Birds have many capabilities which humans do not possess like the ability to fly, the ability to weave nest out of twigs and straws, etc. Now in the list of abilities, one more ability has been added. It is the birdâs ability to see more colors than a human being can see. In the very recent issue of 23 June of the journal called Behavioral Ecology, a report was published on the study of avian visual system, that says that since birds can see a variety of colors, they have included those colors in their plumage also and hence the colors of their plumage have also developed from dull to bright colors over a period of years.
It is exactly the same way as humans have developed many colors of their clothes after invention of aniline dyes. Humans have included as much colors in their life as much they can see, whereas, though the birds are capable of seeing a wide variety of colors including ultraviolet colors, which naked human eyes canât see, they have not included the rich diversity of colors in their plumage.
The research was conducted by researchers from Yale University and University of Cambridge. Richard Prum, William Robertson Coe, professor in the Department of Ornithology, Ecology and Evolutionary Biology and Mary Caswell Stoddard of Cambridge.
Ms. Stoddard began investigating the avian visual system as an undergraduate at Yale University and continued her research after graduation too, is still searching about the fact that why the birds have not developed the ability to produce whole gamut of colors in their plumage, which they can see.
“We don’t know why plumage colors are confined to this subset,” Stoddard said. “The out of gamut colors may be impossible to make with available mechanisms or they may be disadvantageous.”
The next question which pops up is why are birds capable of seeing more colors than human beings? The answer lies in the anatomy of birdâs eye. A birdâs eye consists of three types of photoreceptors that translate light into nervous impulses whereas humans have only two types of receptors.
The other major difference is that: birdâs retinas donât have any blood vessels, which in turn protects the birdâs vision from shadows and light scattering.
Following are some interesting characteristics of birdâs vision:
1. In nocturnal birds like owl, there lies a layer at the back of eye, tapetum lucidium, which works as a mirror for retina and strikes sensory cells in retina and make the bird see much better at night.
2. Birds of prey have high density receptors and other modifications which helps in making their vision accurate. Their eyes are so placed that they have binocular vision which helps them in determining vision accurately.
3. In seabirds like gull and albatross, the color receptors have yellow or red droplets that improves their distance vision especially in hazy conditions.
4. Migratory birds have the ability to detect magnetic field with the help of light. The birds tend to move their head to detect the magnetic field and on neutral pathways, they can easily see magnetic fields and help them with directions while flying.