If you were to compare a pigeon to a flying machine, you’d probably think airplane–they’ve both got wings, a tail and landing gear. But when it comes to turning in the air, pigeons have more in common with helicopters than planes, say scientists who report their findings this week in PNAS.
There are two ways for a flying object, whether it be living or mechanical, to change its direction: it can (A) alter the direction of its body or (B) alter the direction of the force of propulsion. Helicopters and most insects use method A, while airplanes use method B.
Researchers from Harvard University and Harvey Mudd College filmed pigeons on high-speed video as they flew at low speed down a corridor with a sharp, 90-degree turn. They found that a bird, as it turns, changes the orientation of its whole body and redirects the aerodynamic forces so that they stay in line with its body. “We didn’t expect the forces to change direction relative to the body this little–as little as is observed in helicopters,” lead author Ivo Ross of Harvard University told New Scientist.