Costs and Benefits of Testosterone in Birds

-Individual male birds can differ dramatically in their behavior determined by the different levels of testosterone in their body's.
-Testosterone and the behaviors it mediates may predict how well a male succeeds.
- An aggressive male may be more likely to obtain high-quality territories that attract females.
-Aggression might pose a survival risk, because aggressive males might be more likely to engage in costly fights.
-Researchers found strong relationships between testosterone and both reproduction and survival, demonstrating that natural selection is currently acting on testosterone production in this population of juncos.

Reflection: It is interesting to see how testosterone affects birds because we recently learned how it affects people in biology class. Now that i've read the article, I found that the hormone affects birds in pretty much the same way. But it is also interesting to know that natural selection is pushing birds towards more testosterone. I would think that there would be a balance in the testosterone levels of birds because too much testosterone is a bad thing and hinders a birds ability to survive. Maybe I'm wrong but this explains why some birds are extremely aggressive.


Link: http://www.sciencedaily.com/releases/2010/05/100513112753.htm

Picture: http://www.ornithology.com/images/BabyBirds_Miller_061705.jpg

Citation: University of Chicago Press Journals. "Costs and Benefits of Testosterone in Birds." ScienceDaily 13 May 2010. 17 May 2010 .