[He opens up his notebook to show off the map he's drawn of Fayren, complete with little Xs marked over the approximate locations of where people were traveling.]

So far, we know that there are two shadow mages, and that they're stealing herbs. Based on the map and the places they've struck, it appears that they're going after people in places where there's plenty of shade.

[While it's true that a wide open field wouldn't be an optimal place to rob someone anyway, he suspects there's a little more to it.]

If we carry some cooking herbs from the grocery store and walk around the areas where they've struck before, that should lure them out. They'd have to get close enough to realize that we're not carrying what they're looking for in the first place.