Super duper humane mouse "trap" - bird feeder add on

We were unable to catch the mice in humane catch-and-release traps because they were too smart for them. We figured that intelligent mice deserve to be treated as such, so we put this on.

c. 2"X2" or 50mmX50mm, which seems to be the magic number for many store bought bird feeders.

Important note: this may not work well if you live in a place where English is not the official language, so YMMV.