Kate on song in new roles

Mon, 23 Jun 2008 18:00:00 +1000

Although she's only been at Deakin University a short time, Dr Kate Buchanan is already making a vital contribution to the university's ever-growing research reputation.

Dr Buchanan, who was formerly at Cardiff University before shifting to Geelong, has just been appointed as editor of the of the science journal Emu Austral Ornithology.

The journal has been published by the CSIRO for more than 100 years and is that organisation's premier journal documenting avian research.

"It is a great honour to be asked to edit this publication," Dr Buchanan said. "I am really looking forward to the challenge of communicating the important work scientists are doing in avian research to a broader audience.

"A lot of the work has a very serious environmental component."

The journal's website is: http://www.publish.csiro.au/nid/96.htm

Dr Buchanan's own ground-breaking research was also recognised in May when she appeared on The Science Show on ABC Radio National, interviewed by the country's top science broadcaster, Robyn Williams.

A transcript of the interview features below.

The interview began with birdsong.

Robyn Williams: No, not a whale pretending to be a bird, that's a starling, and the discovery made by Dr Kate Buchanan is that their song becomes distorted, more complex if they suck up poisonous chemicals from water. And the worrying thing is that the effect on bird populations is profound.

Kate Buchanan: We're interested in the effects of toxic chemicals on neurobiology and behaviour in birds. I've been interested in the effects of stress on birdsong. But these chemicals are a specific case because they work as oestrogen mimics, and song development is oestrogen dependent.

Robyn Williams: So you thought that if these chemicals were having an effect on the nervous system, obviously the brain being the main part, then if you wanted some sort of test of an effect, birdsong might be the very one.

Kate Buchanan: Absolutely. Birdsong hasn't been considered to be condition dependent but it is a biomarker of developmental conditions, and that's because it is strongly dependent on the neural machinery underlying its production, in particular one centre called the HVC, the high vocal centre in the brain which determines how complicated the birdsong is.

Robyn Williams: Which bird, what sort?

Kate Buchanan: We've been following European starlings which have very complicated song which is very plastic, it changes from year to year, and females prefer to mate with males that have more complex songs.

Robyn Williams: I wonder why? The simple message I would have thought would be as attractive. So they go in for complicated songs, and how complicated does the pollutant make it?

Kate Buchanan: We measured levels of these pollutants in the worms that these birds are taking in, we fed them ecologically relevant doses, and we found that it significantly enhanced song complexity, so it made them sing longer, it made them sing longer bouts, and it made their repertoire size larger, which means they sing more different kinds of syllables, 'syllables' being...an analogy would be words in a sentence.

Robyn Williams: So in some ways these pollutants were good for the birds.

Kate Buchanan: Absolutely, it makes them sexier.

Robyn Williams: I see. So did it do any damage in the long-term to the creatures?

Kate Buchanan: Absolutely, yes, this is the problem is that females will bias their reproductive decisions towards these males, but we have hints that these males are actually physiologically less fit. We ran some immune function tests on these birds, and males who were dosed artificially with these pollutants had suppressed immune function using two different immune tests. So we suspect these males are actually not very well, but females will choose to mate with them regardless.

Robyn Williams: And in the real world, how does that add up? Because in the real world you want your mate to be healthy and strong, and having a complex song is an indication of that. So what would make the song complex in the natural world where there is no pollutant?

Kate Buchanan: The problem with this is we would expect to see a population decline if females are choosing to mate with males that are in poor condition, and in fact that's exactly what we've seen in European populations of starling which are now listed as a Red Data Book species because they are showing such sharp decline in populations. So of course there are other reasons for this decline but we're suggesting that environmental pollutants might be one of them.

Robyn Williams: Where do the birds go to get, in the wild, these chemicals? Where do they pick them up?

Kate Buchanan: Our hypothesised route was foraging on sewage treatment filter beds, and there may be other sources of oestrogen mimics but our study focuses on a number of different chemicals which are largely products of the plastics industry and also natural oestrogen which is bioaccumulating in invertebrates on sewage treatment filter beds.

Robyn Williams: With other animals who are also picking up these chemicals, the ones that don't have birdsong, how would you test the same sort of thing with them?

Kate Buchanan: It depends on oestrogen dependent behaviours. So you would have to look at hormone levels in those animals or neural development in centres that are dependent on oestrogen, or other condition indices.

Robyn Williams: So what's your broad conclusion about this? If you've got widespread oestrogen-like chemicals in the water generally and birds are picking them up, there's a broader story about the things we should worry about, surely, that we should be concerned that there are these pollutants around.

Kate Buchanan: I think endocrine disrupters are extremely worrying because these levels are relatively low in the water and they're bio-accumulating in the invertebrates. It's a difficult area to work in because the pollutants can have synergistic effects. The effects are not ubiquitous, so it depends on the dispersion in the water column, whether it's bio-accumulated up the food chain. So it's a difficult area to assess exactly what kind of effects you're going to have, but it is certainly very worrying.

Robyn Williams: You know the Canadians have done an experiment by putting some of these chemicals in the lake to see what would happen to the fish. Have you come across that?

Kate Buchanan: No, I haven't come across that one, but there is a great deal of work which has looked at endocrine disrupters in aquatic environments and there's very well publicised effects on fish and alligator morphology and behaviour and reproductive success showing alarming effects of these chemicals.

Robyn Williams: Dr Kate Buchanan is at Deakin University in Geelong Victoria, and she's following up that work on pollutants coming from industrial waste, not rom pharmaceuticals used by women, by the way.

To hear this interview, or the one the following week with Bronwyn Fox and Betime Nuhji from the Centre for Material and Fibre Innovation, click on to: www.abc.net.au/rn/scienceshow/default.htm


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20th August 2012