Start it up and let it get good and warm. I'll bet he'll get out pretty quickly.
Honk that horn... That would be the first real reason for having one that I can think of...
I see that your problem is solved, but I's have done what BOTH these guys said and give him 2 reasons to leave.
My wife, on the other hand, would have said "Burn The Bike!" That's her "Blanket Answer"
Let me tell you a quick story:
Went out to my storage building out back one day and I suddenly found myself looking at a snake in a wall locker in there. I closed the locker door and went to find something to take care of it with (there were cans of WD40 and such, in that wall locker). Only thing I could find was a new can of WASP spray.
I took that sucker out there, opened the door slightly, emptied the can, closed the door, left it for a bit and returned to find that snake gone! I have no idea where he went, when he went or how! Found another one last year and I ought to tell that one in a separate thread.
Later on, Bill