They, in principle, do not have to be birch. Just birch hares look more natural. In addition to the firewood itself, you will need old sunglasses - you can also break a hat, which you do not mind throwing away. And, of course, a little imagination and creativity, artistic taste.
Such a composition will look especially relevant near a reservoir, possibly a river. It would seem that you don’t need to have any special craftsmanship for making these crafts, but they look, as they say, “cool”. Children will be delighted as much as anything unusual.