Book 31, Question 36
Why do woodpeckers have two toes pointing backward?
Most birds have three toes pointing forward and one pointing back.
Woodpeckers, parrots, and some others have two forward and two backward. That arrangement works like a clamp. It lets a woodpecker grip a tree trunk tightly and lean back as it pecks. Its stiff tail feathers prop it up like a third leg, so the bird is steady while it works.