One day, years ago, I was working from home and I heard the intermittent "beep!" my uninterruptible power supplies make when they're unplugged and running on battery. I checked all of my UPS's, then turned off all of my equipment, but still every few seconds, "beeep! ... beeep!" It seemed to be coming from underneath my computer desk.

Eventually a spark of inspiration hit me, and I reached up and pulled the cord on the window blinds behind the computer desk. I found myself nose to beak (through glass) with a startled mockingbird. "Beep?" it said, and flew off.