We set the trap up again, though, and the next day had another mouse. One of our first trio? An independent mouse? How to tell? I got some food dye and, on opening the trap, squirted the mouse's head pretty solidly with blue. If all went well the mouse would probably try to wash it off, and get a distinctly blue shade, and if we re-captured a blue-tinted mouse we'd know. The next day was one more mouse, not dyed. This one was faster out of the trap when we released it; while I'm pretty sure I squired some of his back with green, I couldn't be sure.
And at that point we stopped being able to trap mice, although we kept seeing at minimum one in the house.
Again plenty of questions: was there one mouse or multiple mice? Why were they avoiding the trap? And we got a new trap, a very open trap with doors that swing shut and that's extremely sensitive. It takes about fifteen minutes to learn how to set up the trap, as the doors are held open by very delicately arranged levers, and any sort of rattling can make them slam shut. We baited the center with peanut butter; on any bite, the doors should shut and the mouse be trapped. The mouse was having none of it.
It went like this for weeks, and we feared the mouse would never be trapped. But we kept trying, refreshing the peanut butter and slipping in some candy popcorn that the mice had got into earlier, and hoped.
Finally, the day before Thanksgiving, we found one in the trap. He was tiny, and anxious, but we had a cage we could set up. There was the problem of how to get him from the long cylinder of the trap and into the cage; we settled this by putting the cage and trap in a bigger box and opening the trap. He flew out and we trusted that he would eventually go in, and so he did. He was a tiny mouse, and went into hiding in a concealed part of the cage, but, at least that was taken care of.
We re-set the trap, not because we knew of any mice there but because we were used to doing so, I suppose. And the next morning ... well, there wasn't anything in there, but sometime in the course of making lunch the female mouse wandered in and trapped herself.
We've left the trap set up since then, but haven't caught any further mice. Nor have we seen others inside the house. We hope this means the garage mice are comfortable enough they're not trying to venture inside, and that there aren't undiscovered mice yet inside. We're hoping.
Trivia: Pennsylvania and North Carolina voted against independence on the first of July, 1776. New York abstained and Delaware was deadlocked. Source: Signing Their Lives Away: The Fame and Misfortune of the Men who Signed the Declaration of Independence, Denise Kiernan, Joseph D'Agnese.
Currently Reading: King of Infinite Space: Donald Coxeter, The Man Who Saved Geometry, Siobhan Roberts.