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Gang-gang

New research highlights strangeness of the Australian Water Dragon

Perhaps it's because the world of human behaviour is so shocking (for example, in recent days Christendom has been left ashen-faced by a Vatican-horrifying art show of Ken and Barbie dolls as Jesus and as the Virgin Mary) that this column turns so often to topics of blameless wildlife.

Here we go again, recoiling from the Ken and Barbie outrage (although the Devil, typically, made me go online against my will to look at the blasphemous dolls) to dwell with the birds and the lizards. Our pictures are of a praiseworthily monogamous pair of Gang-gang cockatoo and of the Australian Water Dragon Physignathus lesueurii.  

Conspicuous star: A Water Dragon at Australian National Botanic Gardens.
Conspicuous star: A Water Dragon at Australian National Botanic Gardens. 

The dragon gets a guernsey here today for two overlapping reasons. It is a creature of Canberra's waterways and of course those waterways are on all thinking minds at the moment because Lake Burley Griffin's 50th birthday is looming. This paper is understandably obsessed with the event.

Then, there is some new, just-published research about the species, of course a conspicuous star of the Australian National Botanical Gardens (where the dragon of our picture was snapped), that will increase our already breathless appreciation of their strangeness. For instance, can you guess why this dragon is a water dragon, always found in fresh-water watery places? After all, lizard species richness is highest in arid spots. What is Physignathus lesueurii doing hugging waterways, lakes and ponds?

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An explanation is offered in the scholarly paper Patterns of Predation and Antipredator Behaviour In The Australian Water Dragon Physignathus Lesueurii, just published in the journal Herpetological Conservation and Biology. There are scholars of the University of Canberra's Institute of Applied Ecology and of the Australian National Botanical Gardens among the paper's brains trust of eight authors.

They fancy that the species has evolved to be always near water, so as to be able to retreat to it and hide in it (even sleeping underwater) because it has such a galaxy of creatures, especially birds, that want to eat it. The scholars calculate that there are 25 species of predators that will kill and eat Physignathus lesueurii if they can. Twenty five!

The scholars say that most of the 25 threatening species are "aerial" (they're raptors, and for example the paper includes a grisly eyewitness account of a Brown Goshawk carrying and dropping a horribly wounded dragon). Known aerial predators of the dragons include eagles, owls, kites, goshawks, harriers and even (horror!) kookaburras. Needless to say currawongs, too, those driven carnivores, add to the dragons' dangers.

Meanwhile "aquatic predators" are "rare" and so the dragons, far safer in the water, scuttle to it when danger looms.

Young imagination: A North Ainslie Primary School Gang-gang painting.
Young imagination: A North Ainslie Primary School Gang-gang painting. 

"Water Dragons possess one obvious antipredator behaviour, aquatic escape" the scholars divine, "and another potential antipredator behaviour [in their ability to sleep underwater". But it may be, they think, that the dragons underwater snoozing is done to regulate body temperatures.

"[But] when threatened, Water Dragons dive into the water, lie motionless on the bottom, and can remain submerged for up to 90 minutes." 

Yes, the Gardens, suppliers of this fabulous portrait of one of their characterful dragons, apologises to us for not having any pictures of dragons interacting with Gardens-goers. And of course this must be because experience shows one can only get so close a Gardens' dragon before, being cautious, it dives to where humans (and kookaburras) can no longer perturb it.

Imagining Gang-gangs

Today's column's painting of Gang-gang Cockatoos, faunal symbol of the ACT (and of course of a critically-acclaimed Fairfax Media column), is by children of North Ainslie Primary School.

The Canberra Ornithologists Group, sending us the picture, asks us to remind the world of the Imagining Gang-gangs student art competition.

COG's Kathryn Eyles, a coordinator of COG's Gang-gang matters in this year of the year-long Gang-gang Survey of the mysterious species, says "We want Canberra kids to learn more about the Gang-gang cockatoo, the ACT's faunal emblem, and put their imaginations to work to make Gang artworks using the medium of their choice. 

"The school holidays are a great opportunity for Canberra families to get out and enjoy our nature reserves and visit some Gang-gang hot spots to inspire the young imagination. Black Mountain, the Botanical Gardens and along Daley Road in the ANU are Gang-gang hot spots."       

She reports that "Rumour has it that  a number of schools in another Gang-gang hotspot, the inner north, are busy preparing their entries for the competition. Lyn Gascoigne, the art teacher at North Ainslie Primary School got her students off to a great start painting Gang-gangs."

Her school has an exhibition of Gang-gang artworks in its foyer and the school has an important connection with this special fowl because it adorns the school logo. 

The competition is open to students aged 5-18 years (including pre-schoolers) and entries close on 7 November 2014. Artworks will be exhibited at the M16 Artspace, Griffith from 26-30 November 2014.  More info about the competition can be found on the Canberra birds website:  canberrabirds.org.au/observing-birds/gang-gang-survey/