If it was a Wildcat the chances are you'd never see it and if you did it would be fleeting glances and not very many. They are considerably bigger than most domestics. If your dad's seen it around for years but it only started coming for food it could mean anything from it's housemates moving or changing to a different brand of catfood or it could just fancy one of your cats, BUT if it is staring at YOU beware.....