Feathers too weak for early bird flight

May 13, 2010
Life reconstruction of the earliest fossil bird, Archaeopteryx. Credit: Artwork by Todd Marshall

(PhysOrg.com) -- The evolution of flight took longer than previously thought with the ancestors of modern birds “rubbish” at flying, if they flew at all, according to a Manchester scientist.

Archaeopteryx, the theropod dinosaur believed to be the earliest bird, was discovered 150 years ago but debates about how flight evolved still persist. The two theories are that flight evolved in running bipeds through a series of short jumps or that Archaeopteryx leapt from tree to tree using its wings as a balancing mechanism.

Dr Robert Nudds at The University of Manchester is carrying out a series of biomechanical investigations to shed light on the subject with his colleague Dr Gareth Dyke at University College Dublin.

For their latest paper Dr Nudds and Dr Dyke applied a novel biomechanical analysis to the flight feathers of the early birds Archaeopteryx and Confuciusornis to find out if they were strong enough to allow flight.

They found that the dinosaur feathers’ much thinner central stem (rachis) must have been solid or they would have broken under the lift forces generated during flight or by gusts of wind. This solid structure is very different to modern birds, whose rachises are broader, hollow straws. If the dinosaurs’ feathers had had hollow rachises, they would not have been able to fly at all.

“These are surprising results,” says Dr Nudds, whose findings are published in Science today (13th May 2010).

“I thought the feathers would be strong enough with a hollow rachis to fly but they weren’t. Even with a solid rachis, they were not very good. These dinosaurs were rubbish at flying.

“This pushes the origin of flapping flight to after Archaeopteryx and Confuciusornis. It must have come much later.”

It is impossible to tell from fossils whether the rachises were solid or hollow. However Dr Nudds, at Manchester’s Faculty of Life Sciences, believes the dinosaurs’ feathers were solid and therefore they could fly, but very poorly.

“The fossilsof Confuciusornis and Archaeopteryx suggest flight and at this stage it would be a brave person to say they couldn’t fly” he says.

“However their feathers must have been very different to modern birds and they were poor fliers. I believe the feathers were originally for insulation or display purposes then they found that by elongating them they had a parachuting surface, then a gliding surface.

“Archeopteryx and Confuciusornis are still at a very early stage in the evolution of flight.”

Dr Nudds’ and Dr Dykes’ work builds on their previous paper, in the journal Evolution, which investigated how the movement of feathered dinosaur forelimbs evolved into flapping flight. Again they found the flight was a consequence of gradual changes in wing shape and movement - a long, slow evolution.

Dr Nudds adds: “Our analysis also shows that Confuciusornis, which is younger by 25 million years, was worse at flying than Archaeopteryx. This raises the further question of lineage - did the dinosaur-bird line branch off, giving rise to flying and flightless birds?”

He and Dr Dyke plan to analyse other fossilized feathers to find out when flapping flight evolved. However such specimens are rare.

“I don’t mind,” says Dr Nudds. “It makes it more exciting and all the more intriguing.”

Explore further: New hadrosaur noses into spotlight

More information: Science: http://www.sciencemag.org

Provided by University of Manchester

3.6 /5 (11 votes)

Related Stories

Ancient Birds Flew On All-Fours

Sep 26, 2006

The earliest known ancestor of modern-day birds took to the skies by gliding from trees using primitive feathered wings on their arms and legs, according to new research by a University of Calgary paleontologist. In a paper ...

The color of dinosaur feathers identified

Jan 27, 2010

(PhysOrg.com) -- The colour of some feathers on dinosaurs and early birds has been identified for the first time, reports a paper published in Nature this week.

Recommended for you

New hadrosaur noses into spotlight

Sep 19, 2014

Call it the Jimmy Durante of dinosaurs – a newly discovered hadrosaur with a truly distinctive nasal profile. The new dinosaur, named Rhinorex condrupus by paleontologists from North Carolina State Univer ...

Militants threaten ancient sites in Iraq, Syria

Sep 19, 2014

For more than 5,000 years, numerous civilizations have left their mark on upper Mesopotamia—from Assyrians and Akkadians to Babylonians and Romans. Their ancient, buried cities, palaces and temples packed ...

New branch added to European family tree

Sep 17, 2014

The setting: Europe, about 7,500 years ago. Agriculture was sweeping in from the Near East, bringing early farmers into contact with hunter-gatherers who had already been living in Europe for tens of thousands ...

User comments : 2

Adjust slider to filter visible comments by rank

Display comments: newest first

jsovine
1 / 5 (4) May 13, 2010
I don't understand how this can possibly tie into natural selection...

Same thing goes for bacterial flagellum.
Rute
4 / 5 (1) May 14, 2010
I think the research doesn't take into account the thicker Jurassic atmosphere which provided more uplift for both gliding and flying compared to the current day atmosphere.

Jsovine: there are examples of modern animals that rely on passive gliding like the flying squirrel, and animals that rely on the extension of gliding distance through active flapping like Colugo (Colugo flaps it's tail along with the calcar-like membrane).