While flashy colors come and go in the fashion world, bright beaks are always in style for male birds seeking to woo a mate. New research suggests that the red and orange-hued beaks of certain male birds are signs of a healthy immune system--a "must have" in any mating season.

A pair of studies appearing in the 04 April issue of the journal, Science, published by the American Association for the Advancement of Science, provide the first direct evidence that the colorful beaks on the males of two bird species gives honest information about individual immune systems. When females choose bright beaks, they select healthy males. A U.K. research group focused on beak color in male zebra finches, and a French team studied beak color in male blackbirds.

In the animal kingdom, males often sport the species' more flamboyant features, from peacock's tails to rooster's combs. While scientists have long guessed that these traits advertised the males' fitness two new studies confirm this hypothesis with direct measurements and connect male-bird's bright beak colors with a strong immune system.

"These two papers complement each other. They both use immune system measurements to move beyond assumptions and show that brighter beaks accurately highlight healthier birds," said Stephen Simpson, a Science editor working in Cambridge, U.K.

"Lots of people since Darwin have pondered how male display is linked to physical condition," said Jonathan Blount from the University of Glasgow in Scotland, UK. His research team found that the male finches with the reddest beaks received the most sexual interest from females and had the healthiest immune systems.

Carotenoids are the red and yellow pigments that color the beaks of the males of certain species of birds including blackbirds and zebra finches. Birds can not synthes
'"/>

Contact: Lisa Onaga
lonaga@aaas.org
202-326-7088
American Association for the Advancement of Science
3-Apr-2003