingly hunts upon unimproved land devoted to the preservation of wildlife and owned by a corporation organized under Title 13, chapter 81, including that portion of any public way which crosses or abuts said land, provided that all boundaries of said land are posted with signs at least every 50 feet indicating that said land is a wildlife preserve, shall be punished by a fine of not more than $50.   [PL 1967, c. 202 (RPR).]