Apparently the Siamese forgot that this is the Domain of Scarlett, because it came over to the bedroom window the other day to check her out. By the time I got the camera, the neighbor cat had retreated about fifteen feet away, but the two were still watching each other.
After a while, Melly came in to see what all of the fuss was about. She joined Scarlett on the window sill and the two continued to keep an eye on the other cat.
The Siamese eventually wandered away, and Melly found herself on the window sill with nothing to do. The obvious solution to this problem was to play with Scarlett's tail.