Visual tricks may aid male great bowerbird’s mating success
14 April 2014
New research has uncovered the visual tricks male great bowerbirds employ to enhance their chances of mating.
Professor John Endler, from Deakin University's School of Life and Environmental Sciences (Centre for Integrative Ecology), says researchers know that male great bowerbirds construct a bower to restrict and refine the female's view.
"Now we've discovered that males also make rapid and colourful movements within this restricted field of vision and build bowers from materials specifically to alter the female's perception of colour," Professor Endler says.
Professor Endler says the bower is made from two semi-circles known as 'courts' which contain uncoloured items. The courts connect via a thatched 'avenue' making a tunnel lined with reddish sticks.
Professor Endler studied two populations of male great bowerbirds in the dry tropics of northern Queensland, between 2010 and 2012.
"Throughout the courting process, males repeatedly and briefly present their heads and coloured objects into the female's field of vision at the avenue entrance, and then hide it again. It's likely he's doing this to surprise the female bird with coloured flashes," Professor Endler says.
"We also wanted to understand how the reddish avenue walls affect the female's perception of the colours of objects presented by the male."
"The reddish avenue walls cause a visual effect known as chromatic adaptation in the female birds, causing heightened experience of some coloured objects as well as the male's crest," he says.
The research, published in Proceedings of the Royal Society B, found that the male great bowerbird withholds objects from the female's field of vision when it isn't actively displaying them.
Professor Endler says the birds' behaviour does not directly increase mating success but 'could play a role in attracting and holding the attention of female bowerbirds.'
"Generally, the longer a female watches the male's performance, the higher the rate of mating success," he says.
"The male's ability to present coloured objects without repeating the same colours could also imply that he has more advanced cognitive and foraging abilities," he says.
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