Michigan list here; DNR - Michigan's Snakes

I agree with you on the slugs leeches and amphibians, but I'm a bit stymied by the fact that, at least in the areas I have searched, not terribly abundant. (And all heavily colonized by worms.)
I wonder if Garter numbers have increased in response to the availablity of this 'new' food source.
I also can't shake the feeling that worms may be garter junk food- delicious stuff they will jump on with relish when they can get it, but a long way from being nutritionally complete.

Slugs would provide a good bit more calcium wouldn't they? Descriptions of duff laden Native woods lead me to think slugs would have been a lot more abundant. Has anyone experimented with raising and feeding native slugs?

I'm tossing this out here to get people thinking and discussing- the more we can figure out about how they would have lived in the wild, the better we can duplicate those needs in captivity. Small litters and mysterious sicknesses lead me to think there is a lot left to study and figure out.