This study was the focus of a lab group run by David Lentink, an assistant professor of mechanical engineering at Stanford. The group’s focus spans biology, engineering and biomimicry. Their goal is to improve drone design and performance by adopting key characteristics of birds in flight.
Birds have built-in vision stabilization to compensate for the up-and-down motion from flapping their wings. Lentink and his colleagues devised a method of measuring the morphology of this stabilization mechanism while a bird is in flight.
They compared a high-speed video of a whooper swan in flight with a computer model that approximated the spring-damping effects of the bird’s neck. This damping effect stabilizes the bird’s head to vertical disturbances.
The team compared the bird’s neck function to the suspension system of a car on a bumpy road. The neck vertebrae and muscles respond with a combination of stiffness and flexibility that passively keeps the head steady during flapping flight.
"This simple mechanism is a remarkable finding considering the daunting complexity of avian neck morphology with about 20 vertebrae and more than 200 muscles on each side," said Lentink.Studies of bird neck morphology, as well as a bird’s head motions while walking or stationary, have been done in the past. For this project, the research team focused on measuring this mechanism while the bird is in flight.
Lentink, senior author on the study, credits much of the work to now-graduated master's student, Ashley Pete. She developed the idea and methodology for the study while taking Lentink's class on the biomechanics of flight.
"The paper she wrote for this class was so good that we expanded it together and submitted it to The Journal of the Royal Society Interface, where it got published," Lentink said. "This really shows how students can make remarkable discoveries in the classroom, going beyond textbooks, based on their creativity and enthusiasm."
For more information, the study’s paper is available here.