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Aeroplanes owe much of their design to birds, and now it appears man-made flying machines and birds have more in common than ever.

This is because scientists have discovered that bird feathers are constructed from sinewy material that's as strong as carbon fibre, used to build planes such as Boeing's 787 Dreamliner aircraft.

The natural material is stronger and lighter than steel and allows the plume to bend and twist to cope with the stresses of flight, British researchers claim.

Scientists have discovered that bird feathers are constructed from sinewy material that's as strong as carbon fibre. A swan feather is pictured. The natural material is stronger and lighter than steel and allows the plume to bend and twist to cope with the stresses of flight while remaining light as a feather, British researchers claim

Since their appearance more than 150 million years ago, feather shafts - or rachises - have evolved to be some of the lightest and strongest natural structures.

But until now, relatively little was known about their biology from a mechanical perspective and almost nothing at the nanoscale.

Scientists at the University of Southampton used hardness experiments at a microscopic scale, known as nano-indentation, to show that the shafts are made of a multiple layers of keratin, a fibrous material similar in construction to carbon fibre.

Engineers use carbon fibre to build sports car, bicycles and jets, because it is five times as strong as steel, yet weighs two thirds less.

Scientists found the structure and number of feathers varies according to birds' style of flight. The bald eagle (pictured left) is a glider, while the mute swan (right) is a flapper, requiring more strength from its feathers

The nanoscale discovery of nature's equivalent could lead to more efficient propeller blades and vehicles, the researchers say.

The study, reported in the Royal Society journal Interface, also revealed the number and organisation of the shaft layers is not fixed, as previously believed, and varies according to flight style.

Christian Laurent, who led the research, said: 'We started looking at the shape of the rachis and how it changes along the length of it to accommodate different stresses. Then we realised we had no idea how elastic it was, so we indented some sample feathers.

'Previously, the only mechanical work on feathers was done in the 1970s but under the assumption the material properties of feathers are the same when tested in different directions, known as isotropic. Our work has now invalidated this.'

His team tested the material properties of feathers from the mute swan, the bald eagle and the partridge - three birds with very different styles of flight.

For example, the bald eagle is a glider and spends most of it time soaring, while the mute swan is a flapper.

'Our results indicate the number and the relative thickness of layers around the circumference of the rachis and along the feather's length are not fixed, and may vary either in order to cope with the stresses of flight particular to the bird or to the lineage that the individual belongs to,' Dr Laurent explained. 

The researchers now hope to fully model feather functions and link biological aspects to particular flight styles and species, which has several paleontological implications and engineering applications.

'We hope to be able to scan fossil feathers and finally answer a number of questions including what flew first, did flight start from the trees down or from the ground up, could Archaeopteryx fly and Was Archaeopteryx the first flying bird,' he said.

'In terms of engineering, we hope to apply our future findings in materials science to yacht masts and propeller blades, and to apply the aeronautical findings to build better micro air vehicles in a collaboration with engineers at the university.'

All birds have feathers and most share a common structure, but adaptations allow them to be used for specialised roles. Pictured is the iridescent blue and green sheen on a magpie's wing feathers

Feather he shafts are made of a multiple layers of keratin, a fibrous material, similar in construction to carbon fibre. Engineers use the material to build sports car and jets such as the Boeing 787 (pictured), because it is five times as strong as steel, yet weighs two thirds less