OK...here goes my tree frog story. Several years ago, I heard a chirp in the detached garage that sounded like a tree frog. It would only "croak" occasionally, and very intermittently. Well, at the time, several critters had entered the garage and eventually died (lizards, spiders, etc.). Somehow, a tree frog had entered and because of the garage acoustics, I couldn't quite place where it was coming from. I put out a big bowl of antifreeze (tee hee!), but no luck...the chirping/croaking continued. I finally traced it to the small utility room with the refrigerator, so I pulled the refrigerator outside for a few hours, hoping that the critter would finally leave its hiding place inside the reefer. No luck. After several days of this, I finally told the wife about my problems, and she helped me isolate the critter by sound. We went into the utility room, and she found the critter real quick: it was up on the ceiling! Damn!
It was the fire alarm chirping that the battery was low on voltage....