Male birds can't fool their mates for long

New research reveals that some male birds use their song to dupe females they have just met into thinking they are in excellent physical condition. Singing is a test of a bird's condition because it uses a lot of energy.

Researchers at the University of Exeter studied zebra finches to establish how trustworthy birdsong was in providing honest signals about the male's value as a mate. Fit and healthy birds are thought to be able to sustain a high song rate for longer, making them more attractive to females.

Researchers discovered that male birds in poor condition could "cheat" and vary their song to give a false impression to stranger females. But they did not even try to fool female birds who knew them.

Dr Sasha Dall, of the University of Exeter, was involved in the research. He said: "Every man wants to cast himself in a favorable light when he meets an attractive female, and we have shown that birds are no different. But just like many humans, it seems zebra finch males are unable to dupe females who know them well enough. When the birds were in an established relationship, the female could tell the true condition of a male by his song, and judge whether he would make a good father for her next brood."

Zebra finches are Australia's most popular finch. They make common pets and are used widely in scientific research because they adapt extremely well. For zebra finches, both color and birdsong are important factors in choosing a mate.

Dr Morgan David, who led the research, said: "This is the first study to find evidence that the link between male body condition and birdsong differs depending on the context of the encounter with the opposite sex. It could have significant implications for learning more about the evolution of courtship patterns such as birdsong."

Story Source: Birdsong bluster may dupe strange females, but it won't fool partners
http://www.eurekalert.org/pub_releases/2012-12/uoe-bbm121412.php