Maybe I've missed it being mentioned here, but if mice in the backcountry are wild animals and by this being protected, isn't it prohibited then to feed them for the very same reason?

Seriously, we have a 98yr old aunt living in our house, and a few years back when we could still leave her alone for several days to go out hiking, one day when we came back she had covered the whole kitchen table bith breadcrumbs. A mess.
Asked why she'd done this, she said she had intended to keep the mice off her crochetwork (her main business all day long).
Sure enough, from then on we had a heavy mouse plague it took us weeks to fight back, and her nice handcraft got chewed up by mice anyway.