Birds improve vision by stabilizing head position relative to their surroundings, while their
body is forced up and down during flapping flight. Stabilization is facilitated by compensatory
motion of the sophisticated avian head–neck system. While relative head motion has been
studied in stationary and walking birds, little is known about how birds accomplish head
stabilization during flapping flight. To unravel this, we approximate the avian neck with a
linear mass–spring–damper system for vertical displacements, analogous to proven head …