They aren't Fey.
In my game I make a distinction between "earthly spirits" and "fey". The earthly spirits are native to the game's primary world and arise from this world's natural environment. They aren't native to anywhere else. They include treants, dryads, naiads, unicorns, etc. They also include gnomes and kobolds. There's basically a range of spirit "manifestations", from the pure spirit (who can only be perceived magically) to the entirely flesh. But they're all tied to one degree or another to the land, water, rocks, etc. from which they arose. Some are tied to their place. Others can go wherever they want.
Fey on the other hand are not natives to this world. They're from the invisible realm that exists right next to ours and is accessible via mushroom circles, fairy mounds, and the like. Elves and goblins are originally from here, along with others.