With the appearance of a Victorian, mechanical toy, the head-bobbing walk of pigeons has prompted many theories over centuries. Many authors have believed that, like a crank, there must be a physical connection between the bird’s head and feet. But perhaps the truth is stranger than folktales, as the bird is believed to use head-bobbing to boost its eyesight, particularly as an aid to judging distances.
Birds with sideways-looking eyes don’t have the benefit of stereo vision, so looking at the world from a single point of view seems very flat. But by bobbing their heads to-and-fro the birds are able to compensate for monocular vision by observing the world from slightly different positions, helping with depth perception. This will boost the attribute necessary for survival: finding food and avoiding predators.
Grahame Madge, spokesman, RSPB