Hummingbirds are nature’s versatile fliers. They swoosh faster than 50 kilometers per hour and quickly stop when navigating through dense vegetation. Recently, scientists discovered that the hummingbird vision is adapted to high-speed flight.
Research has revealed that these small birds take in visual information completely differently from other species, probably because they have to balance out their acrobatics.
Birds are quicker than insects in flight, so the danger of a collision increases. Roslyn Dakin, a Ph.D. fellow and study leader, wanted to know what helps hummingbirds to avoid collisions. Research also had to point out how big is the difference between them and insects, when establishing a clear path.
Researchers put hummingbirds in a special tunnel, where they projected nature patterns on the walls. This helped them realize how the birds steer clear to avoid collisions in flight. Scientists installed cameras to track the movements of hummingbirds. They flew in a 5.5-meter long tunnel.
The experiment worked by taking advantage of the hummingbirds’ appetite for sugar. So a feeder containing sugar was placed on one side of the tunnel and water was put on the other side. This made the tiny birds fly back and forth all day long. Scientists were this way able to test many different visual stimuli.
To date, we don’t know too many things about birds’ orientation in high-speed flight. We only know that bees process distance similarly to humans. For example, a bird processes distance by how quickly the object passes through their field of vision, just like we do, when driving on a road. We see poles closer to the street and buildings in the distance. Timing tells us how far away they are from us.
Hummingbirds did not react to bee-mode simulations. But they did react to fly-like simulation. Objects getting bigger or smaller in the distance tell birds if they move further away or closer to the object.
In the end, scientists found that hummingbirds have the same technique as flies. This is known as “image velocity” and it helps both species to know their altitude and distance. Humming birds are even able to fly backward. This is done with about the same amount of energy and oxygen as flying forward.
Image Source – Wikipedia