Birds lose colour vision at twilight
19 Nov 2009 by Evoluted New Media
Birds lose their colour vision earlier in the day than previously thought, which has important implications for previous research into colour vision.
Birds lose their colour vision earlier in the day than previously thought, which has important implications for previous research into colour vision.
Birds have highly developed colour vision, needing between five and 20 times more light than humans to see colours. They can see a wider range of colours and ultraviolet light, but their colour vision ceases to work at twilight, according to research conducted by the Lund University Vision Group.
“Using behavioural experiments we can now demonstrate that birds lose their colour vision in the twilight and show just how much light is needed for birds to be able to interpret colour signals,” said Olle Lind, a doctoral candidate at the Department of Cell and Organism Biology.
The research findings – published in the Journal of Experimental Biology – showed the colour vision of birds stopped working at light intensities corresponding to that shortly after the sun goes down, earlier than other vertebrates tested so far. Humans and horses lose their colour vision after dusk – at light intensities corresponding to moonlight - but geckos can see colours at night.
Lind suggests that with these findings, it is now possible to start drawing conclusions about how birds use their colour vision at dawn and dusk. “We should re-evaluate earlier research about how birds perceive the colour of their eggs and their young in the nest,” he added.
It was not previously known what amount of light is necessary for birds to see colours – this has limited the validity of all research on this colour vision to bright sunlight only.
