Ralph our cat: Preserver of the Home

Once or twice a year Black-Tail or "Mule" deer invade our yard. We don't know where they are coming from or where they are going to but we enjoy seeing them. At up to 300 pounds they are the largest wild animal we get in our yard, bigger than the bobcats or the javelinas. We have a birdbath outside our front window and that is the first thing they head for, evidently always in need of water, and this is where our cat Ralph meets up with them. He is an indoor cat because we don't want him by day catching our birds and lizards, or by night getting cornered by a pack of coyotes. But he seems to go into a rage when he looks outside and sees some animal staring in at him. Here is an example from the other day when he woke up suddenly to three deer looking in at him.