Sunday, July 4, 2010

Study says watching "sexy" males leads to better chicks

Watching attractive males strut their stuff makes female birds more fertile and leads to healthier chicks, a new study suggests. The finding could help improve breeding programs for endangered or threatened birds, because it highlights the importance of mating displays, scientists say.

French researchers studied the mating success of the Houbara bustard, a sandy-colored desert bird found throughout parts of northern Africa and Asia. The species is listed as "vulnerable"—considered to be facing a high risk of extinction in the wild—by the International Union for Conservation of Nature. When courting females, male Houbara bustards run in circles as they throw back their heads to reveal white throat feathers. Healthier, and thus more attractive, males can run more laps while taking fewer and shorter breaks.



For the experiment, the team allowed 90 female Houbara bustards to watch other birds before being artificially inseminated. Of that total, 30 females watched healthy-male displays, 30 watched poor-male displays, and 30 saw nondisplaying females. Females that had watched the healthier males dance laid eggs containing about twice as much of the growth hormone testosterone as the eggs laid by females that watched inferior dances or no dances at all. Testosterone in both genders is associated with building bone density and muscle mass.

In addition, more of the eggs laid by stimulated females hatched into chicks than those laid by the other two groups. Sperm quality didn't play a role, because the scientists had randomly selected the vials of semen used for artificial insemination. Even if a female that had watched a high-quality dance was inseminated with low-quality sperm, the resulting eggs had more testosterone.

Many thanks Marilyn!

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