Peacock coutship

To: Peter Shute <>
Subject: Peacock coutship
From: John Tongue <>
Date: Fri, 19 Feb 2010 07:00:59 +1100
Not sure how they prove all these claims in Dr. Karl's thesis, nor what they 


An intrigueing thing I've noticed about a Peacock's display, ever since we had 
Peafowl when I was a kid, is that once the male erects his 'tail' and begins 
his shimmering display, is that he turns his back on the object of his desire.  
She mostly gets to see the plain feathers around his backside!!  I wonder what 
criteria she is really using to make her choice??

John Tongue
Ulverstone, Tas.

On 19/02/2010, at 6:39 AM, Peter Shute wrote:

> What Dr Karl said is here:
> "Just recently, my primary school daughter, little Lola, did a school project 
> on the peacock.
> She made a magnificent model, and wrote an essay that included the 
> widely-held belief that the purpose of the splendid plumage of the male (the 
> peacock) is to attract the female (the peahen).
> But this simple "fact" is actually a puzzle, and is almost certainly wrong.
> Now the first thing to realize is that the peacock's "tail" is not actually 
> his tail.
> His real tail feathers are quite small and nondescript. The big showy plumage 
> comes from feathers which are on his back, not his tail. To avoid confusion, 
> the bird scientists call it a "train".
> The standard belief is that the peacock does his magnificent feather display 
> specifically to attract the female peahen.
> The peacock can raise the long feathers of the train into a glorious 
> semicircle, about two metres across (not bad for a bird only about a metre 
> long).
> Each brilliant metallic-green feather carries an iridescent eye. The feathers 
> keep growing during the autumn and winter, and molt once each year in the 
> summer.
> The story goes that when the peacock spies a potential mate, he erects the 
> feathers in his train into a fan.
> He then draws the fan forward and wraps himself in it, and then sends ripples 
> running through the feathers.
> He then draws the fan further forward, and quivers it so violently that it 
> takes on a shimmering appearance while the feathers make a rattling sound. 
> This part of the courtship is called the ecstasy.
> He will then manipulate the muscles at the bottom of each feather to change 
> the loudness of the sound, and does this about twice each second.
> This is called a shiver, and a peacock keen to impress a peahen can generate 
> up to 20 bouts of shivering, with each bout lasting up to six minutes, or 
> more.
> The display is spectacular, and it's definitely done for the benefit of the 
> female peahen. But, she is not automatically won over.
> Instead, she will normally perform one of three behaviours: ignore it and 
> pass on by; passively accept the display; or actively solicit the display.
> On the surface, this seems like a classic case of sexual advertisement by the 
> peacock. But over the years, there have been pieces of data that don't fit in 
> with this simple picture.
> First, the peacock often displays his train after the female has started the 
> courtship routine, not before.
> If the Big Display is his advertisement as to how good it can get, surely he 
> should do a display before the female starts the courtship?
> Second, over the years, there has been conflicting evidence both for and 
> against the link between the train display and mating success by the male. 
> There is not a general consensus.
> And as a part of this conflict, there are still continuing arguments about 
> what are the most successful aspects of the train.
> Would it be its length, or the diameter of the eyes in the feathers, or the 
> number of eyes per square metre, or the frequency of the shiver, or the 
> symmetry of the train, and so on? The question is far from resolved.
> Fourth, the manufacture of the train is controlled by oestrogen (female) 
> hormones, which is very unusual for a display ornament that supposedly 
> affects mating success.
> Testosterone (male) hormones are far more common in this arena.
> Fifth, there is actually not that much difference between the trains of 
> peacocks across different populations of the birds. So, to a potential mate, 
> one peacock's plumage is as good as another's.
> And finally, the quality of the train itself does not accurately reflect the 
> genetic and health conditions of the peacock — thus making it a false sexual 
> advertisement.
> So that leaves us with the increasingly probable position that the glorious 
> train and display of the peacock is an advertisement that once might have had 
> significance, but is now obsolete.
> In other words, the peahen is really interested in other aspects of the 
> peacock (perhaps his stimulating conversation) but even to qualify in the 
> mating stakes, he needs a pretty train.
> So why does he still have this magnificent spread of plumage? Maybe, like 
> most males, he's his own biggest fan."
> Peter Shute
> ________________________________________
> From:   
> On Behalf Of Philip Veerman 
> Sent: Thursday, 18 February 2010 11:51 PM
> To: 'Nathan'
> Cc: 'Birding Aus'
> Subject: RE: [Birding-Aus] Peacock coutship
> Sounds like someone has got their wires crossed. That sounds
> nonsensical. For one thing males court the female, not the other way
> around. The female is the one who decides. Of course everything in
> evolution is an accident but it is also driven by a process, so it is
> not without reason. The train of a male peacock is so elaborate and the
> behaviour that goes with it is so extreme that it is absurd to suggest
> it is not a huge advantage to the males who grow the biggest brightest
> trains. So in that way it is not an accident, it is surely driven by
> female choice over the generations (it is not actually a tail, it is the
> overgrown rump feathers).
> Philip
> -----Original Message-----
> From: 
>  On Behalf Of Nathan
> Sent: Wednesday, 17 February 2010 8:55 AM
> To: birding-aus
> Subject: [Birding-Aus] Peacock coutship
> I was listening to an ol podcast of Dr Karl yesterday and he said that
> the female peafowl decided whether to cout a male before she even sees
> the males tail and that the tail was an 'Evolutionary Accident' I don't
> doubt this as fact but I am wondering how on earth you would test that?
> ~Thanks
> ~Nathan Ruser
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