In my courtyard two semi-feral cats took up residence some time ago. One is a sweet tabby grey female, about 4 years old, she arrived about two years ago. The other one is a black (well, actually very dark brown) young male, about 18 months old, who arrived last year in April. I had them fixed and they live quietly and peacefully in my yard, where they have their dishes and a nice timber house, a two-room cat house I had bought a few years back for another cat that a year later went to the Rainbow Bridge. The house is this one (photo taken from the web, not mine) I altered that house a bit, I closed the upper floor with thick styrofoam walls and added lots of thermal insulation for the winter on the ground floor too, and the lower room has a nice electric heating pad in it, to keep a bit a warmth inside. Both cats appreciate this house. They are quite friendly, especially the boy. Some days ago a new feral cat joined the pair. This is a rather aggressive young cat, unfriendly to humans and cats. He steals the food and sleeps in the cat house, especially in the warmed room. The two semi-feral cats are a bit scared by him, and too often they leave the house, sleep in the cold, and sometimes they give up eating. Every now and then, like yesterday, I hear cats fighting very early in the morning or at night, and my two semi-ferals are scared afterwards and don't come near when it's meal time. I tried almost everything to shoo that nasty cat away, I yelled at him, I sprayed him with the garden hose, I threw something at him. He comes back, and he's getting braver lately. Is there a harmless way to get rid of him? Any advice is welcome. Thank you!