I installed - at Mrs. Marauder's insistence - a special cat door in our back door that recognizes only him, or more specifically a magnet on his collar, and springs a little solenoid-actuated latch and lets him in.
The only problem is that he won't wear the collar, so I have to tape the little latch so he can get in and out at will. There's about $55.00 wasted, since that's the difference in cost between that and a plain one. He only comes in to eat, because he stays outside by his own choice.
Up until you said what you did in your other post about your cat getting dive-bombed by a mockingbird, I thought my cat was the only one who got his butt kicked by a bird.
I was cat sitting for a friend when his cat got attacked by a mockingbird. This cat was only let outside with supervision, and he never left the yard. This mockingbird had been harassing people in the area as well as pets; it was not defending a nest (winter, no nests around in trees or on houses), it was just attacking things for no good reason. This poor orange tabby couldn't deal with the bloody thing and was starting to not want to go outside.
The next time the little bugger decided to come down and annoy the cat, I shot it down with the garden hose. The cat took care of matters after that.