My cat, Rizzo was making some wierd noises, like a cat with a cricket in it's throat. He was sitting at the window, looking out side, and finally I could hear what was he was chirping at, there was a fair size magpie right outside the window, and getting closer as it could see Rizzo wasn't getting out.
I finally got up and yelled, and the magpie took off, only to come right back a few minutes later. So same thing, I yelled, the bird left, but came back.
I finally got up, and releases the screen hooks, but, left the screen in place.
When he came back after a few minutes Rizzo "accidently" knocked the screen out, and went after the magpie. He didn't catch him, but it hasn't come back since. They really are a noisey bird.