Sunday, December 4, 2011

A Bit About Bustards

[This was written by Fran Siebrits and published online by Wild Magazine http://www.wildcard.co.za/, 2011]


When it comes to attracting a female, there are many similarities between men and bustards. For one thing, size matters!

Bustards are among the most sexually dimorphic types of birds, with males and females differing distinctly in size and colour. In addition, males have an interesting array of mating displays such as glamorously feathered chests and throat sacks that can be inflated.

If you are familiar with the open plains of the South African countryside, then you’ll certainly be familiar with the kori bustard. Broad wings, long legs, big toes, a powerful stride… One of the heaviest flying birds in the world, a kori bustard can weigh up to 20 kg. Included in their bird family are korhaans and floricans from Southeast Asia, but none are quite so elaborate as the bustards.

The great bustard (Otis tarda) of Spain is equal in size and weight to our local kori bustard. Males have a characteristic ‘beard’ which appears during the mating season to attract females. But there is more to the beard than just sexual attraction.

The long white neck bristles of great bustards are also used to communicate with other males of their species as the beard indicates each male’s age, size and weight. "The heaviest males (best physical condition) make it known to other males through the length and number of 'beards', and thereby avoid bloody fights to ascend in rank," says Juan Carlos Alonso, main author and researcher.

A weaker male will therefore not challenge a stronger specimen, allowing the ‘better genes’ a chance to butter up the ladies.  

When it comes to presentation, another equally conspicuous species is the houbara bustard (Chlamydotis undulate), which is found in the deserts of the Russia and the Middle East. The sexual display of these birds is so extravagant that it actually speeds up their aging rate.

For six months of the year, these male bustards perform extensively in the hope of attracting a suitable female’s attention. But recent research has shown that it can be to the detriment of their lifespan. Males which do not spend so much energy on ostentatious behaviour prove to live longer than those that parade around making all this visual noise.

"This is the bird equivalent of the posers who strut their stuff in bars and nightclubs every weekend," says lead author Dr Brian Preston. They raise their white head- and throat-feathers while withdrawing their heads in a flamboyant mating display.

Apparently all this posing works. Chicks dig it!

Sources:
  • •WIKIPEDIA, 2011. Bustard. Viewed online [http://en.wikipedia.org/wiki/Bustard]
  • WIKIPEDIA, 2011. Great bustard. Viewed online [http://en.wikipedia.org/wiki/Great_bustard]
  • WIKIPEDIA, 2011. Houbara bustard. Viewed online [http://en.wikipedia.org/wiki/Houbara_bustard]
  • Brian T. Preston, Michel Saint Jalme, Yves Hingrat, Frédéric Lacroix, Gabriele Sorci. Sexually extravagant males age more rapidly. Ecology Letters, 2011; DOI: 10.1111/j.1461-0248.2011.01668.x
  • Viewed online [http://www.sciencedaily.com/releases/2011/08/110804081742.htm
  • Juan C. Alonso, Marina Magaña, Carlos A. Martín, Carlos Palacín. Sexual Traits as Quality Indicators in Lekking Male Great Bustards. Ethology, 2010; 116 (11): 1084 DOI: 10.1111/j.1439-0310.2010.01827.x
  • Viewed online [http://www.sciencedaily.com/releases/2011/02/110208101406.htm]

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