Leslie I think you would make an excellent kitty mommy but in my heart of hearts I think he/she probably has "family." He/she definitely does not sound feral. I would put up the signs and knock on doors (after of course taking him home with me just to keep him off the street). If, after an appropriate amount of time passes and no responses, I would say consider him yours!

Although my cats have never even attempted to venture outside and do not wear collars or tags for this reason, I know that some kitties will dart out an open door. I hope that, whatever happens, that this cutie pie winds up safe. Good luck and keep us posted!

Move over Graham and Kersey - I think you're about to get a feline buddy!