As regular CFZ-watchers will know, for some time Corinna has been doing a column for Animals & Men and a regular segment on On The Track... particularly about out-of-place birds and rare vagrants. There seem to be more and more bird stories from all over the world hitting the news these days so, to make room for them all - and to give them all equal and worthy coverage - she has set up this new blog to cover all things feathery and Fortean.

Friday 17 June 2016

Color vision helps birds find good food and the right partner


Date: June 16, 2016
Source: Lund University

The researchers have established that chickens -- just like people -- have colour constancy. For birds, this means that they, in different environments and under different lighting conditions, recognise the colour of, for instance, berries and can thereby distinguish those that are ripe from those that are not. Without colour constancy, they would not be able to rely on their colour vision -- they would simply see the berries in different colours as the light changed. They would certainly also not be able to recognise their own kind of species.

The results were achieved by the researchers from training chickens. Initially, the chickens were kept in an environment with white light and had access to containers marked in three different colours: red, yellow and orange. Only by selecting the orange container would the birds receive food. The researchers then studied which container the chickens selected when the light in the room was switched to different shades of red. The results showed that the chickens continued to select the orange container.

"We studied many different lighting conditions to find out how big the changes in light could be without the chickens losing their colour constancy. This type of study has never been done before," says Peter Olsson, biologist and one of the researchers of the world-leading Lund Vision Group at the Faculty of Science at Lund University.

By using a mathematical model, the researchers calculated how big the changes in light are inside the chickens' eyes. The same model can be used on other animals and thereby allow researchers for the first time to compare the colour constancy of chickens and birds to the colour constancy ability in other animals.

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