For the first time, researchers have observed that birds that fly actively and flap their wings save energy.
Researchers showed that jackdaws minimize their energy consumption when they lift off and fly because the feathers on their wing tips create several small vortices - a circular pattern of rotating air left behind a wing - instead of a single large one, which requires more energy.
The researchers say the discovery could lead to more efficient drones based on the design of the jackdaw.
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Researchers showed that jackdaws (pictured) minimize their energy consumption when they lift off and fly because the feathers on their wing tips create several small vortices - a circular pattern of rotating air - instead of a single large one, which requires more energy
Wing tip vortices are spiral patterns of rotating air that trail of the tips of an airplane's wings.
These wing tip vortices steal energy from the motion of the airplane, creating vortex drag.
Researchers at Lund University in Sweden have discovered that the wingtips of jackdaw birds generate several small air vortices instead of one large vortex, as on an aeroplane with rectangular or elliptical wing tip.
It requires more energy and costs more to lift off when only one large wing tip vortex is generated, so the jackdaws are able to conserve energy by flapping their wings and creating several small vortices.
Source: Smithsonian National Air and Space Museum
The researchers, based at Lund University in Sweden, published their findings in the Journal of the Royal Society Interface.
Previously, multiple wingtip vortices have only been associated with large gliders such as eagles, vultures and storks.
But now, researchers have discovered the same phenomenon in jackdaws (Corvus monedula), which flap their wings when they lift off and fly.
The researchers conducted the experiments in a wind tunnel at the Department of Biology in Lund, Sweden.
Advanced cameras captured the jackdaw's lift off and flight through a thin mist that reflects laser light.
Using multiple images from several cameras, the researchers were able to build up three-dimensional images of the air flow around the jackdaw's wing tips.
Commenting on the findings, Dr Marco Klein Heerenbrink, a co-author of the research and now a post-doctoral researcher at the University of Oxford , told the DailyMail.com: 'By spreading the outer primary feathers, the wing tip effectively acts as several wings stacked on top of each other.
'Each feather contributes to lift and produces