Why don't birds fall over when they jump?

October 30, 2018, University of Manchester
Why don't birds fall over when they jump?

Scientists have been analysing the way birds jump when they take-off to help us understand why they simply don't just fall over when attempting to fly.

The researchers, based in the School of Mechanical, Aerospace and Civil Engineering at The University of Manchester, have been investigating the biomechanics of how , and will use the findings to design jumping robots in the future.

Jumping robots that are highly agile and able to manoeuvre quickly through debris are extremely useful for exploring such as earthquakes and floods.

To perform the standing start take-off that we often see birds do in nature, they have to lean so far forwards that their centre of gravity is well ahead of their feet. If they were to pause during this manoeuvre, they would simply tip forwards, fall over, and never take-off. But they don't. That's because the birds 'pitch' their bodies upwards during the take-off.

The researchers have found that by pitching the body upwards as the bird pushes off the ground or a perch it maintains stability in one fluid manoeuvre. This combination of pitching while accelerating has long been known in the field of walking biomechanics, but this is the first time it has been found and applied in relation to jumping.

Computer simulation of a guinea fowl performing a jumping take-off. Credit: Dr. Ben Parslew, The University of Manchester

The researchers also found that, as well as pitching, birds have a 'compliance' in their joints which allows them to flex in a unique way during a jump. Without this compliance the birds would experience 'stutter' or 'chatter' which is a high frequency vibration between the feet at the ground

For the study the researchers used computer simulations to understand the stability of birds taking-off from a perch and from the ground.

Dr. Ben Parslew, Lecturer in Aerospace Engineering and lead author, explains: "Traditionally jumping take-offs are viewed as conceptually complex to understand or try to recreate.

Diamond Dove jumping take-off from a perch. Credit: Dr. Pauline Provini, Functional Morphology Lab, Muséum national d'Histoire naturelle
"But our research, for the first time, shows that you can ignore the movement of the individual leg segments, and the , and just treat a jumping bird as a single body.

"This is enough to understand how birds remain stable when they take-off and, more importantly, these findings teach us the fundamentals about how a jumping robot would have to move to avoid tipping over when it jumps."

The study also found that a bird's wings weren't as fundamental in its take off as previously thought.

X-ray of Diamond Dove jumping take off. Credit: Dr Pauline Provini, Functional Morphology Lab, Muséum national d'Histoire naturelle

Dr. Parslew added: "Jumping take-off in birds is an explosive behaviour with the goal of providing a rapid transition from ground to airborne locomotion. This study found that for jumping diamond doves, the wing contributes very little to the physics of take-off and 'it's all about the legs' with the wings only coming into play once the bird is airborne."

The study is published in Royal Society Open Science.

Explore further: New study may provide clues to how birds began to fly

More information: A Dynamics and Stability Framework for Avian Jumping Take-off, Royal Society Open Science, rsos.royalsocietypublishing.or … /10.1098/rsos.181544

Related Stories

New study may provide clues to how birds began to fly

October 19, 2018

For the first time, researchers have measured what is known as the ground effect of flying animals—and it turns out that they save a lot more energy by flying close to the ground than previously believed. The study from ...

Uncovering the role of the ilio-sacral joint in frogs

October 10, 2018

A trio of researchers, two with the Royal Veterinary College, the other the University of Portsmouth, has found evidence that suggests that the ilio-sacral joint in frogs evolved after they started jumping. In their paper ...

Trap-jaw ants exhibit previously unseen jumping behavior

December 1, 2015

A species of trap-jaw ant has been found to exhibit a previously unseen jumping behavior, using its legs rather than its powerful jaws. The discovery makes this species, Odontomachus rixosus, the only species of ant that ...

Recommended for you

Discovery could neutralize West Nile virus

November 20, 2018

Researchers at Vanderbilt University Medical Center and colleagues have isolated a human monoclonal antibody that can "neutralize" the West Nile virus and potentially prevent a leading cause of viral encephalitis (brain inflammation) ...

The taming of the dog, cow, horse, pig and rabbit

November 20, 2018

Research at the Earlham Institute into one of the 'genetic orchestra conductors', microRNAs, sheds light on our selectively guided evolution of domestic pets and farmyard animals such as dogs and cows.

A Mexican cavefish with a scarred heart

November 20, 2018

Scientists are studying a guppy-sized, blind, translucent fish that lives in the cave systems of northern Mexico to figure out why some animals can regenerate their hearts, while others just scar. Their research appears November ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.