Well, actually, I'm working with one where there are two hypotheses. But, both of them require intelligence, since one is a choice, and the other requires study.
So -- do I include magical animals of any kind? Monsters, in short? Or plants, but there I think I will opt for the simple route of omission. Elegant, to be sure, and lends a certain amount of unity. But -- no fun. At least for this story. Because the monsters would fit in the theme very nicely in some respect. And the world shouldn't be too simple.
Of course, if it's study, it could be that someone could inflcit magic on the aniamls. Might be wise as a test. And if it's a choice, critters can "choose" well enough, even if not all of them would do so definitively as a magpie, since in this world, the choice actually involves a physical object. One small enough that a critter could knock it over or otherwise indicate it.
I think Halley and whatsherface, the troll-wife, will dispute over it, whether it points to one or the other.