Small birds use ultraviolet light - forskning.se

Some birds’ eyes are adapted to ensure ultraviolet light. Research from Lund University shows that small birds eye lenses let through UV light, while larger birds have eye lenses which instead blocks the light.

Blackbird (Photo: Mindaugas Mitkus)

It is known that birds can see ultraviolet light. They are considered to use UV vision to many important behaviors, such as finding food or a suitable partner to mate with. But not all birds are equal. Now researchers at Lund University studied how much ultraviolet light as the eyes of different species of birds passes to the retina. The results show that small eyes of small birds let through much UV light, big eyes of larger birds allows only little UV light. Thus, only small birds, such as songbirds, be UV specialists.

class=”normal”> – Contrary to what was thought before, not all species so interested to see UV light. Raptors and swifts stop much of the UV light in the lenses, much like humans, says Olle Lind, a researcher at the Department of Biology, Lund University.

class=”normal”> To use UV light requires two things, first, that the retina of the eye reacts to this type of light, and the lens in the eye transmits UV light so that it can meet the retina. Some of the larger species of birds in the current research study, for example, birds of prey and swift, seems to have pigmented lenses to actively block out UV light.

class=”normal”> – This could be a way to protect the eyes while chasing flying in open and very bright environments, says Olle Lind.

class=”normal”> Olle Lind and his colleagues include interested in studying eye configuration to better understand what topics birds have in their lenses and how these affect the UV transparency. Besides that this is important for a physiological understanding of birds’ eyes, it is possible that the investigations could ultimately have important practical applications. For some reason cope birds well away both damage to the retina as cataract, two UV-related disorders that usually affect people who are exposed to UV light.

class=”normal”> So far, research on birds and UV light mainly focused on the birds’ retinas, but few have studied how permeable bird eye lenses. By finding out how much UV light that reaches the retina in different species can be safer rule on the actual UV vision in birds and thus easier to sort out what this vision plays role in bird ecology and evolution, says Olle Lind.

class=”normal”> – We also believe that there are similar associations in other animal groups, such as mammals. Large ungulates have far fewer opportunities to use UV light compared to small rodents, says Olle Lind.

class=”normal”> study published Nov. 20 in the Proceedings of the Royal Society B.