Turbulence? Why Hummingbirds Don't Even Notice it
Hummingbirds have always been impressive fliers. Constantly searching for fresh sources of sweet nectar, the birds can move their wings at incredible speeds, flitting around with great agility and precision even in tumbling winds. Now a new study of hummingbirds in slow motion footage has revealed just how they overcome turbulence with their unique wings.
The study, recently published in the Journal of Experimental Biology, details how researchers at Australia's RMIT University slipped four female ruby-throated hummingbirds into a wind tunnel to record how they coped with varied types of turbulence mid-flight.
Past studies have shown how hummingbirds fly with such incredible precision in stagnant or consistent air flow, but RMIT's Sridhar Ravi, who led the new study, argues that that's like studying how bears walk on asphalt. In the real world, terrestrial animals are bound to see a lot more rugged circumstances.
He recently explained to Popular Mechanics that air is no different, with everyday things like vegetation, buildings, and rugged topography making simple wind patterns no walk in the park for these tiny flitting birds.
And yet, when the researchers simulated increasingly intense and chaotic turbulence in their wind tunnel, the four ruby-throats always managed to keep their beaks perfectly aligned with nectar from a tube. Specifically, the study details how the birds managed to somehow keep their heads stable even in whipping 10-mph winds under a maximum of "15 percent turbulence intensity." When the same feat was attempted with drones, the man-made aircraft couldn't even pull off a fraction of that feat.
So how do they do it? At about 1,000 frames per second, the slowed-down video footage revealed that the hummingbirds were madly adjusting their wings and body to suppress the force of each and every directional change of the turbulent wind. Even while their wings madly flapped to stay aloft, they also twisted and tilted with their bodies and tails to serve as incredibly impressive and nearly omnidirectional rudders, keeping their beaks straight and true to suck down that sweet, sweet nectar.
Ravi even went as far as to compare this to "asking a person to maintain perfect handwriting in a car as it is being driven off-road" - even while that person is being buffeted by forces equivalent to their own weight!
He added that drones and other craft could take a hint from the incredible hummingbird - arguably the most stable flier in the world.
Still, it should be noted that this impressive bird has some competition. The sphinx moth (Manduca sexta) is currently seen as a prime candidate for biobot search-and-rescue technology, as it can fly with impressive stability even through storm-force winds.
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