Book 31, Question 49
How do birds scratch an itch on their heads?
Birds cannot reach their heads with their wings, so they use their feet.
Some birds lift a foot over the wing to reach, and others swing the foot underneath the wing. Scientists call these styles over-the-wing and under-the-wing scratching. Different kinds of birds usually do it the same way, so it can be a clue to which family a bird belongs to.