Brush turkey mathematics

Four hens + eleven teenaged brush turkeys + several decoy eggs in the henhouse = one fresh chicken egg a day.  I can’t quite nut out this equation.  There are three intractable maths problems here.
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One is agricultural-cum-mathematical.  Why are three of our pampered pets failing to lay eggs?
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The second is at the point where philosophy meets mathematics, along the lines of “how many angels can dance on the head of pin”. Just exactly how many brush turkeys can occupy one suburban backyard?  And why are there so damn many of them?
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And then there’s the ethological question.  Given the apparently infinite number of turkeys, and clear evidence that they are unrepentant egg eaters, why are we enjoying any omelettes at all?
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What with the festival of poultry diseases we have been hosting lately, it’s not a big surprise that only sprightly Shyla continues to lay a regular egg.  She’s an Australorp, a new fangled breed, presumably with disease resistance as one of her mod cons, while, say, Treasure with her tedious moulting and brooding, is a Light Sussex, a breed that’s been around since Roman times.  I reckon that kind of pedigree is going to her a proclivity to old fashioned things, like the distinctly medieval-sounding fowl pox.

Being Top Chook doesn’t hurt Shyla’s capacity to pump out eggs. She makes sure she gets the best snacks by belting up to the garden gate as soon as she hears me coming and bounding in the air to grab scraps before I get a chance to dish them out.

But I’m not sure the other girls are getting quite enough to eat.

Now, I’m not saying that they’re wimps.  Even ancient, diminutive Snowball the silky bantam will frighten off nosy megapodes that try to butt in while she’s in the middle of breakfast.  But the trouble is, the chooks never sit down for a three course meal.  They’re snackers.  A few minutes of frenzied eating, and they wander off to nibble grass, have a dust bath, or in Shyla’s case, follow me around hoping I have better treats – say, limp grapes or weevil ridden grain.  If that’s not forthcoming she’ll taste-test the wet washing or have a red hot go at pecking my butt.

Shyla’s certainly not one to let starvation diminish her egg supply.  But by the time the other hens realise seconds wouldn’t go astray, it’s a teeny bit late.

No-one is 100% sure why there are so many damn brush turkeys in Brisbane and the northern suburbs of Sydney.  “I’m supposed to be the expert on brush turkeys and I still can’t explain why that’s going on,” commented Professor Darryl Jones of Griffith University, talking to the ABC.  He reckons numbers in Brisbane have increased by 700 percent in the last 20 years.

In the early 1990s, scientists thought moggies snacking on the unprotected chicks would put a stop to the urban invasion.  Nope.  The cluey babies will listen out for the alarm calls of just about any old bird, and as long as there’s enough cover they’ve got a chance.  Fox and dingo baiting mean grown-up life has been less brutish and short, and the water-wise mulching habits of modern gardeners have made mound building in suburbia extremely convenient.  The odd gormless adult bird might be taken by an ambitious powerful owl, willing to have a go at prey “at least 103%” of its own body weight, according to the remarkably precise estimates of scholarly birdwatchers.  But let’s face it, these owls are just not powerful enough in the brush turkey execution caper for my liking.

If anyone knows about megapodes it’s Dr Anne “Brushturkey robochickGöth, working down the road from here at Macquarie University. She’s explored every aspect of the weird story of how brush turkey babies, all on their own, dig their way out of their giant natal compost heaps – “the most nonavian life history you can get among creatures that are still feathered and lay hard-shelled eggs” – and then figure out without any parental guidance what they should eat and what will eat them, not to mention what the hell other brush turkeys look like without a glimpse of their parents or siblings.  Its no wonder they have a thing about mirrors.

Dr Göth’s erstwhile colleague up in Queensland, Prof. Jones, comments “fortuitously her arrival [in Sydney] coincided with a marked expansion of populations in the vicinity of the northern suburbs of the city” (2007, 3).  Mmmm.  Coincidence, eh, Dr Göth?  The gardeners and chicken keepers of the north shore are deeply, deeply suspicious.  Anyway, whether or not she has been deliberately breeding an evil army of brush turkeys in her secret underground lab, Dr Göth is on the money about the cause of the population explosion in my back garden – the ready supply of chook food.

So onto the final maths problem.  If there is an apparently infinite number of megapodes in our backyard, how come they haven’t spotted Shyla’s daily egg, sitting there, sometimes all day, next to its plastic companions?  Can’t brush turkeys count?

Rumour has it domestic chickens are a dab hand at maths.  Three day old chicks can figure out where to go left or right for a bigger pile of edible stuff even when items are added one by one, and each pile is hidden behind a screen.  This research by Rosa Rigosa from the University of Padua has been reported in the Telegraph under the headline “Chickens are cleverer than toddlers”.  But on my reading, 3 day old chicks should be put in charge of pairing our socks after washing, as they seem to a better grip on arithmatic and object permanence than the adults in our household do.

I have looked and failed to find for research on megapode counting skills. Dr Göth obviously hasn’t started work yet on this critical issue in animal cognition.  So I can’t tell if our continuing egg supply is a consequence of brush turkey innumeracy or if they are just lulling us into a false sense of security before brutally snatching away our remaining hope of home grown-protein. I guess we’ll have to see how this one plays out with our convenience sample in the back yard lab.

And if 1000 words on brush turkeys is barely enough for you, why not go read some more?

  • Goth, Ann and Maloney, Mary. Powerful Owl preying on an Australian Brush-turkey in Sydney [online]. Australian Field Ornithology, Vol. 29, No. 2, Jun 2012: 102-104
  • Göth, Ann and Uwe Vogel (2002) Chick survival in the megapode Alectura lathami (Australian brush-turkey) Wildlife Research 29(5) 503 – 511 Published: 30 December 2002
  • Göth, A., Nicol, K.P., Ross, G. & Shields, J.J. (2006). Present and past distribution of Australian Brush-turkeys Alectura lathami in New South Wales – implications for management. Pacific Conservation Biology 12, 22–30
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6 thoughts on “Brush turkey mathematics

  1. Great article!. “deliberately breeding an evil army of brush turkeys in her secret underground lab”- Damm you are onto us. I am off the hide the tanks/bathtubs etc etc that are perhaps responsible for a similar explosion of frog numbers round these parts.

    • Glad you enjoyed it Lachlan. I’ve enjoyed looking at your blog too… Yep, those scientists, what are they up to? It’s pretty interesting to think about the way you can tweak a habitat by adding extra food, or competitors for food, or changing the landscape. Having read that baby brush turkeys like scrubby undergrowth (Ann Goth theorises that the decline of brush turkeys out west was in part because of the removal of prickly pears – which were both a fruit supply and a place to hide out for the babies) I suddenly started feeling differently about the hakeas and other spiky shrubs I have been planting to try to encourage small insectivorous birds. If there’s anything I’ve learned from my often futile food gardening efforts it is that ecosystems are extremely complicated and not at all easily managed by people, even people of good will! Maybe that’s a good thing…..!

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