Steve, good story. I can't see the bird from my house but you make a good point about them getting the message.
In my case, I've been driving my car around my ponds several times a day and honking the car horn.
Bird doesn't like the car horn. I didn't see him/it yesterday at all. However, they do work at night. In pairs. So I'll install the alarms when they arrive on Tues.
Will keep you all posted.