Backward, sideways, straight up: the hummingbird is known for its special flying ability. Scientists have now discovered how the bird manages to fly through openings smaller than the span of its wings.
Whether they are looking for food or building a nest, birds often move into dense foliage. That requires some art and craft. Hummingbirds, the world’s smallest bird family, appear to have not one, but two tricks for this, American scientists have discovered.
It is the first time that scientists have been able to see the flight maneuvers in the lab. That makes the findings ‘spectacular’, says David Lentink, biomechanics and bird expert at the University of Groningen and not involved in the research.
The University of California researchers studied four specimens of the species Calypt anna, or Anna’s hummingbird (named after the wife of an ornithologist friend of the discoverer). In search of a meal of nectar, the birds flew hundreds of times in front of the cameras through an opening from one room to another.
Adjust while diving
The first flight strategy works sideways: one wing goes through the hole first, then the body, and only then the second wing. According to the researchers, this method is useful in unfamiliar environments: the birds slow down and can make adjustments during the dive, allowing them to fly carefully through the hole. According to Lentink, who has also conducted extensive research into flying hummingbirds, this ‘asymmetrical flapping’ is unique compared to other birds.
As the experiment progressed and the fist-sized birds became more confident, they preferred to use the diving method. The hummingbirds press their wings against themselves, causing them to shoot through the opening like a bullet. That method does require some fearlessness. By temporarily holding their wings still, the hummingbirds fall down at considerable speed. Moreover, they cannot make adjustments.
A good experimental setup is difficult in animal research, says Lentink. ‘You never know in advance how the animals behave.’ That is why the scientists first conducted preliminary research in which they tested, among other things, how large the openings should be for the birds.
Learning from the hummingbird
According to Lentink, the results, which were published in the Journal of Experimental Biology, are not only fun for bird lovers. Engineers and designers of flying robots can also learn from the hummingbird: ‘Nature often already has a solution for a technical problem.’
The hummingbird is a unique bird family. For example, due to their lightning-fast wing beat: the bee hummingbird, about 5 centimeters in size, flaps 80 to 200 times per second. Furthermore, the hummingbird’s wing movement is in the shape of a figure of eight, while most birds only move their wings up and down. These qualities allow hummingbirds to hover in one place, something no other bird can do.
