Physics Buzz: Chicken Head Tracking

The technique – which you could generally call “tracking” but is also pretty much the same thing as “dead reckoning” (or is it ded reckoning?) – is utilized by aircraft and some car navigation systems. (I love it when “high tech” turns up in Nature.) The chicken’s body communicates its movements so well with her head, that she can almost instantaneously compensate for her movement of the lower body, and keep her head stationary in relation to her environment. To do this, her body has to have some fixed point, some center, and determine how far her bum has moved away it, then move her head an equal but opposite distance from it. Once again this requires very rapid communication, and then action, on the part of her body.