Cats

[Saltheart]

You could keep feeding him and some people put out a box shelter , like a dog house but for a cat , to help him over the tough weather. You can look on line for the design of a ferrel cat shelter box. Animal control will put it down almost for sure unless its ear has been bobbed showing that it was neutered as part of some ferrel cat assistance program.

[massbassman]

I'm no cat expert, but these type of cats can actually do quite well, providing they are free from disease or injuries, for longer than you think. They are very proficient hunters, and can easily kill small birds and animals to sustain. The problem comes from this time of year when animals go into hibernation and food becomes scarce, and the weather gets cold. It's biggest obstacle will be from becoming a meal for another predator. Cats have great memories, and will continue to come back to your house as long as you continue to offer food. You can be sure that your house isn't it's only stop during the course of a day. Although it may look mangy, it may actually be quite healthy.
But, I would caution you to be real careful when approaching it that you don't get bit or scratched, as it could be carrying some diseases and even a scratch could lead to nasty infection.
Animal control varies from town to town on how they handle strays, depending on their availability to take care of the animal, and the assessment of its health. If it's skiddish and aggressive like you say, it wont be very compatible for an adoption and would probably be put down. Hopefully it can learn enough to survive, and find adequate shelter before the real cold sets in.