Al Jazeera (Qatar): compared to the Hummingbird, people are color — blind

According to the latest study published in the American journal Proceedings of the National Academy of Sciences on 15 June this year, hummingbirds can distinguish several nespecially colors that the human eye is not able to see.

This is due to the presence of these birds are additional sensitive to colors cones, which in humans is missing. Man has three types of cones in the retina that are sensitive to red, green and blue colors. Hummingbirds can distinguish and ultraviolet rays.

Excellent color perception

The research team led by biologist Mary Caswell Stoddard (Mary Caswell Stoddard) from Princeton University conducted a series of experiments, the results of which it was discovered that birds distinguish mixed color, such as UV+yellow, UV+red.

Excellent perception plays a very important role in bird life, including such aspects as the search for food, couples, escape from predators, and navigate a variety of terrain.

“Compared to birds and many animals, people suffer from blindness,” says Stoddard.

She continues: “the Presence of a fourth type of cone cell not only extends the range of distinguishable colors birds up to ultraviolet radiation, but also allows them to perceive mixed color, such as UV + and UV green + red, but still checking it was difficult.”

Niespecjalnie color

The greatest interest for the team Stoddard niespecjalnie represent colors that are combinations of colors of different parts of the spectrum. People can distinguish only one nespecially color purple, which occurs when you have used our blue and red cones.

According to the findings, birds with additional cones can distinguish up to five aspectually colors including purple, UV + red, UV + yellow, UV + yellow, UV + purple.

Stoddard and her colleagues conducted a series of experiments to test whether hummingbirds can see these colors niespecjalnie.

In the course of these experiments racecommittee Hummingbird Selasphorus platycercus were trained to distinguish colors, and to conduct them, a team of researchers has developed a special led light tube intended for the display of several colors, including respectfully, that is inaccessible to the human eye. Then these devices were placed near the feeders with water. Some of them were sugar water (poultry love it), and the tube emitted a certain light, while other feeders were the usual water and emitted another light.

The researchers then changed the position of these feeders and was trying to figure out if the birds to match the color with some water.

The world through the eyes of a Hummingbird

The aim of a long series of experiments (several thousand visits to the feeders), which lasted three years, was to find out if hummingbirds show a preference for feeding at the feeders, which displayed combinations of ultraviolet and other colors.

According to the results, birds can easily distinguish between different types of aspectually colors, trying to choose sweetened water.

“It was great to watch… while the combination of ultraviolet and green and normal green seemed to us identical, Hummingbird correctly chose the UV + green, where there was a trough with water,” says study co-author Harold Hester of the University of British Columbia.

“Our research has allowed us to understand how the world looks through the eyes of storm”, — he added.

How to look niespecjalnie color?

As explained by the researchers, understanding how birds can distinguish several types nespecially colors, gives you the opportunity to take a step forward in our knowledge of avian vision.

Nevertheless, we still do not know much about the neural mechanisms that allow the brain of animals to perceive these colors. Scientists need to study a large number of such issues.

In addition, as the researchers note, the most important question is how exactly niespecjalnie the colors look in the eyes of Hummingbird? Appears if, for example, ultra-violet + green as a mixture of these colors and new color?

At the moment we cannot answer this question, as the lack of sensitivity to espectrales colors — our human characteristic.

At least for birds, the important thing is not how these colors look, and what they mean for them. For example, these colors allow them to gain information about food, other hummingbirds or raptors.