Unique camera shows how birds view the world
Image credit: Dreamstime
A study by researchers at Lund University in Sweden has successfully recreated how birds see colours in their surroundings for the first time, all by using a specially designed camera.
Based on the images taken from the camera, the study revealed that birds see a different reality compared to what the human eye can see. Human colour vision is based on three primary colours: red, green and blue; birds can see the same three colours but also see ultraviolet.
Biologists at Lund have also found that birds see contrasts in dense forest foliage, whereas people only see a wall of green, and this is being showed in the images below.
“What appears to be a green mess to humans are clearly distinguishable leaves for birds. No one knew about this until this study,” said Dan-Eric Nilsson, professor at the university’s Department of Biology.
Collaborating with Cynthia Tedore – a research associate from the University of Hamburg who specialises in behavioural biology and who took the photos shown below – the researchers have succeeded in imitating bird colour vision with a high degree of precision for the first time.
The camera used in the study was designed within the Lund Vision Group and is equipped with rotating filter wheels and specially manufactured filters, which makes it possible to show what different animals can clearly see.
Furthermore, the camera imitates with a high degree of accuracy the colour sensitivity of the four different types of cone cells in bird retinas, according to the Lund researchers.
Based on the photographs, for birds, the upper sides of leaves appear much lighter in ultraviolet. From below, the leaves are very dark. Therefore, the images showed that the three-dimensional structure of dense foliage is obvious to birds, which in turn makes it easier for them to move, find food and navigate.
On the other hand, humans do not perceive ultraviolet in their line of vision and see the foliage in green – the primary colour where contrast is difficult to determine by the human eye.
“We have discovered something that is probably very important for birds, and we continue to reveal how reality appears also to other animals,” Nilsson said.
“We may have the notion that what we see is the reality, but it’s a highly human reality. Other animals live in other realities, and we can now see through their eyes and reveal many secrets. Reality is in the eye of the beholder,” he concludes.
Last December, researchers from Cardiff University found that thermal-sensing cameras mounted on drones could offer a safer and more cost-effective way to locate nests of the elusive European nightjar in forestry work and construction areas.