Grey Tail has been coming by for food and staying a few minutes-not more.
Today s/he parked itself at the glass door and settled in.
I tried to bring it in with civilized means but it would not allow me to approach close enough to make contact or come to the door.
I put a self heating bed out there and it hung out for an hour. The trap is set and in the morning or at next visit Grey Tail will be among the indoor cats. Not a moment too soon as the nights are decidedly brisk.