Evolution - the experience

Why are so many Australian birds so colourful?

And what impact is climate change having on those colours?

They’re the sorts of questions that would have enchanted Charles Darwin, and 150 years after the publication of his landmark work “The Origin of Species”, are being addressed by Deakin University’s Professor Andy Bennett.

That’s not the only link Professor Bennett has with Charles Darwin as the world also prepares to celebrate the 200th anniversary of the English scientist's birth.

While working in England, Professor Bennett led a number of visits to Darwin’s fabled Galapagos Islands.

Accordingly Professor Bennett, who is originally from Australia, is well placed to play a key role in celebration in this country.

Already s a range of events have been planned for next year to celebrate the two important Darwinian anniversaries.

Deakin has joined with Monash and Melbourne universities to stage a symposium in February - centred around Darwin’s birthday on the 12th - details of which can be found at: www.evolution09.com.au

From February through to November, the 150th anniversary of the publication of “The Origin of Species", a number of community events will also be held.

In addition, there will be a special edition of the Emu Austral Ornithology journal, published by CSIRO and edited by Deakin’s Kate Buchanan.

Both Professor Bennett and Dr Buchanan are prize recruits to Deakin’s ever-growing pool of talented researchers.

Dr Buchanan’s work on environmental changes in birdsong was recently the subject ABC Radio National’s The Science Show.

For Professor Bennett, birds are a way to watch the processes of evolution in action.

His work on them here in Australia stems from a love of the parrots he used to watch in his childhood garden in the Adelaide Hills.
As well as the impact of climate change of bird colouring, Professor Bennett is also looking at why birds see more colours than humans as he leads an international team of scientists who have been studying parrots, in particular the Crimson Rosella.

The team – which also includes the CSIRO and Dutch and UK scientists – has been studying this parrot for five years, with field sites across Victoria, NSW, South Australia and Queensland.

“Explaining diversity of colour is a fundamental question in biology,’’ Professor Bennett said.

“We’re trying to explain what maintains colour variability in parrots, particularly the Crimson Rosella which in southern Victoria is deep crimson red but along the Murray and Murrumbidgee is a pale yellow. In South Australia it is a splotchy orangey-yellow.”

The Crimson Rosella is known in some localities as the Yellow Rosella and Adelaide Rosella.

To date the research has found that around Albury-Wodonga, yellow versions of the parrots meet red forms and yet they are genetically the same. Further west along the Murray River, they are genetically different, but all pale yellow.

“There is no simple link between the geographic distribution of the colour forms and the separate genetic groups,’’ Professor Bennett said.

The researchers are looking at other possibilities which might explain colour variation, such as whether differences in light in forests and habitat might have an impact.

“In more arid parts the birds are more pale yellow and in higher rainfall areas they are crimson red,’’ Professor Bennett said.

“So part of our work facilitates some predictions about how colouration and distribution should change with increasing climate change.’’

The research team is also looking at whether red and yellow individuals preferentially choose mates of the same colour, and if mating preferences are influenced by different acoustics in different forms of the parrot.

The research has special personal significance for Professor Bennett, who has admired these birds since childhood. “I grew up in the Adelaide Hills and these birds were in our garden when I was a kid, and it always intrigued me why they were so highly variable in coloration,’’ he said.

Professor Bennett said the team was also researching how and why birds see more colours than humans and how they use the extra ‘dimensions’ to their colour vision.

“Building a colour television for birds is much more difficult than building one for humans,” he said.

Previous Deakin Research story on Professor Andy Bennett:
http://www.deakin.edu.au/research/stories/dynamic.php?story_id=47

Previous Deakin Research story on Dr Kate Buchanan:
http://www.deakin.edu.au/research/stories/dynamic.php?story_id=66

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