I think this is on the right track. I'm basing my assumption on that fact I know some animals have specific
"danger" calls (blue jays, f'rinstance), but I don't know of any animals that have equivalents of your other two
suggestions.

Good point, Flatlander! I think, then, we could safely narrow our search down to this one. Unless, of course, someone comes up with a better theory, I'd welcome it.