[Mr. Sandman]

Now that my dog died, I have noticed a cat that comes out of the woods behind my house every so often and will hang out under my deck. He/She? is very skittish and looked a little hungry so I opened a can of tunafish and put it out. He ate it in no time. For the last month or so he would come by for a few days then disappear for a week then be back. Now that it is getting cold I noticed he is around a lot more. I feed him when I see him. My son calls him Willie Nelson. (He is a little crusty like willie and he is always "on the road again") When I was cleaning out my bait freezer I found a hunk of freezer burned tuna and hacked a piece off and microwaved it and put it out. It didn't look that good to me and smelled a little fishy but he wolfed it down. He will sleep against the house on the deck but he will not let you get close to him. He will arch his back and hisss at you if you try and get close. I know very little about cats other than I sneeze when I get close to them. (an old girlfriend had them and it was a problem)
Anyway, will this animal make it thru the winter? Or should I call the animal control people and let them deal with it? If it will survive I don't mind it around but I if I call animal control I don't want to see it killed (put down), I also don't want to see it suffer all winter either.
please advise...