The sighting on Monday was not "potential".
When I looked into the pantry, the first thing I saw was the trap still set. The second thing I saw was the pile of birdseed in front
of the trap. The third thing I saw was a small bundle of brown scurry, bouncing from the floor to the first shelf, to the second, and than back down to the floor. At one point it looked at me, but quickly decided I wasn't going to eat it, so it didn't go hide. By Tuesday there was also a pile of seed behind the (empty) shelf to more efficiently serve cans. I set up the rolling pin with a smear of PB atop a rolling pin across the top of a bucket. Don't know it can't climb out of the bucket, but it hasn't been tested yet. (Yes, I left the broom nearby for use as a ladder getting in.) And if I see one has taken the PB but not been trapped, the next step will be to grease the bucket!
Today I cleaned up both of those piles and (painstakingly) re-set the trap -- the door is SO touchy that this is a chore. I also cleaned up the larger pile of seed on the ground behind the bottles waiting to be returned.
On the way home, I stopped off at Sam's Club, and found someone from the bakery, who got all the icing containers I'd asked for and more, verifying that the lids fit. Very very nice woman.
Extra thanks to the 2 folks who gave me the ideas used above. (Rolling pin & icing.)